Ask About PHP » PHP Tutorials http://www.askaboutphp.com Wed, 09 Jun 2010 07:17:33 +0000 http://wordpress.org/?v=2.9.2 en hourly 1 PHP and jQuery: Submit a form without refreshing the page http://www.askaboutphp.com/213/php-and-jquery-submit-a-form-without-refreshing-the-page.html http://www.askaboutphp.com/213/php-and-jquery-submit-a-form-without-refreshing-the-page.html#comments Wed, 09 Jun 2010 06:55:39 +0000 Eldee http://www.askaboutphp.com/?p=213 Lately, I’ve been chancing on quite a number of posts at various places asking about how to perform a web action without the webpage reloading/refreshing? For example, dynamically updating a list on a page without a reload or submitting a form to PHP without leaving the webpage the form sits on.

I guess this is as good a time to start branching into some posts on PHP and Javascript, or more specifically, jQuery.


To be honest, I’ve never been partial to using Javascript (ie client-side programming) in my web applications, prefering instead to rely on server-side processing for all my programming needs. I guess this has to do with my frustrations of Javascript incompatibility between different browsers back in the day. However, with a javascript library (or framework) like jQuery, I’m starting to use more client-side actions to complement all the server-side PHP stuff. Here’s 6 reasons why you should use JavaScript Libraries & Frameworks.

You can download my example source code if it helps you understand how the whole thing works.

Download: download icon

And here’s a demo of what we’re trying to do.

The traditional way of doing form submissions
Back in the “old” days, in order to perform a form submission, you need to do something like this.

When you click the “Submit” button on form.php, the web server knows to send the name and email values using the POST method to the php script called process.php. The web server will load process.php page and the PHP script will start to read in the form values posted from form.php, maybe perform some validation to check that the information received is correct, then perhaps do something with the form values such as storing it in a database or sending it via email and output a “thank you” message.

What if something goes wrong, for example, the person submitting the form wrote in a badly-formed email address, the validation at process.php will throw a nicely worded error message and stop running the rest of the script. The person then would need to go back to the form to correct the email address and he would submit the form again.

This might have been an OK way of doing things 10 years ago, but in this era of Facebook and Twitter, that’s a pretty antiquated and tedious method.

The jQuery way of doing form submissions
Here’s the jQuery way, which is made possible by something called AJAX (which stands for Asynchronous JavaScript and XML). AJAX is bascially the technology that makes it possible to exchange data with a server, and update parts of a web page – without reloading the whole page. jQuery includes the necessary functions to implement AJAX into your web application.

The diagram looks quite similar to the “old” way of doing things, except that process.php is now represented by a ‘circle’. This is because process.php is now hidden for lack of a better word. In the traditional method, when you click the submit, your browser will load process.php and it will jump from form.php to process.php.

With the jQuery/AJAX way, process.php becomes a background process which the web server will call on, and when you click on the “Submit” button, form.php pushes the data to process.php, but your browser will remain showing form.php. Once the process.php has done what it needs to, it will return to form.php some output to be displayed.

Here’s the source code for form.php

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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 
<html>
<head>
	<title>JQuery Form Example</title> 
	<script type="text/javascript" src="http://code.jquery.com/jquery-1.4.2.min.js"></script>
	<script type="text/javascript" src="http://ajax.microsoft.com/ajax/jquery.validate/1.7/jquery.validate.min.js"></script>
	<script type="text/javascript">
	$(document).ready(function(){
		$("#myform").validate({
			debug: false,
			rules: {
				name: "required",
				email: {
					required: true,
					email: true
				}
			},
			messages: {
				name: "Please let us know who you are.",
				email: "A valid email will help us get in touch with you.",
			},
			submitHandler: function(form) {
				// do other stuff for a valid form
				$.post('process.php', $("#myform").serialize(), function(data) {
					$('#results').html(data);
				});
			}
		});
	});
	</script>
	<style>
	label.error { width: 250px; display: inline; color: red;}
	</style>
</head>
<body>
<form name="myform" id="myform" action="" method="POST">  
<!-- The Name form field -->
    <label for="name" id="name_label">Name</label>  
    <input type="text" name="name" id="name" size="30" value=""/>  
	<br>
<!-- The Email form field -->
    <label for="email" id="email_label">Email</label>  
    <input type="text" name="email" id="email" size="30" value=""/> 
	<br>
<!-- The Submit button -->
	<input type="submit" name="submit" value="Submit"> 
</form>
<!-- We will output the results from process.php here -->
<div id="results"><div>
</body>
</html>

and the source code for process.php

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<?php
	print "Form submitted successfully: <br>Your name is <b>".$_POST['name']."</b> and your email is <b>".$_POST['email']."</b><br>";
?>

Here’s what’s happening
I included jQuery’s form validation because it provides a more real world example. Usually, most sites will perform processes like form validation at the client-side before the form is submitted. It’s just more intuitive and a much better user experience. In fact if you can offload as much workload as you can to the browser, it will greatly reduce the hit on your server.

So here’s a quick high-level walk through what’s happening on the jQuery part.

I call the validate method (make sure you have included the jquery validate plugin – see form.php Line 6) on my form #myform, and proceed to define what to validate. In this case, we’re checking that the name field is ‘required’, and we’re checking the email field is not only ‘required’, but must be an email format. I also define the custom error message I want to display if the validation fails.

Lastly, the submitHandler is what gets processed if the validation is successful. In this case, I’m doing an ajax post method, sending my form data to process.php, and get back any results as HTML data which will be displayed into #results.

Over at process.php, I’m simply printing out the data received to show you the information was sent and returned.

That’s basically it. If you want to know more, do check out the jQuery website to get more details on how to do AJAX and Validation.

Feel free to comment your thoughts or suggestions.

