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Coding

Playing with JavaScript and JQuery – the Ebook link HTML string generator and the EZproxy bookmarklet generator

***This post has been published in ACRL TechConnect on April 8, 2013. ***

In this post, I will describe two cases in which I solved a practical problem with a little bit of JavaScript and JQuery. Check them out first here before reading the rest of the post which will explain how the code works.

  1. Library ebook link HTML string generator
  2. EZproxy bookmarklet generator – Longer version (with EZproxy Suffix)
  3. EZproxy bookmarklet generator – Shorter version (with EZproxy Prefix)

Source: http://www.flickr.com/photos/albaum/448573998/

1. Library ebook link HTML string generator

If you are managing a library website, you will be using a lot of hyperlinks for library resources. Sometimes you can distribute some of the repetitive tasks to student workers, but they are usually not familiar with HTML. I had a situation in which I needed to add a number of links for library e-books for my library’s Course E-book LibGuide page, when I was swamped with many other projects at the same time. So I wondered if I could somehow still use the library’s student assistant’s help by creating an providing a simple tool, so that the student only needs to input the link title and url and get me the result as HTML. This way, I can still delegate some work when I am swamped with other projects that require my attention. (N.B. Needless to say, this doesn’t mean that what I did was the best way to use the student assistance for this type of work. I didn’t want them to edit the page directly because this page had tabs tabs and the student using the WYSWYG editor might inadvertently remove part of the tabbed box code.)

The following code exactly does that.

This HTML form takes an e-book title and the link to the book as input and spits out a hyperlink as a list item as a result. For example, if you fill in the title field with ‘Bradley’s Neurology in Clinical Practice’ and the link field with its url: http://ezproxy.fiu.edu/login?url=http://www.mdconsult.com/public/book/view?title=Daroff:+Bradley’s+Neurology+in+Clinical+Practice, then the result would be shown in the text area : <li><a href=”http://ezproxy.fiu.edu/login?url=http://www.mdconsult.com/public/book/view?title=Daroff:+Bradley’s+Neurology+in+Clinical+Practice”> Bradley’s Neurology in Clinical Practice</a></li>  I also wanted the library student assistant to be able to do this for many e-books at once and just send me the whole set of HTML snippets that cover all ebooks. So after running the form once, if one fills out the title and the link field with another e-book information, the result would be added to the end of the previous HTML string and be displayed in the text area. The result would be like this: <li><a href=”http://ezproxy.fiu.edu/login?url=http://www.mdconsult.com/public/book/view?title=Daroff:+Bradley’s+Neurology+in+Clinical+Practice”> Bradley’s Neurology in Clinical Practice</a></li><li><a href=”http://ezproxy.fiu.edu/login?url=http://www.accessmedicine.com/resourceTOC.aspx?resourceID=64″>Cardiovascular Physiology</a></li>. Since the code is in the text area, the student can also edit if there was any error when s/he was filling out the form after clicking the button ‘Send to Text Area’.

Now, let’s take a look at what is going on behind the scene. This is the entire html file. The Javascript/JQuery code that is generating the html string in the text area is from line 22-32.

<html>
<head>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js"></script>
</head>
<body>
	<p>
		This page creates the html-friendly string for a link with a title and a url. 
		<ul>
		<li>Fill out the form below and click the button. </li>
		<li>If the link is messy, clean up first by using the <a href="http://meyerweb.com/eric/tools/dencoder/">URL decoder</a>.</li>
		<li>Copy and paste the result inside the text area after you are done.</li>
		</ul>	
	</p>
	<p>
		Title: <input type="text" id="title1" size="100"/><br/>
		Link: <input type="text" id="link1" size="100"/><br/>
		<button id="b1">Send to Text Area</button>
	</p>
	<p id="result1"></p>
	<textarea rows="20" cols="80"></textarea>

	<script type="text/javascript">
	$(document).ready(function(){	
	  $("#b1").click(function(){
	  //  alert('<a href="'+$("#link").val()+'">' + $("#title").val()+"</a>");
	    $('#result1').text('<li><a href="'+$("#link1").val()+'">' + $("#title1").val()+"</a></li>");
	    var res1='<li><a href="'+$("#link1").val()+'">' + $("#title1").val()+"</a></li>";
	    $('textarea').val($('textarea').val()+res1);
	 //   $('textarea').text(res1);
	  });
	}); // doc ready
	</script>

</body>
</html>

Since I am using JQuery I am starting with the obligatory $(document).ready in line 2. In line 3,  I am giving a callback function that will be executed when the #b1 – the button with the id of b1 in line 17 above- is clicked.  Line 4 is commented out. I used this initially to test if I am getting the right string out of the input from the title and the link field using the JS alert. Line 5 is filling the p tag with the id of result 1 in line 19 above with the thus-created string. The string is also saved in variable res1 in line 7. Then it is attached to the content of the textarea field in line 8. Line 9 is commented out. If you use line 9 instead of line 8, any existing content in the textarea will be removed and only the new string created from the title and the link field will show up in the text area.

<script type="text/javascript">
	$(document).ready(function(){	
	  $("#b1").click(function(){
	  //  alert('<a href="'+$("#link").val()+'">' + $("#title").val()+"</a>");
	    $('#result1').text('<li><a href="'+$("#link1").val()+'">' + $("#title1").val()+"</a></li>");
	    var res1='<li><a href="'+$("#link1").val()+'">' + $("#title1").val()+"</a></li>";
	    $('textarea').val($('textarea').val()+res1);
	 //   $('textarea').text(res1);
	  });
	}); // doc ready
</script>

You do not have to know a lot about scripting to solve a simple task like this!

2. EZproxy bookmarklet generator – Longer version

My second example is a bookmarklet that reloads the current page through a specific EZproxy system.

If you think that this bookmarklet reinvents the wheel since the LibX toolbar already does this, you are correct. And also if you are a librarian working with e-resources, you already know to add the EZproxy suffix at the end of the domain name of the url when a patron asks if a certain article on a web page is available through the library or not. But I found that no matter how many times I explain this trick of adding the EZproxy suffix to patrons, the trick doesn’t seem to stick in their busy minds. Also, many doctors and medical students, who are the primary patrons of my library, work at the computers in hospitals and they do not have the necessary privilege to install a toolbar on those computers. But they can create a bookmark.

Similarly, many students asked me why there is no LibX toolbar for their mobile devices unlike in their school laptops. (In the medical school where I work, all students are required to purchase a school-designated laptop; this laptop is pre-configured with all the necessary programs including the library LibX toolbar.) Well, mobile devices are not exactly computers and so the browser toolbar doesn’t work. But students want an alternative and they can create a bookmark on their tablets and smartphones. So the proxy bookmarklet is still a worthwhile tool for the mobile device users.

This is where the bookmarklet is: http://htmlpreview.github.com/?https://github.com/bohyunkim/examples/blob/master/bkmklt.html. To test, drag the link on the top that says Full-Text from FIU Library to your bookmark toolbar. Then go to http://jama.jamanetwork.com/Issue.aspx?journalid=67&issueID=4452&direction=P. Click the new bookmarklet you got on your toolbar. The page will reload and you will be asked to log in through the Florida International University EZproxy system. When you are authenticated, you will be seeing the page proxied: http://jama.jamanetwork.com.ezproxy.fiu.edu/Issue.aspx?journalid=67&issueID=4452&direction=P.

