solved chrome streaming issues

ferenda/devel.py

@@ -155,13 +155,23 @@ def handle_streaming_test(self, environ):
                         'src': request_uri(environ) + "?stream=true"})])])
 
     def handle_streaming_test_stream(self, environ, start_response):
+        # using this instead of text/plain prevent chrome from
+        # buffering at the beginning (according to
+        # https://stackoverflow.com/q/20508788, there are three ways
+        # of overcoming this: The "X-Content-Type-Options: nosniff"
+        # header, sending at least 1024 bytes of data right away, or
+        # using a non text/plain content-type. The latter seems the
+        # easiest.
+        content_type = 'application/octet-stream'
         # the second header disables nginx/uwsgi buffering so that
         # results are actually streamed to the client, see
         # http://nginx.org/en/docs/http/ngx_http_uwsgi_module.html#uwsgi_buffering
-        writer = start_response('200 OK', [('Content-Type', 'text/plain'),
+        writer = start_response('200 OK', [('Content-Type', content_type),
                                            ('X-Accel-Buffering', 'no')]) 
         rootlogger = self._setup_streaming_logger(writer)
         log = logging.getLogger(__name__)
+        # log.info("1024 bytes of start data: " + "x" * 1024)
+        # sleep(1)
         log.debug("Debug messages should work")
         sleep(1)
         log.info("Info messages should work")
@@ -224,7 +234,7 @@ def handle_change_parse_options(self, environ, params):
             ])
 
     def handle_change_parse_options_stream(self, environ, start_response):
-        writer = start_response('200 OK', [('Content-Type', 'text/plain'),
+        writer = start_response('200 OK', [('Content-Type', 'application/octet-stream'),
                                            ('X-Accel-Buffering', 'no')]) 
         rootlogger = self._setup_streaming_logger(writer)
         # now do the work

ferenda/res/js/ferenda.js

@@ -123,7 +123,7 @@ $(document).ready(function () {
      window.location.href=suggestion.url
   });
 
-  /* Functionality to show streaming logs for long-running commands (currently not working in Chrome) */
+  /* Functionality to show streaming logs for long-running commands */
   output = $('#streaming-log-output');
   if (output) {
       // console.log("Setting up ajax call to stream log output")
@@ -132,26 +132,15 @@ $(document).ready(function () {
 	  dataType: 'text',
 	  url: output.attr('src'),
 	  xhrFields: {
-	      // Chrome refuses to call this during the actual response time, it's only called when response is finished (works as expected in Safari/Firefox) 
 	      onprogress: function(e) {
 		  // console.log('onprogress: response len is ' + e.currentTarget.response.length);
 		  output.text(e.currentTarget.response);
 	      }
 	  }
       });
-      /* 
-      i = setInterval(function() {
-	  if (connection.readyState > 2) {
-	      console.log('poll: response len is ' + connection.responseText.length);
-	  } else {
-	      console.log('poll: readystate still in ' + connection.readyState);
-	  }
-      }, 200);
-      */
       connection.done(function(data) {
           // console.log('Complete response = ' + data);
 	  output.text(data);
-	  // clearInterval(i);
       });
 
   }