]]> http://www.askaboutphp.com/213/php-and-jquery-submit-a-form-without-refreshing-the-page.html/feed 8 PHP Basics: Sorting Arrays http://www.askaboutphp.com/191/php-basics-sorting-arrays.html http://www.askaboutphp.com/191/php-basics-sorting-arrays.html#comments Sun, 14 Mar 2010 14:56:44 +0000 Eldee http://www.askaboutphp.com/?p=191 Arrays are wonderful things. I can’t imagine using a programming language that does not have support for arrays. For newbies, arrays might be something that’s difficult to understand at first, but once you get used to it, it’s almost impossible to live without. Guaranteed!

If you are not familiar with what arrays are, visit the PHP manual. Alternatively, there’s a introduction to arrays at developer.com.

In this post, I’m not going to cover the same ground but instead touch on sorting of arrays.


PHP provides a number of function which you can use to sort arrays.

Sorting by its values
Sorting an array by its values is probably the most common way of performing a sort, and the most straighfoward. PHP provides the sort() function for doing this.

Example 1:

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$nums = array(14, 3.2, -5, 1.3, 0);
sort($nums);
print_r($nums);
 
/* Outputs:
Array 
(
    [0] => -5
    [1] => 0
    [2] => 1.3
    [3] => 3.2
    [4] => 14
)
*/

Example 2:

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$movies = array('A Fish Called Wanda', 'The Godfather', 'Finding Nemo', 'Star Wars', 'Grease');
sort($movies);
print_r($movies);
 
/* Outputs:
Array
(
    [0] => A Fish Called Wanda
    [1] => Finding Nemo
    [2] => Grease
    [3] => Star Wars
    [4] => The Godfather
)
*/

Example 3:

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$movies = array('Comedy'=>'A Fish Called Wanda', 'Drama'=>'The Godfather', 
		'Animation'=>'Finding Nemo', 'Sci-Fi'=>'Star Wars', 'Musical'=>'Grease');
sort($movies);
print_r($movies);
 
/* Outputs:
Array
(
    [0] => A Fish Called Wanda
    [1] => Finding Nemo
    [2] => Grease
    [3] => Star Wars
    [4] => The Godfather
)
*/

So, it all looks pretty straightfoward right? The arrays are sorted in ascending order. But what has happened to the keys for the last example for $movies? sort() will reset all the indexes, so you have lost your original keys. To get around this you can use the asort() function instead, which works the same as sort except that it preserves the original key/value mapping.

Example 4:

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$movies = array('Comedy'=>'A Fish Called Wanda', 'Drama'=>'The Godfather', 
		'Animation'=>'Finding Nemo', 'Sci-Fi'=>'Star Wars', 'Musical'=>'Grease');
asort($movies);
print_r($movies);
 
/* Outputs:
Array
(
    [Comedy] => A Fish Called Wanda
    [Animation] => Finding Nemo
    [Musical] => Grease
    [Sci-Fi] => Star Wars
    [Drama] => The Godfather
)
*/

So how about sorting in descending order? Well, the functions to in this case are rsort() and arsort()

Example 5:

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$movies = array('Comedy'=>'A Fish Called Wanda', 'Drama'=>'The Godfather', 
		'Animation'=>'Finding Nemo', 'Sci-Fi'=>'Star Wars', 'Musical'=>'Grease');
arsort($movies);
print_r($movies);
 
/* Outputs:
Array
(
    [Drama] => The Godfather
    [Sci-Fi] => Star Wars
    [Musical] => Grease
    [Animation] => Finding Nemo
    [Comedy] => A Fish Called Wanda
)
*/

Sorting by its keys
For associative arrays, it is just as important to be able to sort the array by its keys. The ksort() and krsort() functions does exactly that.

Example 6:

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$movies = array('Comedy'=>'A Fish Called Wanda', 'Drama'=>'The Godfather', 
		'Animation'=>'Finding Nemo', 'Sci-Fi'=>'Star Wars', 'Musical'=>'Grease');
ksort($movies);
print_r($movies);
 
/* Outputs:
Array
(
    [Animation] => Finding Nemo
    [Comedy] => A Fish Called Wanda
    [Drama] => The Godfather
    [Musical] => Grease
    [Sci-Fi] => Star Wars
)
*/

Example 7:

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$movies = array('Comedy'=>'A Fish Called Wanda', 'Drama'=>'The Godfather', 
		'Animation'=>'Finding Nemo', 'Sci-Fi'=>'Star Wars', 'Musical'=>'Grease');
krsort($movies);
print_r($movies);
 
/* Outputs:
Array
(
    [Sci-Fi] => Star Wars
    [Musical] => Grease
    [Drama] => The Godfather
    [Comedy] => A Fish Called Wanda
    [Animation] => Finding Nemo
)
*/

Sorting using custom comparison functions
It is also possible to create your own sort criteria and apply it to an array. Three functions are provided for you to do just that – usort(), uasort() and uksort(). The following example, I’m going to sort my fruits array by arranging the quantity with odd numbers first followed by even numbers, in descending order. I’m going to use uasort() because more often than not, you want to preserve your keys, which usort() will not do.

Example 8:

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function oddfirst($i, $j)
{
	$value = 0; # default return value (do nothing)
	if($i % 2) $value--;
	if($j % 2) $value++;	
	if($value == 0) $value = $j < $i;
	return $value;
}
$fruits = array( 'apples' => 37, 'mangoes' => 72, 'oranges' => 92, 'bananas' => 15, 'grapes' => 52, 'kiwis' => 43);
uasort($fruits, 'oddfirst');
print_r($fruits);
 
/* Outputs:
Array
(
    [bananas] => 15
    [apples] => 37
    [kiwis] => 43
    [grapes] => 52
    [mangoes] => 72
    [oranges] => 92
)
*/

So how does this actually works? The uasort() function takes in 2 arguments – the first argument defines the array to be sorted, the second argument states the name of the function to call. In my example, that would be ‘oddfirst’.