You will be surprised to see how simple the bookmarklet is (and there is even a shorter version than this which I will show in the next section). It is a JavaScript function wrapped inside a hyperlink. Lines 2-5 each takes the domain name, the path name, and any search string after the url path from the current window location object. So in the case of http://jama.jamanetwork.com.ezproxy.fiu.edu/Issue.aspx?journalid=67&issueID=4452&direction=P, location.host is http://jama.jamanetwork.com and location.pathname is Issue.aspx . The rest of the url ?journalid=67&issueID=4452&direction=P – is location.search. In line 4, I am putting my institution’s ezproxy suffix between these two, and in line 5, I am asking the browser load this new link.

<a href="javascript:(function(){
	var host=location.host;
	var path=location.pathname;
	var srch=location.search;
	var newlink='http://'+host+'.ezproxy.fiu.edu'+path+srch;
	window.open(newlink);
})();">Full-Text from FIU Library</a>

Now let’s take a look at the whole form. I created this form for those who want to create a ready-made bookmarklet recipe. All they need is their institution’s EZproxy suffix and whatever name they want to give to the bookmarklet. Once one fills out those two fields and click ‘Customize’ button, one will get the full HTML page code with the bookmarklet as a link in it.

<html>
<head>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js"></script>
</head>
<body>
<h1>EZproxy Bookmarklet</h1>	
<p><ul><li>
	<a href="javascript:(function(){
		var host=location.host;
		var path=location.pathname;
                var srch=location.search;
                var newlink='http://'+host+'.ezproxy.fiu.edu'+path+srch;
		window.open(newlink);
	})();">Full-Text from FIU Library</a> 
	(Drag the link to the bookmark toolbar!)
</li></ul></p>
<p>This is a bookmarket that will reroute a current page through FIU EZproxy.
	<br/>
If you have the LibX toolbark installed, you do not need this bookmarklet. Simply select 'Reload Page via XYZ EZproxy' on the menu that appears when you right click.
	<br/>
Created by Bohyun Kim on March, 2013. 	
</p>
<h2>How to Test</h2>
<ul>
	<li>Drag the link above to the bookmark toolbar of your web browser.</li>
	<li>Click the bookmark when you are on a webpage that has an academic article.</li>
	<li>It will ask you to log in through the FIU EZproxy.</li>
	<li>Once you are authenticated and the library has a subscription to the journal, you will will able to get the full-text article on the page.</li>
	<li>Look at the url and see if it contains .ezproxy.fiu.edu. If it does, the bookmarklet is working.</li>
</ul>	

<h2>Make One for Your Library</h2>
	<p>
		Bookmark title: <input type="text" id="title1" size="40" placeholder="e.g. Full-Text ABC Library"/>
		<em>e.g. Full-text ABC Library</em>
		<br/>
		Library EZproxy Suffix: <input type="text" id="link1" size="31" placeholder="e.g. ezproxy.abc.edu"/>
		<em>e.g. ezproxy.abc.edu
		<br/>
		<button id="b1">Customize</button></em>
	</p>
	<p><strong>Copy the following into a text editor and save it as an html file.</strong></p>
	<ul>
		<li>Open the file in a web browser and drag your link to the bookmark toolbar.</li>
	</ul>	
	<p id="result1" style="color:#F7704F;">**Customized code will appear here.**</p>
	<p><strong>If you want to make any changes to the code:</strong></p>
	<textarea rows="10" cols="60"></textarea>

	<script type="text/javascript">
	$(document).ready(function(){	
	  $("#b1").click(function(){
		var pre="&lt;html&gt; &lt;head&gt; &lt;script type=&quot;text/javascript&quot; src=&quot;http://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js&quot;&gt;&lt;/script&gt; &lt;/head&gt; &lt;body&gt; &lt;a href=&quot;javascript:(function(){ var hst=location.host; var path=location.pathname; var srch=location.search; var newlink='http://'+hst";
		var link1=$('#link1').val();
		var post="'+path+srch; window.open(newlink); })();">";
	  	var title=$("#title1").val();
	  	var end="&lt;/a&gt; &lt;/body&gt; &lt;/html&gt;";
	  	var final=$('<div />').html(pre+"+'."+link1+post+title+end).text()
	  	$('#result1').text(final);
	    $('textarea').val(final);
	  });
	}); // doc ready
	</script>

</body>
</html>

That ‘customize’ part is done here with several lines of JQuery. You will notice that the process is quite similar to what I did in my first example. In lines 4-8, I am just stitching together a bunch of text strings to spit out the whole code in the text area eventually when the ‘Customize’ button is clicked. All special characters used in HTML tags such as ‘<’ and ‘>’ have been changed to html enities. In line 9, I am taking the entire string saved in the variable end –I hope you name your variables a little more carefully than I do!–  and adding it to an empty div so that the string would be set as the inner HTML property of that div. And then I retrieve it using the .text() method. The result is the HTML code with the html entities decoded.

<script type="text/javascript">
	$(document).ready(function(){	
	  $("#b1").click(function(){
		var pre="&lt;html&gt; &lt;head&gt; &lt;script type=&quot;text/javascript&quot; src=&quot;http://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js&quot;&gt;&lt;/script&gt; &lt;/head&gt; &lt;body&gt; &lt;a href=&quot;javascript:(function(){ var hst=location.host; alert(hst); var path=location.pathname; var srch=location.search; var newlink='http://'+hst";
		var link1=$('#link1').val();
		var post="'+path+srch; window.open(newlink); })();">";
	  	var title=$("#title1").val();
	  	var end="&lt;/a&gt; &lt;/body&gt; &lt;/html&gt;";
	  	var final=$('<div />').html(pre+"+'."+link1+post+title+end).text()
	  	$('#result1').text(final);
	    $('textarea').val(final);
	  });
	}); // doc ready
</script>

Not too bad, right? I hope these examples show how just a few or several lines of code can be used to solve your practical problems at work. Coding is there for you to automate time-consuming and/or repetitive tasks.

3. EZproxy bookmarklet generator – Shorter version

There is a simpler way to create a EZproxy bookmarklet than the one sketched above. If you simply add EZproxy prefix in front of the entire url of the page where a user is is, you achieve the same result. In this case, you do not have to break the url with host, pathname, search string, etc.

<a href="javascript:void(location.href=%22http://ezproxy.fiu.edu/login?url=%22+location.href)">Full-Text from FIU Library</a>

Here are the code for this much simpler EZproxy bookmarklet and the bookmarklet generator. If you know the prefix of you library’s EZproxy prefix, you can make one for your library.

So there are many ways to get the same thing done. Some are more elegant and some are less so. Usually a shorter one is a more elegant solution. The lesson is that you usually get to the most elegant solution after coming up with many less elegant solutions first.

Do you have a problem that can be solved by creating several lines of code? Have you ever solved a practical problem using a bit of code? Share your experience in the comments!

 

Using Git with BitBucket: Basic commands – pull, add, commit, push

If you do coding, you will be making lots of tiny little changes to a file. You are also likely to be working on multiple computers at different locations. For documents and other types of files, we often use Dropbox or Google Drive/Docs. Tools like Dropbox and Google Drive/Docs are central repositories, and they allow you to always keep the most up-to-date version of the file, make changes to it, save it, and then access it at another computer. Dropbox and Google Drive/Docs also supports version-control. With those tools, you can review changes and revert to the previous state of file if you would like.

BitBucket is a tool similar to Dropbox. And it works with Git. Git is is a distributed revision control and source code management (SCM) system.  GitHub, which is another version-controlled repository web site is popular among coders and also uses Git. (If you want to try this with GitHub, the process is pretty much the same, but you may want to start by cloning somebody’s existing repo. Check out this ACRL TechConnect post by Eric.) BitBucket is similar to GitHub but it allows a completely private repository which is not supported in the free GitHub plan. So if you are working on stuff and don’t want them to be seen publicly until you are ready to release, BitBucket is a good choice.

