feat(http-client): Expose buildRequest helper API

buildRequest was a private method. This commit makes it a public method that developers can use to build a `Request` object. This is particularly useful when returning a `Request` from a response interceptor.

Author: davismj

src/http-client.js

@@ -104,7 +104,7 @@ export class HttpClient {
   fetch(input: Request|string, init?: RequestInit): Promise<Response> {
     this::trackRequestStart();
 
-    let request = this::buildRequest(input, init, this.defaults);
+    let request = this.buildRequest(input, init);
     return processRequest(request, this.interceptors)
       .then(result => {
         let response = null;
@@ -122,13 +122,46 @@ export class HttpClient {
       })
       .then(result => {
         if (Request.prototype.isPrototypeOf(result)) {
-          debugger;
           return this.fetch(result);
         }
         this::trackRequestEnd();
         return result;
       });
   }
+
+  buildRequest(input: string, init: RequestInit): Request {
+    let defaults = this.defaults || {};
+    let request;
+    let body;
+    let requestContentType;
+
+    let parsedDefaultHeaders = parseHeaderValues(defaults.headers);
+    if (Request.prototype.isPrototypeOf(input)) {
+      request = input;
+      requestContentType = new Headers(request.headers).get('Content-Type');
+    } else {
+      init || (init = {});
+      body = init.body;
+      let bodyObj = body ? { body } : null;
+      let requestInit = Object.assign({}, defaults, { headers: {} }, init, bodyObj);
+      requestContentType = new Headers(requestInit.headers).get('Content-Type');
+      request = new Request(getRequestUrl(this.baseUrl, input), requestInit);
+    }
+    if (!requestContentType) {
+      if (new Headers(parsedDefaultHeaders).has('content-type')) {
+        request.headers.set('Content-Type', new Headers(parsedDefaultHeaders).get('content-type'));
+      } else if (body && isJSON(body)) {
+        request.headers.set('Content-Type', 'application/json');
+      }
+    }
+    setDefaultHeaders(request.headers, parsedDefaultHeaders);
+    if (body && Blob.prototype.isPrototypeOf(body) && body.type) {
+      // work around bug in IE & Edge where the Blob type is ignored in the request
+      // https://connect.microsoft.com/IE/feedback/details/2136163
+      request.headers.set('Content-Type', body.type);
+    }
+    return request;
+  }
 }
 
 const absoluteUrlRegexp = /^([a-z][a-z0-9+\-.]*:)?\/\//i;
@@ -157,40 +190,6 @@ function parseHeaderValues(headers) {
   return parsedHeaders;
 }
 
-function buildRequest(input, init) {
-  let defaults = this.defaults || {};
-  let request;
-  let body;
-  let requestContentType;
-
-  let parsedDefaultHeaders = parseHeaderValues(defaults.headers);
-  if (Request.prototype.isPrototypeOf(input)) {
-    request = input;
-    requestContentType = new Headers(request.headers).get('Content-Type');
-  } else {
-    init || (init = {});
-    body = init.body;
-    let bodyObj = body ? { body } : null;
-    let requestInit = Object.assign({}, defaults, { headers: {} }, init, bodyObj);
-    requestContentType = new Headers(requestInit.headers).get('Content-Type');
-    request = new Request(getRequestUrl(this.baseUrl, input), requestInit);
-  }
-  if (!requestContentType) {
-    if (new Headers(parsedDefaultHeaders).has('content-type')) {
-      request.headers.set('Content-Type', new Headers(parsedDefaultHeaders).get('content-type'));
-    } else if (body && isJSON(body)) {
-      request.headers.set('Content-Type', 'application/json');
-    }
-  }
-  setDefaultHeaders(request.headers, parsedDefaultHeaders);
-  if (body && Blob.prototype.isPrototypeOf(body) && body.type) {
-    // work around bug in IE & Edge where the Blob type is ignored in the request
-    // https://connect.microsoft.com/IE/feedback/details/2136163
-    request.headers.set('Content-Type', body.type);
-  }
-  return request;
-}
-
 function getRequestUrl(baseUrl, url) {
   if (absoluteUrlRegexp.test(url)) {
     return url;

test/http-client.spec.js

@@ -1,6 +1,6 @@
 import 'aurelia-polyfills';
 import {json} from '../src/util';
-import {HttpClient} from '../src/http-client';
+import {HttpClient, buildRequest} from '../src/http-client';
 import {HttpClientConfiguration} from '../src/http-client-configuration';
 
 describe('HttpClient', () => {
@@ -274,7 +274,17 @@ describe('HttpClient', () => {
       const path = 'retry';
       let retry = 3;
       fetch.and.returnValue(Promise.reject(new Response(null, { status: 500 })));
-      let interceptor = { response(r) { return r; }, responseError(r) { if (retry--) { return new Request(path) } else { throw r; } } };
+      let interceptor = { 
+        response(r) { return r; },
+        responseError(r) { 
+          if (retry--) {
+            let request = client.buildRequest(path);
+            return request;
+          } else { 
+            throw r; 
+          } 
+        } 
+      };
       spyOn(interceptor, 'response').and.callThrough();
       spyOn(interceptor, 'responseError').and.callThrough();