Forward errors along to error handling middlewares

Author: Arjan Singh

src/index.js

@@ -36,17 +36,24 @@ function fastbootExpressMiddleware(distPath, options) {
       result.html()
         .then(html => {
           let headers = result.headers;
+          let statusMessage = result.error ? 'NOT OK ' : 'OK ';
 
           for (var pair of headers.entries()) {
             res.set(pair[0], pair[1]);
           }
 
-          log(result.statusCode, 'OK ' + path);
+          if (result.error) {
+            log("RESILIENT MODE CAUGHT:", result.error.stack);
+            next(result.error);
+          }
+
+          log(result.statusCode, statusMessage + path);
           res.status(result.statusCode);
           res.send(html);
         })
         .catch(error => {
-          console.log(error.stack);
+          log(500, error.stack);
+          next(error);
           res.sendStatus(500);
         });
     }
@@ -55,6 +62,7 @@ function fastbootExpressMiddleware(distPath, options) {
       if (error.name === "UnrecognizedURLError") {
         next();
       } else {
+        next(error);
         log(500, "Unknown Error: " + error.stack);
         if (error.stack) {
           res.status(500).send(error.stack);

test/helpers/test-http-server.js

@@ -21,6 +21,13 @@ class TestHTTPServer {
 
     app.get('/*', this.middleware);
 
+    if (options.errorHandling) {
+      app.use((err, req, res, next) => {
+        res.set('x-test-error', 'error handler called');
+        next();
+      });
+    }
+
     return new Promise((resolve, reject) => {
       let port = options.port || 3000;
       let host = options.host || 'localhost';
@@ -42,9 +49,17 @@ class TestHTTPServer {
     });
   }
 
-  request(urlPath) {
+  request(urlPath, options) {
     let info = this.info;
     let url = 'http://[' + info.host + ']:' + info.port;
+
+    if (options && options.resolveWithFullResponse) {
+      return request({
+        resolveWithFullResponse: options.resolveWithFullResponse,
+        uri: url + urlPath
+      });
+    }
+
     return request(url + urlPath);
   }
 

test/middleware-test.js

@@ -65,7 +65,7 @@ describe("FastBoot", function() {
       });
   });
 
-  it("renders an empty page if the resilient flag is set", function() {
+  it("renders no FastBoot markup if the resilient flag is set", function() {
     let middleware = fastbootMiddleware({
       distPath: fixture('rejected-promise'),
       resilient: true
@@ -79,6 +79,54 @@ describe("FastBoot", function() {
       });
   });
 
+  it("propagates to error handling middleware if the resilient flag is set", function() {
+    let middleware = fastbootMiddleware({
+      distPath: fixture('rejected-promise'),
+      resilient: true
+    });
+    server = new TestHTTPServer(middleware, { errorHandling: true });
+
+    return server.start()
+      .then(() => server.request('/', { resolveWithFullResponse: true }))
+      .then(({ body, statusCode, headers }) => {
+        expect(statusCode).to.equal(200);
+        expect(headers['x-test-error']).to.match(/error handler called/);
+        expect(body).to.match(/hello world/);
+      });
+  });
+
+  it("propagates to error handling middleware if the resilient flag is not set", function() {
+    let middleware = fastbootMiddleware({
+      distPath: fixture('rejected-promise'),
+      resilient: false,
+    });
+    server = new TestHTTPServer(middleware, { errorHandling: true });
+
+    return server.start()
+      .then(() => server.request('/', { resolveWithFullResponse: true }))
+      .catch(({ statusCode, response: { headers } }) => {
+        expect(statusCode).to.equal(500);
+        expect(headers['x-test-error']).to.match(/error handler called/);
+      });
+  });
+
+  it("is does not propagate errors when the reslient flag is set and there is no error handling middleware", function() {
+    let middleware = fastbootMiddleware({
+      distPath: fixture('rejected-promise'),
+      resilient: true,
+    });
+    server = new TestHTTPServer(middleware, { errorHandling: false });
+
+    return server.start()
+      .then(() => server.request('/', { resolveWithFullResponse: true }))
+      .then(({ body, statusCode, headers }) => {
+        expect(statusCode).to.equal(200);
+        expect(headers['x-test-error']).to.not.match(/error handler called/);
+        expect(body).to.not.match(/error/);
+        expect(body).to.match(/hello world/);
+      });
+  });
+
   it("can be provided with a custom FastBoot instance", function() {
     let fastboot = new FastBoot({
       distPath: fixture('basic-app')