post - PHP: upload file from one server to another server

Question

I'm developing a website in a server and the storage is in another server and I have to deal with that somehow. I nerve experience this case and I found that the solution is to use curl.

Kindly explain to me how to use Curl in detail from zero.

Update:

I use the following code to test if cURL is installed and enabled:

<?PHP
phpinfo(); 

$toCheckURL = "http://board/accSystem/webroot/";
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $toCheckURL);
curl_setopt($ch, CURLOPT_HEADER, true);
curl_setopt($ch, CURLOPT_NOBODY, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($ch, CURLOPT_MAXREDIRS, 10);
$data = curl_exec($ch);
curl_close($ch);
preg_match_all("/HTTP/1.[1|0]s(d{3})/",$data,$matches);
$code = end($matches[1]);
if(!$data) {
  echo "Domain could not be found";
} else {
  switch($code) {
    case '200':
      echo "Page Found";
      break;
    case '401':
      echo "Unauthorized";
      break;
    case '403':
      echo "Forbidden";
      break;
    case '404':
      echo "Page Not Found";
      break;
    case '500':
      echo "Internal Server Error";
      break;
  }
}
?>

Here is the result:

And I got (Page found) message

Now I can use cURL without worry, right ?

Note: Both servers are local

Answer 1

As a PHP developer, you may already be familiar with PHP's most handy file system function, fopen. The function opens a file stream and returns a resource which can then be passed to fread or fwrite to read or write data. Some people don't realize though that the file resource doesn't necessarily have to point to a location on the local machine.

Here's an example that transfers a file from the local server to an ftp server:

$file = "filename.jpg";
$dest = fopen("ftp://username:password@example.com/" . $file, "wb");
$src = file_get_contents($file);
fwrite($dest, $src, strlen($src));
fclose($dest); 

A listing of different protocols that are supported can be found in Appendix M of the PHP manual. You may wish to use a protocol that employs some encryption mechanism such as FTPS or SSH depending on the network setup and the sensitivity of the information youa€?re moving.

The curl extension makes use of the Client URL Library (libcurl) to transfer files. The logic of implementing a curl solution generally follows as such: first initialize a session, set the desired transfer options, perform the transfer and then close the session.

Initializing the curl session is done with the curl_init function. The function returns a resource you can use with the other curl functions much as how a resource is obtained with fopen in the file system functions.

The upload destination and other aspects of the transfer session are set using curl_setopt which takes the curl resource, a predefined constant representing the setting and the optiona€?s value.

Here's an example that transfers a file from the local host to a remote server using the HTTP protocol's PUT method:

$file = "testfile.txt";

$c = curl_init();
curl_setopt($c, CURLOPT_URL, "http://example.com/putscript");
curl_setopt($c, CURLOPT_USERPWD, "username:password");
curl_setopt($c, CURLOPT_RETURNTRANSFER, true);
curl_setopt($c, CURLOPT_PUT, true);
curl_setopt($c, CURLOPT_INFILESIZE, filesize($file));

$fp = fopen($file, "r");
curl_setopt($c, CURLOPT_INFILE, $fp);

curl_exec($c);

curl_close($c);
fclose($fp); 

A list of valid options for curl can be found in the php documentation.

The ftp extension allows you to implement client access to ftp servers. Using ftp to transfer a file is probably overkill when options like the previous two available... ideally this extension would be best used more advanced functionality is needed.

A connection is made to the ftp server using ftp_connect. You authenticate your session with the ftp server using ftp_login by supplying it a username and password. The file is placed on the remote server using the ftp_put function. It accepts the name of the destination file name, the local source file name, and a predefined constant to specify the transfer mode: FTP_ASCII for plain text transfer or FTP_BINARY for a binary transfer. Once the transfer is complete, ftp_close is used to release the resource and terminate the ftp session.

$ftp = ftp_connect("ftp.example.com");
ftp_login($ftp, "username", "password");
ftp_put($ftp, "destfile.zip", "srcfile.zip", FTP_BINARY); 
ftp_close($ftp);