Handle asyncrhonous errors

Author: dcramer

README.md

@@ -150,9 +150,9 @@ The callback is called **after** the event has been sent to the Sentry server.
 
 ## Integrations
 ### Connect/Express middleware
-The Raven middleware can be used as-is with either Connect or Express in the same way. Take note that in your middlewares, Raven must appear _after_ your main handler to pick up any errors that may result from handling a request.
+The Raven middleware can be used as-is with either Connect or Express in the same way.
 
-#### Connect
+#### Connect and Express
 ```javascript
 var connect = require('connect');
 function mainHandler(req, res) {
@@ -165,22 +165,34 @@ function onError(err, req, res, next) {
   res.end(res.sentry+'\n');
 }
 connect(
+  // Should be the first item listed
+  raven.middleware.connect.requestHandler('{{ SENTRY_DSN }}'),
+
   connect.bodyParser(),
   connect.cookieParser(),
   mainHandler,
-  raven.middleware.connect('{{ SENTRY_DSN }}'),
+
+  // Should come before any other error middleware
+  raven.middleware.connect.errorHandler('{{ SENTRY_DSN }}'),
   onError, // optional error handler if you want to display the error id to a user
 ).listen(3000);
 ```
 
 #### Express
 ```javascript
 var app = require('express')();
+
 app.get('/', function mainHandler(req, res) {
   throw new Error('Broke!');
 });
-app.use(raven.middleware.express('{{ SENTRY_DSN }}'));
+
+// Should be the first item listed
+app.use(raven.middleware.express.requestHandler('{{ SENTRY_DSN }}'));
+
+// Should come before any other error middleware
+app.use(raven.middleware.express.errorHandler('{{ SENTRY_DSN }}'));
 app.use(onError); // optional error handler if you want to display the error id to a user
+
 app.listen(3000);
 ```
 

lib/middleware/connect.js

@@ -1,7 +1,14 @@
 var raven = require('../client');
 var parsers = require('../parsers');
 
-module.exports = function connectMiddleware(client) {
+// Legacy support
+var connectMiddleware = function(client) {
+    return connectMiddleware.errorHandler(client);
+};
+
+// Error handler. This should be the last item listed in middleware, but
+// before any other error handlers.
+connectMiddleware.errorHandler = function(client) {
     client = (client instanceof raven.Client) ? client : new raven.Client(client);
     return function(err, req, res, next) {
         var status = err.status || err.statusCode || err.status_code || 500;
@@ -16,3 +23,15 @@ module.exports = function connectMiddleware(client) {
         });
     };
 };
+
+// Ensures asynchronous exceptions are routed to the errorHandler. This
+// should be the **first** item listed in middleware.
+connectMiddleware.requestHandler = function(client) {
+    return function(req, res, next) {
+        var reqDomain = domain.create();
+        reqDomain.on('error', next);
+        return reqDomain.run(next);
+    };
+};
+
+module.exports = connectMiddleware;