In this post, I will show you the very basic commands of Git and  how I make changes to files, sync my local repository with the BitBucket repository, add/commit them to my local repo and push them to the remote repo in BitBucket for those who are not familiar with Git. Here, I assume that you already have git installed and set up a repository in BitBucket. If not, there are many tutorials online and also the instruction you get after signing up for BitBucket is quite clear and straightforward.

Once you are all set, the first step I run in my repo is always status command. When I type in git status in the command line (I am using Terminal in Mac), git shows in red that in my repo there are two files that I modified but have not committed. This means that the files were added, meaning they were explicitly added by the git add command but changed without being committed. You can make all sorts of changes to files but until you run the git commit command, it is sort of not official and you cannot push your changes and sync your updated files in the local repo with the remote repo.

**If the image is blurry, just double-click it and you will be able to see the clear version.**

git status

Git_status

But I also vaguely remember that I worked on some files in this remote repo from home several days ago and pushed the changes. Those changes have not yet been reflected in my local repo at my work computer. So I want to sync my local repo with the remote repo first, which has more up-to-date files. To do this, I run the following command. This literally pulls in all the changes from the remote repo to my local repo. And after a few seconds, you get the message that everything went well and you are good to go.

git pull origin master

Git_pull

Now at this point, I can start work on all the up-to-date files. So I go ahead and make some more changes to the two files – bkmklt.html and link.html. After that, I am ready to make the changes official, I run the commit command. You can type in a specific file name you want to commit  or you can just use a dot to make Git to commit all modified files. The commit command requires a commit message. So you have to add some message at the end. Here I write that I removed some comment lines. The message is more important if the change is for other people but try to make it as specific as possible.

If I have created a completely new file in my local repo (that is a designated folder where I set up a Git repo), I will have to add the file first in order to be able to commit it. You can do so by git add filename.xyz and you should be ready to commit it. If you want to add all new files you can also use a dot (.)  instead of a file name.

Below, I ran the status command again before running the commit command.

git commit . -m “removing some comment lines”

Git_commit

So the modified files have been committed now. But they are still in my local repo. If I want to get to them later from another computer however, I need to sync these files with the central repo in BitBucket. The push command does that. You are pushing out your local changes into the remote repo here. If all goes well, you will get the success message as  shown below. (Type in your BitBucket password when prompted.)

git push origin master

Git_push

The change is also recorded in my BitBucket account page.

bitbucket

 

I can also view the changes I made in BitBucket. The red part means what I deleted and the green part means what I added.

diff

Now when I go home and want to work on these files, I will start with “git pull origin master” to sync my home computer with the remote that is up-to-date.

It is really very much like Dropbox or Google Docs except that you get to type in lots of commands. I hope this will help those who are curious about Git but somewhat intimidated by the command lines! So try it out if you are curious.

Here is a great diagram that shows the command sequence of Git. And the entire Git cheatsheet is at: http://byte.kde.org/~zrusin/git/git-cheat-sheet-medium.png

Screen Shot 2013-03-25 at 4.23.29 PM

If you want to go to the next level and try working on someone else’s project in GitHub by forking and branching, here is a good tutorial “How to GitHub: Fork, Branch, Track, Squash and Pull Request” by Rich Jones. There are also many other resources for learning and using Git and GitHub at the ALA ALCTS/LITA CodeYear IG github repository.

 

 

 

 

 

 

 

Effectively Learning How To Code: Tips and Resources

*** This post has been originally published in ACRL TechConnect on Dec. 10, 2012. ***

Librarians’ strong interest in programming is not surprising considering that programming skills are crucial and often essential to making today’s library systems and services more user-friendly and efficient for use. Not only for system-customization, computer-programming skills can also make it possible to create and provide a completely new type of service that didn’t exist before. However, programming skills are not part of most LIS curricula, and librarians often experience difficulty in picking up programming skills.

In this post, I would like to share some effective strategies to obtain coding skills and cover common mistakes and obstacles that librarians make and encounter while trying to learn how to code in the library environment based upon the presentation that I gave at Charleston Conference last month, “Geek out: Adding Coding Skills to Your Professional Repertoire.” (slides: http://www.slideshare.net/bohyunkim/geek-out-adding-coding-skills-to-your-professional-repertoire). At the end of this post, you will also find a selection of learning and community resources.

How To Obtain Coding Skills, Effectively

1. Pick a language and concentrate on it.

There are a huge number of resources available on the Web for those who want to learn how to program. Often librarians start with some knowledge in markup languages such as HTML and CSS. These markup languages determine how a block of text are marked up and presented on the computer screen. On the other hand, programming languages involve programming logic and functions. An understanding of the basic programming concepts and logic can be obtained by learning any programming language. There are many options, and some popular choices are JavaScript, PHP, Python, Ruby, Perl, etc. But there are many more.  For example, if you are interested in automating tasks in Microsoft applications such as Excel, you may want to work with Visual Basic. If you are unsure about which language to pick, search for a few online tutorials for a few languages to see what their different syntaxes and examples are like. Even if you do not understand the content completely, this will help you to pick the language to learn first.

2. Write and run the code.

Once you choose a language to learn, there are many paths that you can follow. Taking classes at a local community college or through an online school may speed up the initial process of learning, but it could be time-consuming and costly. Following online tutorials and trying each example is a good alternative that many people take. You may also pick up a few books along the way to supplement the tutorials and use them for reference purposes.

If you decide on self-study, make sure that you actually write and run the code in the examples as you follow along the books and the tutorials. Most of the examples will appear simple and straightforward. But there is a big difference between reading through a code example and being actually able to write the code on your own and to run it successfully. If you read through programming tutorials and books without actually doing the hands-on examples on your own, you won’t get much benefit out of your investment. Programming is a hands-on skill as much as an intellectual understanding.

3. Continue to think about how coding can be applied to your library.

Also important is to continue to think about how your knowledge can be applied to your library systems and environment, which is often the source of the initial motivation for many librarians who decide to learn how to program. The best way to learn how to program is to program, and the more you program the better you will become at programming. So at every chance of building something with the new programming language that you are learning, no matter how small it is, build it and test out the code to see if it works the way you intended.

4. Get used to debugging.

While many who struggle with learning how to code cite lack of time as a reason, the real cause is likely to be failing to keep up the initial interest and persist in what you decided to learn. Learning how to code can be exciting, but it can also be a huge time-sink and the biggest source of frustration from time to time. Since the computer code is written for a machine to read, not for a human being, one typo or a missing semicolon can make the program non-functional. Finding out and correcting this type of error can be time-consuming and demoralizing. But learning how to debug is half of programming. So don’t be discouraged.

5. Find a community for social learning and support.

Having someone to talk to about coding problems while you are learning can be a great help. Sign up for listservs where coding librarians or library coders frequent, such as code4lib and web4lib to get feedback when you need. Research the cause of the problem that you encounter as much as possible on your own. When you still are unsure about how to go about tackling it, post your question to the sites such as Stack Overflow for suggestions and answers from more experienced programmers. It is also a good idea to organize a study group with like-minded people and get support for both coding-related and learning-related problems. You may also find local meet-ups available in your area using sites like MeetUp.com.

Don’t be intimidated by those who seem to know much more than you in those groups (as you know much more about libraries than they do and you have things to contribute as well), but be aware of the cultural differences between the developer community and the librarian community. Unlike the librarian community that is highly accommodating for new librarians and sometimes not-well-thought-out questions, the developer community that you get to interact with may appear much less accommodating, less friendly, and less patient. However, remember that reading many lines of code, understanding what they are supposed to do, and helping someone to solve a problem occurring in those lines can be time-consuming and difficult even to a professional programmer. So it is polite to do a thorough research on the Web and with some reference resources first before asking for others’ help. Also, always post back a working solution when your problem is solved and make sure to say thank you to people who helped you. This way, you are contributing back to the community.

