Below suggested patches to omit broken output, if unicode is returned instead of string. Problem occurred during localization with gettext, see this sample code: ------------------------------------------------------------------- import gettext from twisted.internet import reactor from twisted.protocols import http from nevow import inevow, rend, loaders, tags, appserver, static, guard class Index(rend.Page): addSlash = True child_css = static.File('static/css') child_img = static.File('static/img') docFactory = loaders.xmlfile('static/index.html') def renderHTTP(self, ctx): request = inevow.IRequest(ctx) # Dynamic LOCALIZATION =============================================== # inspired by http://www.ospace.net/index.en.html language = request.getHeader('accept-language').split(',')[0][:2] try: tran = gettext.translation('PROJECT', 'static/locale', languages = [language]) except IOError: print 'Cannot find catalog for "', language, '", installing null translations' tran = gettext.NullTranslations() tran.install(unicode = 1) # ==================================================================== # got from: nevow/examples/http_auth.py username, password = request.getUser(), request.getPassword() if (username, password) == ('', ''): request.setHeader('WWW-Authenticate', 'Basic realm="Whatever"') request.setResponseCode(http.UNAUTHORIZED) return _("Authentication required.") # THIS RETURN UNICODE ## They provided a username and password, so let's let them in! hurray self.data_username, self.data_password = username, password return rend.Page.renderHTTP(self, ctx) site = appserver.NevowSite(Index()) reactor.listenTCP(8080, site) reactor.run() ------------------------------------------------------------------- Paul Reznicek Necessary patch: =================================================================== --- nevow/appserver.py (Revision 1126) +++ nevow/appserver.py (local) @@ -167,8 +167,8 @@ self.deferred.callback("") def _cbFinishRender(self, html, ctx): - if isinstance(html, str): - self.write(html) + if isinstance(html, basestring): + self.write(html.encode('utf8')) server.Request.finish(self) elif html is errorMarker: ## Error webpage has already been rendered and finish called I believe, the wsgi.py can have similar problem: =================================================================== --- nevow/wsgi.py (Revision 1126) +++ nevow/wsgi.py (local) @@ -84,8 +84,8 @@ p = rend.FourOhFour() result = p.renderHTTP(pctx) - if isinstance(result, str): - request.write(result) + if isinstance(result, basestring): + request.write(result.encode('utf8')) else: ## Exhaust the generator list(result)