Posts Tagged 'Development'

February 14, 2013

Tips and Tricks – Building a jQuery Plugin (Part 2)

jQuery plugins don't have to be complicated to create. If you've stumbled upon this blog in pursuit of a guide to show you how to make a jQuery plugin, you might not believe me ... It seems like there's a chasm between the "haves" of jQuery plugin developers and the "have nots" of future jQuery developers, and there aren't very many bridges to get from one side to the other. In Part 1 of our "Building a jQuery Plugin" series, we broke down how to build the basic structure of a plugin, and in this installment, we'll be adding some usable functionality to our plugin.

Let's start with the jQuery code block we created in Part 1:

(function($) {
    $.fn.slPlugin = function(options) {
            var defaults = {
                myVar: "This is", // this will be the default value of this var
                anotherVar: "our awesome",
                coolVar: "plugin!",
            };
            var options = $.extend(defaults, options);
            this.each(function() {
                ourString = myVar + " " + anotherVar + " " + coolVar;
            });
            return ourString;
    };
}) (jQuery);

We want our plugin to do a little more than return, "This is our awesome plugin!" so let's come up with some functionality to build. For this exercise, let's create a simple plugin that allows truncates a blob of text to a specified length while providing the user an option show/hide the rest of the text. Since the most common character length limitation on the Internet these days is Twitter's 140 characters, we'll use that mark in our example.

Taking what we know about the basic jQuery plugin structure, let's create the foundation for our new plugin — slPlugin2:

(function($) {
    $.fn.slPlugin2 = function(options) {
 
        var defaults = {
            length: 140,
            moreLink: "read more",
            lessLink: "collapse",
            trailingText: "..."
        };
 
        var options = $.extend(defaults, options);
    };
})(jQuery);

As you can see, we've established four default variables:

  • length: The length of the paragraph we want before we truncate the rest.
  • moreLength: What we append to the paragraph when it is truncated. This will be the link the user clicks to expand the rest of the text.
  • lessLink: What we append to the paragraph when it is expanded. This will be the link the user clicks to collapse the rest of the text.
  • trailingText: The typical ellipses to append to the truncation.

In our jQuery plugin example from Part 1, we started our function with this.each(function() {, and for this example, we're going to add a return for this to maintain chainability. By doing so, we're able to manipulate the segment with methods. For example, if we started our function with this.each(function() {, we'd call it with this line:

$('#ourParagraph').slPlugin2();

If we start the function with return this.each(function() {, we have the freedom to add further manipulation:

$('#ourParagraph').slPlugin2().bind();

With such a simple change, we're able to add method calls to make one massive dynamic function.

Let's flesh out the actual function a little more. We'll add a substantial bit of code in this step, but you should be able to follow along with the changes via the comments:

(function($) {
    $.fn.slPlugin2 = function(options) {
 
        var defaults = {
            length: 140, 
            moreLink: "read more",
            lessLink: "collapse",
            trailingText: "..."
        };
 
        var options = $.extend(defaults, options);
 
        // return this keyword for chainability
        return this.each(function() {
            var ourText = $(this);  // the element we want to manipulate
            var ourHtml = ourText.html(); //get the contents of ourText!
            // let's check if the contents are longer than we want
            if (ourHtml.length > options.length) {
                var truncSpot = ourHtml.indexOf(' ', options.length); // the location of the first space (so we don't truncate mid-word) where we will end our truncation.
 
   // make sure to ignore the first space IF the text starts with a space
   if (truncSpot != -1){
       // the part of the text that will not be truncated, starting from the beginning
       var firstText = ourHtml.substring(0, truncSpot);
 
       // the part of the text that will be truncated, minus the trailing space
       var secondText = ourHtml.substring(truncSpot, ourHtml.legnth -1);
                }
            }
        })
    };
})(jQuery);

Are you still with us? I know it seems like a lot to take in, but each piece is very straightforward. The firstText is the chunk of text that will be shown: The first 140 characters (or whatever length you define). The secondText is what will be truncated. We have two blobs of text, and now we need to make them work together:

(function($) {
    $.fn.slPlugin2 = function(options) {
 
        var defaults = {
            length: 140, 
            moreLink: "read more",
            lessLink: "read less",
            trailingText: "..."
        };
 
        var options = $.extend(defaults, options);
 
        // return this keyword for chainability
        return this.each(function() {
            var ourText = $(this);  // the element we want to manipulate
            var ourHtml = ourText.html(); //get the contents of ourText!
            // let's check if the contents are longer than we want
            if (ourHtml.length > options.length) {
                var truncSpot = ourHtml.indexOf(' ', options.length); // the location of the first space (so we don't truncate mid-word) where we will end our truncation.
 
