ui: Use `X-Range` header/meta to decide whether to reconcile or not

Previously we used a `shouldReconcile` method in order to decide whether
a response should trigger a reconciliation of the frontend ember-data
'source of truth' or not. It's a lot nicer/clearer if this 'flag' can be set
alongside the HTTP request information, moreover we almost have the same
functionality in `If-Range`/`Partial Content` HTTP functionality.

Here we partly follow this HTTP semantics but use a custom `X-Range` header
instead.

ui-v2/app/serializers/application.js

@@ -92,7 +92,11 @@ export default Serializer.extend({
       // and they need the slug key AND potential namespace in order to
       // create the correct uid/fingerprint
       return {
-        [primaryKey]: this.fingerprint(primaryKey, slugKey, data[DATACENTER_KEY])({
+        [primaryKey]: this.fingerprint(
+          primaryKey,
+          slugKey,
+          data[DATACENTER_KEY]
+        )({
           [slugKey]: data[slugKey],
           [NSPACE_KEY]: data[NSPACE_KEY],
         })[primaryKey],
@@ -151,6 +155,9 @@ export default Serializer.extend({
       dc: headers[HTTP_HEADERS_DATACENTER.toLowerCase()],
       nspace: headers[HTTP_HEADERS_NAMESPACE.toLowerCase()],
     };
+    if (typeof headers['x-range'] !== 'undefined') {
+      meta.range = headers['x-range'];
+    }
     if (requestType === 'query') {
       meta.date = this.timestamp();
       payload.forEach(function(item) {

ui-v2/app/services/client/http.js

@@ -68,7 +68,7 @@ const parseBody = function(strs, ...values) {
   return [body, ...values];
 };
 
-const CLIENT_HEADERS = [CACHE_CONTROL, 'X-Request-ID'];
+const CLIENT_HEADERS = [CACHE_CONTROL, 'X-Request-ID', 'X-Range'];
 export default Service.extend({
   dom: service('dom'),
   connections: service('client/connections'),

ui-v2/app/services/data-source/protocols/http.js

@@ -33,16 +33,17 @@ export default Service.extend({
     // so we might get urls like //dc/services
     let find;
     const repo = this[model];
-    if (repo.shouldReconcile(src)) {
-      configuration.createEvent = function(result = {}, configuration) {
-        const event = {
-          type: 'message',
-          data: result,
-        };
-        repo.reconcile(get(event, 'data.meta'));
-        return event;
+    configuration.createEvent = function(result = {}, configuration) {
+      const event = {
+        type: 'message',
+        data: result,
       };
-    }
+      const meta = get(event, 'data.meta') || {};
+      if (typeof meta.range === 'undefined') {
+        repo.reconcile(meta);
+      }
+      return event;
+    };
     let method, slug;
     switch (model) {
       case 'datacenters':

ui-v2/app/services/repository.js

@@ -15,9 +15,6 @@ export default Service.extend({
   },
   //
   store: service('store'),
-  shouldReconcile: function(method) {
-    return true;
-  },
   reconcile: function(meta = {}) {
     // unload anything older than our current sync date/time
     if (typeof meta.date !== 'undefined') {

ui-v2/app/services/repository/intention.js

@@ -12,15 +12,6 @@ export default RepositoryService.extend({
     delete obj.Namespace;
     return this._super(obj);
   },
-  shouldReconcile: function(method) {
-    // TODO: This is to be switched out for something at an adapter level
-    // so it works for both methods of interacting with data-sources
-    switch (true) {
-      case method === 'findByService' || method.indexOf('for-service') !== -1:
-        return false;
-    }
-    return this._super(...arguments);
-  },
   findByService: function(slug, dc, nspace, configuration = {}) {
     const query = {
       dc: dc,

ui-v2/app/services/repository/service.js

@@ -5,13 +5,6 @@ export default RepositoryService.extend({
   getModelName: function() {
     return modelName;
   },
-  shouldReconcile: function(method) {
-    switch (method) {
-      case 'findGatewayBySlug':
-        return false;
-    }
-    return this._super(...arguments);
-  },
   findBySlug: function(slug, dc) {
     return this._super(...arguments).then(function(item) {
       // TODO: Move this to the Serializer

ui-v2/app/services/repository/type/event-source.js

@@ -9,17 +9,17 @@ import { cache as createCache, BlockingEventSource } from 'consul-ui/utils/dom/e
 const createProxy = function(repo, find, settings, cache, serialize = JSON.stringify) {
   const client = this.client;
   // custom createEvent, here used to reconcile the ember-data store for each tick
-  let createEvent;
-  if (repo.shouldReconcile(find)) {
-    createEvent = function(result = {}, configuration) {
-      const event = {
-        type: 'message',
-        data: result,
-      };
-      repo.reconcile(get(event, 'data.meta'));
-      return event;
+  const createEvent = function(result = {}, configuration) {
+    const event = {
+      type: 'message',
+      data: result,
     };
-  }
+    const meta = get(event, 'data.meta') || {};
+    if (typeof meta.range === 'undefined') {
+      repo.reconcile(meta);
+    }
+    return event;
+  };
   // proxied find*..(id, dc)
   return function() {
     const key = `${repo.getModelName()}.${find}.${serialize([...arguments])}`;