This comparison function needs to take in 2 parameters (in my case $i and $j) and return one of three possible values – a negative number, a positive number and zero. In most cases, returning -1, 0, 1, would be sufficient. This number tells uasort() how $i compares with $j as follows.

  • If a negative number (-1) is returned, then $i is less than $j
  • If a positive number (1) is returned, then $i is greater than $j
  • If zero (0) is returned, then $i is equal to $j

For the oddfirst() function, my algorithm goes like this:

  • If $i is odd, $j is even then return a negative number ($value=-1) because I want $i to be sorted first
  • If $i is even, $j is odd then return a positive number ($value=1) because I want $j to be sorted first
  • if both $i and $j are even or both are odd, then $value is zero, and I need to make a further comparison to sort the numbers in ascending order. Hence, $j < $i tests which number is greater and return $value=1 when $i is greater than $j.

Sorting multi-dimensional arrays
So far, we’ve only dealt with single dimensional arrays. What about multi-dimensional arrays? PHP provides only one function to this multiple array sorting – array_multisort(). The function takes in a number of arrays as arguments, each followed optionally by one or more sort flags. Let’s take a look at the following example of movies with genre and global box office revenue, and attempt to sort the movies by revenue.

Example 9:

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$moviedata = array(
	array('movie'=>'Home Alone', 'genre'=>'Comedy', 'revenue'=>285),
	array('movie'=>'The Godfather', 'genre'=>'Drama', 'revenue'=>268),
	array('movie'=>'Finding Nemo', 'genre'=>'Animation', 'revenue'=>866),
	array('movie'=>'Star Wars', 'genre'=>'Sci-Fi', 'revenue'=>797),
	array('movie'=>'Grease', 'genre'=>'Musical', 'revenue'=>387),
	array('movie'=>'Ghostbusters', 'genre'=>'Comedy', 'revenue'=>238),
	array('movie'=>'Titanic', 'genre'=>'Drama', 'revenue'=>600)
);
 
$cols = array();
foreach($moviedata as $row) {
	foreach($row as $key => $value) {
		if( !isset($cols[$key]) )
		$cols[$key] = array();
		$cols[$key][] = $value;
	}
}
$data = $cols;
array_multisort($data['revenue'], $data['movie'], $data['genre']);
print_r($data);
 
/* Outputs:
Array
(
    [movie] => Array
        (
            [0] => Ghostbusters
            [1] => The Godfather
            [2] => Home Alone
            [3] => Grease
            [4] => Titanic
            [5] => Star Wars
            [6] => Finding Nemo
        )
 
    [genre] => Array
        (
            [0] => Comedy
            [1] => Drama
            [2] => Comedy
            [3] => Musical
            [4] => Drama
            [5] => Sci-Fi
            [6] => Animation
        )
 
    [revenue] => Array
        (
            [0] => 238
            [1] => 268
            [2] => 285
            [3] => 387
            [4] => 600
            [5] => 797
            [6] => 866
        )
 
)
*/

To be effective, array_multisort() requires that multidimensional arrays be arranged in a columnar fashion, which is done by the foreach block at line 12 in the example. After that, just call array_multisort() to sort the movie data, I define which columns I want to sort first followed by the next and so on.

You may notice that revenue is sorted in ascending order. If you want sort by descending order, just call array_multisort() with sort flags like so:

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array_multisort($data['revenue'], SORT_DESC, $data['movie'], $data['genre']);

Well, that’s it. I hope this post helps you get started with how to sort arrays. Remember to check out PHP’s page on sorting arrays. Feel free to comment and contribute your tips on sorting arrays.

QGYMRRM2NK7K

]]> http://www.askaboutphp.com/191/php-basics-sorting-arrays.html/feed 5 Codeigniter: Handling errors http://www.askaboutphp.com/172/codeigniter-handling-errors.html http://www.askaboutphp.com/172/codeigniter-handling-errors.html#comments Tue, 09 Feb 2010 04:19:53 +0000 Eldee http://www.askaboutphp.com/?p=172 As coders, I’m sure we all know the value of good error handling. So I thought a quick post about how Codeigniter deals with those pesky errors would be a good post.

The way I see it, there are 2 types of errors we have to work with. The ones which are displayed out in nice friendly text to your users, and the type which are hidden and shown only to you as the coder to figure out where something has gone wrong. CI provides the means to do both, thankfully.

System/Application Errors
Let’s start with having a look at how CI deals with PHP errors. By default, on a clean install, CI will display ALL php errors of all severity. So if you make a mistake in your PHP coding, you’ll see plenty of these…

CI uses PHP’s error_reporting() function to define the level of error reporting, and you can find this in the main index.php file in the root of your CI install. It’s the first function you see.

Instead of E_ALL, you can change it to any of the predefined error constant that PHP understands to suit your needs. Obviously, once your site goes live, you should change from E_ALL to E_ERROR to show only messages for fatal run time problems. This will hide all php errors except those that will halt your script execution.

So, if the error messages are hidden, how else can we tell if something is not working right? Well, CI can writes out any errors it encounters into its log file. You can configure your CI log file by going to the config.php file in your applications/config directory.

By default, the logs are turned off, so you should turn it on by setting the $config['log_threshold'] variable. Once enabled, the logs will appear in the system/logs folder of your CI install. You can set the location of your log file if you wish to keep your logs elsewhere by defining a path for the $config['log_path'] variable.

You may notice that the $config['log_threshold'] allows a few settings.

  • 1 – ERROR
    This will log down all E_ALL level php generated errors, HTML status code errors (like 404s) and any user-defined errors.
  • 2 – DEBUG
    In addition to ERROR messages, this will show messages which helps you to debug your CI application.
  • 3 – INFO
    This level will show all ERROR & DEBUG messages as well as any user-defined informational messages. CI doesn’t natively generate any INFO messages but you can do so in your application.
  • 4 – All Messages
    This will show all log messages. I could not see any difference between this level and level 3 setting. If you do know a difference, post it into the comments.

