Tag Archives: PHP programming language

PHP Strings Don’t Need Quotes

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I bet you didn’t know that PHP strings don’t need quotes! Indeed PHP developers work with strings with either single or double quotes, but actually in some cases you don’t need them.

PHP by Book

Here’s how PHP developer declare a string, which is something very common in any programming language.

$my_var = 'hello world';
// or
$my_var = "hello world";

PHP Tricks

What if you do the following:

echo hello;

That appears to be correct … Well, it’s not absolutely correct. You’ll be “noticed”.

// Notice: Use of undefined constant hello
echo hello;

However if you disable error reporting, the code will be completely fine.

error_reporting(0);
 
// no problem now
echo hello;

Variations

What follows from the thing above is that you can use strings without quotes:

// hello
echo hello;
 
// hello world (concatenated)
echo hello . ' world';
 
// helloworld
echo hello . world;

However you can’t have spaces and most of the “special” symbols.

// syntax error
echo hello world;
 
// syntax error
echo hello!;

Final Words

Although you can do this in PHP, that is completely wrong. The code becomes more difficult to read and understand. In the second place you can miss a $ sign in front of a variable declaration and thus the PHP interpreter will assume this is a string. So disable error reporting isn’t so great sometimes.

How to Dump the Generated Zend_Db SQL Query

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The Typical PHP Approach

Typically a PHP programmer will write his SQL query as a string and will execute it via mysql_query.

$sql = "SELECT * FROM my_table";
$resource = mysql_query($sql);

So eventually when you want to dump this “complex” query, or whatever query there is, you can simply “echo” it and see what’s its syntax.

// this query is WRONG because of the where clause
$sql = "SELECT * FROM my_table WHERE id = ";
 
// dump and debug the wrong query
die($sql);
 
// this line won't be executed
$resource = mysql_query($sql);

So far so good, but things appear to be a bit different when you start to work with Zend Framework. Higher levels of abstraction come with slightly more difficult ways to dump (debug) your SQL queries.

OK you’ve two options. Using Zend_Db_Select or … not.
Continue reading How to Dump the Generated Zend_Db SQL Query →

Object Cloning and Passing by Reference in PHP

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In PHP everything’s a reference! I’ve heard it so many times in my practice. No, these words are too strong! Let’s see some examples.

Passing by reference in PHP can be tricky!
Some developers think that everything's passed by reference in PHP.

Passing Parameters by Reference

Clearly when we pass parameters to a function it’s not by reference. How to check this? Well, like this.

function f($param)
{
	$param++;
}
 
$a = 5;
f($a);
 
echo $a;

Now the value of $a equals 5. If it were passed by reference, it would be 6. With a little change of the code we can get it.

function f(&$param)
{
	$param++;
}
 
$a = 5;
f($a);
 
echo $a;

Now the variable’s value is 6.

So far, so good. Now what about copying objects?
Continue reading Object Cloning and Passing by Reference in PHP →

POST with Zend_Http_Client

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CURL and Zend_Http

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.

HTTP requests can be performed with Zend_Http_Client
Zend_Http_Client is mostly used to perform GET requests, but it can be also very helpful for POST HTTP 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;

Use fopen() to Check File Availability?

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Zend Framework and Zend_Http_Client

PHP's fopen() can be used to check remote file existence
PHP's fopen() can be used to check remote file existence

I’ve posted about Zend_Http_Client. Simply there you can ‘make’ your own http client and you can request a remote file. Just to check what’s going on with this file.

// new HTTP request to a file
$httpClient = new Zend_Http_Client('http://www.example.com/myfile.mp4');
 
// get the HEAD of the response and match agains the
// Content-Length. That's because using the Content-Type is slower
$response = $httpClient->request(Zend_Http_Client::HEAD);
 
// if the Content-Length is 0 the file doesn't exists
if (0 === (int)$response->getHeader('Content-Length')) {
	echo 'the file doesn\'t exits';
}

However is there any other way to answer the same question?

fopen()

Yes and no? Perhaps yes, but you should be careful. I’m still not sure it can be used in any case. However here’s the snippet.

if (FALSE === @fopen('http://www.example.com/myfile.mp4', 'r')) {
	echo 'the file doesn\'t exists';
}

fopen() will return FALSE whenever the file doesn’t exists.

In both cases I request a remote file – an MPEG-4 file. Note that fopen()’s first parameter can be a HTTP resource.