   // make sure to ignore the first space IF the text starts with a space
   if (truncSpot != -1){
       // the part of the text that will not be truncated, starting from the beginning
       var firstText = ourHtml.substring(0, truncSpot);
 
       // the part of the text that will be truncated, minus the trailing space
       var secondText = ourHtml.substring(truncSpot, ourHtml.legnth -1);
 
       // perform our truncation on our container ourText, which is technically more of a "rewrite" of our paragraph, to our liking so we can modify how we please. It's basically saying: display the first blob then add our trailing text, then add our truncated part wrapped in span tags (to further modify)
       ourText.html(firstText + options.trailingText + '<span class="slPlugin2">' + secondText + '</span>');
 
       // but wait! The secondText isn't supposed to show until the user clicks "read more", right? Right! Hide it using the span tags we wrapped it in above.
       ourText.find('.slPlugin2').css("display", "none");
                }
            }
        })
    };
})(jQuery);

Our function now truncates text to the specified length, and we can call it from our page simply:

<script src="jquery.min.js"></script>
<script src="jquery.slPlugin2.js"></script>
<script type="text/javascript">
$(document).ready(function() {  
    $('#slText').slPlugin2();  
});
</script>

Out of all the ways to truncate text via jQuery, this has to be my favorite. It's feature-rich while still being fairly easy to understand. As you might have noticed, we haven't touched on the "read more" and "read less" links or the expanding/collapsing animations yet, but we'll be covering those in Part 3 of this series. Between now and when Part 3 is published, I challenge you to think up how you'd add those features to this plugin as homework.

-Cassandra

December 27, 2012

Using SoftLayer Object Storage to Back Up Your Server

Before I came to my senses and moved my personal servers to SoftLayer, I was one of many victims of a SolusVM exploit that resulted in the wide-scale attack of many nodes in my previous host's Chicago data center. While I'm a firm believer in backing up my data, I could not have foreseen the situation I was faced with: Not only was my server in one data center compromised with all of its data deleted, but my backup server in one of the host's other data centers was also attacked ... This left me with old, stale backups on my local computer and not much else. I quickly relocated my data and decided that I should use SoftLayer Object Storage to supplement and improve upon my backup and disaster recovery plans.

With SoftLayer Object Storage Python Client set up and the SoftLayer Object Storage Backup script — slbackup.py — in hand, I had the tools I needed to build a solid backup infrastructure easily. On Linux.org, I contributed an article about how to perform MySQL backups with those resources, so the database piece is handled, but I also need to back up my web files, so I whipped up another quick bash script to run:

#!/bin/bash
 
# The path the backups will be dumped to
DUMP_DIR="/home/backups/"
 
# Path to the web files to be backed up
BACKUP_PATH="/var/www/sites /"
 
# Back up folder name (mmddyyyy)
BACKUP_DIR="`date +%m%d%Y`"
 
# Backup File Name
DUMP_FILE="`date +%m_%d_%Y_%H_%M_%S`_site_files"
 
# SL container name
CONTAINER="site_backups"
 
# Create backup dir if doesn't exist
if [ ! -d $DUMP_DIR$BACKUP_DIR ]; then
        mkdir -p $DUMP_DIR$BACKUP_DIR
fi
 
tar -zcvpf $DUMP_DIR$BACKUP_DIR/$DUMP_FILE.tar.gz $BACKUP_PATH
 
# Make sure the archive exists
if [ -f $DUMP_DIR$BACKUP_DIR/$DUMP_FILE.tar.gz ]; then
        /root/slbackup.py -s $DUMP_DIR$BACKUP_DIR/ -o "$CONTAINER" -r 30
 
        # Remove the backup stored locally
        rm -rf $DUMP_DIR$BACKUP_DIR
 
        # Success
        exit 0
else
        echo "$DUMP_DIR$BACKUP_DIR/$DUMP_FILE.tar.gz does not exist."
        exit 1
fi

It's not the prettiest bash script, but it gets the job done. By tweaking a few variables, you can easily generate backups for any important directory of files and push them to your SoftLayer Object Storage account. If you want to change the retention time of your backups to be longer or shorter, you can change the 30 after the –r in the line below to the number of days you want to keep each backup:

