server: send response to client with res.end()

Using res.end() to write result instead of res.write() followed by
res.end() will cause node not to use chunked encoding and include
Content-Length header. (See nodejs/node#26005) This small distinction is
important with some client. For example, Windows 10's MDM enrollment
system will not accept chunked response
(https://docs.microsoft.com/en-us/windows/client-management/mdm/on-premise-authentication-device-enrollment).

This might improve compatibility with some other clients, too. However,
there's a small chance that some client may expect the response to be
chunked.

lib/server.js

@@ -147,8 +147,7 @@ Server.prototype._processRequestXml = function (req, res, xml) {
       if (statusCode) {
         res.statusCode = statusCode;
       }
-      res.write(result);
-      res.end();
+      res.end(result);
       if (typeof self.log === 'function') {
         self.log("replied", result);
       }
@@ -157,17 +156,15 @@ Server.prototype._processRequestXml = function (req, res, xml) {
     if (err.Fault !== undefined) {
       return self._sendError(err.Fault, function (result, statusCode) {
         res.statusCode = statusCode || 500;
-        res.write(result);
-        res.end();
+        res.end(result);
         if (typeof self.log === 'function') {
           self.log("error", err);
         }
       }, new Date().toISOString());
     } else {
       error = err.stack ? (self.suppressStack === true ? err.message : err.stack) : err;
       res.statusCode = 500;
-      res.write(error);
-      res.end();
+      res.end(error);
       if (typeof self.log === 'function') {
         self.log("error", error);
       }

test/server-test.js

@@ -483,6 +483,25 @@ describe('SOAP Server', function() {
     });
   });
 
+  it('should not use chunked encoding and return Content-Length header', function(done) {
+    soap.createClient(test.baseUrl + '/stockquote?wsdl', function(err, client) {
+      var clientArgs = { tickerSymbol: 'AAPL'};
+
+      assert.ifError(err);
+
+      client.on('response', function(body, response, eid) {
+        var headers = response.headers;
+        assert.notEqual(headers['content-length'], undefined);
+        assert.equal(headers['transfer-encoding'], undefined);
+      })
+
+      client.GetLastTradePrice(clientArgs, function(err, result, raw, headers) {
+        assert.ifError(err);
+        done();
+      });
+    });
+  });
+
 // NOTE: this is actually a -client- test
 /*
 it('should return a valid error if the server stops responding': function(done) {