If processing a request fails, by default Klein (and Twisted) show an error page that prints the traceback and other useful debugging information.
This is not desirable when you deploy code publicly, in such a case, you should disable this behaviour.
There are multiple ways to do this, you can do this on a Klein-app scope or change the default for the python process.
We will use following Klein app:
from klein import Klein
app = Klein()
@app.route('/OK')
def requestOK(self, request):
return 'OK'
@app.route('/KO')
def requestKO(self, request):
raise RuntimeError('Oops')
This works by passing the displayTracebacks
argument as False
to app.run
.
if __name__ == '__main__':
import sys
displayTracebacks = '--production' not in sys.args
# The Klein app will not display tracebacks if the script is called
# with a --production argument, but it will otherwise.
app.run('localhost', 8080, displayTracebacks=displayTracebacks)
This method also affects other Twisted Sites.
Under the hood, Klein uses twisted.web.server.Site
, which has an
instance variable displayTracebacks
that defaults to True
.
For the rationale behind that, check trac#135.
# Disable tracebacks by default for any Site object.
from twisted.web.server import Site
Site.displayTracebacks = False
if __name__ == '__main__':
# The Klein app won't display tracebacks
app.run('localhost', 8080)