Follow redirects (#3)

* Attempt a cleaner error handling

package.json

@@ -4,9 +4,10 @@
   "description": "Extract prominent colors from an image",
   "main": "src/server.js",
   "dependencies": {
+    "cors": "^2.8.1",
     "express": "^4.14.1",
     "node-vibrant": "^2.1.2",
-    "cors": "^2.8.1"
+    "request": "^2.79.0"
   },
   "devDependencies": {
     "should": "^11.2.0",

src/server.js

@@ -2,31 +2,52 @@ const http = require('http');
 const express = require('express');
 const cors = require('cors');
 const Vibrant = require('node-vibrant');
+const request = require('request');
 
 const app = express();
 const server = http.createServer(app);
 
 app.use(cors());
 
-app.get('/', (req, res) => {
+app.get('/', (req, res, next) => {
   const imgUrl = req.query.imgUrl;
 
   if (imgUrl == undefined || imgUrl == '') {
-    res.status(400).send('Missing `imgUrl` parameter');
-    return;
+    let err = new Error('missing `imgUrl` parameter');
+    err.status = 400;
+    throw err;
   }
 
-  Vibrant.from(imgUrl).getPalette((err, palette) => {
-    if (err != null) {
-      res.status(500).send(err.toString());
+  request({
+    url: imgUrl,
+    encoding: null
+  }, (error, response, body) => {
+    if (error != null) {
+      res.status(500).send(error);
+      return next(error);
     }
 
-    const maxAge = process.env.MAX_AGE || 1296000;  // 15 days
-    res.set('Cache-Control', 'public, max-age=' + maxAge);
-    res.json(palette);
+    Vibrant.from(body).getPalette((err, palette) => {
+      if (err != null) {
+        res.status(500).send(err.toString());
+        return next(err);
+      }
+
+      const maxAge = process.env.MAX_AGE || 1296000;  // 15 days
+      res.set('Cache-Control', 'public, max-age=' + maxAge);
+      res.json(palette);
+    });
   });
 });
 
+app.use(function(err, req, res, next) {
+  if (err.status !== 400) {
+    return next();
+  }
+
+  res.status(400).send(err.toString());
+});
+
 server.listen(process.env.PORT || 3000, process.env.IP || '0.0.0.0', () => {
   const addr = server.address();
   console.log('Vivace listening at', addr.address + ':' + addr.port);

test/test.js

@@ -25,6 +25,18 @@ describe('loading express', () => {
       });
   });
 
+  it('follows redirects', (done) => {
+    request(server)
+      .get('/?imgUrl=https://backend.cloudesire.com/api/productImageFile/static/883.png')
+      .expect(200)
+      .end((err, res) => {
+        res.body.should.have.property('LightMuted');
+        res.body.LightMuted.should.have.property('rgb');
+        res.body.LightMuted.rgb.should.containDeep([153, 170, 171]);
+        done();
+      });
+  });
+
   it('responds to preflight cors requests', (done) => {
     request(server)
       .options('/?imgUrl=https://appshop.cloud/images/marketplace/logo.png')
@@ -36,7 +48,7 @@ describe('loading express', () => {
       });
   });
 
-  const error = 'Missing `imgUrl` parameter';
+  const error = 'Error: missing `imgUrl` parameter';
 
   it('imgUrl parameter is required', (done) => {
     request(server).get('/').expect(400, error, done);
@@ -51,4 +63,10 @@ describe('loading express', () => {
       .get('/foo/bar')
       .expect(404, done);
   });
+
+  it('500 when not 200 or 300', (done) => {
+    request(server)
+      .get('/?imgUrl=https://httpbin.org/status/418')
+      .expect(500, done);
+  }).timeout(5000);
 });