In addition CI’s natively generated messages, you can define your own messages by calling the log_message() function. You can call this anywhere in your code, and you can set what level of messaging (error, debug, or info) you want logged. (See CI’s guide on how to use the log_message() function.)

Displaying Errors
Next, let’s look at what options are available if you want to display error messages to your user. CI provides 2 functions for this purpose – show_error() and show_404(). (See CI’s guide on how to use the show_error() and show_404() functions.)

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if (SHOW_ERROR==true) {
	show_error('This is where your error message will appear surrounded by this default template.');
}

When you call show_error(), you will generate page that looks like this. The layout can changed by modifying this file application/errors/error_general.php)

show_404() works in a similar way, except it will display the application/errors/error_404.php layout and will throw a HTTP status code of 404.

Both of these functions are breakpoints and will stop the execution of your script, so any functions that follows these will not be processed.

That’s it. Feel free to comment.

]]> http://www.askaboutphp.com/172/codeigniter-handling-errors.html/feed 5 Codeigniter: Intergrating OpenFlashCharts http://www.askaboutphp.com/113/codeigniter-intergrating-openflashcharts.html http://www.askaboutphp.com/113/codeigniter-intergrating-openflashcharts.html#comments Fri, 06 Nov 2009 05:12:34 +0000 Eldee http://www.askaboutphp.com/?p=113 Yes I know, it has been some time since I last posted anything on the site. Things have just been crazy at work, trying to get up to speed on using Pentaho for a major project. In fact, I might start posting some Pentaho related topics in the future. There’s definitely a need for more help and guides on using Pentaho for beginners.

Anyway, one of the things on the project was to pull data from Pentaho and display it inside OpenFlashCharts on a CI platform. If you don’t know what OpenFlashCharts is, go visit the website. It’s a pretty awesome kit.

There’s been quite a bit of chatter on the net about integrating CI with OpenFlashCharts, but ever since version 2 came out there have been more questions about how to do it.

In the new version of OpenFlashCharts, it uses the JSON format to describe what type of chart to render in the flash object. OFC comes with a bunch of libraries (in various programming languages) which will generate the JSON format for the flash object. For PHP, the kit comes with the generic PHP version and a PHP5 version.

Somebody by the name of Thomas did managed to stitch OpenFlashCharts 2 with CI and he posted it up on the CI wiki. So kudos to Thomas (whoever you are) for making my life easier. If you like you can download his library and give it a spin.

For Thomas, he used the PHP5 libraries of OpenFlashCharts, which unfortunately is a bit incomplete. I wasn’t able to generate more advance graphs such as Hollow Areas, Dotted lines etc. The flash object gave me an ‘infinity’ error. After some investigation, I found that the OFC PHP5 libraries are not generating the same JSON as the generic PHP version. Taking a page out of his book, I modified his library to work with the generic PHP version instead.

One advantage of doing this is that suddenly, you can apply all the tutorial codes on the OFC website because they were written for the generic PHP library and not the PHP5 version.

Download: download icon

So, download the zip file and extract the files to the relevant folders of your CI install. The assets folder should go to wherever you put your stuff like images and javascript files. Just make sure you change the view to reflect the correct path. I put my assets in the root of my webserver folder, and I access my CI through http://dev.ci/.

When I run the http://dev.ci/charts, I would get this graph with 3 data lines.

OFC Test Chart

So how does it all work?
The OFC library, php-ofc-library and the OpenFlashChartLib.php can now be accessed by calling the load library call.

$this->load->library('OpenFlashChartLib', NULL, 'OFCL');

If you look inside the view folder for chart_view.php, you can see where the OFC flash object is getting its JSON feed from, http://dev.ci/charts/get_data.

Inside get_data() function of the charts controller, it’s basically the same code as the tutorial at http://teethgrinder.co.uk/open-flash-chart-2/data-lines-2.php

The difference here is that instead of calling the

$chart = new open_flash_chart();

I’m now doing

$chart = $this->OFCL->create('open_flash_chart');

to perform the same instantiation but through the OpenFlashChartLib (OFCL) library.

So, just change all the object instantiation call accordingly, and the graph should show up nice and neat.

Here’s Dilbert to close out…

Dilbert Pie Chart

]]> http://www.askaboutphp.com/113/codeigniter-intergrating-openflashcharts.html/feed 3 Codeigniter: Setting up multiple sites on one install http://www.askaboutphp.com/88/codeigniter-setting-up-multiple-sites-on-one-install.html http://www.askaboutphp.com/88/codeigniter-setting-up-multiple-sites-on-one-install.html#comments Wed, 19 Aug 2009 08:19:40 +0000 Eldee http://www.askaboutphp.com/?p=88 It’s been awhile since I last posted about Codeigniter. In this post, I’m going to walkthrough how I setup a CI install that can support multiple sites. This is by no means the only way to do it, but it’s what works for me.

CI’s default folder structure is really geared towards one site domain, and having both the application folder and the system folder visible to the browser is not exactly a secure approach.

By configuring your install to support multiple sites, not only do you make the updating of the CI core easier, but also make the CI install more secure as a whole. So without delay, let’s get started…

In this walkthrough, I’m setting up my multiple CI sites on my local XAMPP install, which is on my M:\ drive. Your Apache setup might be different, so do take note of my settings and adjust according to your own web server environment.

I’m planning to setup two sites just for illustration – http://dev.ci/ and http://live.ci/.

Codeigniter default folder structure
When you first unzip the downloaded CI file, you would get something like this:

You would have set your Apache’s configuration to point to your CI folder (which is M:\xampplite\CodeIgniter_1.7.1 for me) as the document root. Once you hit the site in your browser, you would get the standard welcome page.

