How can I log request POST body in Flask?

Question

I'm using flask server, and I want to log each request data and header (so I can use it afterwards to test my server). I took the werkzeug logger with

    self._app.log = logging.getLogger('werkzeug')
    self._app.log.addHandler(RotatingFileHandler('log.txt', mode='w'))
    self._app.log.setLevel(logging.DEBUG)

But I don't understand how to change the log format to include request.data and request.headers, all I have is the default log

    127.0.0.1 - - [17/Feb/2015 17:09:43] "POST /helloworld HTTP/1.1" 200 -

Solution

You can log additional info for each request with a Flask.before_request hook:

@app.before_request
def log_request_info():
    app.logger.debug('Headers: %s', request.headers)
    app.logger.debug('Body: %s', request.get_data())

Comments

[Martijn Pieters]

Flask includes logging setup; app.logger gives you a pre-configured logging logger.

[Pedro Caseiro]

When implementing this solution, please be aware that this logs every request, including login and registration endpoints. You'll log user's passwords in plain text if frontend sends it in plaintext.