StoreFetchMiddleware

CHANGELOG.md

@@ -5,6 +5,7 @@ Expect active development and potentially significant breaking changes in the `0
 ### vNEXT
 - Fixed an issue with named fragments in batched queries. [PR #509](https://github.com/apollostack/apollo-client/pull/509) and [Issue #501](https://github.com/apollostack/apollo-client/issues/501).
 - Fixed an issue with unused variables in queries after diffing queries against information available in the store. [PR #518](https://github.com/apollostack/apollo-client/pull/518) and [Issue #496](https://github.com/apollostack/apollo-client/issues/496).
+- Added a `storeFetchMiddleware` option to `ApolloClient` that allows transformation of values returned from the store. Also exposes a `cachedFetchById` middleware to handle the common case of fetching cached resources by id. [PR #376](https://github.com/apollostack/apollo-client/pull/376)
 
 ### v0.4.11
 

ambient.d.ts

@@ -103,6 +103,11 @@ declare module 'lodash.pick' {
   export = main.pick;
 }
 
+declare module 'lodash.every' {
+  import main = require('~lodash/index');
+  export = main.every;
+}
+
 /*
 
   GRAPHQL

package.json

@@ -42,6 +42,7 @@
     "lodash.assign": "^4.0.8",
     "lodash.clonedeep": "^4.3.2",
     "lodash.countby": "^4.4.0",
+    "lodash.every": "^4.4.0",
     "lodash.flatten": "^4.2.0",
     "lodash.forown": "^4.1.0",
     "lodash.has": "^4.3.1",

src/QueryManager.ts

@@ -60,6 +60,10 @@ import {
   removeUnusedVariablesFromQuery,
 } from './data/diffAgainstStore';
 
+import {
+  StoreFetchMiddleware,
+} from './data/fetchMiddleware';
+
 import {
   MutationBehavior,
   MutationQueryReducersMap,
@@ -103,6 +107,7 @@ export class QueryManager {
   private networkInterface: NetworkInterface;
   private reduxRootKey: string;
   private queryTransformer: QueryTransformer;
+  private storeFetchMiddleware: StoreFetchMiddleware;
   private queryListeners: { [queryId: string]: QueryListener };
 
   // A map going from queryId to the last result/state that the queryListener was told about.
@@ -140,13 +145,15 @@ export class QueryManager {
     store,
     reduxRootKey,
     queryTransformer,
+    storeFetchMiddleware,
     shouldBatch = false,
     batchInterval = 10,
   }: {
     networkInterface: NetworkInterface,
     store: ApolloStore,
     reduxRootKey: string,
     queryTransformer?: QueryTransformer,
+    storeFetchMiddleware?: StoreFetchMiddleware,
     shouldBatch?: Boolean,
     batchInterval?: number,
   }) {
@@ -156,6 +163,7 @@ export class QueryManager {
     this.store = store;
     this.reduxRootKey = reduxRootKey;
     this.queryTransformer = queryTransformer;
+    this.storeFetchMiddleware = storeFetchMiddleware;
     this.pollingTimers = {};
     this.batchInterval = batchInterval;
     this.queryListeners = {};
@@ -325,12 +333,15 @@ export class QueryManager {
           try {
             const resultFromStore = {
               data: readSelectionSetFromStore({
-                store: this.getDataWithOptimisticResults(),
+                context: {
+                  store: this.getDataWithOptimisticResults(),
+                  fragmentMap: queryStoreValue.fragmentMap,
+                  fetchMiddleware: this.storeFetchMiddleware,
+                },
                 rootId: queryStoreValue.query.id,
                 selectionSet: queryStoreValue.query.selectionSet,
                 variables: queryStoreValue.variables,
                 returnPartialData: options.returnPartialData || options.noFetch,
-                fragmentMap: queryStoreValue.fragmentMap,
               }),
               loading: queryStoreValue.loading,
             };
@@ -558,15 +569,17 @@ export class QueryManager {
     }
 