If you have setup the default CI before, you may know that within the system folder are a bunch of core folders which you don’t normally need to touch and the application folder which will house all your codes for your site. You may also have noticed the index.php file in the root of the CI directory, which you didn’t really need to touch before but will become crucial in setting up multiple sites.

Adjusting the application folders
First thing I do is to move the application folder out of the system folder to the same level as the system folder.

Since I’m setting up to run two distinct sites sharing the same CI core, I will make another copy of the application folder and rename both folders to reflect the different sites.

Create the web root folders
Next, we would need two folders which will be the website’s root folders. This is how I setup mine.

Make copies of the index.php file located in the CI’s root folder (ie M:\xampplite\CodeIgniter_1.7.1) into each of the htdocs folder. In this case, I would have one index.php in each of my htdocs_ci_dev and htdocs_ci_live folders.

Open index.php file for each site and edit the following lines.

At Line 26:
	$system_folder = "system";
Change to 
	$system_folder = "../system";
 
At Line 43:
	$application_folder = "application";
Change to 
	$application_folder = "../app_ci_dev"; (for the htdocs_ci_dev)
or 
	$application_folder = "../app_ci_live"; (for the htdocs_ci_live)

Configure Apache virtual hosts
Once that’s done, the last thing to do is to setup the Apache virtual host configuration of my XAMPP install.

My Apache virtual host configuration looks like this:

Don’t forget to edit your local hosts file so that your system recognizes the dev.ci and live.ci domains.

Once you fire up your Apache web server, you should be able to load either site accordingly (*fingers crossed*)

Renaming the system folder
If you want to go further you can rename the system folder to reflect the different CI versions. This way, when a new version of the CI core is released, you can configure your sites easily by just changing $system_folder parameter in the index.php file (Line 26) for each site.

Conclusion
I think you will agree that with this setup, you can easily expand the CI install to more sites. There is also no doubt that this is more secure than the default CI setup, as the only folders which are exposed to the browser are the htdocs folders – all the application and system folders are no longer accessible through the web server.

Of course, this is not the only way you can configure CI for multiple sites/applications, check out some of these alternatives:
- CodeIgniter Wiki – Multiple Applications
- Michael Wales – CodeIgniter Advent: Day 1
- Multiple codeigniter sites, using symlinks

Please feel free to give your thoughts and feedback. Thanks!

]]> http://www.askaboutphp.com/88/codeigniter-setting-up-multiple-sites-on-one-install.html/feed 12 PHP Basics: Accessing Remote URLs using cURL http://www.askaboutphp.com/65/php-basics-accessing-remote-urls-using-curl.html http://www.askaboutphp.com/65/php-basics-accessing-remote-urls-using-curl.html#comments Fri, 19 Jun 2009 08:40:52 +0000 Eldee http://www.askaboutphp.com/?p=65 In this post, I’m going back to basics to talk about accessing remote URLs with cURL.

In PHP, there are actually four ways to access a remote URL – fopen() fsockopen(), cURL extensions and HTTP_Request class from the PEAR library. Now, choosing one way over another really depends on your needs for simplicity, control, and portability.

Generally, I prefer using cURL simply because it’s easy to understand and it’s really powerful. cURL supports a number of different protocols and gives your access to the response headers. It even has the capability to do parallel access if you call the ‘curl_multi’ group of functions (I’ll save this for another post one day).

To use cURL, you need to make sure that your PHP install has the library enabled. Read this posting on how to enable cURL for your PHP.

Fetching a URL with the GET Method
The simplest way to start using cURL is to fetch a URL with the GET method.

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<?php
$c = curl_init('http://www.askaboutphp.com/robots.txt');
curl_setopt($c, CURLOPT_RETURNTRANSFER, 1);
$page = curl_exec($c);
curl_close($c);
?>

So what is going on? The simple example above really maps out 4 stages of using cURL. You start by calling the curl_init() to get a handle on the URL you wan to access. Then, you set some options using curl_setopt().After that, you execute what you want to do with curl_exec(). Lastly, you close the handle using curl_close().

The control of the curl functions is all to do with what options you set using curl_setopt(). PHP lists out all the options available at curl_setopt() page. Frankly, this is probably the hardest part about using the cURL library – understanding what all these options do. It was pretty daunting when I first started using.

Following on, here are some of the more commonly used (at least by me anyway) options for cURL.

Fetching a protected URL with the GET Method
To do this, you need to set the CURLOPT_USERPWD option, like so:

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<?php
$c = curl_init('http://www.askaboutphp.com/protected-page.html');
curl_setopt($c, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($c, CURLOPT_USERPWD, 'askme:anything'); 
$page = curl_exec($c);
curl_close($c);
?>

Submitting data to a URL with the POST Method
In this case, you need to set the CURLOPT_POST and CURLOPT_POSTFIELDS option.

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<?php
$c = curl_init('http://www.askaboutphp.com/submit.php');
curl_setopt($c, CURLOPT_POST, 1);
curl_setopt($c, CURLOPT_POSTFIELDS, 'father=dad&mother=mum');
curl_setopt($c, CURLOPT_RETURNTRANSFER, 1);
$result = curl_exec($c);
curl_close($c);
?>

The parameters you want to pass should be formatted like a querystring. If you are expecting some response after posting, then you need to enable the CURLOPT_RETURNTRANSFER option.

Fetching a URL with Custom Headers
You can also retrieve URLs that requires specific headers to be sent with the request. You can do so with CURLOPT_HTTPHEADER option.

