Programming
11 February 2011 0 Comments

Upload a File to a PHP Page with C#

How do you upload a file from a C# program to a PHP webpage? Here is a short example.

First we have the C# part that will be sending a file. Using the WebClient object this is quite easily achieved. The code below will upload an image to a PHP script upload.php.

System.Net.WebClient Client = new WebClient();
Client.Headers.Add("Content-Type","binary/octet-stream");
 
byte[] result = Client.UploadFile("http://www.myhost.com/upload.php", "test.gif");
 
string response = System.Text.Encoding.UTF8.GetString(result, 0, result.Length);
Console.WriteLine(response);

I suggest using the binary/octet-stream type because this will also work with things that are not text (images, binary data). The HTTP response generated by the upload.php script will be stored in the response variable and subsequently printed. Be aware that this block can throw an exception, for example when the host / page cannot be found. As for all exceptions: catch them if you have a plan for handling them (i.e. printing an error message in the GUI).

Now for the PHP part.

// The uploaded file will end up in the /upload/ subdirectory of the PHP script location.
$uploaddir = 'upload/'; // Relative Upload Location of data file
 
if (is_uploaded_file($_FILES['file']['tmp_name']))
{
  $uploadfile = $uploaddir . basename($_FILES['file']['name']);
 
  echo "File ". $_FILES['file']['name'] . " uploaded successfully.";
 
  if (move_uploaded_file($_FILES['file']['tmp_name'], $uploadfile))
  {
    echo "File upload succesful!";
  }
  else 
  {
    print_r($_FILES);
  }
}
else
{
  echo "Upload Failed!";
  print_r($_FILES);
}

Note the use of is_uploaded_file(), this is critical to prevent malicious users from tricking you into accessing the wrong file.

Tags: $_FILES, , c sharp, is_uploaded_file, php, uploadfile, webclient