The Route from $_GET to String

The global arrays in PHP contain request parameters. Either GET or POST. As you know if the page address is something like:

http://www.example.com/index.php?a=b&key=value

This means that you pass to the index.php file two parameters – “a” and “key” with their values: “b” and “value”. Now in this case you can dump the $_GET global array somewhere in index.php and you’ll receive something like this.

array(
	"a"   => "b",
	"key" => "value",
);

This is however pseudocode, but in fact $_GET will be very similar to this sample array.

$_GET to String

Very often when a developer need to process the $_GET array to a string, which means generating again the query string from $_GET, he often comes to some operation like this one.

$queryString = '';
foreach ($_GET as $key => $value) {
	$queryString .= $key . '=' . $value . '&';
}

However this will result in something quite ugly like a=b&key=value& which comes with a trailing & at the end of the string.

There is however another approach – using an array.

$queryString = array();
foreach ($_GET as $key => $value) {
	$queryString[] = $key . '=' . $value;
}
$queryString = implode('&', $queryString);

But that invokes one function more and this is still not the most elegant solution. As I said at the beginning PHP is full of useful functions and here comes the http_build_query.

http_build_query

This is exactly what you need. As it name describe you can build the query string even by using a different from & separator.

$queryString = http_build_query($_GET, '', '|');

Thus $queryString will contain a=b|key=value and at least the code will look pritier.

It’s a well know fact that you can preform HTTP requests with CURL. Zend Framework does the same job with Zend_Http. Especially Zend_Http_Client can be used to “replace” the usual client – the browser, and to perform some basic requests.

I’ve seen mostly GET requests, although Zend_Http_Client can perform various requests such as POST as well.

// new HTTP request to some HTTP address
$httpClient = new Zend_Http_Client('http://www.example.com/');
// GET the response
$response = $httpClient->request(Zend_Http_Client::GET);

Here’s a little snippet showing how to POST some data to a server.

// new HTTP request to some HTTP address
$client = new Zend_Http_Client('http://www.example.com/');
// set some parameters
$client->setParameterPost('name', 'value');
// POST request
$response = $client->request(Zend_Http_Client::POST);

Note that the request method returns a response. Thus if you are simulating a form submit action you can “redirect” to the desired page just like the form.

// new HTTP request to some HTTP address
$client = new Zend_Http_Client('http://www.example.com/');
// set some parameters
$client->setParameterPost('name', 'value');
// POST request
$response = $client->request(Zend_Http_Client::POST);
echo $response->location;

You’ve definitely seen the “share a link” screen in Facebook. When you paste a link into the box (fig. 1) and press the “Attach” button you’ll get the prompted cite parsed with a title, description and possibly thumb (fig. 2). This functionality is well known in Facebook, but it appears to be well known also in various social services. In fact Linkedin, Reddit, Dzone‘s bookmarklet use it.

Fist thing to notice is that this information, prompted by Facebook, is the same as the meta tag information. However there is a slight difference.

Facebook prefers for the thumb the image set into the <meta property=”og:image” … />. In the case above this tag appears to be:

And the image pointed in the SRC attribute is exactly the same as the one prompted by Facebook (fig. 3).

First thing to note is that the real thumb is bigger than the thumb shown in Facebook, so Facebook resizes it and the second thing to note is that there are more meta tags of the og:… format.

Meta Tags and The Open Graph Protocol

By default meta tags contain various information about the web page. They are not visible in the webpage, but contain some info about it. The most common meta tags are the title, description and keywords tags. They of course contain the title of the page, not that this can be different from the <title> tag, a short description of the page and some keywords describing the content of the page. They are well known also because the search engines make use of them when trying to collect information about the page and the process of SEO passes through it.

However the default HTML meta tags cannot contain everything. Thus for example you cannot point the preferable thumbnail for a webpage. The solution is the Open Graph Protocol. It comes with meta tags that can contain more and more valuable info. Such a tag is the og:image meta tag. Note that all the Open Graph (og) meta tags are defined by the og: prefix before the entity name. Thus og:image comes for images, while og:longitude for geo positioning.