6. Start working on a real-life problem ‘now.’ Don’t wait!

Librarians are often motivated to learn how to code in order to solve real-life problems they encounter at their workplace. Solving a real-life problem with programming is therefore the most effective way to learn and to keep up the interest in programming. One of the greatest mistake in learning programming is putting off writing one’s own code and waiting to work on a real-life problem for the reason that one doesn’t know yet enough to do so. While it is easy to think that once you learn a bit more, it would be easier to approach a problem, this is actually a counter-productive learning strategy as far as programming is concerned because often the only way to find out what to learn is by trying to solve a problem.

7. Build on what you learned.

Another mistake to avoid in learning how to program is failing to build on what one has learned. Having solved one set of problem doesn’t mean that you will remember that programming solution you created next time when you have to solve a similar problem. Repeating what one has succeeded at and expanding on that knowledge will lead to a stronger foundation for more advanced programming knowledge. Also instead of trying to learn more than one programming language (e.g. Python, PHP, Ruby, etc.) and/or a web framework (e.g. Django, cakePHP, Ruby On Rails, etc.) at the same time, first try to become reasonably good at one. This will make it much easier to pick up another language later in the future.

8. Code regularly and be persistent.

It is important to understand that learning how to program and becoming good at it will take time. Regular coding practice is the only way to get there. Solving a problem is a good way to learn, but doing so on a regular basis as often as possible is the best way to make what you learned stick and stay in your head.

While is it easy to say practice coding regularly and try to apply it as much as possible to the library environment, actually doing so is quite difficult. There are not many well-established communities for fledgling coders in libraries that provide needed guidance and support. And while you may want to work with library systems at your workplace right away, your lack of experience may prove problematic in gaining a necessary permission to tinker with them. Also as a full-time librarian, programming is likely to be thrown to the bottom of your to-do list.

Be aware of these obstacles and try to find a way to overcome them as you go. Set small goals and use them as milestones. Be persistent and don’t be discouraged by poor documentation, syntax errors, and failures. With consistent practice and continuous learning, programming can surely be learned.

Resources

A. Resources for learning

B. Communities

 

More APIs: writing your own code (2)

*** This blog post has been originally published in ACRL TechConnect 0n October 9, 2012. ***

My previous post “The simpest AJAX: writing your own code (1)” discussed a few Javascript and JQuery examples that make the use of the Flickr API. In this post, I try out APIs from providers other than Flickr. The examples will look plain to you since I didn’t add any CSS to dress them up. But remember that the focus here is not in presentation but in getting the data out and re-displaying it on your own. Once you get comfortable with this process, you can start thinking about a creative and useful way in which you can present and mash up the same data. We will go through 5 examples I created with three different APIs.  Before taking a look at the codes, check out the results below first.

I. Pinboard API

The first example is Pinboard. Many libraries moved their bookmarks in Del.icio.us to a different site when there was a rumor that Del.cio.us may be shut down by Yahoo. One of those sites were Pinboard.  By getting your bookmark feeds from Pinboard and manipulating them, you can easily present a subset of your bookmark as part of your website.

(a) Display bookmarks in Pinboard using its API

The following page uses JQuery to access the JSONP feed of my public bookmarks in Pinboard. $.ajax() method is invoked on line 13. Line 15, jsonp:”cb”, gives the name to a callback function that will wrap the JSON feed data in it. Note line 18 where I print out data received into the console. This way, you can check if you are receiving JSONP feed in the console of Firebug. Line 19-22 uses $.each() function to access each element in the JSONP feed and the .append() method to add each bookmark’s title and url to the “pinboard” div. JQuery documentation has detailed explanation and examples for its functions and methods. So make sure to check it out if you have any questions about a JQuery function or method.

Pinboard API – example 1

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Pinboard: JSONP-AJAX Example</title>
<script type="text/javascript" src="http://jqueryjs.googlecode.com/files/jquery-1.3.2.min.js"></script>
</head>
<body>
<p> This page takes the JSON feed from <a href="http://pinboard.in/u:bohyunkim/">my public links in Pinboard</a> and re-presents them here. See <a href="http://feeds.pinboard.in/json/u:bohyunkim/">the Pinboard's JSON feed of my links</a>.</p>
<div id="pinboard"><h1>All my links in Pinboard</h1></div>
<script>
$(document).ready(function(){	
$.ajax({
  url:'http://feeds.pinboard.in/json/u:bohyunkim',
  jsonp:"cb",
  dataType:'jsonp',
  success: function(data) {
  	console.log(data); //dumps the data to the console to check if the callback is made successfully
    $.each(data, function(index, item){
      $('#pinboard').append('<div><a href="' + item.u + '">' + item.d
+ '</a></div>');
      }); //each
    } //success
  }); //ajax

});//ready
</script>
</body>
</html>

Here is the screenshot of the page. I opened up the Console window of the Firebug (since I dumped the received in line 18) and you can see the incoming data here. (Note. Click the images to see the large version.)

But it is much more convenient to see the organization and hierarchy of the JSONP feed in the Net panel of Firebug.

And each element of the JSONP feed can be drilled down for further details by clicking the object in each row.

(b) Display only a certain number of bookmarks

Now, let’s display only five bookmarks. In order to do this, only one more line is needed. Line 9 checks the position of each element and breaks the loop when the 5th element is processed.

Pinboard API – example 2

$.ajax({
  url:'http://feeds.pinboard.in/json/u:bohyunkim',
  jsonp:"cb",
  dataType:'jsonp',
  success: function(data) {
    $.each(data, function(index, item){
      	$('#pinboard').append('<div><a href="' + item.u + '">' + item.d
+ '</a></div>');
    	if (index == 4) return false; //only display 5 items
      }); //each
    } //success
  }); //ajax

(c) Display bookmarks with a certain tag

Often libraries want to display bookmarks with a particular tag. Here I add a line using JQuery method $.inArray() to display only bookmarks tagged with ‘fiu.’ $.inArray()  method takes value and array as parameters and returns 0 if the value is found in the array otherwise -1. Line 7 checks if the tag array of a bookmark (item.t) does include ‘fiu,’ and only in such case displays the bookmark. As a result, only the bookmarks with the tag ‘fiu’ are shown in the page.

Pinboard API – example 3

$.ajax({
  url:'http://feeds.pinboard.in/json/u:bohyunkim',
  jsonp:"cb",
  dataType:'jsonp',
  success: function(data) {
    $.each(data, function(index, item){
    	if ($.inArray("fiu", item.t)!==-1) // if the tag is 'fiu'
      		$('#pinboard').append('<div><a href="' + item.u + '">' + item.d
+ '</a></div>');
	}); //each
    } //success
  }); //ajax

II. Reddit API

My second example uses Reddit API. Reddit is a site where people comment on news items of interest. Here I used $.getJSON() instead of $.ajax() in order to process the JSONP feed from the Science section of Reddit. In the case of Pinboard API, I could not find out a way to construct a link that includes a call back function in the url. Some of the parameters had to be specified such as jsonp:”cb”, dataType:’jsonp’. For this reason, I needed to use $.ajax() function. On the other hand, in Reddit, getting the JSONP feed url was straightforward: http://www.reddit.com/r/science/.json?jsonp=cb.

