Introduction to php using parse_url and parse_str to parse URLs

This article mainly introduces you to two methods of parsing URLs in PHP (parse_url and parse_str), as well as the introduction and usage of these two methods. It is very comprehensive and recommended to friends in need.

There are two methods in PHP that can be used to parse URLs, namely parse_url and parse_str.

parse_url
Parse the URL and return its components

mixed parse_url ( string $url [, int $component = -1 ] )

This function parses a URL and returns an associative array, containing various components that appear in the URL part.

This function is not used to verify the validity of the given URL, but to break it down into the parts listed below. Incomplete URLs are also accepted and parse_url() will try to parse them as correctly as possible.

Parameters

url The URL to be parsed. Invalid characters will be replaced with _.

component Specify one of 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 to get the string of the specified part of the URL. (Except when specified as PHP_URL_PORT, an integer value will be returned).

Return value

For severely unqualified URLs, parse_url() may return FALSE.

If the component parameter is omitted, an associative array array will be returned, and at least one element will currently be in the array. Possible keys in the array are:

scheme - such as http
host
port
user
pass
path
query - after the question mark?
fragment - after the hash symbol
#If the component parameter is specified, parse_url() returns a string (or an integer when specified as PHP_URL_PORT) instead of an array. If the specified component in the URL does not exist, NULL will be returned.

Example

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

The above routine will output:

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

parse_str

Parse the string into multiple Variable

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

If str is the query string passed in by the URL, parse it into a variable and set it to the current scope.

To get the current QUERY_STRING, you can use the $_SERVER['QUERY_STRING'] variable.

Parameters

str Input string.

arr If the second variable arr is set, the variable will be stored in this array as an array element instead. ,

Example

<?php
$str = "first=value&arr[]=foo+bar&arr[]=baz";
parse_str($str);
echo $first;  // value
echo $arr[0]; // foo bar
echo $arr[1]; // baz
parse_str($str, $output);
echo $output[&#39;first&#39;];  // value
echo $output[&#39;arr&#39;][0]; // foo bar
echo $output[&#39;arr&#39;][1]; // baz
?>

I was reading the source code of php-resque some time ago, and saw the application of these two methods. I feel that it is used very well. It is used to parse redis links. set up.

The format of the redis link is: redis://user:pass@host:port/db?option1=val1&option2=val2. Is it the same as the URL, so it is easy to parse using the above two methods.

Address: https://github.com/chrisboulton/php-resque/blob/master/lib/Resque/Redis.php

The code is as follows:

    /**
     * Parse a DSN string, which can have one of the following formats:
     *
     * - host:port
     * - redis://user:pass@host:port/db?option1=val1&option2=val2
     * - tcp://user:pass@host:port/db?option1=val1&option2=val2
     *
     * Note: the 'user' part of the DSN is not used.
     *
     * @param string $dsn A DSN string
     * @return array An array of DSN compotnents, with 'false' values for any unknown components. e.g.
     *               [host, port, db, user, pass, options]
     */
    public static function parseDsn($dsn)
    {
        if ($dsn == '') {
            // Use a sensible default for an empty DNS string
            $dsn = 'redis://' . self::DEFAULT_HOST;
        }
        $parts = parse_url($dsn);
        // Check the URI scheme
        $validSchemes = array('redis', 'tcp');
        if (isset($parts['scheme']) && ! in_array($parts['scheme'], $validSchemes)) {
            throw new \InvalidArgumentException("Invalid DSN. Supported schemes are " . implode(', ', $validSchemes));
        }
        // Allow simple 'hostname' format, which `parse_url` treats as a path, not host.
        if ( ! isset($parts['host']) && isset($parts['path'])) {
            $parts['host'] = $parts['path'];
            unset($parts['path']);
        }
        // Extract the port number as an integer
        $port = isset($parts['port']) ? intval($parts['port']) : self::DEFAULT_PORT;
        // Get the database from the 'path' part of the URI
        $database = false;
        if (isset($parts['path'])) {
            // Strip non-digit chars from path
            $database = intval(preg_replace('/[^0-9]/', '', $parts['path']));
        }
        // Extract any 'user' and 'pass' values
        $user = isset($parts['user']) ? $parts['user'] : false;
        $pass = isset($parts['pass']) ? $parts['pass'] : false;
        // Convert the query string into an associative array
        $options = array();
        if (isset($parts['query'])) {
            // Parse the query string into an array
            parse_str($parts['query'], $options);
        }
        return array(
            $parts['host'],
            $port,
            $database,
            $user,
            $pass,
            $options,
        );
    }

Above These are the two methods of parsing URLs in PHP. I hope you will like them.

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