That’s really useful, but how you can read them?

PHP, Meta Tags and Regexps

When you try to read information from a webpage source the first possible path is by using regular expressions. However PHP is smart enough to offer you some useful functions. Such a function is get_meta_tags(). As you may guess this method reads the meta tags by given URL.

$a = get_meta_tags('http://vimeo.com/10758212');
var_dump($a);

However this method can’t read Open Graph tags. So finally you’ve to use some regexps.

preg_match('//', $source, $matches);

Now you can grab the og:image tag. And even more – grab every image (<img>) from that page.

preg_match_all('/

Related posts:

How to Sanitize User Input in PHP? 
HTML Tags: <base> 
Automatically Upload Images with PHP Directly from the URI 
Download Images with PHP 


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				On Focus

Perhaps you think of onfocus and onblur events as a default behavior existing in any web page. This is not quite true! Onfocurs and onblur are well known in web developing (js) and are fired, of course, when the user tries to point something or leaves some element. Onfocurs is fired when the user either goes to an element with the Tab button on with the mouse. When the element is on focus, evidently, the onfocus event is fired. Actually you can see which element is on focus, like an anchor or input, when the element is outlined by the browser by default. In the same scenario, when some element has been on focus and than the user switches to another element, the onblur event is fired. Thus you may guess that this element is no longer on focus.
This in general are the onfocus/onblur events. The interesting part is that by default are known as built-in events in every page, but that is wrong.
Where Are My Events?
A typical use case is to take the code from some web page, where you’re sure this works perfectly, you can focus and blur element with no obstacle, but once you paste it inside your markup everything’s going wrong. Imagine you’ve the following markup (a typical search box text):


This works perfectly until you paste it to your site. And than nothing works correctly. Why? Where’s the problem?
Make Them Work
Actually the problem isn’t hiding somewhere in the markup above. It’s in the HTML definition. There are lots of web pages using strict HTML definition, that looks like this:



	...


	...

while you’ve to use the pure HTML definition to make onfocus/onblur work.
You’ve to switch to:


	...


	...

Than you can continue using these useful events!

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How to Sanitize User Input in PHP? 
jQuery live() vs bind() performance 
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		Continue reading Diving into Node.js – A Long Polling Example →


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Diving into Node.js – Introduction & Installation 
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POST with Zend_Http_Client 


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				Node.js vs. The World

What is typical for most of the web servers is that they listen for requests and respond as quickly as possible on every one of them. In fact the speed of the response is one of the main targets of optimization for developers. Fast servers are what everyone needs. From web developers to website visitors!
In the field of the that battle different web servers have different “weapons” to gain time. While this is useful in most of the cases, when it comes to a chat-like applications and Node.js approaches, the response is not always immediately returned. As I described in my posts until now about Node.js, a simple web server may wait for an event to be emitted, and than return the response.
I wrote about how to write the very first server, but than I didn’t described how to make a “non-responding” server. By the term “non-responding” I mean a server that responds not immediately after it has received and parsed/executed the request.
A typical web server, responding immediately on every request, written with Node, this may look like so:
var http = require('http');
http.createServer(function (req, res) {
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.end('Hello World\n');
}).listen(8124, "127.0.0.1");
console.log('Server running at http://127.0.0.1:8124/');

The code that shows us that the request is executed and responds in these lines:
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.end('Hello World\n');

Actually by commenting/removing those lines you’ll get a server that simply doesn’t respond – ever! This of course is not the main goal, but you can start from somewhere.
var http = require('http');
http.createServer(function (req, res) {
  // res.writeHead(200, {'Content-Type': 'text/plain'});
  // res.end('Hello World\n');
}).listen(8124, "127.0.0.1");
console.log('Server running at http://127.0.0.1:8124/');

This is how you can hold for a while. Perhaps putting these lines in a conditional statement and periodically checking for some event to occur will do the job.
var http = require('http');
http.createServer(function (req, res) {
  if (something) {
     res.writeHead(200, {'Content-Type': 'text/plain'});
     res.end('Hello World\n');
  }
}).listen(8124, "127.0.0.1");
console.log('Server running at http://127.0.0.1:8124/');