     const previousResult = readSelectionSetFromStore({
-      // In case of an optimistic change, apply reducer on top of the
-      // results including previous optimistic updates. Otherwise, apply it
-      // on top of the real data only.
-      store: isOptimistic ? this.getDataWithOptimisticResults() : this.getApolloState().data,
+      context: {
+        // In case of an optimistic change, apply reducer on top of the
+        // results including previous optimistic updates. Otherwise, apply it
+        // on top of the real data only.
+        store: isOptimistic ? this.getDataWithOptimisticResults() : this.getApolloState().data,
+        fragmentMap: createFragmentMap(fragments || []),
+      },
       rootId: 'ROOT_QUERY',
       selectionSet: queryDefinition.selectionSet,
       variables: queryOptions.variables,
       returnPartialData: queryOptions.returnPartialData || queryOptions.noFetch,
-      fragmentMap: createFragmentMap(fragments || []),
     });
 
     return {
@@ -674,12 +687,15 @@ export class QueryManager {
     initialResult: Object,
   } {
     const { missingSelectionSets, result } = diffSelectionSetAgainstStore({
+      context: {
+        store: this.store.getState()[this.reduxRootKey].data,
+        fragmentMap,
+        fetchMiddleware: this.storeFetchMiddleware,
+      },
       selectionSet: queryDef.selectionSet,
-      store: this.store.getState()[this.reduxRootKey].data,
       throwOnMissingField: false,
       rootId,
       variables,
-      fragmentMap,
     });
 
     const initialResult = result;
@@ -761,12 +777,15 @@ export class QueryManager {
             // this will throw an error if there are missing fields in
             // the results if returnPartialData is false.
             resultFromStore = readSelectionSetFromStore({
-              store: this.getApolloState().data,
+              context: {
+                store: this.getApolloState().data,
+                fragmentMap,
+                fetchMiddleware: this.storeFetchMiddleware,
+              },
               rootId: querySS.id,
               selectionSet: querySS.selectionSet,
               variables,
               returnPartialData: returnPartialData || noFetch,
-              fragmentMap,
             });
             // ensure multiple errors don't get thrown
             /* tslint:disable */

src/data/diffAgainstStore.ts

@@ -1,5 +1,6 @@
 import isArray = require('lodash.isarray');
 import isNull = require('lodash.isnull');
+import isUndefined = require('lodash.isundefined');
 import has = require('lodash.has');
 import assign = require('lodash.assign');
 
@@ -16,6 +17,10 @@ import {
   isIdValue,
 } from './store';
 
+import {
+  StoreFetchMiddleware,
+} from './fetchMiddleware';
+
 import {
   SelectionSetWithRoot,
 } from '../queries/store';
@@ -52,6 +57,14 @@ export interface DiffResult {
   missingSelectionSets?: SelectionSetWithRoot[];
 }
 
+// Contexual state and configuration that is used throught a request from the
+// store.
+export interface StoreContext {
+  store: NormalizedCache;
+  fragmentMap: FragmentMap;
+  fetchMiddleware?: StoreFetchMiddleware;
+}
+
 export function diffQueryAgainstStore({
   store,
   query,
@@ -64,7 +77,7 @@ export function diffQueryAgainstStore({
   const queryDef = getQueryDefinition(query);
 
   return diffSelectionSetAgainstStore({
-    store,
+    context: { store, fragmentMap: {} },
     rootId: 'ROOT_QUERY',
     selectionSet: queryDef.selectionSet,
     throwOnMissingField: false,
@@ -86,7 +99,7 @@ export function diffFragmentAgainstStore({
   const fragmentDef = getFragmentDefinition(fragment);
 
   return diffSelectionSetAgainstStore({
-    store,
+    context: { store, fragmentMap: {} },
     rootId,
     selectionSet: fragmentDef.selectionSet,
     throwOnMissingField: false,
@@ -126,28 +139,22 @@ export function handleFragmentErrors(fragmentErrors: { [typename: string]: Error
  * @return {result: Object, missingSelectionSets: [SelectionSet]}
  */
 export function diffSelectionSetAgainstStore({
+  context,
   selectionSet,
-  store,
   rootId,
   throwOnMissingField = false,
   variables,
-  fragmentMap,
 }: {
+  context: StoreContext,
   selectionSet: SelectionSet,
-  store: NormalizedCache,
   rootId: string,
   throwOnMissingField: boolean,
   variables: Object,
-  fragmentMap?: FragmentMap,
 }): DiffResult {
   if (selectionSet.kind !== 'SelectionSet') {
     throw new Error('Must be a selection set.');
   }
 