/root/slbackup.py -s $DUMP_DIR$BACKUP_DIR/ -o "$CONTAINER" -r 30

I created a script for each website on my server, and I set a CRON (crontab –e) entry to run each one on Sundays staggered by 5 minutes:

5 1 * * 0  /root/bin/cron/CRON-site1.com_web_files > /dev/null
10 1 * * 0  /root/bin/cron/CRON-site2.com_web_files > /dev/null
15 1 * * 0  /root/bin/cron/CRON-site3.com_web_files > /dev/null 

If you're looking for an easy way to automate and solidify your backups, this little bit of code could make life easier on you. Had I taken the few minutes to put this script together prior to the attack I experienced at my previous host, I wouldn't have lost any of my data. It's easy to get lulled into "backup apathy" when you don't need your backups, but just because nothing *has* happened to your data doesn't mean nothing *can* happen to your data.

Take it from me ... Be over-prepared and save yourself a lot of trouble.

-Ronald

December 19, 2012

SoftLayer API: Streamline. Simplify.

Building an API is a bit of a balancing act. You want your API to be simple and easy to use, and you want it to be feature-rich and completely customizable. Because those two desires happen to live on opposite ends of the spectrum, every API finds a different stasis in terms of how complex and customizable they are. The SoftLayer API was designed to provide customers with granular control of every action associated with any product or service on our platform; anything you can do in our customer portal can be done via our API. That depth of functionality might be intimidating to developers looking to dive in quickly and incorporate the SoftLayer platform into their applications, so our development team has been working to streamline and simplify some of the most common API services to make them even more accessible.

SoftLayer API

To get an idea of what their efforts look like in practice, Phil posted an SLDN blog with a perfect example of how they simplified cloud computing instance (CCI) creation via the API. The traditional CCI ordering process required developers to define nineteen data points:

Hostname
Domain name
complexType
Package Id
Location Id
Quantity to order
Number of cores
Amount of RAM
Remote management options
Port speeds
Public bandwidth allotment
Primary subnet size
Disk size
Operating system
Monitoring
Notification
Response
VPN Management - Private Network
Vulnerability Assessments & Management

While each of those data points is straightforward, you still have to define nineteen of them. You have all of those options when you check out through our shopping cart, so it makes sense that you'd have them in the API, but when it comes to ordering through the API, you don't necessarily need all of those options. Our development team observed our customers' API usage patterns, and they created the slimmed-down and efficient SoftLayer_Virtual_Guest::createObject — a method that only requires seven data points:

Hostname
Domain name
Number of cores
Amount of RAM
Hourly/monthly billing
Local vs SAN disk
Operating System

Without showing you a single line of code, you see the improvement. Default values were established for options like Port speeds and Monitoring based on customer usage patterns, and as a result, developers only have to provide half the data to place a new CCI order. Because each data point might require multiple lines of code, the volume of API code required to place an order is slimmed down even more. The best part is that if you find yourself needing to modify one of the now-default options like Port speeds or Monitoring, you still can!

As the development team finds other API services and methods that can be streamlined and simplified like this one, they'll ninja new solutions to make the API even more accessible. Have you tried coding to the SoftLayer API yet? If not, what's the biggest roadblock for you? If you're already a SLAPI coder, what other methods do you use often that could be streamlined?

-@khazard

November 27, 2012

Tips and Tricks - Building a jQuery Plugin (Part 1)

I've written several blogs detailing the use of different jQuery plugins (like Select2, LazyLoad and equalHeights), and in the process, I've noticed an increasing frustration among the development community when it comes to building jQuery plugins. The resources and documentation I've found online have not as clear and easy as they could be, so in my next few posts, I'll break down the process to make jQuery plugin creation simple and straightforward. In this post, we'll cover the basic structure of a plugin and where to insert your own functionality, and in Part 2, we'll pick a simple task and add on to our already-made structure.

Before I go any further, it's probably important to address a question you might be asking yourself: "Why would I want to make my own plugin?" The best reason that comes to my mind is portability. If you've ever created a large-scale project, take a look back into your source code and note how many of the hundreds of lines of jQuery code you could put into a plugin to reuse on a different project. You probably invested a lot of time and energy into that code, so it doesn't make sense to reinvent the wheel if you ever need that functionality again. If that's not enough of a reason for you, I can also tell you that if you develop your own jQuery plugin, you'll level-up in cool points, and the jQuery community will love you.

