# URL Functions

## Introduction

Dealing with URL strings: encoding, decoding and parsing.

## Requirements

No external libraries are needed to build this extension.

## Installation

There is no installation needed to use these functions; they are part of the PHP core.

## Runtime Configuration

This extension has no configuration directives defined in php.ini.

## Resource Types

This extension has no resource types defined.

## Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

The following constants are meant to be used with parse_url() and are available since PHP 5.1.2.

`PHP_URL_SCHEME` (integer)
`PHP_URL_HOST` (integer)
`PHP_URL_PORT` (integer)
`PHP_URL_USER` (integer)
`PHP_URL_PASS` (integer)
`PHP_URL_PATH` (integer)
`PHP_URL_QUERY` (integer)
`PHP_URL_FRAGMENT` (integer)

## Table of Contents

- base64_decode — Decodes data encoded with MIME base64
- base64_encode — Encodes data with MIME base64
- get_headers — Fetches all the headers sent by the server in response to a HTTP request
- get_meta_tags — Extracts all meta tag content attributes from a file and returns an array
- http_build_query — Generate URL-encoded query string
- parse_url — Parse a URL and return its components
- rawurldecode — Decode URL-encoded strings
- rawurlencode — URL-encode according to RFC 1738
- urldecode — Decodes URL-encoded string
- urlencode — URL-encodes string