Starting serverside print job via PHP

Question

This is most likely not an easy one but here is the situation:

I have written a C# command line application which:

• creates a PDF using ITextSharp
• writes it to disk
• uses Acrord32.exe (this is Acrobat Reader) via System.Diagnostics.Process in order to silently print the generated PDF

If I build my solution and double click the pdfGen.exe, it works as expected. The PDF is created and printed.

Now, my app has to be deployed on a internal server with Windows Vista running IIS 7. This server has some PHP webapp running. And it will be called via PHP using shell_exec() so that the resulting PDF will be printed on the printer attached to the server.

So my PHP page looks basically like this:

shell_exec('/path/to/pdfGen.exe');

But here things go wrong. What happens is according to task manager etc.:

• pdfGen.exe starts
• the PDF is created
• Acrord32.exe starts
• pdfGen.exe hangs forever (and so does the PHP script) and nothing is printed

I am pretty sure it is some permission related problem. I already gave IIS_IUSRS access to the default printer, and to the directory where Acrord32.exe is located. But still, no printing. However, if I start my pdfGen.exe manually it works.

Any idea what I am missing?

EDIT:

I am not bound to use Acrobat Reader in order to print the PDF. If there is another way in order to silently print the created PDF serverside, I would not mind at all.

Answer 1

that's an interesting program.

IIS_IUSRS seems to have no permission to print, try adding IIS_IUSRS to Print Operators Group / grant Print permission to the user.

Answer 2

Shell_exec() is almost intended for shell commands (ls/dir, cp, etc.) Have you tried to use exec() instead of shell_exec() ?

Answer 3

In order to check what is going on, try to run the process monitor from Sysinternals and filter the events to the adobe acrobat process. You will see the system calls of acrobat and it will allow you to know more or less what is going wrong.

Answer 4

Thanks all for your comments. Unfortunately this "php start printjob" thing was part of a larger project that was cancelled today because of, well... I dont know... political reasons. Guess the project is pretty much dead.

Anyway, I tried myself a few more times in the last days and could not get it to work with IIS. My solution that I implemented and tested already: remove IIS, install a XAMPP or WAMPP package with a local apache and PHP that runs with admin access rights.

This did the trick. I used pclose(popen('...command...', 'r')); in PHP in order to start the .exe and so that PHP does not wait until the PDF is finished. It all worked great.

Here is my C# code which starts the print job using Acrobat Reader

    public void Print(string pathname, string acrobatDirectory)
    {
        var proc = new Process
        {
            StartInfo =
            {
                Arguments               = String.Format("/t \"{0}\"", pathname),
                FileName = acrobatDirectory,
                UseShellExecute         = false,
                CreateNoWindow          = true,
                RedirectStandardOutput  = false,
                RedirectStandardError   = false,
            }
        };

        proc.Start();  
    }

The first argument is the path to the PDF that should be printed, the second parameter is the absolute path to the AcroRd32.exe.

The only problem left was that AcroRd32.exe was started, printed and never got closed again. So every printjob started a new instance of AcroRd32.exe (I am using Acrobat Reader 9.0). So if you printed 10 times, 10 acrobat reader instances were created.

What I did was starting the print job, then waiting X seconds, hoping that the printer was finished and then killing all AcroRd32.exe instances:

    public void Print(string pathname, string acrobatDirectory)
    {
        Debug.WriteLine("Printing...");

        Printer.Print(pathname, acrobatDirectory);

        Thread.Sleep(30000);

        try
        {
            Debug.WriteLine("Trying to kill runnung AcroRd32.exe's ");

            FindAndKillProcess("AcroRd32");
        }
        catch (Exception)
        {
            Debug.WriteLine("AcroRd32.exe could not be killed...");
        }
    }

    private bool FindAndKillProcess(string name)
    {
     foreach (Process clsProcess in Process.GetProcesses()) {
      if (clsProcess.ProcessName.StartsWith(name))
      {
       clsProcess.Kill();
       return true;
      }
     }

     return false;
    }

This worked out quite well.

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Note that the above (killing all AcroRd32.exe and running PHP with admin privilegs) was only doable because: The whole thing is only used by one user at a time and has a very limited area of use.

It should be used on a touchscreen application deployed at the clients POS. A salesman would use the PHP app in order to configure a product, and then PHP would call my .exe which would create and print a PDF in the background. The printed document is then handed to the client. So security etc. was not really a concern in this case.

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If anyone has a solution in order to use it with IIS, I am still willing to accept it as an answer.