Transform Uploads to Streams before calling action (#71)

Update the upload feature to transform object resolved from GraphQL upload to a stream before calling the resolution action.  This allows uploads to work properly across the transporter.

Author: dylanwulf

README.md

@@ -258,6 +258,107 @@ module.exports = {
 };
 ```
 
+### File Uploads
+moleculer-apollo-server supports file uploads through the [GraphQL multipart request specification](https://github.com/jaydenseric/graphql-multipart-request-spec). 
+
+To enable uploads, the Upload scalar must be added to the Gateway:
+
+```js
+"use strict";
+
+const ApiGateway 	= require("moleculer-web");
+const { ApolloService, GraphQLUpload } = require("moleculer-apollo-server");
+
+module.exports = {
+    name: "api",
+
+    mixins: [
+        // Gateway
+        ApiGateway,
+
+        // GraphQL Apollo Server
+        ApolloService({
+
+            // Global GraphQL typeDefs
+            typeDefs: ["scalar Upload"],
+
+            // Global resolvers
+            resolvers: {
+                Upload: GraphQLUpload
+            },
+
+            // API Gateway route options
+            routeOptions: {
+                path: "/graphql",
+                cors: true,
+                mappingPolicy: "restrict"
+            },
+
+            // https://www.apollographql.com/docs/apollo-server/v2/api/apollo-server.html
+            serverOptions: {
+                tracing: true,
+
+                engine: {
+                    apiKey: process.env.APOLLO_ENGINE_KEY
+                }
+            }
+        })
+    ]
+};
+
+```
+
+Then a mutation can be created which accepts an Upload argument. The `fileUploadArg` property must be set to the mutation's argument name so that moleculer-apollo-server knows where to expect a file upload. When the mutation's action handler is called, `ctx.params` will be a [Readable Stream](https://nodejs.org/api/stream.html#stream_readable_streams) which can be used to read the contents of the uploaded file (or pipe the contents into a Writable Stream). File metadata will be made available in `ctx.meta.$fileInfo`.
+
+**files.service.js**
+```js
+module.exports = {
+    name: "files",
+    settings: {
+        graphql: {
+            type: `
+                """
+                This type describes a File entity.
+                """			
+                type File {
+                    filename: String!
+                    encoding: String!
+                    mimetype: String!
+                }
+            `
+        }
+    },
+    actions: {
+        uploadFile: {
+            graphql: {
+                mutation: "uploadFile(file: Upload!): File!",
+                fileUploadArg: "file",
+            },
+            async handler(ctx) {
+                const fileChunks = [];
+                for await (const chunk of ctx.params) {
+                    fileChunks.push(chunk);
+                }
+                const fileContents = Buffer.concat(fileChunks);
+                // Do something with file contents
+                return ctx.meta.$fileInfo;
+            }
+        }
+    }
+};
+```
+
+To accept multiple uploaded files in a single request, the mutation can be changed to accept an array of `Upload`s and return an array of results. The action handler will then be called once for each uploaded file, and the results will be combined into an array automatically with results in the same order as the provided files.
+
+```js
+...
+graphql: {
+    mutation: "upload(file: [Upload!]!): [File!]!",
+    fileUploadArg: "file"
+}
+...
+```
+
 ### Dataloader
 moleculer-apollo-server supports [DataLoader](https://github.com/graphql/dataloader) via configuration in the resolver definition.
 The called action must be compatible with DataLoader semantics -- that is, it must accept params with an array property and return an array of the same size,
