Add emulation of simpleSubscriptions: true to V4 preset (#1878)

graphile · Dec 4, 2023 · 8c16aeb · 8c16aeb
2 parents bfedf68 + f5a03db
commit 8c16aeb
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diff --git a/.changeset/red-swans-sing.md b/.changeset/red-swans-sing.md
@@ -0,0 +1,5 @@
+---
+"postgraphile": patch
+---
+
+Add emulation for `--simple-subscriptions` to V4 preset.
diff --git a/.changeset/thirty-ants-admire.md b/.changeset/thirty-ants-admire.md
@@ -0,0 +1,5 @@
+---
+"graphile-build": patch
+---
+
+Export getNodeIdHandlerByTypeName to make writing plugins easier
diff --git a/grafast/grafast/src/steps/node.ts b/grafast/grafast/src/steps/node.ts
@@ -38,7 +38,7 @@ export class NodeStep
     private possibleTypes: {
       [typeName: string]: NodeIdHandler;
     },
-    $id: ExecutableStep<string>,
+    $id: ExecutableStep<string | null | undefined>,
   ) {
     super();
     const decodeNodeId = makeDecodeNodeId(Object.values(possibleTypes));
@@ -94,7 +94,7 @@ export function node(
   possibleTypes: {
     [typeName: string]: NodeIdHandler;
   },
-  $id: ExecutableStep<string>,
+  $id: ExecutableStep<string | null | undefined>,
 ): NodeStep {
   return new NodeStep(possibleTypes, $id);
 }
@@ -126,7 +126,8 @@ export function specFromNodeId(
 export function makeDecodeNodeId(handlers: NodeIdHandler[]) {
   const codecs = [...new Set(handlers.map((h) => h.codec))];
 
-  function decodeNodeIdWithCodecs(raw: string) {
+  function decodeNodeIdWithCodecs(raw: string | null | undefined) {
+    if (raw == null) return null;
     return codecs.reduce(
       (memo, codec) => {
         try {
@@ -142,5 +143,6 @@ export function makeDecodeNodeId(handlers: NodeIdHandler[]) {
     );
   }
   decodeNodeIdWithCodecs.isSyncAndSafe = true; // Optimization
-  return ($id: ExecutableStep<string>) => lambda($id, decodeNodeIdWithCodecs);
+  return ($id: ExecutableStep<string | null | undefined>) =>
+    lambda($id, decodeNodeIdWithCodecs);
 }
diff --git a/graphile-build/graphile-build-pg/src/plugins/PgPolymorphismPlugin.ts b/graphile-build/graphile-build-pg/src/plugins/PgPolymorphismPlugin.ts
@@ -845,7 +845,7 @@ export const PgPolymorphismPlugin: GraphileConfig.Plugin = {
                           );
                           return object({
                             match: lambda($specifier, (specifier) => {
-                              const value = specifier[handler.codec.name];
+                              const value = specifier?.[handler.codec.name];
                               return value != null
                                 ? handler.match(value)
                                 : false;
@@ -916,7 +916,7 @@ export const PgPolymorphismPlugin: GraphileConfig.Plugin = {
                           );
                           return object({
                             match: lambda($specifier, (specifier) => {
-                              const value = specifier[handler.codec.name];
+                              const value = specifier?.[handler.codec.name];
                               return value != null
                                 ? handler.match(value)
                                 : false;

diff --git a/graphile-build/graphile-build/src/plugins/AddNodeInterfaceToSuitableTypesPlugin.ts b/graphile-build/graphile-build/src/plugins/AddNodeInterfaceToSuitableTypesPlugin.ts
@@ -43,7 +43,11 @@ export const AddNodeInterfaceToSuitableTypesPlugin: GraphileConfig.Plugin = {
         const {
           getTypeByName,
           inflection,
+
+          // To get this in your own plugin, use
+          // `const nodeIdHandlerByTypeName = build.getNodeIdHandlerByTypeName();` instead
           [NODE_ID_HANDLER_BY_TYPE_NAME]: nodeIdHandlerByTypeName,
+
           [NODE_ID_CODECS]: nodeIdCodecs,
           graphql: { GraphQLNonNull, GraphQLID },
         } = build;