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<?php
$c = curl_init('http://www.askaboutphp.com/custom-header.php');
curl_setopt($c, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($c, CURLOPT_HTTPHEADER, array('My-Custom-Header: PHPISCOOL'));
$page = curl_exec($c);
curl_close($c);
?>

cURL has special options for setting the Referer and User-Agent request headers —
CURLOPT_REFERER and CURLOPT_USERAGENT:

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<?php
$c = curl_init('http://www.askaboutphp.com/fetch.php');
curl_setopt($c, CURLOPT_VERBOSE, 1);
curl_setopt($c, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($c, CURLOPT_REFERER, 'http://www.askaboutphp.com/form.php');
curl_setopt($c, CURLOPT_USERAGENT, 'CURL via PHP');
$page = curl_exec($c);
curl_close($c);
?>

I’m going to stop here. If you’re new to cURL, hopefully this has been a good broad tutorial to get you started. In the Web 2.0 age, online services constantly pop-up to allow you to programmatically connect to them, cURL is the best tool you can have to help you access those services.

]]> http://www.askaboutphp.com/65/php-basics-accessing-remote-urls-using-curl.html/feed 6 Google Analytics API class for PHP http://www.askaboutphp.com/63/google-analytics-api-class-for-php.html http://www.askaboutphp.com/63/google-analytics-api-class-for-php.html#comments Fri, 29 May 2009 09:13:56 +0000 Eldee http://www.askaboutphp.com/?p=63 GA marblesAbout a month back, Google opened the Google Analytics API service to all Analytics users. the API allows developers to integrate the GA reports into their own applications or websites, or even access the reports from a phone!

I’ve been thinking about how I can make use of this API to enhance the sites I’m working on. But before kicking off ideas, I had to find out how to access and use the API. I finally came up with a PHP class that will do all the grunt work of calling the API, you just need to supply your report’s parameter and the PHP class will return you an array of Analytics data.


Getting Started
Ok, first thing’s first, you need to have Google Analytics (obviously) and login credentials to GA. Then you should download my PHP class available at the end of this post.

To access the API is basically a 2 step process. First is to authenticate against Google with your GA account credentials to get an authentication code. After that you can use the authentication code to access your list of website profiles in GA and extract out the data you want.

Google Analytics PHP Class
Here’s how you access a report showing pageviews and visits, by date and country, filtered by ‘Australia’, sorted by pageviews in descending order.

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<?php
// include the Google Analytics PHP class
include "googleanalytics.class.php";
try {
	// create an instance of the GoogleAnalytics class using your own Google {email} and {password}
	$ga = new GoogleAnalytics('{email}','{password}');
 
	// set the Google Analytics profile you want to access - format is 'ga:123456';
	$ga->setProfile('{GA Profile ID}');
 
	// set the date range we want for the report - format is YYYY-MM-DD
	$ga->setDateRange('2009-04-01','2009-04-07');
 
	// get the report for date and country filtered by Australia, showing pageviews and visits
	$report = $ga->getReport(
		array('dimensions'=>urlencode('ga:date,ga:country'),
			'metrics'=>urlencode('ga:pageviews,ga:visits'),
			'filters'=>urlencode('ga:country=@Australia'),
			'sort'=>'-ga:pageviews'
			)
		);
 
	//print out the $report array
	print_r($report);
 
} catch (Exception $e) { 
	print 'Error: ' . $e->getMessage(); 
}
?>

Hopefully, the code is quite self-explanatory. setProfile() requires your website profile id number. To get the profile id number, you go to your GA dashboard, click on ‘View Report’ for your website, and look at the URL. There should be an ‘id=xxxxxx’ in the URL. That is your id number. You have to specify it as ‘ga:xxxxxxx’ in setProfile().

Profile ID Alternatively, included within the class is a function called getWebsiteProfiles(), if you call this function, after authenticating, you will get an array of all the website profiles available under your account. You can find the id number from there also.

The only major function you need to really pay attention to is the getReport() function. This is where you craft the report parameters that you want results from.

If you’re familiar with GA, you will know that GA basically works with 2 field types – dimensions and metrics. If you’re not sure of what these these things are, I recommend reading the Google documentation on them. Simplistically, you could think of metrics as the columns of your GA reports, and dimensions as the rows.

Google has also listed out the available dimensions and metrics you can use in the API.

With the getReport() function, you are basically doing the same thing as the Custom Reports feature of GA. You decide which dimension and metrics you want and the API will return you the data.

What you will get from getReport() is an array that looks something like this:

Array
(
    [20090401~~Australia] => Array
        (
            [ga:pageviews] => 6
            [ga:visits] => 3
        )
 
    [20090402~~Australia] => Array
        (
            [ga:pageviews] => 4
            [ga:visits] => 3
        )
 
    [20090407~~Australia] => Array
        (
            [ga:pageviews] => 4
            [ga:visits] => 4
        )
 
    [20090403~~Australia] => Array
        (
            [ga:pageviews] => 3
            [ga:visits] => 3
        )
 
    [20090405~~Australia] => Array
        (
            [ga:pageviews] => 3
            [ga:visits] => 3
        )
 
    [20090406~~Australia] => Array
        (
            [ga:pageviews] => 3
            [ga:visits] => 3
        )
 
    [20090404~~Australia] => Array
        (
            [ga:pageviews] => 2
            [ga:visits] => 2
        )
)

To keep the array simple, I’ve basically pushed the dimensions as the 1st array dimension keys, separated by ‘~~’ pattern so that you can parse the keys if you require. The metrics are listed in the sub-array, with the metric as the key and value of the metric.

Do know that not every dimension has a corresponding metric. Google has put up a compatibility chart for you to verify which combination of dimensions and metrics are valid.

This class requires the use of the cURL function in PHP. The functions are normally enabled, but if its not, here a guide on how you enable cURL in PHP.

That’s basically it. Feel free to download the class and play with it. Do bear in mind that this is not a ‘production’ ready class. There’s hardly any validation and error checking and die() is not the best fail-safe method for the class to fail gracefully. When I have more time, I will look at improving the class.. The class has been updated with some exception catching, so hopefully this will give more meaningful error messages for those of you facing problems.