Line 19 adds a title of the page. Line 20-22 extracts the title and link to the news article that is being commented and displays it. Under the news item, the link to the comments for that article in Reddit is added as a bullet item. You can see that, in Line 17 and 18, I have used the console to check if I get the right data and targeting the element I want and then commented out later.

This is just an example, and for that reason, the result is a rather simplified version of the original Reddit page with less information. But as long as you are comfortable accessing and manipulating data at different levels of the JSONP feed sent from an API, you can slice and dice the data in a way that suits your purpose best. So in order to make a clever mash-up, not only the technical coding skills but also your creative ideas of what different sets of data and information to connect and present to offer something new that has not been available or apparent before.

My second example uses Reddit API. Reddit is a site where people comment on news items of interest. Here I used $.getJSON() method instead of $.ajax() in order to process the JSONP feed from the Science section of Reddit. In the case of Pinboard API, I could not find out a way to construct a link for a call back function. Some of the parameters had to be specified such as jsonp:”cb”, dataType:’jsonp’. So I needed to use $.ajax() method.

On the other hand, in Reddit, getting the JSONP feed url was straightforward: http://www.reddit.com/r/science/.json?jsonp=cb.   Line 19 adds a title of the page. Line 20-22 extracts the title and link to the news article that is being commented and displays it. Under the news item, the link to the comments for that article in Reddit is added as a bullet item.You can see that in Line 17 and 18, I have used the console to check if I get the right data and targeting the element I want.

This is just an example, and for that reason, the result is rather a simplified version of the original Reddit page with less information. But as long as you are comfortable accessing and manipulating data at different levels of the JSONP feed sent from an API, you can slice and dice the data in a way that suits your purpose best.

Reddit API – example

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Reddit-Science: JSONP-AJAX Example</title>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js"></script>
</head>

<body>
<p> This page takes the JSONP feed from <a href="http://www.reddit.com/r/science/">Reddit's Science section</a> and presents the link to the original article and the comments in Reddit to the article as a pair. See <a href="http://www.reddit.com/r/science/.json?jsonp=?">JSONP feed</a> from Reddit.</p>

<div id="feed"> </div>
<script type="text/javascript">
	//run function to parse json response, grab title, link, and media values, and then place in html tags
$(document).ready(function(){		
	$.getJSON('http://www.reddit.com/r/science/.json?jsonp=?', function(rd){
		//console.log(rd);
		//console.log(rd.data.children[0].data.title);
		$('#feed').html('<h1>*Subredditum Scientiae*</h1>');
		$.each(rd.data.children, function(k, v){
      		$('#feed').append('<div><p>'+(k+1)+': <a href="' + v.data.url + '">' + v.data.title+'</a></p><ul><li style="font-variant:small-caps;font-size:small"><a href="http://www.reddit.com'+v.data.permalink+'">Comments from Reddit</a></li></ul></div>');
      }); //each
	}); //getJSON
});//ready	
</script>

</body>
</html>

The structure of a JSON feed can be confusing to make out particularly. So make sure to use the Firebug Net window to figure out the organization of the feed content and the property name for the value you want.

But what if the site from which you would like to get data doesn’t offer JSONP feed? Fortunately you can convert any RSS or XML feed into JSONP feed. Let’s take a look!

III. PubMed Feed with Yahoo Pipes API

Consider this PubMed search. This is simple search that looks for items in PubMed that has to do with Florida International University College of Medicine where I work. You may want to access the data feed of this search result, manipulate, and display in your library website. So far, we have performed a similar task with the Pinboard and the Reddit API using JQuery. But unfortunately PubMed does not offer any JSON feed. We only get RSS feed instead from PubMed.

This is OK, however. You can either manipulate the RSS feed directly or convert the RSS feed into JSON, which you are more familiar with now. Yahoo Pipes is a handy tool for just that purpose. You can do the following tasks with Yahoo Pipes:

  • combine many feeds into one, then sort, filter and translate it.
  • geocode your favorite feeds and browse the items on an interactive map.
  • power widgets/badges on your web site.
  • grab the output of any Pipes as RSS, JSON, KML, and other formats.

Furthermore, there may be a pipe that has been already created for exactly what you want to do by someone else. As PubMed is a popular resource, I found a pipe for PubMed search. I tested, copied the pipe, and changed the search term. Here is the screenshot of my Yahoo Pipe.

If you want to change the pipe, you can click “View Source” and make further changes. Here I just changed the search terms and saved the pipe.

After that, you want to get the results of the Pipe as JSON. If you hover over the “Get as JSON” link in the first screenshot above, you will get a link: http://pipes.yahoo.com/pipes/pipe.run?_id=e176c4da7ae8574bfa5c452f9bb0da92&_render=json&limit=100&term=”Florida International University” and “College of Medicine” But this returns JSON, not JSONP.

In order to get that JSON feed wrapped into a callback function, you need to add this bit, &_callback=myCallback, at the end of the url: http://pipes.yahoo.com/pipes/pipe.run?_id=e176c4da7ae8574bfa5c452f9bb0da92&_render=json&limit=10&term=%22Florida+International+University%22+and+%22College+of+Medicine%22&_callback=myCallback. Now the JSON feed appears wrapped in a callback function like this: myCallback( ). See the difference?

Line 25 enables you to bring in this JSONP feed and invokes the callback function named “myCallback.” Line 14-23 defines this callback function to process the received feed. Line 18-20 takes the JSON data received at the level of data.value. item, and prints out each item’s title (item.title) with a link (item.link). Here I am giving a number for each item by (index+1). If you don’t put +1, the index will begin from 0 instead of 1. Line 21 stops the process when the processed item reaches 5 in number.

Yahoo Pipes API/PubMed – example

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>PubMed and Yahoo Pipes: JSONP-AJAX Example</title>
<script type="text/javascript" src="http://jqueryjs.googlecode.com/files/jquery-1.3.2.min.js"></script>
</head>
<body>
<p> This page takes the JSONP feed from <a href="http://pipes.yahoo.com/pipes/pipe.info?_id=e176c4da7ae8574bfa5c452f9bb0da92"> a Yahoo Pipe</a>, which creates JSONP feed out of a PubMed search results and re-presents them here. 
<br/>See <a href="http://pipes.yahoo.com/pipes/pipe.run?_id=e176c4da7ae8574bfa5c452f9bb0da92&_render=json&limit=10&term=%22Florida+International+University%22+and+%22College+of+Medicine%22&_callback=myCallback">the Yahoo Pipe's JSON feed</a> and <a href="http://www.ncbi.nlm.nih.gov/pubmed?term=%22Florida%20International%20University%22%20and%20%22College%20of%20Medicine%22">the original search results in PubMed</a>.</p>
<div id="feed"></div>
<script type="text/javascript">
	//run function to parse json response, grab title, link, and media values - place in html tags
	function myCallback(data) {
		//console.log(data);
		//console.log(data.count);
		$("#feed").html('<h1>The most recent 5 publications from <br/>Florida International University College of Medicine</h1><h2>Results from PubMed</h2>');
		$.each(data.value.items, function(index, item){
      		$('#feed').append('<p>'+(index+1)+': <a href="' + item.link + '">' + item.title
+ '</a></p>');
        if (index == 4) return false; //display the most recent five items
      }); //each
	} //function
	</script>
<script type="text/javascript" src="http://pipes.yahoo.com/pipes/pipe.run?_id=e176c4da7ae8574bfa5c452f9bb0da92&_render=json&limit=10&term=%22Florida+International+University%22+and+%22College+of+Medicine%22&_callback=myCallback"></script>
</body>
</html>

Do you feel more comfortable now with APIs? With a little bit of JQuery and JSON, I was able to make a good use of third-party APIs. Next time, I will try the Worldcat Search API, which is closer to the library world and see how that works.