diff --git a/graphile-build/graphile-build/src/plugins/NodePlugin.ts b/graphile-build/graphile-build/src/plugins/NodePlugin.ts
@@ -20,6 +20,7 @@ declare global {
       registerNodeIdHandler?(matcher: NodeIdHandler): void;
       getNodeIdHandler?(typeName: string): NodeIdHandler | undefined;
       getNodeTypeNames?(): string[];
+      getNodeIdHandlerByTypeName?(): Readonly<Record<string, NodeIdHandler>>;
     }
 
     interface ScopeObjectFieldsField {
@@ -77,8 +78,13 @@ export const NodePlugin: GraphileConfig.Plugin = {
         return build.extend(
           build,
           {
+            /** @internal */
             [NODE_ID_CODECS]: nodeIdCodecs,
+            /** @internal */
             [NODE_ID_HANDLER_BY_TYPE_NAME]: nodeIdHandlerByTypeName,
+            getNodeIdHandlerByTypeName() {
+              return nodeIdHandlerByTypeName;
+            },
             registerNodeIdCodec(codec) {
               const codecName = codec.name;
               if (nodeIdCodecs[codecName]) {
@@ -169,8 +175,8 @@ export const NodePlugin: GraphileConfig.Plugin = {
           extend,
           graphql: { GraphQLNonNull, GraphQLID },
           inflection,
-          [NODE_ID_HANDLER_BY_TYPE_NAME]: nodeIdHandlerByTypeName,
         } = build;
+        const nodeIdHandlerByTypeName = build.getNodeIdHandlerByTypeName!();
         const nodeIdFieldName = build.inflection.nodeIdFieldName();
         const nodeType = getTypeByName(inflection.builtin("Node")) as
           | GraphQLObjectType

diff --git a/graphile-build/graphile-utils/tsconfig.json b/graphile-build/graphile-utils/tsconfig.json
@@ -9,7 +9,6 @@
   "include": ["src"],
   "references": [
     { "path": "../../utils/graphile-config" },
-    { "path": "../../grafast/grafast" },
-    { "path": "../../postgraphile/postgraphile/tsconfig.build.json" }
+    { "path": "../../grafast/grafast" }
   ]
 }
diff --git a/postgraphile/postgraphile/graphile.config.ts b/postgraphile/postgraphile/graphile.config.ts
@@ -287,6 +287,7 @@ const preset: GraphileConfig.Preset = {
       graphiql: true,
       graphiqlRoute: "/",
       ignoreRBAC: false,
+      simpleSubscriptions: true,
     }),
     // PgManyToManyPreset,
     // PostGraphileConnectionFilterPreset,

