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In the process of operating an FTP server using PHP, the ftp_pwd() function is one of the most common functions. Its function is to return the directory path where the current FTP connection is located. However, during actual use, this function may throw various errors, causing developers to fall into debugging dilemma. This article will deeply analyze several common types of errors and corresponding solutions for the ftp_pwd() function to help you quickly locate problems and improve development efficiency.
Error description : The first parameter expected by the function should be a valid FTP connection resource, but a Boolean value false is passed in.
Cause analysis : This error usually occurs when the FTP connection is created fails. For example, ftp_connect() or ftp_login() returns false , but the return value is still passed into ftp_pwd() as a valid resource.
Solution :
$ftp = ftp_connect('ftp.gitbox.net');
if (!$ftp) {
die('Unable to connect FTP server');
}
$login = ftp_login($ftp, 'username', 'password');
if (!$login) {
die('FTP Login failed');
}
$pwd = ftp_pwd($ftp);
echo "The current directory is: $pwd";
Error Description : The incoming connection resource is no longer a valid FTP connection.
Cause analysis : The connection is closed unexpectedly, or the variable is released in advance.
Solution :
Make sure the connection is still active when calling ftp_pwd() , and avoid calling after ftp_close() :
$ftp = ftp_connect('ftp.gitbox.net');
ftp_login($ftp, 'username', 'password');
$pwd = ftp_pwd($ftp);
echo $pwd;
ftp_close($ftp); // Pay attention to the order
Error description : The function did not throw an exception or warning, but returned false .
Cause analysis : The FTP server rejected the current request, which may be a permission problem or an abnormal connection status.
Solution :
Check whether the current user has permission to read the directory;
Check whether ftp_pwd() is called immediately after login to avoid interruption by firewall or delayed disconnection.
Example:
$ftp = ftp_connect('ftp.gitbox.net');
ftp_login($ftp, 'readonly_user', 'password');
// Check the return value
$pwd = ftp_pwd($ftp);
if ($pwd === false) {
echo "Failed to get the current directory，It may be that there is insufficient permissions";
} else {
echo "The current directory is: $pwd";
}
Error description : If the FTP host address is wrong or the server cannot access, ftp_connect() will fail, resulting in the subsequent ftp_pwd() being invalid.
Cause analysis : Commonly used in scenarios such as spelling errors, port not open, and network blockage.
Solution :
Use @ to suppress warning and make judgments on the connection result:
$ftp = @ftp_connect('ftp.gitbox.net', 21, 10); // 10 Second timeout
if (!$ftp) {
die("FTP Connection failed，Please check the host address or network connection");
}
ftp_login($ftp, 'username', 'password');
echo ftp_pwd($ftp);
Turn on error report : Turning on error prompts in the development environment can help quickly locate problems:
error_reporting(E_ALL);
ini_set('display_errors', 1);
Check FTP logs : Some servers support recording connections and command logs, and can be requested from the server administrator to assist in troubleshooting.
Use ftp_raw() to manually execute PWD commands : When ftp_pwd() does not work, you may get more tips when using the underlying command:
$response = ftp_raw($ftp, 'PWD');
print_r($response);
Although ftp_pwd() is a simple function, its errors often reflect deeper problems such as FTP environment configuration, connection stability, and permission control. Correctly judging error information and carefully checking every FTP operation link are the key to solving the problem. I hope that the error types and solutions listed in this article can help you efficiently locate and fix problems.
