How to copy files in PHP using SCP – Step-by-Step

When it comes to moving files securely between servers, using SCP in PHP is a solid choice. This method uses the Secure Copy Protocol (SCP) to transfer files over SSH, ensuring everything stays safe during the process. In this guide, I’ll show you how to set it up and use it, so you can get files where they need to be without any headaches.

What you will need

Before diving into the setup, make sure your environment has these:

• PHP Installed: Your server should have PHP installed. If you’re not sure, run php -v to check.
• SSH2 Extension: PHP needs the SSH2 extension enabled for this to work. Use phpinfo() to confirm it’s active. If not, you’ll need to install it.

How to Install the SSH2 Extension

If the SSH2 extension isn’t installed yet, here’s a quick way to get it running:

For Linux

1. Open your terminal and run this command to install the required libraries:
   sudo apt-get install libssh2-1-dev libssh2-php
2. Add the extension to your php.ini file:
   extension=ssh2.so
3. Restart your server:
   sudo service apache2 restart

For Windows

1. Download the right DLL file for your PHP version from PECL.
2. Move the DLL file into your PHP ext directory (usually something like C:\php\ext).
3. Edit your php.ini file and add this line:
   extension=php_ssh2.dll
4. Restart your web server to apply the changes.

Copy Files from Local to Remote Server

Now, let’s transfer a file from your local server to a remote server using SCP in PHP.

1. Start by creating an SSH connection. $connection = ssh2_connect('remote.server.com', 22); ssh2_auth_password($connection, 'username', 'password'); Replace 'remote.server.com' with your remote server’s address, and fill in your username and password.
2. Once connected, use ssh2_scp_send() to send the file: ssh2_scp_send($connection, '/local/path/to/file.txt', '/remote/path/to/file.txt', 0644); Update the paths to point to your file’s location and the destination on the remote server.

Copy Files from Remote to Local Server

Want to copy files the other way around? No problem. Here’s how you can bring a file from a remote server to your local machine.

1. Just like before, start with the SSH connection: $connection = ssh2_connect('remote.server.com', 22); ssh2_auth_password($connection, 'username', 'password');
2. Then, use ssh2_scp_recv() to pull the file: ssh2_scp_recv($connection, '/remote/path/to/file.txt', '/local/path/to/file.txt'); Make sure the paths reflect where your file is located and where you want to save it.

Use SSH Keys for Better Security

Passwords work, but using SSH keys for authentication is safer and more convenient. With key-based authentication, you won’t need to type your password every time.

Generate SSH Keys

1. On your local computer, open a terminal and run this:
   ssh-keygen -t rsa -b 4096
2. It will generate two files: a private key and a public key.
3. Copy the contents of your public key to the remote server’s ~/.ssh/authorized_keys file.

Update Your PHP Code

When using keys, update your connection code like this:

$connection = ssh2_connect('remote.server.com', 22);  
ssh2_auth_pubkey_file($connection, 'username', '/path/to/id_rsa.pub', '/path/to/id_rsa');  

Final Thoughts

Copying files with SCP in PHP doesn’t have to be complicated. Whether you’re using passwords or SSH keys, the SSH2 extension provides a reliable way to get the job done. With the steps in this guide, you’ll have a secure and smooth file transfer process ready to go.

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