Added ability to use custom render functions to send JSON, HTML, and …

…XML responses.

README.md

@@ -82,12 +82,15 @@ The content type of the response depends on the request's `Accepts` header.
 | debug | Boolean    | `false` | If `true`, HTTP responses include all error properties, including sensitive data such as file paths, URLs and stack traces. See [Example output](#example) below. |
 | log | Boolean | `true` |  If `true`, all errors are printed via `console.error`, including an array of fields (custom error properties) that are safe to include in response messages (both 4xx and 5xx). <br/> If `false`, sends only the error back in the response. |
 | safeFields | [String] | `[]` |  Specifies property names on errors that are allowed to be passed through in 4xx and 5xx responses. See [Safe error fields](#safe-error-fields) below. |
+| jsonRenderer | String | 'send-json' | Operation function to render JSON with signature `fn(res, data)`. Defaults to `./send-json` (`lib/send-json.js`). |
+| htmlRenderer | String | 'send-html' | Operation function to render HTML with signature `fn(res, data)`. Defaults to `./send-html` (`lib/send-html.js`). |
+| xmlRenderer | String | 'send-xml' | Operation function to render XML with signature `fn(res, data)`. Defaults to `./send-xml` (`lib/send-xml.js`). |
 
 ### Customizing log format
 
-**Express** 
+**Express**
 
-To use a different log format, add your own custom error-handling middleware then disable `errorHandler.log`. 
+To use a different log format, add your own custom error-handling middleware then disable `errorHandler.log`.
 For example, in an Express application:
 
 ```js
@@ -155,6 +158,34 @@ Using the above configuration, an error containing an `errorCode` property will
 }
 ```
 
+### Custom Renderer Functions
+
+You can switch out the default renderers for HTML, JSON, and XML responses with custom renderers:
+
+```
+{
+  // ...
+  "final:after": {
+    "strong-error-handler": {
+      "params": {
+        "htmlRenderer": "$!./lib/send-html"
+      }
+    }
+}
+```
+
+The `$!` characters indicate that the path is relative to the location of `middleware.json`.
+
+*./lib/send-html.js:*
+
+```
+module.exports = function(res, data) {
+  res.send("Hello.");
+}
+```
+
+Using the above configuration, a request with `Content-type: text/html` that is handled by strong-error-handler will return a `Content-type: text/html` and a response body of `Hello.`.
+
 ## Migration from old LoopBack error handler
 
 NOTE: This is only required for applications scaffolded with old versions of the `slc loopback` tool.
@@ -201,7 +232,7 @@ To migrate a LoopBack 2.x application to use `strong-error-handler`:
   }
 </pre>
 
-For more information, see 
+For more information, see
 [Migrating apps to LoopBack 3.0](http://loopback.io/doc/en/lb3/Migrating-to-3.0.html#update-use-of-rest-error-handler).
 
 ## Example
@@ -219,17 +250,17 @@ The same error generated when `debug: true` :
   { statusCode: 500,
   name: 'Error',
   message: 'a test error message',
-  stack: 'Error: a test error message    
-  at Context.<anonymous> (User/strong-error-handler/test/handler.test.js:220:21)    
-  at callFnAsync (User/strong-error-handler/node_modules/mocha/lib/runnable.js:349:8)    
-  at Test.Runnable.run (User/strong-error-handler/node_modules/mocha/lib/runnable.js:301:7)    
-  at Runner.runTest (User/strong-error-handler/node_modules/mocha/lib/runner.js:422:10)    
-  at User/strong-error-handler/node_modules/mocha/lib/runner.js:528:12    
-  at next (User/strong-error-handler/node_modules/mocha/lib/runner.js:342:14)    
-  at User/strong-error-handler/node_modules/mocha/lib/runner.js:352:7    
-  at next (User/strong-error-handler/node_modules/mocha/lib/runner.js:284:14)    
-  at Immediate._onImmediate (User/strong-error-handler/node_modules/mocha/lib/runner.js:320:5)    
-  at tryOnImmediate (timers.js:543:15)    
+  stack: 'Error: a test error message
+  at Context.<anonymous> (User/strong-error-handler/test/handler.test.js:220:21)
+  at callFnAsync (User/strong-error-handler/node_modules/mocha/lib/runnable.js:349:8)
+  at Test.Runnable.run (User/strong-error-handler/node_modules/mocha/lib/runnable.js:301:7)
+  at Runner.runTest (User/strong-error-handler/node_modules/mocha/lib/runner.js:422:10)
+  at User/strong-error-handler/node_modules/mocha/lib/runner.js:528:12
+  at next (User/strong-error-handler/node_modules/mocha/lib/runner.js:342:14)
+  at User/strong-error-handler/node_modules/mocha/lib/runner.js:352:7
+  at next (User/strong-error-handler/node_modules/mocha/lib/runner.js:284:14)
+  at Immediate._onImmediate (User/strong-error-handler/node_modules/mocha/lib/runner.js:320:5)
+  at tryOnImmediate (timers.js:543:15)
   at processImmediate [as _immediateCallback] (timers.js:523:5)' }}
 ```
 

lib/content-negotiation.js

@@ -6,11 +6,12 @@
 'use strict';
 var accepts = require('accepts');
 var debug = require('debug')('strong-error-handler:http-response');
-var sendJson = require('./send-json');
-var sendHtml = require('./send-html');
-var sendXml = require('./send-xml');
 var util = require('util');
 
+var sendJson;
+var sendHtml;
+var sendXml;
+
 module.exports = negotiateContentProducer;
 
 /**
@@ -20,9 +21,9 @@ module.exports = negotiateContentProducer;
  * @param req request object
  * @param {Object} options options of strong-error-handler
  * @param {Function} logWarning a logger function for reporting warnings
- * @returns {Function} Opeartion function with signature `fn(res, data)`
+ * @returns {Function} Operation function with signature `fn(res, data)`
  */
-function negotiateContentProducer(req, logWarning, options) {
+function negotiateContentProducer(req, options, logWarning) {
   var SUPPORTED_TYPES = [
     'application/json', 'json',
     'text/html', 'html',
@@ -43,6 +44,25 @@ function negotiateContentProducer(req, logWarning, options) {
     }
   }
 
+  // resolve renderer functions
+  if (!('jsonRenderer' in options)) {
+    options.jsonRenderer = './send-json';
+  }
+
+  sendJson = require(options.jsonRenderer);
+
+  if (!('htmlRenderer' in options)) {
+    options.htmlRenderer = './send-html';
+  }
+
+  sendHtml = require(options.htmlRenderer);
+
+  if (!('xmlRenderer' in options)) {
+    options.xmlRenderer = './send-xml';
+  }
+
+  sendXml = require(options.xmlRenderer);
+
   // decide to use resolvedType or defaultType
   // Please note that accepts assumes the order of content-type is provided
   // in the priority returned