PHP is_file Function: Check if a File Exists

If you are working with PHP and need a way to confirm if something is indeed a file, the is_file function will be the fit for this task.

In this tutorial, I will walk you through everything you need to know about is_file. You will learn how it works, its syntax, and how to use it.

What is is_file?

The is_file function in PHP is a built-in tool that checks if a given path points to a regular file. This is different from checking if something exists in general because is_file specifically verifies if the path leads to an actual file—not a directory, symbolic link, or any other type of filesystem object.

If You have a directory named “data” and a file named “data.txt” in the same location. If your code assumes “data” refers to a file, it could lead to some frustrating bugs.

Using is_file ensures you are targeting the right object. It is particularly useful when:

• Validating user-uploaded files.
• Preventing accidental overwriting of directories.
• Building scripts that process specific file types.

Anyway, here is the syntax of is_file:

// It returns boolean type
is_file(string $filename)

Here is how it works:

• Parameter: It takes one argument, $filename, which is the path to the file you want to check.
• Return Value: It returns true if the path points to a valid file and false otherwise.

Here is a comparing table for is_file with other file functions:

Function	Purpose	Returns
is_file	Checks if a path is a file.	true/false
file_exists	Checks if a file or directory exists.	true/false
is_dir	Checks if a path is a directory.	true/false
is_readable	Checks if a file is readable.	true/false

In the following section, you will see an example about is_file in PHP. let’s move on.

PHP is_file Example

Here, I have to check if the file already exists before trying to read it.

$filePath = "documents/report.txt";

if (is_file($filePath)) {
    echo "The file exists";
} else {
    echo "This file is not acceptable.";
}

It checks if report.txt is an actual file. If the file is available, it continues the script; otherwise, it handles error and outputs a message.

Let’s summarize it.

Wrapping Up

The is_file is an built-in function in PHP that validates whether a path is pointing to a file.

Thus, when handling uploads, processing or storing data (temporary files), or just managing your projects, is_file gives you another roadblock to write code securely.