diff --git a/postgraphile/postgraphile/src/plugins/PgV4SimpleSubscriptionsPlugin.ts b/postgraphile/postgraphile/src/plugins/PgV4SimpleSubscriptionsPlugin.ts
@@ -0,0 +1,86 @@
+import type { JSONParseStep } from "@dataplan/json";
+import { jsonParse } from "@dataplan/json";
+import { context, lambda, listen, node } from "grafast";
+import { EXPORTABLE, gql, makeExtendSchemaPlugin } from "graphile-utils";
+
+export const PgV4SimpleSubscriptionsPlugin = makeExtendSchemaPlugin((build) => {
+  const nodeIdHandlerByTypeName = build.getNodeIdHandlerByTypeName?.();
+  return {
+    typeDefs: [
+      gql`
+        extend type Subscription {
+          listen(topic: String!): ListenPayload
+        }
+
+        type ListenPayload {
+          event: String
+        }
+      `,
+      ...// Only add the relatedNode if supported
+      (nodeIdHandlerByTypeName
+        ? [
+            gql`
+              extend type ListenPayload {
+                relatedNode: Node
+                relatedNodeId: ID
+              }
+            `,
+          ]
+        : []),
+    ],
+    plans: {
+      Subscription: {
+        listen: {
+          subscribePlan: EXPORTABLE(
+            (context, jsonParse, lambda, listen) =>
+              function subscribePlan(_$root, { $topic }) {
+                const $pgSubscriber = context().get("pgSubscriber");
+                const $derivedTopic = lambda(
+                  $topic,
+                  (topic) => `postgraphile:${topic}`,
+                );
+                return listen($pgSubscriber, $derivedTopic, jsonParse);
+              },
+            [context, jsonParse, lambda, listen],
+          ),
+          plan: EXPORTABLE(
+            () =>
+              function plan($event) {
+                return $event;
+              },
+            [],
+          ),
+        },
+      },
+      ListenPayload: {
+        event($event) {
+          return $event.get("event");
+        },
+        ...(nodeIdHandlerByTypeName
+          ? {
+              relatedNodeId($event) {
+                return nodeIdFromEvent($event);
+              },
+              relatedNode($event) {
+                const $nodeId = nodeIdFromEvent($event);
+                return node(nodeIdHandlerByTypeName, $nodeId);
+              },
+            }
+          : null),
+      },
+    },
+  };
+}, "PgV4SimpleSubscriptionsPlugin");
+
+// WARNING: this function assumes that you're using the `base64JSON` NodeID codec, which was the case for PostGraphile V4. If you are not doing so, YMMV.
+function nodeIdFromEvent($event: JSONParseStep<{ __node__?: any[] }>) {
+  const $nodeObj = $event.get("__node__");
+  const $nodeId = lambda($nodeObj, nodeObjToNodeId);
+  return $nodeId;
+}
+
+// base64JSON codec copy
+function nodeObjToNodeId(obj: any[] | undefined): string | null {
+  if (!obj) return null;
+  return Buffer.from(JSON.stringify(obj), "utf8").toString("base64");
+}
diff --git a/postgraphile/postgraphile/src/presets/v4.ts b/postgraphile/postgraphile/src/presets/v4.ts
@@ -6,9 +6,15 @@ import type { IncomingMessage, ServerResponse } from "http";
 
 import { PgV4BehaviorPlugin } from "../plugins/PgV4BehaviorPlugin.js";
 import { PgV4InflectionPlugin } from "../plugins/PgV4InflectionPlugin.js";
+import { PgV4SimpleSubscriptionsPlugin } from "../plugins/PgV4SimpleSubscriptionsPlugin.js";
 import { PgV4SmartTagsPlugin } from "../plugins/PgV4SmartTagsPlugin.js";
 
-export { PgV4BehaviorPlugin, PgV4InflectionPlugin, PgV4SmartTagsPlugin };
+export {
+  PgV4BehaviorPlugin,
+  PgV4InflectionPlugin,
+  PgV4SimpleSubscriptionsPlugin,
+  PgV4SmartTagsPlugin,
+};
 
 type PromiseOrDirect<T> = T | Promise<T>;
 type DirectOrCallback<Request, T> = T | ((req: Request) => PromiseOrDirect<T>);
@@ -87,6 +93,8 @@ export interface V4Options<
   watchPg?: boolean;
   /** @deprecated Use 'preset.grafast.context' callback instead */
   defaultRole?: never;
+
+  simpleSubscriptions?: boolean;
 }
 
 function isNotNullish<T>(arg: T | undefined | null): arg is T {
@@ -200,6 +208,7 @@ export const makeV4Preset = (
       PgV4InflectionPlugin,
       PgV4SmartTagsPlugin,
       PgV4BehaviorPlugin,
+      options.simpleSubscriptions ? PgV4SimpleSubscriptionsPlugin : null,
       makeV4Plugin(options),
       ...(options.appendPlugins ? options.appendPlugins : []),
     ].filter(isNotNullish),

diff --git a/postgraphile/postgraphile/tsconfig.build.json b/postgraphile/postgraphile/tsconfig.build.json
@@ -16,6 +16,7 @@
     { "path": "../../utils/graphile-export" },
     { "path": "../../grafast/ruru/tsconfig.build.json" },
     { "path": "../../grafast/grafserv-persisted" },
-    { "path": "../../utils/graphile-config" }
+    { "path": "../../utils/graphile-config" },
+    { "path": "../../graphile-build/graphile-utils" }
   ]
 }