remove content-length header on HEAD requests only for curl user agents (#40)

* remove content-length header on HEAD requests only for curl user agents

* add debug output for troubleshooting travis-ci issue
* use node's HTTP client instead of wget

Author: misterdjules

lib/pre/userAgent.js

@@ -41,11 +41,11 @@ function userAgentConnection(options) {
 
         if (ua && re.test(ua)) {
             res.setHeader('Connection', 'close');
-        }
 
-        if (req.method === 'HEAD') {
-            res.once('header',
-                res.removeHeader.bind(res, 'content-length'));
+            if (req.method === 'HEAD') {
+                res.once('header',
+                    res.removeHeader.bind(res, 'content-length'));
+            }
         }
 
         next();

test/userAgent.js

@@ -0,0 +1,127 @@
+'use strict';
+
+// core requires
+var child_process = require('child_process');
+var http = require('http');
+
+// external requires
+var assert = require('chai').assert;
+var restify = require('restify');
+
+// local files
+var helper = require('./lib/helper');
+var plugins = require('../lib');
+
+// local globals
+var SERVER;
+var SERVER_PORT;
+var SERVER_ADDRESS = '127.0.0.1';
+var SERVER_ENDPOINT;
+var TEST_ENDPOINT;
+var TEST_RESPONSE_DATA = 'foobar';
+var TEST_RESPONSE_DATA_LENGTH = TEST_RESPONSE_DATA.length;
+var TEST_PATH = '/test/userAgent';
+
+describe('userAgent pre-route handler', function () {
+
+    beforeEach(function (done) {
+        SERVER = restify.createServer({
+            dtrace: helper.dtrace,
+            log: helper.getLog('server')
+        });
+
+        // Enable the user agent pre-route handler, since this is the component
+        // under test.
+        SERVER.use(plugins.pre.userAgentConnection());
+
+        SERVER.head('/test/:name', function (req, res, next) {
+            // Explicitly set Content-Length response header so that we can test
+            // for its removal (or lack thereof) by the userAgentConnection
+            // pre-route handler in tests below.
+            res.setHeader('Content-Length', TEST_RESPONSE_DATA_LENGTH);
+            res.send(200, TEST_RESPONSE_DATA);
+            next();
+        });
+
+
+        SERVER.listen(0, SERVER_ADDRESS, function () {
+            SERVER_PORT = SERVER.address().port;
+            SERVER_ENDPOINT = SERVER_ADDRESS + ':' + SERVER_PORT;
+            TEST_ENDPOINT = SERVER_ENDPOINT + TEST_PATH;
+            done();
+        });
+    });
+
+    afterEach(function (done) {
+        SERVER.close(done);
+    });
+
+    // By default, the userAgentConnection pre-route handler must:
+    //
+    // 1. set the 'connection' header to 'close'
+    //
+    // 2. remove the content-length header from the response
+    //
+    // when a HEAD request is handled and the client's user agent is curl.
+    it('sets proper headers for HEAD requests from curl', function (done) {
+        var CURL_CMD =
+            ['curl', '-sS', '-i', TEST_ENDPOINT, '-X', 'HEAD'].join(' ');
+
+        child_process.exec(CURL_CMD, function onExec(err, stdout, stderr) {
+            assert.ifError(err);
+
+            var lines = stdout.split(/\n/);
+
+            var contentLengthHeaderNotPresent =
+                lines.every(function checkContentLengthNotPresent(line) {
+                    return /Content-Length:.*/.test(line) === false;
+                });
+            var connectionCloseHeaderPresent =
+                lines.some(function checkConnectionClosePresent(line) {
+                    return /Connection: close/.test(line);
+                });
+
+            assert.ok(contentLengthHeaderNotPresent);
+            assert.ok(connectionCloseHeaderPresent);
+
+            done();
+        });
+    });
+
+    // When handling a HEAD request, and if the client's user agent is not curl,
+    // the userAgentConnection should not remove the content-length header from
+    // the response, and it should not replace the value of the 'connection'
+    // header by 'close'.
+    it('sets proper headers for HEAD requests from non-curl clients',
+        function (done) {
+            var req = http.request({
+                hostname: SERVER_ADDRESS,
+                port: SERVER_PORT,
+                path: TEST_PATH,
+                method: 'HEAD',
+                headers: {
+                    'user-agent': 'foobar',
+                    connection: 'keep-alive'
+                }
+            }, function onResponse(res) {
+                var responseHeaders = res.headers;
+
+                assert.ok(responseHeaders.hasOwnProperty('content-length'));
+                assert.equal(responseHeaders.connection, 'keep-alive');
+
+                // destroy the socket explicitly now since the request was
+                // explicitly requesting to not destroy the socket by setting
+                // its connection header to 'keep-alive'.
+                req.abort();
+
+                done();
+            });
+
+            req.on('error', function onReqError(err) {
+                assert.ifError(err);
+                done();
+            });
+
+            req.end();
+        });
+});