Download: download icon

Here are some more examples of reports you can create:

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// what browsers visitors to your using?
$report = $ga->getReport(
	array('dimensions'=>urlencode('ga:browser'),
		'metrics'=>urlencode('ga:visits'),
		'sort'=>'-ga:visits'
		)
	);
 
// which are your top landing pages and how long they spent on the page?
$report = $ga->getReport(
	array('dimensions'=>urlencode('ga:landingPagePath,ga:pageTitle'),
		'metrics'=>urlencode('ga:entrances,ga:timeOnPage'),
		'sort'=>'-ga:entrances'
		)
	);
 
// which are your top internal search keywords by pageviews?
$report = $ga->getReport(
	array('dimensions'=>urlencode('ga:searchKeyword'),
		'metrics'=>urlencode('ga:pageview'),
		'sort'=>'-ga:pageviews'
		)
	);

UPDATE 2009-07-15: Google has posted new updates to the Google Analytics API. The changes includes new limit on the amount of data returned, and relaxed restrictions on combinations of dimensions and metrics.

]]> http://www.askaboutphp.com/63/google-analytics-api-class-for-php.html/feed 72 PHP’s alternative syntax and why it’s useful http://www.askaboutphp.com/59/phps-alternative-syntax-and-why-its-useful.html http://www.askaboutphp.com/59/phps-alternative-syntax-and-why-its-useful.html#comments Thu, 16 Apr 2009 06:34:17 +0000 Eldee http://www.askaboutphp.com/?p=59 PHP offers an alternative way to write their control structures for as long as I’ve remembered. It basically does away with the curly brackets and replaces the opening curly with a colon (:) and the closing with ‘end’-whatever. I have to be honest and say I’ve never really found a need to use the alternative syntax, simply because I’m so used to using the curly braces after so many years of using PHP. Plus, it’s less typing!

But having spend time working on CodeIgniter projects, I have found myself adopting this alternative syntax when it comes to buidling the CI’s views templates. I appreciate that there is place in the PHP universe for this alternative coding style.


The best time to use this alternative style is when you need to mix PHP codes with HTML. In CI, this normally happens in views. Have a look at the IF example below of a typical HTML table layout:

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<table>
<tr>
	<td>Site Name</td>
	<td>Site URL</td>
	<td>Site Owner</td>
</tr>
<?php foreach ($sites as $site) { ?>
	<?php if ($site['name'] == 'AskAboutPHP') { ?>
<tr>
	<td><?php echo $site['name'];?></td>
	<td><?php echo $site['url'];?></td>
	<td><?php echo $site['owner'];?></td>
</tr>
	<?php } else { ?>
<tr>
	<td> - </td>
	<td> - </td>
	<td> - </td>
</tr>
	<?php } ?>
<?php } ?>
</table>

The same table can be written in the alternative style as:

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<table>
<tr>
	<td>Site Name</td>
	<td>Site URL</td>
	<td>Site Owner</td>
</tr>
<?php foreach ($sites as $site): ?>
	<?php if ($site['name'] == 'AskAboutPHP') : ?>
<tr>
	<td><?php echo $site['name'];?></td>
	<td><?php echo $site['url'];?></td>
	<td><?php echo $site['owner'];?></td>
</tr>
	<?php else: ?>
<tr>
	<td> - </td>
	<td> - </td>
	<td> - </td>
</tr>
	<?php endif; ?>
<?php endforeach; ?>
</table>

Personally, I find the alternative syntax gels better with HTML even though it’s more verbose. But because this form is more verbose, if a HTML developer was to look at this, I would imagine the second example would make more sense and easier to read and understand than the first table.

This alternative form works for PHP’s ‘if’, ’switch’, ‘while’, ‘for’ and ‘foreach’ control statements.

See Everything PHP’s article on Alternative Syntax for Control Structures for more examples.

Alternative short form ‘if-else’ statement
There is also another shorter way of writing the ‘if-else’ statements which I also found very useful in my CI views. Take for example the following:

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<?php 
if (!empty($a)) {
	$a = TRUE;	
} else {
	$a = FALSE;
}
?>

This can be written as:

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<?php
$a = (!empty($a)) ? TRUE : FALSE; 
?>

The portion before the ‘?’ is the condition, followed by the ‘true’ outcome, then colon, then the ‘false’ outcome.

This helps to keep the coding of ‘if-else’ to the minimum, especially when you have to perform a lot of validation type check which could be a whole stack of ‘if-else’ statements.

]]> http://www.askaboutphp.com/59/phps-alternative-syntax-and-why-its-useful.html/feed 16 Codeigniter: Mixing segment-based URL with querystrings http://www.askaboutphp.com/58/codeigniter-mixing-segment-based-url-with-querystrings.html http://www.askaboutphp.com/58/codeigniter-mixing-segment-based-url-with-querystrings.html#comments Mon, 09 Mar 2009 09:58:16 +0000 Eldee http://www.askaboutphp.com/?p=58 Codeigniter, by default crafts it’s URL in a search engine friendly format. It uses a segment-based approach and does away with the all familiar querystring format that developers have been using for many years to pass parameters via the URL into their applications.

Codeigniter does allow you to turn on the querystring capability, but that would mean you have to use a pure querystring approach, foregoing the segment-based approached.

So, is it possible to mix segments and querystring?

Thankfully, Codeigniter can be configured to mix the segments and querystring, and all it takes are some tweaks in your application/config.php file and perhaps an additional line of code.

Say you would like to have a URL like so:

example.com/product/search/?pname=test&pid=2

By default, Codeigniter would prefer you to craft the equivalent segmented URL, and it would probably look like this.

example.com/product/search/test/2

One of the limitations of this is that the order of the segments becomes important. In your code, you have to remember that the segment after /search/ is the ‘pname’ variable and the segment after that is the ‘pid’ variable. You won’t have this issue if you used a query string.

In most cases, this is not really a show stopper. But there are times when you have no choice but to include querystrings into your URL. For example, a legacy application that interfaces with your application perhaps?