For this post, let's create a jQuery plugin that simply returns, "This is our awesome plugin!" Our first step involves putting together the basic skeleton used by every plugin:

(function($) {
    $.fn.slPlugin = function() {
 
            // Awesome plugin stuff goes here
    };
}) (jQuery);

This is your template — your starting point. Practice it. Remember it. Love it. The "slPlugin" piece is what I chose to name this plugin. It's best to name your plugin something unique ... I always run a quick Google search to ensure I don't duplicate the name of a plugin I (or someone else) might need to use in a project alongside my plugin. In this case, we're calling the example plugin slPlugin because SoftLayer is awesome, and I like naming my plugins after awesome things. I'll save this code in a file called jquery.slPlugin.js.

Now that we have our plugin's skeleton, let's add some default values for variables:

(function($) {
    $.fn.slPlugin = function(options) {
            var defaults = {
                myVar: "default", // this will be the default value of this var
                anotherVar: 0,
                coolVar: "this is cool",                
            };
            var options = $.extend(defaults, options);
    };
}) (jQuery);

Let's look at the changes we made between the first example and this one. You'll notice that in our second line we added "options" to become $.fn.slPlugin = function(options) {. We do this because our function is now accepting arguments, and we need to let the function know that. The next difference you come across is the var defaults blurb. In this section, we're providing default values for our variables. If you don't define values for a given variable when you call the plugin, these default values will be used.

Now let's have our plugin return the message we want to send:

(function($) {
    $.fn.slPlugin = function(options) {
            var defaults = {
                myVar: "This is", // this will be the default value of this var
                anotherVar: "our awesome",
                coolVar: "plugin!",
            };
            var options = $.extend(defaults, options);
            this.each(function() {
                ourString = myVar + " " + anotherVar + " " + coolVar;
            });
            return ourString;
    };
}) (jQuery);

We've defined our default values for our variables, concatenated our variables and we've added a return under our variable declaration. If our jQuery plugin is included in a project and no values are provided for our variables, slPlugin will return, "This is our awesome plugin!"

It seems rather rudimentary at this point, but we have to crawl before we walk. This introductory post is laying the groundwork of coding a jQuery plugin, and we'll continue building on this example in the next installment of this series. As you've seen with the LazyLoad, equalHeights and Select2, there are much more complicated things we can do with our plugin, and we'll get there. Sneak Preview: In the next installment, we'll be creating and implementing a truncation function for our plugin ... Get excited!

-Cassandra

November 6, 2012

Tips and Tricks - Pure CSS Sticky Footers

By now, if you've seen my other blog posts, you know that I'm fascinated with how much JavaScript has evolved and how much you can do with jQuery these days. I'm an advocate of working smarter, not harder, and that maxim knows no coding language limits. In this post, I want to share a pure CSS solution that allows for "sticky" footers on a web page. In comparing several different techniques to present this functionality, I found that all of the other routes were overkill when it came to processing time and resource usage.

Our objective is simple: Make the footer of our web page stay at the bottom even if the page's content area is shorter than the user's browser window.

This, by far, is one of my *favorite* things to do. It makes the web layout so much more appealing and creates a very professional feel. I ended up kicking myself the very first time I tried to add this functionality to a project early in my career (ten years ago ... already!?) when I found out just how easy it was. I take solace in knowing that I'm not alone, though ... A quick search for "footer stick bottom" still yields quite a few results from fellow developers who are wrestling with the same frustrating experience I did. If you're in that boat, fear no more! We're going to your footers in shape in a snap.

Here's a diagram of the problem:

CSS Footer

Unfortunately, a lot of people try to handle it with setting a fixed height to the content which would push the footer down. This may work when YOU view it, but there are several different browser window heights, resolutions and variables that make this an *extremely* unreliable solution (notice the emphasis on the word "extremely" ... this basically means "don't do it").

We need a dynamic solution that is able to adapt on the fly to the height of a user's browser window regardless if the resize it, have Firebug open, use a unique resolution or just have a really, really weird browser!

Let's take a look at what the end results should look like:

CSS Footer

To make this happen, let's get our HTML structure in place first:

<div id="page">
 
      <div id="header"> </div>
 
      <div id="main"> </div>
 
      <div id="footer"> </div>
 
</div>

It's pretty simple so far ... Just a skeleton of a web page. The page div contains ALL elements and is immediately below the

tags in the page code hierarchy. The header div is going to be our top content, the main div will include all of our content, and the footer div is all of our copyrights and footer links.