The simplest AJAX: writing your own code (1)

*** This blog post has been originally published in ACRL TechConnect 0n September 12, 2012. ***

It has been 8 months since the Code Year project started. Back in January, I have provided some tips. Now I want to check in to see if how well you have been following along. Falling behind? You are not alone. Luckily there are still 3-4 months left.

Teaching oneself how to code is not easy. One of the many challenges is keeping at it on a regular basis. Both at home and at work, there seems to be always a dozen things higher in priority than code lessons. Another problem is that often we start a learning project by reading a book with some chosen examples. The Code Year project is somewhat better since it provides interactive tutorials. But at the end of many tutorials, you may have experienced the nagging feeling of doubt about whether you can now go out to the real world and make something that works. Have you done any real-time project yet?

If you are like me, the biggest obstacle in starting your own first small coding project is not so much the lack of knowledge as the fantasy that you still have yet more to learn before trying any such real-life-ish project. I call this ‘fantasy’ because there is never such a time when you are in full possession of knowledge before jumping into a project. In most cases, you discover what you need to learn only after you start a project and run into a problem that you need to solve.

So for this blog post, I tried building something very small. During the process, I had to fight constantly with the feeling that I should go back to the Code Year Project and take those comforting lessons in Javascript and JQeury that I didn’t have time to work through yet. But I also knew that I would be so much more motivated to keep learning if I can just see myself making something on my own. I decided to try some very simple AJAX stuff and started by looking at two examples on the Web. Here I will share those examples and my review process that enabled me to write my own bit of code. After looking at these, I was able to use different APIs to get the same result. My explanation below is intentionally detailed for beginners. But if you can understand the examples without my line-by-line explanation, feel free to skip and go directly to the last section where the challenge is. For what would your AJAX skill be useful? There are a lot of useful data in the cloud. Using AJAX, you can dynamically display your library’s photos stored in Flickr in your library’s website or generate a custom bibliography on the fly using the tags in Pinboard or MESH (Medical Subject Heading) and other filters in PubMed. You can mash up data feeds from multiple providers and create something completely new and interesting such as HealthMap, iSpiecies, and Housing Maps.

Warm-up 1: Jason’s Flickr API example

I found this example, “Flickr API – Display Photos (JSON)” quite useful. This example is at Jason Clark’s website. Jason has many cool code examples and working programs under the Code & Files page. You can see the source of the whole HTML page here . But let’s see the JS part below.

<script type="text/javascript">
//run function to parse json response, grab title, link, and media values - place in html tags
function jsonFlickrFeed(fr) {
    var container = document.getElementById("feed");
    var markup = '<h1>' + '<a href="' + fr.link+ '">' + fr.title + '</a>'+ '</h1>';
    for (var i = 0; i < fr.items.length; i++) {
    markup += '<a title="' + fr.items[i].title + '" href="' + fr.items[i].link + '"><img src="' + fr.items[i].media.m + '" alt="' + fr.items[i].title + '"></a>';
}
container.innerHTML = markup;
}
</script>
<script type="text/javascript" src="http://api.flickr.com/services/feeds/photos_public.gne?tags=cil2009&format=json">
</script>

After spending a few minutes looking at the source of the page, you can figure out the following:

  • Line 12 imports data formatted in JSON from Flickr, and the JSON data is wrapped in a JS function called jsonFlickrFeed. You can find these data source urls in API documentation usually. But many API documentations are often hard to decipher. In this case, this MashupGuide page by Raymond Yee was quite helpful.
  • Line 3-8 are defining the jsonFlickrFeed function that processes the JSON data.

You can think of JSON as a JS object or an associative array of them. Can you also figure out what is going on inside the jsonFlickrFeed function? Let’s go through it line by line.

  • Line 4 creates a variable, container, and sets it to the empty div given the id of the “feed.”
  • Line 5 creates another variable, markup, which will include a link and a title of “fr,” which is an arbitrary name that refers to the JSON data thrown inside the jsonFlickrFeed fucntion.
  • Line 6-8 are a for-loop that goes through every object in the items array and extracts its title and link as well as the image source link and title. The loop also adds the resulting HTML string to the markup variable.
  • Line 9 assigns the content of the markup variable as the value of the HTML content of the variable, container. Since the empty div with the “feed” id was assigned to the variable container, now the feed div has the content of var markup as its HTML content.

So these two JS snippets take an empty div like this:

<div id="feed"></div>

Then they dynamically generate the content inside with the source data from Flickr following some minimal presentation specified in the JS itself. Below is the dynamically generated content for the feed div. The result like this.

<div id="feed">
<h1>
<a href="http://www.flickr.com/photos/tags/cil2009/">Recent Uploads tagged cil2009</a>
</h1>
<a href="http://www.flickr.com/photos/matthew_francis/3458100856/" title="Waiting at Vienna metro (cropped)">
<img alt="Waiting at Vienna metro (cropped)" src="http://farm4.staticflickr.com/3608/3458100856_d01b26cf1b_m.jpg">
</a>
<a href="http://www.flickr.com/photos/libraryman/3448484629/" title="Laptop right before CIL2009 session">
<img alt="Laptop right before CIL2009 session" src="http://farm4.staticflickr.com/3389/3448484629_9874f4ab92_m.jpg">
</a>
<a href="http://www.flickr.com/photos/christajoy42/4814625142/" title="Computers in Libraries 2009">
<img alt="Computers in Libraries 2009" src="http://farm5.staticflickr.com/4082/4814625142_f9d9f90118_m.jpg">
</a>
<a href="http://www.flickr.com/photos/librarianinblack/3613111168/" title="David Lee King">
<img alt="David Lee King" src="http://farm4.staticflickr.com/3354/3613111168_02299f2b53_m.jpg">
</a>
<a href="http://www.flickr.com/photos/librarianinblack/3613111084/" title="Aaron Schmidt">
<img alt="Aaron Schmidt" src="http://farm4.staticflickr.com/3331/3613111084_b5ba9e70bd_m.jpg">
</a>
<a href="http://www.flickr.com/photos/librarianinblack/3612296027/" block"="" libraries"="" in="" computers="" title="The Kids on the ">
<img block"="" libraries"="" in="" computers="" alt="The Kids on the " src="http://farm3.staticflickr.com/2426/3612296027_6f4043077d_m.jpg">
</a>
<a href="http://www.flickr.com/photos/pegasuslibrarian/3460426841/" title="Dave and Greg look down at CarpetCon">
<img alt="Dave and Greg look down at CarpetCon" src="http://farm4.staticflickr.com/3576/3460426841_ef2e57ab49_m.jpg">
</a>
<a href="http://www.flickr.com/photos/pegasuslibrarian/3460425549/" title="Jason and Krista at CarpetCon">
<img alt="Jason and Krista at CarpetCon" src="http://farm4.staticflickr.com/3600/3460425549_55443c5ddb_m.jpg">
</a>
<a href="http://www.flickr.com/photos/pegasuslibrarian/3460422979/" title="Lunch with Dave, Laura, and Matt">
<img alt="Lunch with Dave, Laura, and Matt" src="http://farm4.staticflickr.com/3530/3460422979_96c020a440_m.jpg">
</a>
<a href="http://www.flickr.com/photos/jezmynne/3436564507/" title="IMG_0532">
<img alt="IMG_0532" src="http://farm4.staticflickr.com/3556/3436564507_551c7c5c0d_m.jpg">
</a>
<a href="http://www.flickr.com/photos/jezmynne/3436566975/" title="IMG_0529">
<img alt="IMG_0529" src="http://farm4.staticflickr.com/3328/3436566975_c8bfe9b081_m.jpg">
</a>
<a href="http://www.flickr.com/photos/jezmynne/3436556645/" title="IMG_0518">
<img alt="IMG_0518" src="http://farm4.staticflickr.com/3579/3436556645_9b01df7f93_m.jpg">
</a>
<a href="http://www.flickr.com/photos/jezmynne/3436569429/" title="IMG_0530">
<img alt="IMG_0530" src="http://farm4.staticflickr.com/3371/3436569429_92d0797719_m.jpg">
</a>
<a href="http://www.flickr.com/photos/jezmynne/3436558817/" title="IMG_0524">
<img alt="IMG_0524" src="http://farm4.staticflickr.com/3331/3436558817_3ff88a60be_m.jpg">
</a>
<a href="http://www.flickr.com/photos/jezmynne/3437361826/" title="IMG_0521">
<img alt="IMG_0521" src="http://farm4.staticflickr.com/3371/3437361826_29a38e0609_m.jpg">
</a>
<a href="http://www.flickr.com/photos/jezmynne/3437356988/" title="IMG_0516">
<img alt="IMG_0516" src="http://farm4.staticflickr.com/3298/3437356988_5aaa94452c_m.jpg">
</a>
<a href="http://www.flickr.com/photos/jezmynne/3437369906/" title="IMG_0528">
<img alt="IMG_0528" src="http://farm4.staticflickr.com/3315/3437369906_01015ce018_m.jpg">
</a>
<a href="http://www.flickr.com/photos/jezmynne/3436560613/" title="IMG_0526">
<img alt="IMG_0526" src="http://farm4.staticflickr.com/3579/3436560613_98775afc79_m.jpg">
</a>
<a href="http://www.flickr.com/photos/jezmynne/3437359398/" title="IMG_0517">
<img alt="IMG_0517" src="http://farm4.staticflickr.com/3131/3437359398_7e339cf161_m.jpg">
</a>
<a href="http://www.flickr.com/photos/jezmynne/3436535739/" title="IMG_0506">
<img alt="IMG_0506" src="http://farm4.staticflickr.com/3646/3436535739_c164062d6b_m.jpg">
</a>
</div>