If you follow the (excellent) Codeigniter user guide, and you turn on the querystring capability , Codeigniter will now function with a URL like this:

example.com/?c=product&m=search&pname=test&pid=2

Which is also not the most ideal.

This is what you can do if you need to have a mixed segment and querystring approach. You can enable this either globally for your whole application or just locally within a controller.

Option 1: Mixing Globally
To enable this globally, go to your application/config.php file, and look for $config['uri_protocol'] variable and change it to:

$config['uri_protocol'] = "PATH_INFO";

After that, find the $config['enable_query_strings'] variable and change it to:

$config['enable_query_strings'] = TRUE;

Your application should now accept both segments and querystrings.

Option 2: Mixing Locally
If you don’t want to enable this capability across your whole application, you can restrict it to only the controllers you want.

You can do this by going to the application/config.php file and switching $config['enable_query_strings'] back to ‘FALSE’.

$config['enable_query_strings'] = FALSE;

Leave the $config['uri_protocol'] as PATH_INFO

$config['uri_protocol'] = "PATH_INFO";

and then you can add this line to your controller’s contructor method:

parse_str($_SERVER['QUERY_STRING'],$_GET);

So if you do a test now, only the controller with the above line of code will be able to accept mixed segment and querystring URLs.

]]> http://www.askaboutphp.com/58/codeigniter-mixing-segment-based-url-with-querystrings.html/feed 26 Codeigniter: Helpers, Plugins and Libraries http://www.askaboutphp.com/51/codeigniter-helpers-plugins-and-libraries.html http://www.askaboutphp.com/51/codeigniter-helpers-plugins-and-libraries.html#comments Wed, 03 Dec 2008 03:31:44 +0000 Eldee http://www.askaboutphp.com/?p=51 Codeigniter JigsawHaving used Codeigniter for a few months now, this framework is really turning out to be a joy. My last post, I talked about how to modify native CI Libraries.

With so many published PHP classes and functions, it would be a shame if we couldn’t use them in CI. Fortunately CI (like all good frameworks) provides not one but three ways to integrate 3rd code, by using Helpers, Plugins and Libraries.


Of course, these ‘hooks’ are not just for integrating 3rd party codes. They are also a great way for you to organise your own PHP codes. The CI user guide has done a great job to show how to use Helpers, Plugins and Libraries, so if you haven’t already read those sections of the user guide, I would strongly encourage you to do so.

As I found out during the course of my CI project, Helpers, Plugins and Libraries are nothing more than glorified includes. I can pretty much take any 3rd party code and integrate into my application using any of the 3 methods.

Let me demonstrate by integrating the Google Graph class (by Ryon Sherman which I wrote about in my previous post) as a Helper, a Plugin and a Library, and all achieving the same result.

As a Helper
Once you download a copy of the Google Graph class (or any 3rd party class of your choice), to use it as a helper in your application. This is what you do:

  1. Put the GoogleGraph.php file into application/helpers folder.
  2. Rename the GoogleGraph.php file as GoogleGraph_helper.php

Create a new controller, like so:

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class DrawGraph extends Controller {
 
	function index() {
 
		// include the 3rd party code as a helper
		$this->load->helper('googlegraph');
 
		$graph = new GoogleGraph();
		// set the Graph type to 'line'
		$graph->Graph->setType('line');
		// set the Size of the chart, in this case its 300x150
		$graph->Graph->setSize(300, 150);
		// define which axis we want, which is x,y only.
		// I don't need the top (t) or right (r) axis.
		$graph->Graph->setAxis(array('x','y'));	
		// set the AxisLabels for the x axis		
		$graph->Graph->addAxisLabel(array('A', 'B', 'C', 'D', 'E', 'F'));
		// set the Axis Range for the y axis 
		$graph->Graph->setAxisRange(array(1, 0, 40));
		// define the data points as an array
		$graph->Data->addData(array(5, 10, 20, 15, 30, 40));
		// finally draw the graph.	
		$graph->printGraph();
	}
 
}

You should get a graph like this:

As a Plugin
You can do the same thing by incorporating the GoogleGraph class as a Plugin.

  1. Take your GoogleGraph.php file and put it into either the system/plugins folder or your own application/plugins folder (if you don’t have the folder, just create it)
  2. Rename the GoogleGraph.php file as GoogleGraph_pi.php

Now, instead of loading a helper, change the controller above by changing the load helper statement:

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Change
		$this->load->helper('googlegraph');
To
		$this->load->plugin('googlegraph');

You should still be able to redraw the graph.

As a Library
The same goes for using GoogleGraph class as a Library.

  1. Take your GoogleGraph.php file and put it into your application/libraries folder.
  2. This time you don’t need to rename it.

Now, instead of loading a plugin, change the controller code as follow:

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Change
		$this->load->plugin('googlegraph');
To
		$this->load->library('googlegraph');

Again, you should be able to redraw the same graph without any problems.

So, when to use what?
Since, all three methods achieve the same ends. The question then is when do you use what? Fortunately, CI has also provided that distinction in their user guide which you can go read it yourself.

For me, these are my guidelines on when to use what:

  1. Plugins – I put all 3rd party codes I’m using in my application as Plugins. I would, as best as I can, try to use classes rather than straight function calls.
  2. Helpers – Any standalone straight functions calls, which are repetitive in nature, I classify them as Helpers. For example, sorting functions, my own calculation functions, etc
  3. Libraries – I classify my own classes as ‘Libraries’. Normally, if I’m already writing a class in my application, it would then to be the core logic of the application, as such, I group them all in the Library folder.

Of course all my own or 3rd party codes, I would put them in their respective folders under the application/ folder. I would not mix them into the system/ which is reserved for CI.

Whether you may have your own scheme to organize your own code, or you follow what CI user guide defined, one thing I do know, you should have a scheme to organize your codes. Without which, as your application grows in number of functions and classes, it would become a real mess, real fast!

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