Looping Server
As described in the code above if you put the respond into a conditional you can possibly return the response after some event has fired. The only thing is to periodically loop and check for this condition to be true. Assuming your server’s code is in server.js, started with the “node server.js” command, you’ve to put this code into it:
var http = require("http"),
    fs	 = require("fs");  

// we create a server with automatically binding
// to a server request listener
http.createServer(function(request, response) {
	checkFile(request, response);
}).listen(8124);

function checkFile(request, response)
{
	var date = new Date();
	if (date-request.socket._idleStart.getTime() > 59999) {
		response.writeHead(200, {
			'Content-Type'   : 'text/plain',
			'Access-Control-Allow-Origin' : '*'
		});

		// return response
		response.write('OK', 'utf8');
		response.end();
	}

	// we check the information from the file, especially
	// to know when it was changed for the last time
	fs.stat('filepath', function(err, stats) {
		// if the file is changed
		if (stats.mtime.getTime() > request.socket._idleStart.getTime()) {
			// read it
			fs.readFile('filepath', 'utf8', function(err, data) {
				// return the contents
				response.writeHead(200, {
					'Content-Type'   : 'text/plain',
					'Access-Control-Allow-Origin' : '*'
				});

				// return response
				response.write(data, 'utf8');
				response.end();

				// return
				return false;
			});
		}
	});	

	setTimeout(function() { checkFile(request, response) }, 10000);
};

Note: you must change “filepath” with an existing file path in your system.
Here we can read periodically the file’s mtime, which is the modify time. Thus whenever the file is changed the server will return the response. It’s interesting to note that if no change occurs within the timeout period you’ve to return some status message as we did in those lines:
        
var date = new Date();
if (date-request.socket._idleStart.getTime() > 59999) {
	response.writeHead(200, {
		'Content-Type'   : 'text/plain',
		'Access-Control-Allow-Origin' : '*'
	});
	
	// return response
	response.write('OK', 'utf8');
	response.end();
}

The client side should long poll this server. The example bellow is written in jQuery. The only “special” thing is that after receiving the response, you must call the server again.
The Client
The client is nothing new to the jQuery/JavaScript community except you must call again the server when the response is returned:
function callNode() {
    $.ajax({
        cache : false,
		// setup the server address
        url : 'http://www.example.com:8124/',
        data : {},
        success : function(response, code, xhr) {

            if ('OK' == response) {
            	callNode();
                return false;
            }

            // do whatever you want with the response
            ...

            // make new call
            callNode();
        }
    });
};
callNode();

Summary
As Node can hold the response, the only thing you should do is to check periodically for something as in this example this was a file change. Than it’s important to change the client so it can call the server after the response from it is received.
Typically Node can be used for chat-like applications or whatever apps that must deliver real time data, but for sure it is really great software.

Related posts:

Diving into Node.js – Very First App 
Diving into Node.js – Introduction & Installation 
Read Remote File Content-Type with Zend_Http_Client 
POST with Zend_Http_Client 


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		/?p=2037
		Continue reading Diving into Node.js – Introduction & Installation →


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Diving into Node.js – A Long Polling Example 
Diving into Node.js – Very First App 
Speed up the JavaScript. It can change dramatically the user experience. 
What should be optimized in one web page? 


