allow marko/express to be used as middleware

express.js

@@ -2,33 +2,48 @@ require('./runtime/env-init');
 
 var assign = require('object-assign');
 var express = module.parent.require('express');
-var response = express.response;
-
-response.marko = response.marko || function(template, data) {
-    if(typeof template === 'string') {
-        throw new Error(
-            'res.marko does not take a template name or path like res.render.  ' +
-            'Instead you should use `require(\'./path/to/template.marko\')` ' +
-            'and pass the loaded template to this function.'
-        );
-    }
-
-    var res = this;
-    var req = res.req;
-    var app = res.app;
-    var $global = assign({ app, req, res }, app.locals, res.locals);
-
-    if (data) {
-        data = assign(data, {
-            $global: assign($global, data.$global)
-        });
-    } else {
-        data = { $global };
-    }
-
-    res.set({ 'content-type': 'text/html; charset=utf-8' });
-
-    template.render(data, res);
-};
-
+patchResponse(express.response);
 delete require.cache[__filename];
+
+module.exports = function markoAppMiddleware() {
+    var sacrificialApp = express();
+
+    sacrificialApp.once('mount', function onmount(parent) {
+        // Patch the response
+        patchResponse(parent.response);
+
+        // Remove sacrificial express app
+        parent._router.stack.pop();
+    });
+
+    return sacrificialApp;
+}
+
+function patchResponse(response) {
+    response.marko = response.marko || function(template, data) {
+        if(typeof template === 'string') {
+            throw new Error(
+                'res.marko does not take a template name or path like res.render.  ' +
+                'Instead you should use `require(\'./path/to/template.marko\')` ' +
+                'and pass the loaded template to this function.'
+            );
+        }
+
+        var res = this;
+        var req = res.req;
+        var app = res.app;
+        var $global = assign({ app, req, res }, app.locals, res.locals);
+
+        if (data) {
+            data = assign(data, {
+                $global: assign($global, data.$global)
+            });
+        } else {
+            data = { $global };
+        }
+
+        res.set({ 'content-type': 'text/html; charset=utf-8' });
+
+        template.render(data, res);
+    };
+}

test/autotests/express/headers/test.js

@@ -1,10 +1,10 @@
 exports.createApp = function(express, markoExpressPath) {
     var app = express();
-
-    require(markoExpressPath);
+    var markoExpress = require(markoExpressPath);
 
     app.locals.foo = 'FOO';
 
+    app.use(markoExpress());
     app.use(function(req, res, next) {
         res.locals.bar = 'BAR';
         next();

test/autotests/express/incorrect-usage/test.js

@@ -1,7 +1,8 @@
 exports.createApp = function(express, markoExpressPath) {
-    require(markoExpressPath);
-
     var app = express();
+    var markoExpress = require(markoExpressPath);
+
+    app.use(markoExpress());
 
     return app;
 };

test/autotests/express/locals/test.js

@@ -1,10 +1,10 @@
 exports.createApp = function(express, markoExpressPath) {
-    require(markoExpressPath);
-
     var app = express();
+    var markoExpress = require(markoExpressPath);
 
     app.locals.foo = 'FOO';
 
+    app.use(markoExpress());
     app.use(function(req, res, next) {
         res.locals.bar = 'BAR';
         next();

test/autotests/express/priority/test.js

@@ -1,12 +1,12 @@
 exports.createApp = function(express, markoExpressPath) {
-    require(markoExpressPath);
-
     var app = express();
+    var markoExpress = require(markoExpressPath);
 
     app.locals.foo = 'APP';
     app.locals.bar = 'APP';
     app.locals.baz = 'APP';
 
+    app.use(markoExpress());
     app.use(function(req, res, next) {
         res.locals.foo = 'RES';
         res.locals.bar = 'RES';