http: extract validation functions

PR-URL: #6533
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Fedor Indutny <fedor.indutny@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

lib/_http_outgoing.js

@@ -7,6 +7,8 @@ const util = require('util');
 const internalUtil = require('internal/util');
 const Buffer = require('buffer').Buffer;
 const common = require('_http_common');
+const checkIsHttpToken = common._checkIsHttpToken;
+const checkInvalidHeaderChar = common._checkInvalidHeaderChar;
 
 const CRLF = common.CRLF;
 const trfrEncChunkExpression = common.chunkExpression;
@@ -312,11 +314,11 @@ function _storeHeader(firstLine, headers) {
 }
 
 function storeHeader(self, state, field, value) {
-  if (!common._checkIsHttpToken(field)) {
+  if (!checkIsHttpToken(field)) {
     throw new TypeError(
       'Header name must be a valid HTTP Token ["' + field + '"]');
   }
-  if (common._checkInvalidHeaderChar(value) === true) {
+  if (checkInvalidHeaderChar(value)) {
     debug('Header "%s" contains invalid characters', field);
     throw new TypeError('The header content contains invalid characters');
   }
@@ -350,14 +352,14 @@ function storeHeader(self, state, field, value) {
 
 
 OutgoingMessage.prototype.setHeader = function setHeader(name, value) {
-  if (!common._checkIsHttpToken(name))
+  if (!checkIsHttpToken(name))
     throw new TypeError(
       'Header name must be a valid HTTP Token ["' + name + '"]');
   if (value === undefined)
     throw new Error('"value" required in setHeader("' + name + '", value)');
   if (this._header)
     throw new Error('Can\'t set headers after they are sent.');
-  if (common._checkInvalidHeaderChar(value) === true) {
+  if (checkInvalidHeaderChar(value)) {
     debug('Header "%s" contains invalid characters', name);
     throw new TypeError('The header content contains invalid characters');
   }
@@ -530,11 +532,11 @@ OutgoingMessage.prototype.addTrailers = function addTrailers(headers) {
       field = key;
       value = headers[key];
     }
-    if (!common._checkIsHttpToken(field)) {
+    if (!checkIsHttpToken(field)) {
       throw new TypeError(
         'Trailer name must be a valid HTTP Token ["' + field + '"]');
     }
-    if (common._checkInvalidHeaderChar(value) === true) {
+    if (checkInvalidHeaderChar(value)) {
       debug('Trailer "%s" contains invalid characters', field);
       throw new TypeError('The trailer content contains invalid characters');
     }