Extending the art & spirit of PHP, Zend Framework is based on simplicity, object-oriented best practices, corporate friendly licensing, and a rigorously tested agile codebase. Zend Framework is focused on building more secure, reliable, and modern Web 2.0 applications & web services, and consuming widely available APIs from leading vendors like Google, Amazon, Yahoo!, Flickr, as well as API providers and cataloguers like StrikeIron and ProgrammableWeb.
Do you know that objects in PHP5 are passed by reference, while arrays and other scalar variables are passed by value? Yes, you know it, but it’s not exactly true. Let’s see some example and let’s try to answer few questions.
// depending on the machine but both lines return// expectedly equal values: 331208// 331208echomemory_get_usage();echomemory_get_usage();
// depending on the machine but both lines return
// expectedly equal values: 331208
// 331208
echo memory_get_usage();
echo memory_get_usage();
These two lines of code, expectedly return the same value (in my case 331208), which shows us that because nothing happened in between them the memory usage isn’t growing. Let’s now put some code in between them.
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);
$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$sql="SELECT * FROM my_table WHERE id = ";// dump and debug the wrong querydie($sql);// this line won't be executed$resource=mysql_query($sql);
// 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.
Anyone who has worked with that has come across this problem. I’d like to show different error message on each validator attached to a Zend_Form_Element. Let’s say we validate an text input field. We want it to contain only digits, but also we’d like to display different messages when the field is empty and when the user has entered something that is different from digits.
It can be done by attaching to the form element two validators: Zend_Validate_Digits and Zend_Validate_NotEmpty, but first let’s see how to change the default “Value is required and can’t be empty” error message of a form field.
$element=$form->createElement('text','phone');$element->setLabel('Please, enter your phone number:')->setRequired(true)->addValidator('Digits');$form->addElement($element);
$element = $form->createElement('text', 'phone');
$element->setLabel('Please, enter your phone number:')
->setRequired(true)
->addValidator('Digits');
$form->addElement($element);
Here we validate the field with Zend_Validate_Digits and we have set it to be required. Thus everything containing characters, i.e. “my123name” or “007bond”, will be false, while “1234” will be true.
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.
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);
// 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);
// 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;
// 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 $response->location;
PHP's fopen() can be used to check remote file existence
I’ve posted about Zend_Http_Client. Simply there you can ‘make’ your own http client and you can request a remote file. Just to check what’s going on with this file.
// new HTTP request to a file$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 existsif(0===(int)$response->getHeader('Content-Length')){echo'the file doesn\'t exits';}
// 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.
