Handle quality values for Accept-Encoding field. Handle identity and * encoding types

Author: Mikko Tiihonen

index.js

@@ -307,12 +307,26 @@ SendStream.prototype.getAcceptEncodingExtensions = function() {
   var accepted = []
   var header = this.req.headers['accept-encoding']
   if (header) {
-    this._precompressionFormats.forEach(function (format) {
+    var self = this
+    self._precompressionFormats.forEach(function (format) {
       header.split(',').forEach(function (reqEncoding) {
-        if (reqEncoding.trim().indexOf(format.encoding) === 0)
-          accepted.push(format.extension)
+        var vals = reqEncoding.split(';')
+        var quality = 1
+        if (vals.length > 1) {
+          quality = parseFloat(vals[1].split('=')[1])
+        }
+        var encoding = vals[0].trim()
+        if (encoding === 'identity') {
+          accepted.push({format:'identity', quality:quality})
+        } else if (encoding === '*' || encoding.indexOf(format.encoding) === 0) {
+          accepted.push({format:format.extension, quality:quality})
+        }
       })
     })
+    accepted.sort(function(a,b) {return b.quality - a.quality} );
+    if (accepted.length >= 1 && accepted[0].format === 'identity') {
+       accepted = []
+    }
   }
   return accepted;
 };
@@ -704,7 +718,7 @@ SendStream.prototype.sendFile = function sendFile(path) {
     var extensions = self.getAcceptEncodingExtensions()
     for (var e = 0; e < extensions.length && !preferredContent; e++) {
       for (var c = 0; c < contents.length; c++) {
-        if (extensions[e] === contents[c].ext) {
+        if (extensions[e].format === contents[c].ext) {
           preferredContent = contents[c]
           break
         }

test/send.js

@@ -1087,6 +1087,7 @@ describe('send(file, options)', function(){
           .get('/name.txt')
           .set('Accept-Encoding', 'gzip')
           .expect(shouldNotHaveHeader('Vary'))
+          .expect(shouldNotHaveHeader('Content-Encoding'))
           .expect(200, done)
     })
 
@@ -1100,6 +1101,7 @@ describe('send(file, options)', function(){
           .get('/name.html')
           .set('Accept-Encoding', '')
           .expect('Content-Length', '11')
+          .expect(shouldNotHaveHeader('Content-Encoding'))
           .expect('Content-Type', 'text/html; charset=UTF-8')
           .expect('Vary', 'Accept-Encoding', done)
     })
@@ -1172,6 +1174,7 @@ describe('send(file, options)', function(){
       request(app)
           .get('/name.html')
           .set('Accept-Encoding', 'gzip')
+          .expect(shouldNotHaveHeader('Content-Encoding'))
           .expect('Content-Length', '11', done)
     })
 
@@ -1184,6 +1187,51 @@ describe('send(file, options)', function(){
          .get('/name.html')
          .expect('Vary', 'custom, Accept-Encoding', done);
     })
+
+    it('should honour accept-encoding quality values', function(done){
+      var app = http.createServer(function(req, res){
+        send(req, req.url, {precompressed: true, root: fixtures})
+            .pipe(res);
+      });
+
+      request(app)
+          .get('/name.html')
+          .set('Accept-Encoding', 'gzip;q=0.9, deflate;q=1, br;q=0.1')
+          .expect('Vary', 'Accept-Encoding')
+          .expect('Content-Encoding', 'gzip')
+          .expect('Content-Type', 'text/html; charset=UTF-8')
+          .expect('Content-Length', '31', done)
+    })
+
+    it('should return no encoding if identity encoding preferred in accept-encoding', function(done){
+      var app = http.createServer(function(req, res){
+        send(req, req.url, {precompressed: true, root: fixtures})
+            .pipe(res);
+      });
+
+      request(app)
+          .get('/name.html')
+          .set('Accept-Encoding', 'gzip;q=0.8, identity')
+          .expect('Vary', 'Accept-Encoding')
+          .expect(shouldNotHaveHeader('Content-Encoding'))
+          .expect('Content-Type', 'text/html; charset=UTF-8')
+          .expect('Content-Length', '11', done)
+    })
+
+    it('should return server preferred format for accept-encoding *', function(done){
+      var app = http.createServer(function(req, res){
+        send(req, req.url, {precompressed: true, root: fixtures})
+            .pipe(res);
+      });
+
+      request(app)
+          .get('/name.html')
+          .set('Accept-Encoding', '*;q=0.9; gzip;q=0.8')
+          .expect('Vary', 'Accept-Encoding')
+          .expect('Content-Encoding', 'br')
+          .expect('Content-Type', 'text/html; charset=UTF-8')
+          .expect('Content-Length', '15', done)
+    })
   })
 
   describe('index', function(){