Strictly speaking, Flickr is returning data in JSONP rather than JSON here. You will see what JSONP means in a little bit. But for now, don’t worry about that distinction. What is cool is that you can grab the data from a third party like Flickr and then you can remix and represent them in your own page.

Warm-up 2: Doing the same with JQuery using $.getJSON()

Since I had figured out how to display data from Flickr using Javascript (thanks to Jason’s code example), the next I wanted to try was to do the same with JQuery. After some googling, I discovered that there is a convenient JQeury method called $.getJSON(). The official JQuery page on this $.getJSON() method includes not only the explanation about JSONP (which allows you to load the data from the domain other than yours in your browser and manipulate it unlike JSON which will be restricted by the same origin policy) but also the JQuery example of processing the same Flickr JSONP data. This is the example from the JQuery website.

$.getJSON("http://api.flickr.com/services/feeds/photos_public.gne?jsoncallback=?",
  {
    tags: "mount rainier",
    tagmode: "any",
    format: "json"
  },
  function(data) {
    $.each(data.items, function(i,item){
      $("<img/>").attr("src", item.media.m).appendTo("#images");
      if ( i == 3 ) return false;
    });
  });

As you can see in the first line, the data feed urls for JSONP response have a part similar to &jasoncallback=? at the end. The function name can vary and the API documentation of a data provider provides that bit of information. Let’s go through the codes line by line:

  • Line 1-6 requests and takes in the data feed from the speicified URL in JSONP format.
  • Once the data is received and ready, the script invokes the anonymous function from line 7-11. This function makes use of the JQuery method $.each().
  • For each of data.items, the anonymous function applies another anonymous function from line 9-10.
  • Line 9 creates an image tag – $(“<img/>”), attaches each item’s media.m element as the source attribute to the image tag – .attr(“src”, item.media.m), and lastly appends the resulting string to the empty div with the id of “images” – .appendTo(“#images”).
  • Line 10 makes sure that no more than 4 items in data.items is processed.

You can see the entire HTML page codes in the JQuery website’s $.getJSON() page.

Your Turn: Try out an API other than Flickr

So far we have looked through two examples. Not too bad, right? To keep the post at a reasonable length, I will get to the little bit of code that I wrote in the next post. This means that you can try the same and we can compare the result next time. Now here is the challenge. Both examples we saw used the Flickr API. Could you write code for a different API provider that does the same thing? Remember that you have to pick a data provider that offers feeds in JSONP if you want to avoid dealing with the same origin policy.

Here are a few providers you might want to check out. They all offer their data feeds in JSONP.

First, find out what data URLs you can use to get JSONP responses. Then write several lines of codes in JS and JQuery to process and display the data in the way you like in your own webpage. You may end up with some googling and research while you are at it.

Here are a few tips that will help you along the way:

  • Verify the data feed URL to see if you are getting the right JSONP responses. Just type the source url into the browser window and see if you get something like this.
  • Get the Firebug for debugging if you don’t already have it.
  • Use the Firebug’s NET panel to see if you are receiving the data OK.
  • Use the Console panel for debugging. The part of data that you want to pick up may be in several levels deep. So it is useful to know if you are getting the right item first before trying to manipulate it.

Happy Coding! See the following screenshots for the Firebug NET panel and Console panel. (Click the images to see the bigger and clearer version.) Don’t forget to share your completed project in the comments section as well as any questions, comments, advice, suggestions!

Net panel in Firebug

 

 

Console panel in Firebug

Tips for Everyone Doing the #codeyear

***   This post has been originally posted to the ACRL TechConnect blog.  ***

Learn to Code in 2012!

If you are a librarian interested in learning how to code, 2012 is a perfect year for you to start the project. Thanks to CodeAcademy (http://codeacademy.com), free JavaScript lessons are provided every week at http://codeyear.com/. The lessons are interactive and geared towards beginners. So even if you do not have any previous experience in programming, you will be able to pick up the new skill soon enough as long as you are patient and willing to spend time on mastering each lesson every week.

A great thing about this learn-how-to-program project, called #codeyear in Twitter (#libcodeyear and #catcode in the library-land) is that there are +375,443 people (and counting up) out there who are doing exactly the same lessons as you are. The greatest thing about this #libcodeyear / #catcode project is that librarians have organized themselves around this project for the collective learning experience.  How librarian-like, don’t you think?

Now, if you are ready to dive in, here are some useful resources.  And after these Resources, I will tell you a little bit more about how to best ask help about your codes when they are not working for you.

Resources for Collective Learning

Syntax Error: Catch the most frustrating bugs!

Now what I really like about #codeyear lessons so far is that some of the lessons trip you by trivial things like a typo! So you need to find a typo and fix it to pass a certain lesson. Now you may ask “How the hell does fixing a typo count as a programming lesson?”

Let me tell you. Finding a typo is no triviality in coding. Catching a similar syntax error will save you from the most frustrating experience in coding.

The examples of seemingly innocuous syntax errors are:

  • var myFunction = funtction (){blah, blah, blah … };
  • var myNewFunction = function (]{blah, blah, blah … };
  • for(i=0,  i<10, i++;)
  • var substr=’Hello World’; alert(subst);
  • –//This is my first JavaScript

Can you figure out why these lines would not work?  Give it a try! You won’t be sorry. Post your answers in the comments section.