Let's start by coding the CSS for the full page:

Html, body {
      Padding: 0;
      Margin: 0;
      Height: 100%;
}

Adding a 100% height allows us to set the height of the main div later. The height of a div can only be as tall as the parent element encasing it. Now let's see how the rest of our ids are styled:

#page {
      Min-height: 100%;
      position:relative;
}
 
#main {
      Padding-bottom: 75px;   /* This value is the height of your footer */
}
 
#footer {
      Position: absolute;
      Width: 100%;
      Bottom: 0;
      Height: 75px;  /* This value is the height of your footer */
}

These rules position the footer "absolutely" at the bottom of the page, and because we set #page to min-height: 100%, it ensures that #main is exactly the height of the browser's viewing space. One of the best things about this little trick is that it's compliant with all major current browsers — including Firefox, Chrome, Safari *AND* Internet Explorer (after a little tweak). For Internet Explorer to not throw a fit, we need concede that IE doesn't recognize min-height as a valid property, so we have to add Height: 100%; to #page:

#page {
      Min-height: 100%;  /* for all other browsers */
      height: 100%;  /* for IE */
      position:relative;
}

If the user does not have a modern, popular browser, it's still okay! Though their old browser won't detect the magic we've done here, it'll fail gracefully, and the footer will be positioned directly under the content, as it would have been without our little CSS trick.

I can't finish this blog without mentioning my FAVORITE perk of this trick: Should you not have a specially designed mobile version of your site, this trick even works on smart phones!

-Cassandra

October 17, 2012

Tips and Tricks - jQuery Select2 Plugin

Web developers have the unique challenge of marrying coding logic and visual presentation to create an amazing user experience. Trying to find a balance between those two is pretty difficult, and it's easy to follow one or the other down the rabbit hole. What's a web developer to do?

I've always tried to go the "work smarter, not harder" route, and when it comes to balancing functionality and aesthetics, that usually means that I look around for plugins and open source projects that meet my needs. In the process of sprucing up an form, I came across jQuery Select2, and it quickly became one of my favorite plugins for form formatting. With minimal scripting and little modification, you get some pretty phenomenal results.

We've all encountered drop-down selection menus on web forms, and they usually look like this:

Option Select

Those basic drop-downs meet a developer's need for functionality, but they aren't winning any beauty pageants. Beyond the pure aesthetic concerns, when a menu contains dozens (or hundreds) of selectable options, it becomes a little unwieldy. That's why I was so excited to find Select2.

With Select2, you can turn the old, plain, boring-looking select boxes into beautiful, graceful and more-than-functional select widgets:

Pretty Option Select

Not only is the overall presentation of the data improved, Select2 also includes an auto-complete box. A user can narrow down the results quickly ad easily, and if you've got some of those endlessly scrolling select boxes of country names or currencies, your users will absolutely notice the change (and love you for it).

What's even sexier than the form facelift is that you can add the plugin to your form in a matter of minutes.

After we download Select2 and upload it to our box, we add our the jQuery library and scripts to the <head> of our document:

<script src="jquery.js" type="text/javascript"></script> 
<script src="select2.js" type="text/javascript"></script>

For the gorgeous styling, we'll also add Select2's included style sheet:

<link href="select2.css" rel="stylesheet"/>

Before we close our <head> tag, we invoke the Select2 function:

<script>
$(document).ready(function() { $("#selectPretty").select2(); });
</script>

At this point, Select2 is locked and load, and we just have to add the #selectPretty ID to the select element we want to improve:

<select id="selectPretty">
<option value="Option1">Option 1</option>
<option value="Option2">Option 2</option>
<option value="Option3">Option 3</option>
<option value="Option4">Option 4</option>
</select>

Notice: the selectPretty ID is what we defined when we invoked the Select2 function in our <head> tag.

With miniscule coding effort, we've made huge improvements to the presentation of our usually-boring select menu. It's so easy to implement that even the most black-and-white coding-minded web developers can add some pizzazz to their next form without having to get wrapped up in styling!

-Cassandra

September 12, 2012

How Can I Use SoftLayer Message Queue?

One of the biggest challenges developers run into when coding large, scalable systems is automating batch processes and distributing workloads to optimize compute resource usage. More simply, intra-application and inter-system communications tend to become a bottleneck that affect the user experience, and there is no easy way to get around it. Well ... There *was* no easy way around it.

Meet SoftLayer Message Queue.

As the name would suggest, Message Queue allows you to create one or more "queues" or containers which contain "messages" — strings of text that you can assign attributes to. The queues pass along messages in first-in-first-out order, and in doing so, they allow for parallel processing of high-volume workflows.