-  if (!fragmentMap) {
-    fragmentMap = {};
-  }
-
   const result = {};
   const missingFields: Selection[] = [];
 
@@ -177,12 +184,11 @@ export function diffSelectionSetAgainstStore({
 
     if (isField(selection)) {
       const diffResult = diffFieldAgainstStore({
+        context,
         field: selection,
         throwOnMissingField,
         variables,
         rootId,
-        store,
-        fragmentMap,
         included,
       });
       fieldIsMissing = diffResult.isMissing;
@@ -204,12 +210,11 @@ export function diffSelectionSetAgainstStore({
       if (included) {
         try {
           const diffResult = diffSelectionSetAgainstStore({
+            context,
             selectionSet: selection.selectionSet,
             throwOnMissingField,
             variables,
             rootId,
-            store,
-            fragmentMap,
           });
           fieldIsMissing = diffResult.isMissing;
           fieldResult = diffResult.result;
@@ -232,7 +237,7 @@ export function diffSelectionSetAgainstStore({
         }
       }
     } else {
-      const fragment = fragmentMap[selection.name.value];
+      const fragment = context.fragmentMap[selection.name.value];
 
       if (!fragment) {
         throw new Error(`No fragment named ${selection.name.value}`);
@@ -243,12 +248,11 @@ export function diffSelectionSetAgainstStore({
       if (included) {
         try {
           const diffResult = diffSelectionSetAgainstStore({
+            context,
             selectionSet: fragment.selectionSet,
             throwOnMissingField,
             variables,
             rootId,
-            store,
-            fragmentMap,
           });
           fieldIsMissing = diffResult.isMissing;
           fieldResult = diffResult.result;
@@ -311,26 +315,34 @@ export function diffSelectionSetAgainstStore({
 }
 
 function diffFieldAgainstStore({
+  context,
   field,
   throwOnMissingField,
   variables,
   rootId,
-  store,
-  fragmentMap,
   included = true,
 }: {
+  context: StoreContext,
   field: Field,
   throwOnMissingField: boolean,
   variables: Object,
   rootId: string,
-  store: NormalizedCache,
-  fragmentMap?: FragmentMap,
   included?: Boolean,
 }): FieldDiffResult {
-  const storeObj = store[rootId] || {};
+  const storeObj = context.store[rootId] || {};
   const storeFieldKey = storeKeyNameFromField(field, variables);
 
-  if (! has(storeObj, storeFieldKey)) {
+  let storeValue, fieldMissing;
+  // Give the transformer a chance to yield a rewritten result.
+  if (context.fetchMiddleware) {
+    storeValue = context.fetchMiddleware(field, variables, context.store, () => storeObj[storeFieldKey]);
+    fieldMissing = isUndefined(storeValue);
+  } else {
+    storeValue = storeObj[storeFieldKey];
+    fieldMissing = !has(storeObj, storeFieldKey);
+  }
+
+  if (fieldMissing) {
     if (throwOnMissingField && included) {
       throw new ApolloError({
         errorMessage: `Can't find field ${storeFieldKey} on object (${rootId}) ${JSON.stringify(storeObj, null, 2)}.
@@ -346,8 +358,6 @@ Perhaps you want to use the \`returnPartialData\` option?`,
     };
   }
 
-  const storeValue = storeObj[storeFieldKey];
-
   // Handle all scalar types here
   if (! field.selectionSet) {
     if (isJsonValue(storeValue)) {
@@ -382,12 +392,11 @@ Perhaps you want to use the \`returnPartialData\` option?`,
       }
 
       const itemDiffResult = diffSelectionSetAgainstStore({
-        store,
+        context,
         throwOnMissingField,
         rootId: id,
         selectionSet: field.selectionSet,
         variables,
-        fragmentMap,
       });
 
       if (itemDiffResult.isMissing) {
@@ -409,12 +418,11 @@ Perhaps you want to use the \`returnPartialData\` option?`,
   if (isIdValue(storeValue)) {
     const unescapedId = storeValue.id;
     return diffSelectionSetAgainstStore({
-      store,
+      context,
       throwOnMissingField,
       rootId: unescapedId,
       selectionSet: field.selectionSet,
       variables,
-      fragmentMap,
     });
   }