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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.

Example 33-1. Checking the response code

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.

Example 33-2. Getting all headers from the response

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.

Example 33-3. Getting a specific header

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.

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