Detailed explanation of HTTP request method of PHP web crawler

With the development of the Internet, all kinds of data are becoming more and more accessible. As a tool for obtaining data, web crawlers have attracted more and more attention and attention. In web crawlers, HTTP requests are an important link. This article will introduce in detail the common HTTP request methods in PHP web crawlers.

1. HTTP request method

HTTP request method refers to the request method used by the client when sending a request to the server. Common HTTP request methods include GET, POST, PUT, DELETE, HEAD, OPTIONS, etc.

Among them, GET and POST are the two most commonly used request methods.

1. GET request method

The GET request method is used to request the specified resource, and the server will return the corresponding content. A GET request will request data from the specified resource. The request data will be appended to the URL and sent as part of the HTTP request. GET requests do not modify server state.

The GET request method can be used in PHP in the following ways:

$data = file_get_contents('http://example.com/api?key1=value1&key2=value2');

2. POST request method

The POST request method is used to submit to the specified resource Data, which will be sent in the request body. POST requests may cause server state changes, such as creating new resources or updating existing resources.

Using the POST request method in PHP can be done in the following ways:

$url = 'http://example.com/api';
$data = array('key1' => 'value1', 'key2' => 'value2');

$options = array(
    'http' => array(
        'header'  => "Content-type: application/x-www-form-urlencoded
",
        'method'  => 'POST',
        'content' => http_build_query($data)
    )
);

$context  = stream_context_create($options);
$result = file_get_contents($url, false, $context);

2. Other request methods

1. PUT request method

$url = 'http://example.com/api';
$data = 'This is the new content.';

$options = array(
    'http' => array(
        'header'  => "Content-Type: text/plain
",
        'method'  => 'PUT',
        'content' => $data
    )
);

$context  = stream_context_create($options);
$result = file_get_contents($url, false, $context);

DELETE request method

$url = 'http://example.com/api/123';
$options = array(
    'http' => array(
        'header'  => "Content-Type: application/x-www-form-urlencoded
",
        'method'  => 'DELETE',
    )
);

$context  = stream_context_create($options);
$result = file_get_contents($url, false, $context);

HEAD request method

$url = 'http://example.com/api';
$options = array(
    'http' => array(
        'method'  => 'HEAD',
    )
);

$context  = stream_context_create($options);
$headers = get_headers($url, 1, $context);

OPTIONS request method

$url = 'http://example.com/api';
$options = array(
    'http' => array(
        'method'  => 'OPTIONS',
    )
);

$context  = stream_context_create($options);
$result = file_get_contents($url, false, $context);

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