Fix error with corrupted PDF image download

src/response-handler.js

@@ -6,25 +6,32 @@ class ResponseHandler {
     return (response) => {
       if (debug) { console.log(response); } // eslint-disable-line no-console
 
-      let result = '';
       let isJson      = response.headers['content-type'] == 'text/json';
       let isTiff      = response.headers['content-type'] == 'image/tiff';
       let isPdf       = response.headers['content-type'] == 'application/pdf';
       let isImage     = isTiff || isPdf;
+      let result      = isImage ? [] : '';
 
       let isLocation  = response.headers['location'] !== undefined;
 
       response.on('data', function(chunk) {
-        result += chunk;
+        if (isImage) {
+          result.push(chunk);
+        } else {
+          result += chunk;
+        }
       });
 
       response.on('end', function() {
         if (debug) { console.log(result); } // eslint-disable-line no-console
 
         if (isLocation) { result = new Location(response.headers['location']); }
-        else if (isImage) { result = new Image(result, response.headers['content-type']); }
         else if (isJson && result.length > 0) { result = JSON.parse(result); }
         else if (isJson && result.length == 0) { result = null; }
+        else if (isImage) {
+          const data = Buffer.concat(result);
+          result = new Image(data, response.headers['content-type']);
+        }
 
         if (response.statusCode >= 300) {
           emitter.emit('reject', result);

tests/response-handler.js

@@ -1,6 +1,7 @@
 import ResponseHandler     from '../src/response-handler.js';
 import Image               from '../src/image.js';
 import EventEmitter        from 'events';
+import fs                  from 'fs';
 
 import { expect } from 'chai';
 
@@ -52,9 +53,10 @@ describe('ResponseHandler', () => {
     });
 
     it('should process an image response', (done) => {
+      let pdfData = fs.readFileSync('tests/fixtures/pdf-sample.pdf');
       let emitter = new EventEmitter();
       emitter.on('resolve', (result) => {
-        expect(result).to.eql({ 'data': 'Hello World!', 'contentType' : 'application/pdf', 'extension' : 'pdf' });
+        expect(result.data).to.eql(pdfData);
         expect(result).to.be.instanceof(Image);
         done();
       });
@@ -65,7 +67,7 @@ describe('ResponseHandler', () => {
 
       handler(response);
 
-      response.emit('data', 'Hello World!');
+      response.emit('data', pdfData);
       response.emit('end');
     });