在 Tornado 3 中使用 wekzeug 的调试工具。

tornado3_werkzeug.py

from werkzeug.debug.tbtools import get_current_traceback as get_traceback_context
from werkzeug.debug import DebuggedApplication
import tornado.ioloop
import tornado.web
import tornado.wsgi


class Handler(tornado.web.RequestHandler):
    def get_error_html(self, status_code, **kwargs):
        assert isinstance(self.application, DebugApplication)
        traceback = self.application.get_current_traceback()
        keywords = self.application.get_traceback_renderer_keywords()
        html = traceback.render_full(**keywords).encode('utf-8', 'replace')
        return html.replace(b'WSGI', b'tornado')


class BrokenHandler(Handler):
    def get(self):
        raise Exception('A Test Exception')
        self.write("You'll never get this!")


class DebugApplication(tornado.web.Application):
    def __init__(self, *args, **kwargs):
        self.debug_app = DebuggedApplication(self.debug_wsgi_app, evalex=True)
        self.debug_container = tornado.wsgi.WSGIContainer(self.debug_app)
        super(DebugApplication, self).__init__(*args, **kwargs)

    def __call__(self, request):
        if '__debugger__' in request.uri:
            return self.debug_container(request)
        return super(DebugApplication, self).__call__(request)

    @classmethod
    def debug_wsgi_app(cls, environ, start_response):
        status =  '500 Internal Server Error'
        response_headers = [('Content-type', 'text/plain')]
        start_response(status, response_headers)
        return ['Failed to load debugger.\n']

    def get_current_traceback(self):
        traceback = get_traceback_context(skip=2, show_hidden_frames=False, ignore_system_exceptions=True)
        for frame in traceback.frames:
            self.debug_app.frames[frame.id] = frame
        self.debug_app.tracebacks[traceback.id] = traceback
        return traceback

    def get_traceback_renderer_keywords(self):
        return dict(evalex=self.debug_app.evalex, secret=self.debug_app.secret)


if __name__ == '__main__':
    handlers = [('/', BrokenHandler), ]
    app = DebugApplication(handlers, debug=True)
    app.listen(8888)
    tornado.ioloop.IOLoop.instance().start()