Ftp_nb_get()

Understanding the PHP Function ftp_nb_get()

The ftp_nb_get() function is a built-in PHP function that downloads a file from the FTP server using non-blocking mode. In this article, we'll discuss the function in detail and provide you with a comprehensive guide to using it in your PHP projects.

What is ftp_nb_get()?

The ftp_nb_get() function is a PHP built-in function that downloads a file from the FTP server using non-blocking mode. The function takes three parameters:

1. ftp_stream: The connection identifier returned by the ftp_connect() function.
2. local_file: The local file path where the file will be saved.
3. remote_file: The remote file path.

The function returns true if the operation was successful. Otherwise, it returns false.

Syntax of ftp_nb_get()

The syntax of the ftp_nb_get() function is as follows:

int ftp_nb_get ( resource $ftp_stream , string $local_file , string $remote_file , int $mode [, int $resumepos = 0 ] )

The ftp_nb_get() function takes three required parameters, ftp_stream, local_file, and remote_file, and two optional parameters, mode and resumepos. The ftp_stream parameter is the connection identifier returned by the ftp_connect() function. The local_file parameter is the path to the local file where the downloaded file will be saved. The remote_file parameter is the path to the remote file on the FTP server. The mode parameter specifies the transfer mode, either FTP_ASCII or FTP_BINARY. The resumepos parameter specifies the position in the remote file to start the download from. By default, resumepos is set to 0, which means the download will start from the beginning of the file.

Usage of ftp_nb_get()

To use the ftp_nb_get() function, you first need to establish a connection to the FTP server using the ftp_connect() function. Here's an example:

<?php

// Set up an FTP connection
$conn = ftp_connect('ftp.example.com');

// Login with your FTP credentials
ftp_login($conn, 'username', 'password');

// Initiate an asynchronous FTP operation
ftp_nb_get($conn, 'local_file.txt', 'remote_file.txt', FTP_BINARY);

// Continue the asynchronous FTP operation
while (ftp_nb_continue($conn)) {
    // Do something else while waiting for the FTP operation to complete
}

// Close the FTP connection
ftp_close($conn);

In this example, we establish a connection to the FTP server using the ftp_connect() function. Then we log in using our FTP credentials using the ftp_login() function. We initiate an asynchronous FTP operation using the ftp_nb_get() function. We continue the operation using the ftp_nb_continue() function and close the FTP connection.

Error handling in ftp_nb_get()

It's important to handle errors properly when using the ftp_nb_get() function. If the function returns false, it means that the download was unsuccessful. Here's an example of how to handle errors:

<?php

$download_successful = ftp_nb_get($conn, 'local_file.txt', 'remote_file.txt', FTP_BINARY);

if (!$download_successful) {
    echo "Failed to download file from remote server.\n";
}

while (ftp_nb_continue($conn)) {
    // Do something else while waiting for the FTP operation to complete
}

ftp_close($conn);

By handling errors appropriately and checking the return value of the function, you can ensure the success of your FTP operations using the ftp_nb_get() function.

Conclusion

In conclusion, the ftp_nb_get() function is a useful tool for downloading files from an FTP server using non-blocking mode.