That all sounds pretty complex and "out there," but you might be surprised to learn that you're probably using a form of message queuing right now. Message queuing allows for discrete threads or applications to share information with one another without needing to be directly integrated or even operating concurrently. That functionality is at the heart of many of the most common operating systems and applications on the market.

What does it mean in a cloud computing context? Well, Message Queue facilitates more efficient interaction between different pieces of your application or independent software systems. The easiest way demonstrate how that happens is by sharing a quick example:

Creating a Video-Sharing Site

Let's say we have a mobile application providing the ability to upload video content to your website: sharevideoswith.phil. The problem we have is that our webserver and CMS can only share videos in a specific format from a specific location on a CDN. Transcoding the videos on the mobile device before it uploads proves to be far too taxing, what with all of the games left to complete from the last Humble Bundle release. Having the videos transcoded on our webserver would require a lot of time/funds/patience/knowledge, and we don't want to add infrastructure to our deployment for transcoding app servers, so we're faced with a conundrum. A conundrum that's pretty easily answered with Message Queue and SoftLayer's (free) video transcoding service.

What We Need

  • Our Video Site
  • The SoftLayer API Transcoding Service
  • SoftLayer Object Storage
    • A "New Videos" Container
    • A "Transcoded Videos" Container with CDN Enabled
  • SoftLayer Message Queue
    • "New Videos" Queue
    • "Transcoding Jobs" Queue

The Process

  1. Your user uploads the video to sharevideoswith.phil. Your web app creates a page for the video and populates the content with a "processing" message.
  2. The web application saves the video file into the "New Vidoes" container on object storage.
  3. When the video is saved into that container, it creates a new message in the "New Videos" message queue with the video file name as the body.
  4. From here, we have two worker functions. These workers work independently of each other and can be run at any comfortable interval via cron or any scheduling agent:
Worker One: Looks for messages in the "New Videos" message queue. If a message is found, Worker One transfers the video file to the SoftLayer Transcoding Service, starts the transcoding process and creates a message in the "Transcoding Jobs" message queue with the Job ID of the newly created transcoding job. Worker One then deletes the originating message from the "New Videos" message queue to prevent the process from happening again the next time Worker One runs.

Worker Two: Looks for messages in the "Transcoding Jobs" queue. If a message is found, Worker Two checks if the transcoding job is complete. If not, it does nothing with the message, and that message is be placed back into the queue for the next Worker Two to pick up and check. When Worker Two finds a completed job, the newly-transcoded video is pushed to the "Transcoded Videos" container on object storage, and Worker Two updates the page our web app created for the video to display an embedded media player using the CDN location for our transcoded video on object storage.

Each step in the process is handled by an independent component. This allows us to scale or substitute each piece as necessary without needing to refactor the other portions. As long as each piece receives and sends the expected message, its colleague components will keep doing their jobs.

Video transcoding is a simple use-case that shows some of the capabilities of Message Queue. If you check out the Message Queue page on our website, you can see a few other examples — from online banking to real-time stock, score and weather services.

Message Queue leverages Cloudant as the highly scalable low latency data layer for storing and distributing messages, and SoftLayer customers get their first 100,000 messages free every month (with additional messages priced at $0.01 for every 10,000).

What are you waiting for? Go get started with Message Queue!

-Phil (@SoftLayerDevs)

September 6, 2012

Tips and Tricks - jQuery equalHeights Plugin

Last month, I posted a blog about dynamically resizing divs with jQuery, and we received a lot of positive feedback about it. My quest to avoid iframes proved to be helpful, so I thought I'd share a few more esoteric jQuery tips and tricks that may be of use to the developers and designers in the audience. As I thought back about other challenges I've faced as a coder, a great example came to mind: Making divs equal height, regardless of the amount of content inside.

I haven't seen many elegant div-based solutions for that relatively simple (and common) task, so I've noticed that many people struggle with it. Often, developers will turn back to the "Dark Side" of using tables to format the content since all columns would have the same height as the tallest column by default:

JQuery Tutorial

It was easy theme table columns and to achieve the coveted 100% height that many designers seek, but emulating that functionality with divs proves to be much more difficult. A div is like the Superman of HTML elements (faster-loading, more flexible, more dynamic, etc.), and while it has super powers, it also has its own Kryptonite-like weaknesses ... The one relevant to this blog post being that floating three div elements next to each other isn't going to give you the look of a table:

JQuery Tutorial

Each of the three divs has its own height, so if you're doing something as simple as applying background colors, you're going to wind up with an aesthetically unpleasing result: It's going to look funky.

