Allow to use relative URLs for fetch

packages/ember-cli-fastboot/fastboot/instance-initializers/fetch.js

@@ -0,0 +1,9 @@
+function initialize(instance) {
+  let { request } = instance.lookup('service:fastboot');
+  fetch.__fastbootRequest = request;
+}
+
+export default {
+  name: 'fastboot:fetch', // `ember-fetch` addon registers as `fetch`
+  initialize,
+};

packages/fastboot/src/sandbox.js

@@ -4,6 +4,9 @@ const chalk = require('chalk');
 const vm = require('vm');
 const sourceMapSupport = require('source-map-support');
 
+const httpRegex = /^https?:\/\//;
+const protocolRelativeRegex = /^\/\//;
+
 module.exports = class Sandbox {
   constructor(globals) {
     this.globals = globals;
@@ -56,27 +59,83 @@ module.exports = class Sandbox {
   }
 
   buildFetch() {
+    let globals;
+
     if (globalThis.fetch) {
-      return {
+      globals = {
         fetch: globalThis.fetch,
         Request: globalThis.Request,
         Response: globalThis.Response,
         Headers: globalThis.Headers,
         AbortController: globalThis.AbortController,
       };
+    } else {
+      let nodeFetch = require('node-fetch');
+      let {
+        AbortController,
+        abortableFetch,
+      } = require('abortcontroller-polyfill/dist/cjs-ponyfill');
+      let { fetch, Request } = abortableFetch({
+        fetch: nodeFetch,
+        Request: nodeFetch.Request,
+      });
+
+      globals = {
+        fetch,
+        Request,
+        Response: nodeFetch.Response,
+        Headers: nodeFetch.Headers,
+        AbortController,
+      };
     }
 
-    let nodeFetch = require('node-fetch');
-    let { AbortController, abortableFetch } = require('abortcontroller-polyfill/dist/cjs-ponyfill');
-    let { fetch, Request } = abortableFetch({ fetch: nodeFetch, Request: nodeFetch.Request });
+    let originalFetch = globals.fetch;
 
-    return {
-      fetch,
-      Request,
-      Response: nodeFetch.Response,
-      Headers: nodeFetch.Headers,
-      AbortController,
+    globals.fetch = function __fastbootFetch(input, init) {
+      if (input && input.href) {
+        input.url = globals.fetch.__fastbootBuildAbsoluteURL(input.href);
+      } else if (typeof input === 'string') {
+        input = globals.fetch.__fastbootBuildAbsoluteURL(input);
+      }
+      return originalFetch(input, init);
+    };
+
+    globals.fetch.__fastbootBuildAbsoluteURL = function __fastbootBuildAbsoluteURL(url) {
+      if (protocolRelativeRegex.test(url)) {
+        let [host] = globals.fetch.__fastbootParseRequest(fetch.__fastbootRequest);
+        url = `${host}${url}`;
+      } else if (!httpRegex.test(url)) {
+        let [host, protocol] = globals.fetch.__fastbootParseRequest(fetch.__fastbootRequest);
+        url = `${protocol}//${host}${url}`;
+      }
+      return url;
     };
+
+    globals.fetch.__fastbootParseRequest = function __fastbootParseRequest(request) {
+      if (!request) {
+        throw new Error(
+          "Trying to fetch with relative url but ember-fetch hasn't finished loading FastBootInfo, see details at https://github.com/ember-cli/ember-fetch#relative-url"
+        );
+      }
+      // Old Prember version is not sending protocol
+      const protocol = request.protocol === 'undefined:' ? 'http:' : request.protocol;
+      return [request.host, protocol];
+    };
+
+    let OriginalRequest = globals.Request;
+    globals.Request = class __FastBootRequest extends OriginalRequest {
+      constructor(input, init) {
+        if (typeof input === 'string') {
+          input = globals.fetch.__fastbootBuildAbsoluteURL(input);
+        } else if (input && input.href) {
+          // WHATWG URL or Node.js Url Object
+          input = globals.fetch.__fastbootBuildAbsoluteURL(input.href);
+        }
+        super(input, init);
+      }
+    };
+
+    return globals;
   }
 
   runScript(script) {

test-packages/basic-app/app/routes/fetch.js

@@ -1,5 +1,6 @@
 import Route from '@ember/routing/route';
 import { assert } from '@ember/debug';
+import { hash } from 'rsvp';
 
 export default class FetchRoute extends Route {
   beforeModel() {
@@ -11,7 +12,18 @@ export default class FetchRoute extends Route {
   }
 
   async model() {
-    let response = await fetch('https://api.github.com/users/tomster');
-    return response.json();
+    let [absoluteURL, absoluteRequest, relativeURL, relativeRequest] = await Promise.all([
+      fetch('http://localhost:45678/absolute-url.json'),
+      fetch('http://localhost:45678/absolute-request.json'),
+      fetch('/assets/relative-url.json'),
+      fetch(new Request('/assets/relative-request.json')),
+    ]);
+
+    return hash({
+      absoluteURL: absoluteURL.json(),
+      absoluteRequest: absoluteRequest.json(),
+      relativeURL: relativeURL.json(),
+      relativeRequest: relativeRequest.json(),
+    });
   }
 }

test-packages/basic-app/app/templates/fetch.hbs

@@ -1 +1,4 @@
-{{@model.login}}
+{{@model.absoluteURL.login}}
+{{@model.absoluteRequest.login}}
+{{@model.relativeURL.login}}
+{{@model.relativeRequest.login}}

test-packages/basic-app/public/absolute-request.json

@@ -0,0 +1,3 @@
+{
+    "login": "absolute-request"
+}

test-packages/basic-app/public/absolute-url.json

@@ -0,0 +1,3 @@
+{
+    "login": "absolute-url"
+}

test-packages/basic-app/public/relative-request.json

@@ -0,0 +1,3 @@
+{
+    "login": "relative-request"
+}

test-packages/basic-app/public/relative-url.json

@@ -0,0 +1,3 @@
+{
+    "login": "relative-url"
+}

test-packages/basic-app/test/fetch-test.js

@@ -26,6 +26,9 @@ describe('fetch', function() {
 
     expect(response.statusCode).to.equal(200);
     expect(response.headers['content-type']).to.equalIgnoreCase('text/html; charset=utf-8');
-    expect(response.body).to.contain('tomster');
+    expect(response.body).to.contain('absolute-url');
+    expect(response.body).to.contain('absolute-request');
+    expect(response.body).to.contain('relative-url');
+    expect(response.body).to.contain('relative-request');
   });
 });