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				Why I Need Something Like Node.js?
First of all the use of some software is needed not because of itself, but because of the need of some specific functionality. In my case this was the need of real time news feed. Of course there is a way to make this without Node.js, as I’ll describe later in this post, but there are several disadvantages. However to begin from somewhere, let me explain what is Node.js.
Introducing Node.js
Perhaps the best way do describe what is Node.js is from its about page.
Node’s goal is to provide an easy way to build scalable network programs. In the “hello world” web server example above, many client connections can be handled concurrently. Node tells the operating system (through epoll, kqueue, /dev/poll, or select) that it should be notified when a new connection is made, and then it goes to sleep. If someone new connects, then it executes the callback. Each connection is only a small heap allocation.
…
In general Node is a program using the Google Chrome’s V8 JavaScript engine, which in turn is a program that can parse and execute code written in JavaScript. V8 is a very very interesting project itself. First of all from Google have developed this engine especially for one of his products – their browser Chrome. It pretends to be and by no means is one of the masterpieces of Google. It is fast and reliable engine, written in C++ and JavaScript, as Wikipedia’s page says. Actually this code is open source and can be embedded in whatever application written in C++. Thus you can have in your application a JavaScript engine.
Such kind of application/server is Node.js. With V8 embedded into, Node is intended to run on a machine and to serve some requests. Just like a normal web server, but with few differences. First of all Node is not only serving HTTP requests, but also TCP. Well I’m not so deep into this yet, but so far that works for me. What I need for now is its web serving functionality.
The way Node works, however is different from what we know from every other web server. Here it is a normal server in general:

Whenever a request comes to the server, it tries to return the response as fast as possible. This is one of the main goals of every web developer team – to make the application as fast as possible. However in Node the things work different:

Here the server doesn’t return immediately the response, but holds as long as possible until some “event” occurs. You can thing of Node as a classical chat server. Until one of the peers doesn’t write a message, the other doesn’t receive anything.
Some may be confused as how you can use both the typical web server, as Apache, with Node as another web server within the same page. The answer is – with AJAX. As you know thus you can have only one chunk of your page talking with the server – in this case the entire page is returned by Apache, but inside the page you can have a chat app using Node as a server, working perhaps on a different port on the same machine.
Typically this scenario can be simulated without Node, but as I said, with some disadvantages. Let’s say you have two browsers and one server – you can infinitely loop AJAX calls to the server and whenever there is new message on the server return it to the browser – this is quite inefficient. There are two approaches in this case.

You can make those AJAX calls too recently and you can have a call every N seconds. In that case if N is to short you’ll have too many calls and in case the other peer doesn’t make anything the server will be unusually loaded with no practical effect.
In the second case you can choose to make N too long – for instance 20 seconds. This is also bad, because during this period of time the peers may want to interact and chat.

In that case Node is a web server, but simply doesn’t return the response until a specific event doesn’t occur. How does this look like in a web browser. You may know how looking into the Firebug console for every AJAX call you see the request and how many seconds it has taken. If you make an AJAX call to a Node server app the request just doesn’t respond immediately.
Installing Node.js
The process of installation is described quite well, so I’m going to describe it in few steps.

Download the application from Git, note that V8 is embedded inside. The version while this post was written and of course was stable is v0.2.4
For those familiar with Unix/Linux systems, there are three simple steps following, however without GCC (Gnu Compiler Collection) you wont be able to proceed! I’m writing this especially for the Mac OS users, as they may know there is no built-in GCC there.
./configure
make
make install
make test (optional)

This in general is enough. After all that you can write the node command in your terminal. However if there are some problems while compiling it you may refer to Git and the Node community for more help. Don’t forget that V8 can work only on x86, x64 and ARM architectures.
Summary
There are few things that can be summarized now:

First of all Node can be a web server, as Apache is, but with the option to respond on event firing.
You can request it either with a web page loaded in your browser or within a chunk of the page via AJAX.
To install Node you need GCC. It comes with V8 JavaScript engine inside, which can run only on x86, x64 and ARM.

So far so good! Now we have Node installed, practically useless, because there is no application running on it. In my next post I’ll describe how to run your first application.

Related posts:

Diving into Node.js – A Long Polling Example 
Diving into Node.js – Very First App 
Speed up the JavaScript. It can change dramatically the user experience. 
What should be optimized in one web page? 


