commit 7e21184d4432b4c25f775eb27aa8b9de68d650b5 Author: Isis Lovecruft <isis@torproject.org> Date: Tue Jan 28 17:01:57 2014 +0000 Implement a simple error page to replace all webserver tracebacks. * ADD HTTPServer.replaceErrorPage() function for catching templating errors and sending them to the logger. The user is served a very simply "Somthing went wrong page". * CHANGE all calls to mako.templates.Template.render() to be wrapped in a try/except block which directs to the new HTTPServer.replaceErrorPage() function. --- lib/bridgedb/HTTPServer.py | 87 +++++++++++++++++++++++++++++++++----------- 1 file changed, 66 insertions(+), 21 deletions(-) diff --git a/lib/bridgedb/HTTPServer.py b/lib/bridgedb/HTTPServer.py index 104e924..5794be7 100644 --- a/lib/bridgedb/HTTPServer.py +++ b/lib/bridgedb/HTTPServer.py @@ -34,6 +34,7 @@ from bridgedb.Filters import filterBridgesByNotBlockedIn from bridgedb.parse import headers from ipaddr import IPv4Address, IPv6Address from random import randint +import mako.exceptions from mako.template import Template from mako.lookup import TemplateLookup from zope.interface import Interface, Attribute, implements @@ -66,6 +67,39 @@ else: logging.info("GeoIP database loaded") +def replaceErrorPage(error, template_name=None): + """Create a general error page for displaying in place of tracebacks. + + Log the error to BridgeDB's logger, and then display a very plain "Sorry! + Something went wrong!" page to the client. + + :type error: :exc:`Exception` + :param error: Any exeption which has occurred while attempting to retrieve + a template, render a page, or retrieve a resource. + :param str template_name: A string describing which template/page/resource + was being used when the exception occurred, + i.e. ``'index.html'``. + :returns: A string containing HTML to serve to the client (rather than + serving a traceback). + """ + logging.error("Error while attempting to render %s: %s" + % (template_name or 'template', + mako.exceptions.text_error_template().render())) + + errmsg = _("Sorry! Something went wrong with your request.") + rendered = """<html> + <head> + <link href="/assets/bootstrap.min.css" rel="stylesheet"> + <link href="/assets/custom.css" rel="stylesheet"> + </head> + <body> + <p>{0}</p> + </body> + </html>""".format(errmsg) + + return rendered + + class CaptchaProtectedResource(twisted.web.resource.Resource): def __init__(self, useRecaptcha=False, recaptchaPrivKey='', recaptchaPubKey='', useForwardedHeader=False, resource=None): @@ -97,18 +131,17 @@ class CaptchaProtectedResource(twisted.web.resource.Resource): logging.fatal("Connection to Recaptcha server failed: %s" % error) if c.image is None: - # TODO: We should have a general "Something went wrong!" page - # which displays here, rather than displaying the img alt text - # (which says "Upgrade your browser to Firefox"), so that users - # don't think the problem is on their end when it's actually a - # problem with ReCaptcha or BridgeDB. logging.warn("No CAPTCHA image received from ReCaptcha server!") - c.image = '' - # TODO: this does not work for versions of IE < 8.0 - imgstr = 'data:image/jpeg;base64,%s' % base64.b64encode(c.image) - template = lookup.get_template('captcha.html') - rendered = template.render(imgstr=imgstr, challenge_field=c.challenge) + try: + # TODO: this does not work for versions of IE < 8.0 + imgstr = 'data:image/jpeg;base64,%s' % base64.b64encode(c.image) + template = lookup.get_template('captcha.html') + rendered = template.render(imgstr=imgstr, + challenge_field=c.challenge) + except Exception as err: + rendered = replaceErrorPage(err, 'captcha.html') + return rendered def render_POST(self, request): @@ -135,21 +168,27 @@ class CaptchaProtectedResource(twisted.web.resource.Resource): randint(1,255),randint(1,255)) recaptcha_response = captcha.submit(challenge, response, - self.recaptchaPrivKey, remote_ip) + self.recaptchaPrivKey, remote_ip) + logging.debug("Captcha from client with masked IP %r. Parameters:\n%r" + % (remote_ip, request.args)) + if recaptcha_response.is_valid: - logging.info("Valid recaptcha from %s. Parameters were %r" - % (remote_ip, request.args)) - return self.resource.render(request) + logging.info("Valid recaptcha from client with masked IP %r." + % remote_ip) + try: + rendered = self.resource.render(request) + except Exception as err: + rendered = replaceErrorPage(err) + return rendered else: - logging.info("Invalid recaptcha from %s. Parameters were %r" - % (remote_ip, request.args)) - logging.info("Recaptcha error code: %r" - % recaptcha_response.error_code) + logging.info("Invalid recaptcha from client with masked IP %r: %r" + % (remote_ip, recaptcha_response.error_code)) logging.debug("Client failed a recaptcha; returning redirect to %s" % request.uri) return redirectTo(request.uri, request) + class WebResource(twisted.web.resource.Resource): """This resource is used by Twisted Web to give a web page with some bridges in response to a request.""" @@ -312,11 +351,17 @@ class WebResource(twisted.web.resource.Resource): """ if format == 'plain': request.setHeader("Content-Type", "text/plain") - return answer + rendered = bridgeLines else: request.setHeader("Content-Type", "text/html; charset=utf-8") - return lookup.get_template('bridges.html').render(answer=bridgeLines, - rtl=rtl) + try: + template = lookup.get_template('bridges.html') + rendered = template.render(answer=bridgeLines, rtl=rtl) + except Exception as err: + rendered = replaceErrorPage(err) + + return rendered + class WebRoot(twisted.web.resource.Resource): """The parent resource of all other documents hosted by the webserver."""