[feature] send blob response

lib/response.js

@@ -19,6 +19,7 @@ var deprecate = require('depd')('express');
 var encodeUrl = require('encodeurl');
 var escapeHtml = require('escape-html');
 var http = require('http');
+var Blob = require('buffer').Blob;
 var isAbsolute = require('./utils').isAbsolute;
 var onFinished = require('on-finished');
 var path = require('path');
@@ -34,12 +35,12 @@ var extname = path.extname;
 var mime = send.mime;
 var resolve = path.resolve;
 var vary = require('vary');
-
 /**
  * Response prototype.
  * @public
  */
 
+
 var res = Object.create(http.ServerResponse.prototype)
 
 /**
@@ -104,7 +105,7 @@ res.links = function(links){
  *     res.send({ some: 'json' });
  *     res.send('<p>some html</p>');
  *
- * @param {string|number|boolean|object|Buffer} body
+ * @param {string|number|boolean|object|Buffer|Blob} body
  * @public
  */
 
@@ -113,10 +114,11 @@ res.send = function send(body) {
   var encoding;
   var req = this.req;
   var type;
-
   // settings
   var app = this.app;
 
+  var isChunkBlob = !!(Blob && chunk instanceof Blob);
+
   // allow status / body
   if (arguments.length === 2) {
     // res.send(body, status) backwards compat
@@ -158,6 +160,9 @@ res.send = function send(body) {
         if (!this.get('Content-Type')) {
           this.type('bin');
         }
+      } else if (isChunkBlob) {
+        this.set('Content-Type', chunk.type || this.get('Content-Type') || 'application/octet-stream')
+        this.set('Content-Length', chunk.size);
       } else {
         return this.json(chunk);
       }
@@ -181,15 +186,14 @@ res.send = function send(body) {
 
   // populate Content-Length
   var len
-  if (chunk !== undefined) {
+  if (chunk !== undefined && !isChunkBlob) {
     if (Buffer.isBuffer(chunk)) {
       // get length of Buffer
       len = chunk.length
     } else if (!generateETag && chunk.length < 1000) {
       // just calculate length when no ETag + small chunk
       len = Buffer.byteLength(chunk, encoding)
     } else {
-      // convert chunk to Buffer and calculate
       chunk = Buffer.from(chunk, encoding)
       encoding = undefined;
       len = chunk.length
@@ -229,7 +233,16 @@ res.send = function send(body) {
     this.end();
   } else {
     // respond
-    this.end(chunk, encoding);
+    if (isChunkBlob) {
+      var response = this;
+      chunk.arrayBuffer().then(function (result) {
+        response.end(Buffer.from(result), encoding);
+      }).catch(function(err){
+        req.next(err);
+      })
+    } else {
+      this.end(chunk, encoding);
+    }
   }
 
   return this;

test/res.send.js

@@ -250,6 +250,70 @@ describe('res', function(){
     })
   })
 
+  describe('.send(Blob)', function(){
+    var buffer = require('buffer');
+
+    it('should send as blob type', function (done) {
+      if (buffer.Blob) {
+        var str = '<h1>express app</h1>';
+        var blob = new buffer.Blob([str], { type: 'text/html' });
+        var app = express();
+        app.use(function (req, res) {
+          res.send(blob);
+        });
+
+        request(app)
+        .get('/')
+        .expect('Content-Type','text/html; charset=utf-8')
+        .expect('Content-Length',blob.size.toString())
+        .expect(200,'<h1>express app</h1>',done)
+      } else {
+        this.skip();
+      }
+    })
+
+    it('should take default content type of application/octet-stream', function(done){
+      if (buffer.Blob) {
+        var str = '<h1>express app</h1>';
+        var blob = new buffer.Blob([str]);
+        var app = express();
+        app.use(function (req, res) {
+          res.send(blob);
+        });
+
+        request(app)
+          .get('/')
+          .expect('Content-Type', 'application/octet-stream')
+          .expect('Content-Length', blob.size.toString())
+          .expect(200,done)
+      } else {
+        this.skip();
+      }
+    })
+
+    it('should throw error',function (done) {
+      if(buffer.Blob) {
+        var blob = new buffer.Blob(['<h1>express app</h1>'], { type: 'text/html' });
+        blob.arrayBuffer = function () {
+          return Promise.reject('unable to read array buffer')
+        }
+        var app = express();
+        app.use('/', function (req, res) {
+          res.send(blob)
+        });
+        request(app)
+        .get('/')
+        .expect(500)
+        .end(function(err,res){
+          assert.strictEqual(/unable to read array buffer/.test(res.text), true, res.text);
+          done();
+        })
+      } else {
+        this.skip();
+      }
+    })
+  })
+
   describe('when the request method is HEAD', function(){
     it('should ignore the body', function(done){
       var app = express();