Load API URL from a settings object, not a <link> tag

The approach of embedding a link tag in the app.html doesn't really give
us a great deal of flexibility. URLs within the application, perhaps as
a result, tend to be created either from baseURI or from the API URL,
called `serviceUrl` in the code.

This commit leaves the <base> tag alone, but:

- replaces the serviceUrl <link> tag with a settings object,
  `window.hypothesis.settings` which is inlined into app.html.
- replaces the serviceUrl angular service with a generic settings
  service.
- renames serviceUrl to apiUrl, to make its purpose more obvious.

h/static/scripts/app.coffee

@@ -162,7 +162,7 @@ module.exports = angular.module('h', [
 .service('unicode', require('./unicode'))
 .service('viewFilter', require('./view-filter'))
 
-.factory('serviceUrl', require('./service-url'))
+.factory('settings', require('./settings'))
 
 .value('AnnotationSync', require('./annotation-sync'))
 .value('AnnotationUISync', require('./annotation-ui-sync'))

h/static/scripts/config/identity.js

@@ -7,8 +7,8 @@ var currentToken = null;
 
 
 // @ngInject
-function fetchToken($http, $q, jwtHelper, serviceUrl, session) {
-  var tokenUrl = new URL('token', serviceUrl).href;
+function fetchToken($http, $q, jwtHelper, session, settings) {
+  var tokenUrl = new URL('token', settings.apiUrl).href;
 
   if (currentToken === null || jwtHelper.isTokenExpired(currentToken)) {
     if (tokenPromise === null) {
@@ -47,13 +47,13 @@ function fetchToken($http, $q, jwtHelper, serviceUrl, session) {
 
 
 // @ngInject
-function tokenGetter($injector, config, serviceUrl) {
+function tokenGetter($injector, config, settings) {
   var requestUrl = config.url;
 
   // Only send the token on requests to the annotation storage service
   // and only if it is not the token request itself.
-  if (requestUrl !== serviceUrl) {
-    if (requestUrl.slice(0, serviceUrl.length) === serviceUrl) {
+  if (requestUrl !== settings.apiUrl) {
+    if (requestUrl.slice(0, settings.apiUrl.length) === settings.apiUrl) {
       return authPromise
         .then(function () {
           return $injector.invoke(fetchToken);

h/static/scripts/service-url.js

-/**
- * @ngdoc service
- * @name  serviceUrl
- *
- * @description
- * The 'serviceUrl' exposes the base URL of the API backend.
- */
-// @ngInject
-function serviceUrl($document) {
-  return $document
-    .find('link')
-    .filter(function () {
-      return (this.rel === 'service' &&
-              this.type === 'application/annotatorsvc+json');
-    })
-    .filter(function () {
-      return this.href;
-    })
-    .prop('href');
-}
-
-module.exports = serviceUrl;

h/static/scripts/settings.js

+'use strict';
+
+var angular = require('angular');
+
+/**
+ * @ngdoc factory
+ * @name  settings
+ *
+ * @description
+ * The 'settings' factory exposes shared application settings, read from the
+ * global variable 'hypothesis.settings' in the app page.
+ */
+// @ngInject
+function settings($window) {
+  var data = {};
+
+  if ($window.hypothesis && $window.hypothesis.settings) {
+    angular.copy($window.hypothesis.settings, data);
+  }
+
+  return data;
+}
+
+module.exports = settings;

h/static/scripts/store.coffee

@@ -10,16 +10,15 @@
 # store.SearchResource().
 ###
 module.exports = [
-  '$http', '$resource', 'serviceUrl'
-  ($http,   $resource,   serviceUrl) ->
+  '$http', '$resource', 'settings'
+  ($http,   $resource,   settings) ->
     camelize = (string) ->
       string.replace /(?:^|_)([a-z])/g, (_, char) -> char.toUpperCase()
 
     store =
       $resolved: false
-      # We call the service_url and the backend api gives back
-      # the actions and urls it provides.
-      $promise: $http.get(serviceUrl)
+      # We call the API root and it gives back the actions it provides.
+      $promise: $http.get(settings.apiUrl)
         .finally -> store.$resolved = true
         .then (response) ->
           for name, actions of response.data.links
@@ -27,6 +26,6 @@ module.exports = [
             # For the search resource, one URL is given for all actions.
             # For the annotations, each action has its own URL.
             prop = "#{camelize(name)}Resource"
-            store[prop] = $resource(actions.url or serviceUrl, {}, actions)
+            store[prop] = $resource(actions.url or settings.apiUrl, {}, actions)
           store
 ]

h/static/scripts/test/store-test.coffee

@@ -13,7 +13,7 @@ describe 'store', ->
 
   beforeEach module ($provide) ->
     sandbox = sinon.sandbox.create()
-    $provide.value 'serviceUrl', 'http://example.com/api'
+    $provide.value 'settings', {apiUrl: 'http://example.com/api'}
     return
 
   afterEach ->