Response Evaluation

Response Evaluation – Evaluating the information from a HTTP response

Introduction

Because HTTP is a protocol based on the Request - Response scheme, every HTTP request is followed by a HTTP response. HTTP_Request offers several methods to evaluate the information from these responses.

Response Codes

A important part of the HTTP response is the response code. The most well-known response code probably is 404, which you may have seen in your browser at several occasions. The meaning of 404 is that the requested ressource could not be found. A complete list of status codes can be found in RFC 2616.

Checking the response code

<?php
require_once "HTTP/Request.php";

$urls = array(
    
"http://www.example.com/",
    
"http://example.com/thisdoesnotexist.html"
    
);

$req =& new HTTP_Request("");
foreach (
$urls as $url) {
    
$req->setURL($url);
    
$req->sendRequest();

    
$code $req->getResponseCode();
    switch (
$code) {
    case 
404:
        echo 
"Document not found\n";
        break;

    case 
200:
        echo 
"Everything's ok\n";
        break;

    
/* ... */
    
}
}
?>

Response Headers

Similar to a HTTP request a HTTP response consists of a header and a body. HTTP_Request offers a method to access the header of the response.

Getting all headers from the response

<?php
require_once "HTTP/Request.php";

$req =& new HTTP_Request("http://example.com/");
$req->sendRequest();

foreach (
$req->getResponseHeader() as $name => $value) {
    echo 
$name " = " $value "\n";
}
?>

This will print all headers and the appendant values.

Getting a specific header

<?php
require_once "HTTP/Request.php";

$req =& new HTTP_Request("http://example.com/");
$req->sendRequest();

echo 
$req->getResponseHeader("Date");
?>

This will print the value of the Date: header.

Response Cookies

Fetching the cookies that are part of the HTTP response is described in the Cookies section.