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		Fri, 24 Sep 2010 08:23:58 +0000
		
				
		
		
		
		
		
		
		
		
		
		
		
		
		
		
		
		
		
		
		

		/?p=1989
		Continue reading 2xjQuery: Select a Selector →


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				Selectors in jQuery

If you’re familiar with jQuery you should already know what are selectors and how they work. However we’re used to get some DOM element with a specific selector, but actually sometimes you cannot select directly what you need. This is especially true when mixing more than one JavaScript libraries. In my case OpenLayers generated a vector layer and jQuery was supposed to change the vectors fill-color property.

With the simple $(‘path’) I easily got all vectors in the current document, but the problem was that I took them as text. Thus it came to me to use nested jQuery – $($(‘selector’));
To describe what actually happened in my case, let me show you a breve example.
Example
Here’s a short HTML markup:
text text


With jQuery I can select both the DIV and SPAN with the simple $(‘div’) and $(‘span’), but just for the example lets assume I’ve only the inner text of the DIV tag:
$('div').html();

That was the case in the OpenLayers/jQuery problem. Now I can easily use another jQuery selector:
$($('div').html());

This will return the same as $(‘span’) – a jQuery object.

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		Continue reading Automatically Upload Images with PHP Directly from the URI →


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				It is a simple task to upload images on the server with PHP using a simple web form. Than everything’s in the $_FILES array and after submitting the form the file’s on the server. By simply move_uploaded_file you can change its location on the server to the desired folder.

However is there a way to “upload” files without using a web form, but only by telling the PHP script where to find the image. First and most important the image should be web visible and accessible by HTTP.
The solution is quite easy – you can grab the file using file_get_contents, and than put it on the desired server folder with file_put_contents. Here’s some source:
$image = file_get_contents('http://www.example.com/image.jpg');
file_put_contents('/var/www/my.jpg', $image);

Extending the Case
You can go even further by downloading any kind of files with the same approach. What will be the case for an mp4 video is shown in the next example:
$video = file_get_contents('http://www.example.com/video.mp4');
file_put_contents('/var/www/my.mp4', $video);

Usage
This can be quite useful when trying to automate an remote upload process. In this case when somebody uploads an image on his site, you can duplicate this file on your server! However don’t forget the copyrights!

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		Continue reading Can Twitter Replace the RSS Feed Readers →


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I’m sure this is not the first time you’ve been asked this question. However there’s nobody today that doesn’t wonder the answer. For me – yes, twitter can replace the RSS feed readers, and NO – feed readers are awsome!
Yes
First of all why do I use a feed reader? I’m simply seeing what’s in it and barely read the article from the reader, but rather I jump to the site, and what’s happening often in twitter is the same scenario, I just see what’s in the tweet and if it seems to be interesting to me I jump to the link (if there’s a link). The good thing is that the tweets are limited and I’m focused. That’s why twitter is my favorite social site. I can follow all of the interesting people I know from their blogs. So perhaps twitter is becoming more useful than the feed readers.
No
In other hand in twitter you’ve to stay all the day long to get all the tweets you need. The timeline is quickly changing and sometimes you get lots of “junk”. While in the feed reader you’ve all the “important” posts as an incoming mail. You cannot miss anything! That’s why I cannot forget the feed readers they are doing a great job!

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Burn Feeds in Zend Framework 


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		Continue reading Fetching Rows With Zend_Db fetch() →


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				Fetching the Entire Row Set

What is really handy in Zend Framework is that you can fetch the entire row set with the fetchAll() method. It comes with some parameters that you can use for limiting the result or ordering, but in general you can use it without specifying parameters. Let say this is the model:
getAdapter()->query($query);
	
		return $rs->fetchAll();
		
	}
	
}

You can simply return the row set with the fetchAll() method as described in the example, but what if you have to loop through the rows and to modify somehow the values?
Fetching a Row
By simply change the code like so:
class User extends Zend_Db_Table
{
		
	public function listAll()
	{
		$query = "SELECT * FROM user";
	
		// exec query
		$rs = $this->getAdapter()->query($query);
	
		// fetch
		$list = array();
		while ($row = $rs->fetch()) {
			// removing the password column value
			$row['password'] = '';
			
		    $list[] = $row;
		}
	
		return $list;
	}
}

you can modify the rows and you’ll have the same result.

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