Syntax:

file_get_contents(string $filename, bool $use_include_path = false, resource $context = null, int $offset = 0, int $length = -1)

Parameters:

• $filename: The file path or URL from which to read the contents.
• $use_include_path (optional): If set to true, PHP will search for the file in the include path.
• $context (optional): A valid context resource created with stream_context_create() (used for advanced stream options).
• $offset (optional): The starting point in the file from where to begin reading.
• $length (optional): The maximum number of bytes to read. Defaults to -1, meaning read the entire file.

Return Value:

It returns the file contents as a string on success or false on failure.

Example 1: Reading a Local File

<?php
$filename = "example.txt";
$content = file_get_contents($filename);

if ($content !== false) {
    echo "File contents: \n" . $content;
} else {
    echo "Error reading the file.";
}
?>

This example reads the contents of example.txt and prints them. If the file is not found or an error occurs, it will display an error message.

Example 2: Reading a URL

<?php
$url = "https://www.example.com";
$content = file_get_contents($url);

if ($content !== false) {
    echo "Content fetched from URL: \n" . $content;
} else {
    echo "Error fetching the URL.";
}
?>

This example fetches the HTML content from the specified URL and prints it.

Example 3: Using Offset and Length to Read a Portion of a File

<?php
$filename = "example.txt";
$content = file_get_contents($filename, false, null, 5, 10);  // Start at offset 5, read 10 characters

if ($content !== false) {
    echo "Part of file content: \n" . $content;
} else {
    echo "Error reading the file.";
}
?>

In this example, the function starts reading from byte 5 and retrieves the next 10 characters.

Example 4: Handling Errors with file_get_contents()

<?php
$filename = "nonexistentfile.txt";
$content = @file_get_contents($filename);

if ($content === false) {
    echo "File could not be read.";
} else {
    echo $content;
}
?>

Here, the @ operator suppresses error messages, and if the file doesn't exist, file_get_contents() will return false.

Example 5: Using Context for Custom HTTP Headers (Fetching a URL with Headers)

<?php
$context = stream_context_create([
    'http' => [
        'header' => "User-Agent: PHP\r\n"
    ]
]);
$url = "https://www.example.com";
$content = file_get_contents($url, false, $context);

if ($content !== false) {
    echo "Content fetched with custom header: \n" . $content;
} else {
    echo "Error fetching the URL.";
}
?>

This example creates a stream context with custom HTTP headers and fetches content from a URL using those headers.

Key Points:

• file_get_contents() is suitable for smaller files or when you want to quickly retrieve file content.
• For large files, it might be better to use other methods like fopen() and fread() to avoid memory issues.
• Be careful when reading files from external URLs to prevent security risks like SSRF (Server-Side Request Forgery).