PHP is_readable: Check File Accessibility

The PHP is_readable helps you validate file readability before any operation like read or include files.

What Is PHP is_readable?

The is_readable() function checks if a given file or directory exists and whether it can be read. It is a built-in PHP function that returns a boolean value—true if the file is readable and false otherwise.

Here is its syntax:

is_readable($filename)

• Parameter: $filename is the file or directory path you want to check.
• Return Value: The function returns true if the specified file or directory exists and is readable; otherwise, it returns false.

Here is a quick example:

$file = 'example.txt';

if (is_readable($file)) {
    echo "File is readable.";
} else {
    echo "File cannot be read.";
}

The example above checks if example.txt can be read with is_readable. This helps make sure your program won’t crash with unexpected errors.

The Difference Between is_readable and is_file

You may like to check about the below:

• Is this a real file?
• Can I open this file and read it?

PHP gives you different functions to check this. Two common ones are is_file() and is_readable(). Let’s look at what they mean.

The is_file function checks if something is a file. It returns true if the path points to a real file (not a folder).

But, is_readable checks if the file or folder can be read. It returns true if your PHP script has permission to open and read it.

Here is a table that shows you the key differences:

You can use both functions together to make sure:

• The file exists
• It’s really a file
• It can be read

Here is an example:

if (is_file("example.txt") && is_readable("example.txt")) {
    echo "This is a readable file.";
}

Examples of PHP is_readable

Validate a File Before read it:

$configFile = 'config.json';

if (is_readable($configFile)) {
    $content = file_get_contents($configFile);
    echo "Configuration loaded successfully.";
} else {
    echo "Cannot access the configuration file.";
}

This makes sure your script doesn’t crash if the file is inaccessible or doesn’t exist.

Ensure Dynamic Includes Work:

$fileToInclude = 'plugin.php';

if (is_readable($fileToInclude)) {
    include $fileToInclude;
} else {
    echo "Plugin file not found.";
}

When your application dynamically includes files, is_readable verifies the file’s existence and readability.

Handle Directory Readability:

$directory = 'uploads';

if (is_readable($directory)) {
    echo "Directory is accessible.";
} else {
    echo "Directory cannot be read.";
}

You have to know that the function is not limited to files—it also works with directories.

Wrapping It Up

In this article, you learned what the is_readable() function does and how it helps you check if files or directories can be read in PHP. You also understood the difference between is_readable() and is_file().

Here is a quick recap:

• is_readable() checks if a file or folder can be opened and read by your script.
• It returns true if the path exists and is readable and false if it isn’t.
• is_file() checks if the path is a real file (not a folder).
• Use both functions together to be extra safe when you write a code to read or include PHP files.
• is_readable() works with both files and directories.
• You saw examples like how to check for config files. That includes PHP plugins and directories that are readable.

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