url is a unified resource locator, a concise representation of the location and access method of resources available from the Internet. It is a standard resource on the Internet. the address of. This article will introduce how to use PHP functions to obtain the parameters of each part of the URL.

parse_url()

This function can parse a URL and return its components. It is used as follows:

array parse_url(string $url)

This function returns an associative array containing the various components of the existing URL. If one of these components is missing, no array entry will be created for this component. The components are:

• scheme - such as http
• host - such as localhost
• port - such as 80
• user
• pass
• path - such as /parse_str.php
• query - after the question mark? such as id=1&category=php&title=php-install
• fragment - after the hash symbol

#This function does not mean that the given URL is valid, it just separates the parts in the list above. parse_url() accepts incomplete URLs and tries to parse them correctly. This function has no effect on relative path URLs.

<?php
    $url = "http://52php.cnblogs.com/welcome/";
    $parts = parse_url($url);
     
    print_r($parts);
?>

The program running results are as follows:

Array
(
    [scheme] => http
    [host] => 52php.cnblogs.com 
    [path] => /welcome/
)

<?php
    $url = &#39;http://username:password@hostname/path?arg=value#anchor&#39;;
    print_r(parse_url($url));
    echo &#39;<br />&#39;;
    echo parse_url($url, PHP_URL_PATH);
?>

Program output:

Array
(
    [scheme] => http
    [host] => hostname
    [user] => username
    [pass] => password
    [path] => /path
    [query] => arg=value
    [fragment] => anchor
)

As you can see, it is easy to decompose the various parts of a URL. It is also easy to extract the specified parts, such as:

echo parse_url($url, PHP_URL_PATH);

is in the second Among the parameters, set the following parameters: PHP_URL_SCHEME, PHP_URL_HOST, PHP_URL_PORT, PHP_URL_USER, PHP_URL_PASS, PHP_URL_PATH, PHP_URL_QUERY or PHP_URL_FRAGMENT.

---

parse_str()

parse_str is used to parse the query string in the URL, that is, the string value that can be obtained through $_SERVER['QUERY_STRING'] , if the URL we request is http://localhost/parse_str.php?id=1&category=php&title=php-install, then the value returned by $_SERVER['QUERY_STRING'] is id=1&category=php&title=php-install, and This form of string happens to be parsed into an associative array using parse_str.

Usage is as follows:

void parse_str(string $str [, array &$arr ])

This function receives two parameters, $str is the string that needs to be parsed , and the optional parameter $arr is the variable name where the array value generated after parsing is stored. If you ignore the optional parameter, you can directly call variables like $id, $category, and $title. The script below simulates a GET request.

<?php
<a href="http://localhost/parse_str.php?id=1&category=php&title=php-install">Click Here</a>
$query_str = $_SERVER[&#39;QUERY_STRING&#39;];
parse_str($query_str); /* 这种方式可以直接使用变量$id, $category, $title */
parse_str($query_str, $query_arr);
?>
<pre class="brush:php;toolbar:false"><?php print_r($query_arr); ?>

?> /* 运行结果 */ Array ( [id] => 1 [category] => php [title] => php-install ) 1 php php-install

---

http_build_query Is to convert an array into a url? The following parameter string will be automatically urlencoded

string http_build_query (array formdata [, string numeric_prefix])

Add subscripts to the array if there is no specified key or the key is a number

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