You could get into some nifty HTML/CSS workarounds, but many frustrated theme creators and designers will tell you that if your parent elements don't have a height of a 100%, you're just wasting coding lines. Some complex solutions create the illusion of all three divs being the same height (which is arguably better than setting fixed heights), but that complexity can be difficult to scale and repeat if you need to perform similar tasks throughout your site or your application. The easiest way to get the functionality you want and the simplicity you need: The jQuery equalHeights plugin!

With a few class declarations in your existing HTML, you get the results you want, and with equalHeights, you can also specify the minimum and maximum parameters so it will create scrollable divs if the tallest element happens to be higher than your specified maximum.

How to Use jQuery equalHeights

First and foremost, include your JQuery lirbraries in the <HEAD> of your document:

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js"></script>
<script language="javascript" type="text/javascript" src="jquery.equalheights.js"></script>

The equalHeights plugin is not a hosted library, so you have to host the file on your server (here's the link again).

With the required libraries called in our document, it's time to make the magic happen in your HTML.

Create Your Divs

<div class="divHeight">This DIV is medium sized, not too big and not too small, but just right.</div>
<div class="divHeight">This DIV has a lot of useful content and media that the user can interact with, thus it's very tall.</div>
<div class="divHeight">This DIV is tiny. Period.</div>

To have them line up next to each other, you'd have them float:left; in your CSS, and now you need to apply the equalHeights function.

Call the equalHeights Plugin
In order for the script to recognize the height of the tallest element, you'd need to call $(document).ready just before the </body> tag on your page. This will ensure that the page loads before the function runs.

The call looks like this:

<script type="text/javascript">$(document).ready(function() {
$(".divHeight").equalHeights();
});</script>

If you want to specify a minimum and maximum (i.e. The div should be at least this tall and should be no taller than [adds scrollbar if the div size exceeds] the maximum), just add the parameters:

<script type="text/javascript">$(document).ready(function() {
$(".divHeight").equalHeights(300, 600);
});</script>

The initial call does not change the appearance of the divs, but the time it takes to do the resizing is so miniscule that users will never notice. After that call is made and the height is returned, each div with the class of divHeight will inherit the the same height, and your divs will be nice and pretty:

JQuery Tutorial

This trick saved me a lot of headache and frustration, so hopefully it will do the same for you too!

-Cassandra

August 8, 2012

No iFrames! Dynamically Resize Divs with jQuery.

It's no secret that iframes are one of the most hated methods of web page layouts in the web development world — they are horrible for SEO, user experience and (usually) design. I was recently charged with creating a page that needed functionality similar to what iframes would normally provide, and I thought I'd share the non-iframe way I went about completing that project.

Before I get into the nitty-gritty of the project, I should probably unpack a few of the reasons why iframes are shunned. When a search engine indexes a page with iframes, each iframe is accurately recorded as a separate page — iframes embed the content of one we page inside of another, so it makes sense. Because each of those "pages" is represented in a single layout, if a user wanted to bookmark your site, they'd probably have a frustrating experience when they try to return to your site, only to find that they are sent directly to the content in one of the frames instead of seeing the entire layout. Most often, I see when when someone has a navigation bar in one frame and the main content in the other ... The user will bookmark the content frame, and when they return to the site, they have no way to navigate the pages. So what's a developer to do?

The project I was tasked with required the ability to resize only certain sections of a page, while asynchronously shrinking another section so that the entire page would always stay the same size, with only the two sections inside changing size.

Let's look at an example with two divs, side by side on a web page:

iFrame Tutorial

One div will contain a navigation menu to jump to different pages of the website (#sidebar), and the second div will contain all the content for that page (#content). If some of the elements in #sidebar are too long to read with the default width of the div, we want to let the user freely resize the two divs without changing the width of the page.

Our task is straightforward: When #sidebar expands in width, also expand the navigation and shrink #content along with the main content inside #content. If #sidebar shrinks, the navigation, #content and main content would respond accordingly as well:

iFrame Tutorial

It's a relatively easy concept to do with iFrames ... But then you remember that iframes are no longer cool (yes, there was a time long ago when iframes were cool). I decided to turn to my favorite alternative — jQuery — and the fix was actually a lot easier than I expected, and it worked beautifully. Let's run through a step-by-step tutorial.

