chore: lift json regex to top of file (#1670)

lib/plugins/bodyParser.js

@@ -10,6 +10,7 @@ var jsonParser = require('./jsonBodyParser');
 var formParser = require('./formBodyParser');
 var multipartParser = require('./multipartBodyParser');
 var fieldedTextParser = require('./fieldedTextBodyParser.js');
+var regex = require('./utils/regex');
 
 ///--- Globals
 
@@ -162,12 +163,6 @@ function bodyParser(options) {
         var parser;
         var type = req.contentType().toLowerCase();
 
-        var jsonPatternMatcher = new RegExp('^application/[a-zA-Z.]+\\+json');
-        // map any +json to application/json
-        if (jsonPatternMatcher.test(type)) {
-            type = 'application/json';
-        }
-
         switch (type) {
             case 'application/json':
                 parser = parseJson[0];
@@ -192,6 +187,18 @@ function bodyParser(options) {
                 break;
         }
 
+        // if we find no matches from the direct string comparisons, perform
+        // more expensive regex matches. map any +json to application/json.
+        // theoretically these could be mapped to application/json prior to the
+        // switch statement, but putting it here allows us to skip the regex
+        // entirely unless absolutely necessary. additional types could be
+        // added later at some point.
+        if (!parser) {
+            if (regex.jsonContentType.test(type)) {
+                parser = parseJson[0];
+            }
+        }
+
         if (parser) {
             parser(req, res, next);
         } else if (opts && opts.rejectUnknown) {

lib/plugins/jsonBodyParser.js

@@ -6,6 +6,7 @@ var assert = require('assert-plus');
 var errors = require('restify-errors');
 
 var bodyReader = require('./bodyReader');
+var regex = require('./utils/regex');
 
 ///--- API
 
@@ -28,13 +29,16 @@ function jsonBodyParser(options) {
         // save original body on req.rawBody and req._body
         req.rawBody = req._body = req.body;
 
-        var jsonPatternMatcher = new RegExp('^application/[a-zA-Z.]+\\+json');
         var contentType = req.getContentType();
 
-        if (contentType !== 'application/json' || !req.body) {
-            if (!jsonPatternMatcher.test(contentType)) {
-                return next();
-            }
+        // check for empty body first, don't pay regex tax unless necessary.
+        // for content type, check for exact match and any of the *+json types
+        if (
+            !req.body ||
+            (contentType !== 'application/json' &&
+                !regex.jsonContentType.test(contentType))
+        ) {
+            return next();
         }
 
         var params;

lib/plugins/utils/regex.js

@@ -0,0 +1,5 @@
+'use strict';
+
+module.exports = {
+    jsonContentType: new RegExp('^application/[a-zA-Z.]+\\+json')
+};