Syntax:
This function can take five arguments. It returns the entire or particular content of a file if the file exists otherwise returns False.
- The first argument is mandatory and it takes the filename that will be read by this function.
- The second argument is optional and the default value of this argument is False. It the value of this argument is set to True then the file will be searched in the path that is used in the include_path value of the php.ini file.
- The third argument is optional that is used to specify the valid context resource or null.
- The fourth argument is optional that is used to set the starting position for reading the file content.
- The fifth argument is optional that is used to set the maximum length of data that will be read from the file.
Different Uses of file_get_contents() Function
Create or select an existing file for reading by using file_get_contents() function. Here, a text file named os.txt has been created with the following content to use in the examples of this tutorial.
os.txt
Windows 10
Windows 8
Windows 7
Ubuntu 20.10
Ubuntu 20.04
Ubuntu 19
Ubuntu 18
Ubuntu 17
macOS Monterey 12.0.1
OS X El Capitan 10.11.6
Mac OS X Puma 10.1.5
Example-1: Read the Entire File
Create a PHP file with the following script to read the content of an existing file. The file_exists() function has been used to check the file exists or not before reading. The is_readable() function has been used to check the read permission of the file. If the file exists and the file has the read permission then the content of the file will be printed by using the file_get_contents() function.
//Set an filename
$filename = 'os.txt';
//Check the file exists or not
if (!file_exists($filename)) {
echo 'File does not exist.';
}
//Check the file has the read permission or not
else if (!is_readable($filename)) {
echo 'File has no read permission.';
}
//Print the entire content of the file
else
echo file_get_contents($filename);
?>
Output:
The following output will appear executing the above script. Here, the newline has been omitted.
Example-2: Read the File Partially
Create a PHP file with the following script to read some particular portion of a file instead of reading the full content by using the file_get_contents() function. Here, the filename will be taken from the URL query parameter. Next, the existence and read permission of the file will be checked. The particular portion of the file will read based on the positive starting position and the length and the negative starting position and the length.
//Check the filename is provided in the URL Query parameter or not
if(isset($_GET['fn']))
{
//Set an filename
$filename = $_GET['fn'];
//Check the file exists or not
if (!file_exists($filename)) {
echo 'File does not exist.';
}
//Check the file has the read permission or not
else if (!is_readable($filename)) {
echo 'File has no read permission.';
}
else
{
//Print the particular portion of the file based on positive starting position
echo "<b>Output for the positive starting position:</b><br/>".file_get_contents($filename, null, null, 5, 30);
//Print the particular portion of the file based on negative starting position
echo "<br/><b>Output for the negative starting position:</b><br/>".file_get_contents($filename, null, null, -24,
20);
}
}
else
//Print message if the filename is not found
echo "Filename has not given."
?>
Output:
The following output will appear executing the above script without giving the filename in the URL.
The following output will appear executing the above script if the filename, os.txt is given in the URL parameter that has been created before.
The following output will appear executing the above script if any non-existence file is given in the URL parameter.
Example-3: Read the File Using the include_path Parameter
The value of the include_path parameter has to be set in the php.ini file. The path of this file on Ubuntu is ‘/etc/php/8.0/apache2/php.ini’. Open the file and set the path of the file from where the file will be read. The second argument of the file_get_contents() is required to set true or FILE_USE_INCLUDE_PATH to read the file from the path defined in the include_path parameter.
//Set an filename
$filename = 'customers.txt';
//Set the second argument value to true
echo "<b>Output-1:</b><br/>".file_get_contents($filename, true);
//Set the second argument value to FILE_USE_INCLUDE_PATH
echo "<br/><b>Output-2:</b><br/>".file_get_contents($filename, FILE_USE_INCLUDE_PATH);
?>
Output:
The following output will appear executing the above script.
Example-5: Read the Content of a URL Using Curl
You have to install the PHP curl library to read the content of an URL address. Run the following command to install the PHP curl module.
Open the php.ini file and remove the semicolon (;) from the curl extension to enable it.
Create a PHP file with the following script to read the content of an URL address that will be provided in the URL query parameter named url. If the URL address exists, then the content of the URL address will be printed.
//Check the URL address is provided in the URL Query parameter or not
if(isset($_GET['url']))
{
//Set the URL value
$url = $_GET['url'];
//Use the CURL library to check the existence of the URL
$curl = curl_init($url);
curl_setopt($curl, CURLOPT_NOBODY, true);
if (curl_exec($curl) !== false)
//Read the page of the URL address
echo file_get_contents($url);
else
echo "URL does not exist.";
}
else
echo "URL value has not given.";
?>
Output:
The following output will appear executing the above script if no URL address is provided.
The following output will appear executing the above script if the valid URL address, ‘https://linuxhint.com/bash_comments/’ is given.
Example-6: Read the Content of the URL Using Stream Context
Create a PHP file with the following script to read the content of a valid URL address using stream_context_create() and file_get_contents() functions. Here, the second and third arguments of the file_get_contents() has used to read the content of ‘http://www.example.com/’.
//Create stream for read content of the URL
$options = array(
'http'=>array(
'method'=>"GET",
'header'=>"Accept-language: en\r\n"
)
);
//Set the context value
$context = stream_context_create($options);
//Read the content of the URL using the HTTP headers
echo file_get_contents('http://www.example.com/', false, $context);
?>
Output:
The following output will appear executing the above script.
Conclusion
The different ways to read the content of a file from different locations and URL addresses by using file_get_contents() have shown in this tutorial. I hope the PHP user will be able to use this function properly after reading this tutorial.