1. HTML

Lay out your two divs:

<div id="sidebar"> 
<div class="sidebar-menu">
<!-- all your sidebar/navigational items go here -->
</div>
</div>
<div id="content">
<!-- all your main content goes here -->
</div>

2. CSS

Style your divs:

#sidebar {
       width: 49%;
}
#content {
width: 49%;
        float: left;
}

3. jQuery

Now that we have our two divs side by side, let's apply some jQuery magic. To do that, Let's include our jQuery files in the <HEAD> of our document:

<link href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery-ui.css" rel="stylesheet" type="text/css"/>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.5/jquery.min.js"></script>
<script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/jquery-ui.min.js"></script>

Now that we have the necessary scripts, we can write our function:

<script type="text/javascript">
  $(document).ready(function() {
    $( "#sidebar" ).resizable({      
    });
    $("#sidebar ").bind("resize", function (event, ui) {
            var setWidth = $("#sidebar").width();
            $('#content).width(1224-setWidth);
            $('.menu).width(setWidth-6);
        });
  });
</script>

I know that might seem like an intimidating amount of information, so let's break it down:

   $( "#sidebar" ).resizable({      
   });

This portion simply makes the div with the ID of "sidebar" resizable (which accomplishes 33% of what we want it to do).

   $("#sidebar ").bind("resize", function (event, ui) {

By using the .bind, we are able to trigger other events when #sidebar is called.

            var setWidth = $("#sidebar").width();
            $('#content).width(1224-setWidth);

This is where the magic happens. We're grabbing the current width of #sidebar and subtracting it from the width you want your site to be. This code is what keeps your page stays the same width with only the divs changing sizes.

            $('.menu).width(setWidth-6);

This part of the code that expands the contents in the navigation along with #sidebar.

You can see a working example of iframe-like functionality with jQuery here: http://jqueryui.com/demos/resizable/

The only part you won't find there is the trick to adjust a corresponding div's size to make it grow/shrink with the first ... I had a heck of a time searching that on the web, so hopefully this quick tutorial will help other developers who might be searching for this kind of functionality!

- Cassandra

August 2, 2012

Meet Memcached: A Developer's Best Friend

Whether you're new to software development or you've been a coder since the punchcard days, at some point, you've probably come across horrendous performance problems with your website or scripts. From the most advanced users — creating scripts so complex that their databases flooded with complex JOINs — to the novice users — putting SQL calls in loops — database queries can be your worst nightmare as a developer. I hate to admit it, but I've experienced some these nightmares first-hand as a result of some less-than-optimal coding practices when writing some of my own scripts. Luckily, I've learned how to use memcached to make life a little easier.

What is Memcached?

Memcached is a free and open source distributed memory object caching system that allows the developer to store any sort of data in a temporary cache for later use, so they don't have to re-query it. By using memcached, a tremendous performance load can be decreased to almost nil. One of the most noteworthy features of the system is that it doesn't cache EVERYTHING on your site/script; it only caches data that is sure to be queried often. Originally developed in 2003 by Brad Fitzpatrick to improve the site performance of LiveJournal.com, memcached has grown tremendously in popularity, with some of the worlds biggest sites — Wikipedia, Flickr, Twitter, YouTube and Craigslist — taking advantage of the functionality.

How Do I Use Memcache?

After installing the memcached library on your server (available at http://memcached.org/), it's relatively simple to get started:

<?php
  // Set up connection to Memcached
  $memcache = new Memcached();
  $memcache->connect('host', 11211) or die("Could not connect");
 
  // Connect to database here
 
  // Check the cache for your query
  $key = md5("SELECT * FROM memcached_test WHERE id=1");
  $results = $memcache->get($key);
 
  // if the data exists in the cache, get it!
  if ($results) {
      echo $results['id'];
      echo 'Got it from the cache!';
  } else {
    // data didn't exist in the cache
    $query = "SELECT * FROM memcached_test WHERE id=1");
  $results = mysql_query($query);
  $row = mysql_fetch_array($results);
  print_r($row);
 
  // though we didn't find the data this time, cache it for next time!
  $memcache->set($key, $row, TRUE, 30); 
  // Stores the result of the query for 30 seconds
  echo 'In the cache now!';
 
  }
 
?>

Querying the cache is very similar to querying any table in your database, and if that data isn't cached, you'll run a database query to get the information you're looking for, and you can add that information to the cache for the next query. If another query for the data doesn't come within 30 seconds (or whatever window you specify), memcached will clear it from the cache, and the data will be pulled from the database.

So come on developers! Support memcached and faster load times! What other tools and tricks do you use to make your applications run more efficiently?

-Cassandra

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