PHP file_get_contents() Function

The PHP file_get_contents() function reads a file into a string.

This function is similar to file(), except that file_get_contents() returns the file in a string, starting at the specified offset up to the specified length bytes. On failure, file_get_contents() returns false.

This function is the preferred way to read the contents of a file into a string. It will use memory mapping techniques if supported by the server, to enhance performance.

Syntax

file_get_contents(filename, use_include_path,
                  context, offset, length)

Parameters

`filename`	`Required.` Specify the path to the file to read.
`use_include_path`	`Optional.` Set to '1' or true if you want to search for the file in the include_path, too. include_path can be set in php.ini.
`context`	`Optional.` Specify a valid context resource created with stream_context_create() function. Context is a set of options that can modify the behavior of a stream. Can be skipped by using null.
`offset`	`Optional.` Specify the offset where the reading starts on the original stream. Negative offsets count from the end of the stream. Seeking (offset) is not supported with remote files.
`length`	`Optional.` Specify the maximum length of data to read. The default is to read until end of file is reached.

Return Value

Returns the read data or false on failure.

Note: This function may return Boolean false, but may also return a non-Boolean value which evaluates to false. Therefore, use === operator for testing the return value of this function.

Exceptions

Generates an E_WARNING level error if filename is not found, length is less than zero, or if seeking to the specified offset in the stream fails. When this function is called on a directory, an E_WARNING level error is generated on Windows, and as of PHP 7.4 on other operating systems as well.

Example: reading a file

Lets assume that we have a file called test.txt. This file contains following content:

This is a test file.
It contains dummy content.

In the example below, file_get_contents() function is used to read the content of it.

<?php
$file = "test.txt";

//reading the content of the file
//and displaying it
echo file_get_contents($file)."\n";
?>

The output of the above code will be:

This is a test file.
It contains dummy content.

Example: reading a section of a file

By using offset and length parameters, we can specify from where to start reading and maximum length of data to read.

<?php
$file = "test.txt";

//using offset and length parameters
echo file_get_contents($file, false, null, 21, 18);
?>

The output of the above code will be:

It contains dummy

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