Python Flask Subprocess Libreoffice hangs when hosted in IIS

Question

When I run my app from cmd, I'm able to call the api very quickly. But when it is hosted in IIS (fastcgi - wfastcgi.py) the run takes forever and I"m unable to get any return from the api.

import flask

app = flask.Flask(__name__)
app.config["DEBUG"] = True
app.config['UPLOAD_FOLDER'] = 'holding'

@app.route('/test', methods=['GET', 'POST'])
def test():
    import subprocess
    import os
    import re

    libreoffice_exe = 'C:/Program Files/LibreOffice/program/soffice'
    inputFileName = r'D:\folder\some_powerpoint_file.pptx'
    outputFileName = r'D:\folder\output.pdf'

    inputFileName = re.sub('\\\\', '/', inputFileName)
    outputFileName = re.sub('\\\\', '/', outputFileName)

    outputFileDir = os.path.dirname(outputFileName)
    call_item = [libreoffice_exe, '--headless', '--convert-to', 'pdf', inputFileName, '--outdir', outputFileDir]
    proc = subprocess.Popen(
        call_item, 
        stdout=subprocess.PIPE, 
        stderr=subprocess.PIPE
    )
    proc.wait()
    (stdout, stderr) = proc.communicate()
    if proc.returncode != 0:
        print(str(stdout))
        print(str(stderr))
        return 'fail'

    return 'success'

if __name__ == '__main__':
    app.run()

I'm not getting any error output from stderr/stdout.. it just runs indefinitely (until timeout)

Answer 1

Hope this will resolve another person's problem..

This helped me: https://ask.libreoffice.org/en/question/182108/not-able-to-launch-soffice-within-an-application-on-the-iis-server/

What worked for me is to add the argument into the subprocess call: "-env:UserInstallation=[file:///C:/test/NPP]" where [file:///C:/test/NPP] can be any url i believe

call_item = [libreoffice_exe, '-env:UserInstallation=file:///C:/test', '--headless', '--convert-to', 'pdf', inputFileName, '--outdir', outputFileDir]