Wkhtmltopdf segfaults

I had the same exact issue as you and I solved it. Here are my findings:

For some reason, the output from wkhtmltopdf goes to STDERR of the process and NOT STDOUT. I have verified this by calling wkhtmltopdf from Java as well as perl

So, for example in java, you would have to do:

//ProcessBuilder is the recommended way of creating processes since Java 1.5 
//Runtime.getRuntime().exec() is deprecated. Do not use. 
ProcessBuilder pb = new ProcessBuilder("wkhtmltopdf.exe", htmlFilePath, pdfFilePath);
Process process = pb.start();

BufferedReader errStreamReader = new BufferedReader(new  InputStreamReader(process.getErrorStream())); 
//not "process.getInputStream()" 
String line = errStreamReader.readLine(); 
while(line != null) 
{ 
    System.out.println(line); //or whatever else
    line = reader.readLine(); 
}

On a side note, if you spawn a process from java, you MUST read from the stdout and stderr streams (even if you do nothing with it) because otherwise the stream buffer will fill and the process will hang and never return.

To futureproof your code, just in case the devs of wkhtmltopdf decide to write to stdout, you can redirect stderr of the child process to stdout and read only one stream like this:

ProcessBuilder pb = new ProcessBuilder("wkhtmltopdf.exe", htmlFilePath, pdfFilePath); 
pb.redirectErrorStream(true); 
Process process = pb.start(); 
BufferedReader inStreamReader = new BufferedReader(new  InputStreamReader(process.getInputStream())); 

Actually, I do this in all the cases where I have to spawn an external process from java. That way I don't have to read two streams.

You should also read the streams of the spawned process in different threads if you dont want your main thread to block, since reading from streams is blocking.

Hope this helps.

UPDATE: I raised this issue in the project page and was replied that this is by design because wkhtmltopdf supports giving the actual pdf output in STDOUT. Please see the link for more details and java code.

or try this (from http://drupal.org/node/870058)

1. Download wkhtmltopdf. Or better install it with a package manager:

   sudo apt-get install wkhtmltopdf
   

2. Extract it and move it to /usr/local/bin/

3. Rename it to wkhtmltopdf so that now you have an executable at /usr/local/bin/wkhtmltopdf
4. Set permissions: sudo chmod a+x /usr/local/bin/wkhtmltopdf

5. Install required support packages.

   sudo apt-get install openssl build-essential xorg libssl-dev
   

6. Check to see if it works: run

   /usr/local/bin/wkhtmltopdf http://www.google.com test.pdf
   

   If it works, then you are done. If you get the error "Cannot connect to X server" then continue to number 7.

7. We need to run it headless on a 'virtual' x server. We will do this with a package called xvfb.

   sudo apt-get install xvfb
   

8. We need to write a little shell script to wrap wkhtmltopdf in xvfb. Make a file called wkhtmltopdf.sh and add the following:

   xvfb-run -a -s "-screen 0 640x480x16" wkhtmltopdf "$@"
   

9. Move this shell script to /usr/local/bin, and set permissions:

   sudo chmod a+x /usr/local/bin/wkhtmltopdf.sh
   

10. Check to see if it works once again: run

    /usr/local/bin/wkhtmltopdf.sh http://www.google.com test.pdf
    

Note that http://www.google.com may throw an error like "A finished ResourceObject received a loading finished signal. This might be an indication of an iframe taking to long to load." You may want to test with a simpler page like http://www.example.com.