How to Ask Help about Your Codes      

by Matteo De Felice in Flickr (http://farm4.staticflickr.com/3577/3502347936_43b5e2a886.jpg)

I am assuming that as #codeyear, #catcode, #libcodeyear project progresses, more people are going to ask questions about problems that stump them. Some lessons already have Q&A in the CodeAcademy site. So check those out. Reading through others’ questions will give valuable insight to how codes work and where they can easily trip you.

That having been said, you may want to ask questions to the places mentioned in the Resources section above. If you do, it’s a good idea to follow some rules. This will make your question more likely to be looked at by others and way more likely to be answered correctly.

  • Before asking a question, try to research yourself. Google the question, check out the Q&A section in the CodeAcademy website, check out other online tutorials about JS (see below for some of the recommended ones).
  • If this fails, do the following:
    • Specify your problem clearly.
      (Don’t say things like “I don’t get lesson 3.5.” or “JavaScript function is too hard” unless the purpose is just to rant.)
    • Provide your codes with any parts/details that are related to the lines with a problem.
      (Bear in mind that you might think there is a problem in line 10 but the problem may lie in line 1, which you are not looking.) Highlight/color code the line you are having a problem. Make it easy for others to immediately see the problematic part.
    • Describe what you have done to troubleshoot this (even if it didn’t work.)
      : This helps the possible commenter to know what your reasoning is behind your codes and what solutions you have already tried, thereby saving their time. So this will make it more likely that someone will actually help you. To believe it or not, what seems completely obvious and clear to you can be completely alien and unfathomable to others.

Some JavaScript Resources

There are many resources that will facilitate your learning JavaScript. In addition to the lessons provided by CodeAcademy, you may also find these other tutorials helpful to get a quick overview of JavaScript syntax, usage, functions, etc. From my experience, I know that I get a better understanding when I review the same subject from more than one resource.

If you have other favorite Javascript please share in the comment section.

ACRL TechConnect blog will continue to cover #libcodeyear / #catcode related topics throughout the year!  The post up next will tell you all about some of the excuses people deploy to postpone learning how to code and what might break the mental blockage!

Why Not Grow Coders from the inside of Libraries?

How fantastic would it be if every small library has an in-house developer? We will be all using open-source software with custom feature modules that would perfectly fit our vision and the needs of the community we serve. Libraries will then truly be the smart consumers of technology not at the mercy of clunky systems. Furthermore, it would re-position libraries as “contributors” to the technology that enables the public to access information and knowledge resources. I am sure no librarian will object to this vision. But at this time of ever-shrinking library budget, affording enough librarians itself is a challenge let alone hiring a developer.

But why should this be the case? Librarians are probably one of the most tech-savvy professionals after IT and science/ engineering/ marketing folks. So why aren’t there more librarians who code? Why don’t we see a surge of librarian coders? After all, we are living in times in which the web is the platform for almost all human activities and libraries are changing its name to something like learning and ‘technology’ center.

I don’t think that coding is too complicated or too much to learn for any librarian regardless of their background. Today’s libraries offer such a wide range of resources and services online and deploy and rely on so many systems from an ILS to a digital asset management system that libraries can benefit a great deal from those staff who have even a little bit of understanding in coding.

The problem is, I think, libraries do not proactively encourage nor strongly support their in-house library staff to become coders. I am not saying that all librarians / library staff should learn how to code like a wizard. But it is an undeniable fact that there are enough people in the library land who are seriously interested in coding and capable of becoming a coder. But chances are, these people will have no support from their own libraries. If they are working in non-technology-related areas, it will be completely up to them to pursue and pay for any type of learning opportunities. Until they prove themselves to be capable of a certain level of coding, they may not even be able to get hands-on experience of working in library technologies/systems/programming. And when they become capable, they may have to seek a new job if they are serious about putting to use their newly acquired programming skills.

It is puzzling to me why libraries neglect to make conscious efforts in supporting their staff who are interested in coding to further develop their skills while freely admitting that they would benefit from having a programmer on staff. Perhaps it is the libraries that are making the wrong distinction between library work and technology work. They are so much more closely intertwined than, say, a decade ago. Even library schools that are slow to change are responding and adding technology courses to their curriculum and teaching all LIS students basic HTML. But certainly libraries can use staff who want to move beyond HTML.

At the 2011 ALA Midwinter, I attended LITA Head of Library Technology Interest Group meeting. One of the issues discussed there was how to recruit and maintain the IT workforce within libraries. Some commented the challenge of recruting people from the IT industry, which often pays more than libraries do. Some mentioned how to quickly acclimate those new to libraries to the library culture and technology. Others discussed the difficulty of retaining IT professionals in libraries since libraries tend to promote only librarians with MLS degrees and tend to exclude non-librarians from the important decision-making process. Other culture differences between IT and libraries were also discussed.

These are all valid concerns and relevant discussion topics. But I was amazed by the fact that almost all assumed that the library IT people would come from the IT sector and outside from libraries. Some even remarked that they prefered to hire from the IT industry outside libraries when they fill a position. This discussion was not limited to programmers but inclusive of all IT professionals. Still, I think perhaps there is something wrong if libraries only plan to steal IT people from the outside without making any attempt to invest in growing some of those technology people inside themselves. IT professionals who come from the general IT industry may be great coders but they do not know about libraries. This is exactly the same kind of cause for inflexible library systems created by programmers who do not know enough about the library’s businesses and workflows.

So why don’t libraries work to change that?

One of the topics frequently discussed in librareis these days is open source software. At the recent 2011 Code4Lib conference, there was a breakout session about what kind of help would allow libraries to more actively adopt open source software adn systems. Those who have experience in working with open source software at the session unanimously agreed that adopting open-source is not cheap. There is a misconception that by adopting open source software, libraries will save money. But if so, at least that would not be the case in any short tem. Open-source requires growing knowledgeable technology staff in-house who would understand the software fully and able to take advantage of its flexibility to benefit the organization’s goals. It is not something you can buy cheap off the shelf and make it work by turning a key. While adopting open-source will provide freedom to libraries to experiment and improve their services and thereby empower lirbaries, those benefits will not come for free without investment.

Some may ask why not simply hire services from a third-party company that will support the open-source software or system that a library will adopt. But without the capability of understanding the source and of making changes as needed, how would libraries harness the real power of open-source unless the goal is just a friendier vendor-library relationship?

In his closing talk at the 2011 Code4Lib conference, Eric Hellman pointed out the fact that many library programmers are self-taught and often ‘fractional’ coders in the sense that they can afford to spend only a fraction of their time on coding. The fact that most library coders are fractional coders is all the more reason for having more coders in libraries, so that more time can be spent collectively on coding for libraries. Although enthusiastic, many novice coders are often lost about how certain programming languages or software tools are or can be applied to current library services and systems and need guidance about which coding skills are most relevant and can be used to produce immediately useful results in the library context. Many novice coders at librareis who often teach themselves programming skills by attending (community) college courses at night at their own expenses and scouring the web for resources and tutorials after work can certainly benefit from some support from their libraries.

Are you a novice or experienced coder working at libraries? Were/are you encouraged to further develop your skills? If a novice, what kind of support would you like to see from your libraries? If experienced, how did you get there? I am all ears. Please share your thoughts.

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N.B. If you are a formally trained CS/E person, you may want to know that I am using the term ‘coding’ loosely in the library context, not in the context of software industry.  Please see this really helpful post “after @bohyunkim: talking across boundaries and the meaning of ‘coder’” by Andromeda Yelton which clarifies this. Will K’s two comments below also address the usage of this term in its intended sense much better than I did.  I tried to clarify a bit more what I meant below in my comments but feel free to comment/suggest a better term if you find this still problematic.  Thanks for sharing your thoughts! (2/22/2011)


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