Follow redirects (#789)

* Follow redirects

Fixes #775

* Follow redirects

Fixing lint error

* Follow redirects

Fix tests

* Added redirect test

* Fixed lint errors

* Skip redirect test in browser as we cannot mock a server

* Different test for browser

* Fixed browser detection

packages/core/src/index.js

@@ -63,6 +63,11 @@ function loadFromURL(options, cb) {
     if (err) {
       return cb(err);
     }
+
+    if('headers' in response && 'location' in response.headers){
+      options.url = response.headers.location;
+      return loadFromURL(options, cb);
+    }
 
     if (typeof data === 'object' && Buffer.isBuffer(data)) {
       return cb(null, data);

packages/core/test/redirect.test.js

@@ -0,0 +1,57 @@
+import { Jimp as jimp, getTestDir } from '@jimp/test-utils';
+
+const fs = require('fs');
+const http = require('http');
+
+const imagesDir = getTestDir(__dirname) + '/images';
+
+const httpHandler = (req, res) => {
+  switch (req.method) {
+    case 'GET':
+      switch (req.url) {
+        case '/redirect.png':
+          res.writeHead(301, {
+            Location: 'http://localhost:5136/corrected.png'
+          });
+          res.end();
+          break;
+        case '/corrected.png':
+          res.writeHead(200, { 'Content-Type': 'image/png' });
+          res.end(fs.readFileSync(imagesDir + '/pixel.png'), 'binary');
+          break;
+        default:
+          res.writeHead(404);
+          res.end('Not a valid test endpoint');
+          break;
+      }
+      break;
+    default:
+      res.writeHead(404);
+      res.end('Invalid request method');
+      break;
+  }
+};
+
+describe('redirect', function() {
+  if (typeof window !== 'undefined' && typeof window.document !== 'undefined') {
+    xit('Not testing redirects in browser');
+  } else {
+    const httpServer = http.createServer(httpHandler);
+    before(function() {
+      httpServer.listen(5136);
+    });
+
+    it('follows 301 redirect', function(done) {
+      jimp
+        .read('http://localhost:5136/redirect.png')
+        .then(() => {
+          httpServer.close();
+          done();
+        })
+        .catch(error => {
+          httpServer.close();
+          done(error);
+        });
+    });
+  }
+});