@@ -312,6 +413,9 @@ It is unlikely that setting any of the options which accept a function will work
 
 - [Simple](examples/simple/index.js)
   - `npm run dev`
+- [File Upload](examples/upload/index.js)
+  - `npm run dev upload`
+  - See [here](https://github.com/jaydenseric/graphql-multipart-request-spec#curl-request) for information about how to create a file upload request
 - [Full](examples/full/index.js)
   - `npm run dev full`
 - [Full With Dataloader](examples/full/index.js)

examples/upload/index.js

@@ -0,0 +1,95 @@
+"use strict";
+
+const { ServiceBroker } = require("moleculer");
+
+const ApiGateway = require("moleculer-web");
+const { ApolloService, GraphQLUpload } = require("../../index");
+
+const broker = new ServiceBroker({ logLevel: "info", hotReload: true });
+
+broker.createService({
+	name: "api",
+
+	mixins: [
+		// Gateway
+		ApiGateway,
+
+		// GraphQL Apollo Server
+		ApolloService({
+			typeDefs: ["scalar Upload"],
+			resolvers: {
+				Upload: GraphQLUpload,
+			},
+			// API Gateway route options
+			routeOptions: {
+				path: "/graphql",
+				cors: true,
+				mappingPolicy: "restrict",
+			},
+
+			// https://www.apollographql.com/docs/apollo-server/v2/api/apollo-server.html
+			serverOptions: {},
+		}),
+	],
+
+	events: {
+		"graphql.schema.updated"({ schema }) {
+			this.logger.info("Generated GraphQL schema:\n\n" + schema);
+		},
+	},
+});
+
+broker.createService({
+	name: "files",
+	settings: {
+		graphql: {
+			type: `
+                """
+                This type describes a File entity.
+                """
+                type File {
+                    filename: String!
+                    encoding: String!
+                    mimetype: String!
+                }
+            `,
+		},
+	},
+	actions: {
+		hello: {
+			graphql: {
+				query: "hello: String!",
+			},
+			handler() {
+				return "Hello Moleculer!";
+			},
+		},
+		singleUpload: {
+			graphql: {
+				mutation: "singleUpload(file: Upload!): File!",
+				fileUploadArg: "file",
+			},
+			async handler(ctx) {
+				const fileChunks = [];
+				for await (const chunk of ctx.params) {
+					fileChunks.push(chunk);
+				}
+				const fileContents = Buffer.concat(fileChunks);
+				ctx.broker.logger.info("Uploaded File Contents:");
+				ctx.broker.logger.info(fileContents.toString());
+				return ctx.meta.$fileInfo;
+			},
+		},
+	},
+});
+
+broker.start().then(async () => {
+	broker.repl();
+
+	broker.logger.info("----------------------------------------------------------");
+	broker.logger.info("For information about creating a file upload request,");
+	broker.logger.info(
+		"see https://github.com/jaydenseric/graphql-multipart-request-spec#curl-request"
+	);
+	broker.logger.info("----------------------------------------------------------");
+});

index.d.ts

@@ -5,7 +5,6 @@ declare module "moleculer-apollo-server" {
 	import { SchemaDirectiveVisitor, IResolvers } from "graphql-tools";
 
 	export {
-		GraphQLUpload,
 		GraphQLExtension,
 		gql,
 		ApolloError,
@@ -18,6 +17,8 @@ declare module "moleculer-apollo-server" {
 		defaultPlaygroundOptions,
 	} from "apollo-server-core";
 
+	export { GraphQLUpload } from 'graphql-upload';
+
 	export * from "graphql-tools";
 
 	export interface ApolloServerOptions {

index.js

@@ -15,13 +15,13 @@
 "use strict";
 
 const core = require("apollo-server-core");
+const { GraphQLUpload } = require("graphql-upload");
 const { ApolloServer } = require("./src/ApolloServer");
 const ApolloService = require("./src/service");
 const gql = require("./src/gql");
 
 module.exports = {
 	// Core
-	GraphQLUpload: core.GraphQLUpload,
 	GraphQLExtension: core.GraphQLExtension,
 	gql: core.gql,
 	ApolloError: core.ApolloError,
@@ -36,6 +36,9 @@ module.exports = {
 	// GraphQL tools
 	...require("graphql-tools"),
 
+	// GraphQL Upload
+	GraphQLUpload,
+
 	// Apollo Server
 	ApolloServer,
 

package.json

@@ -70,6 +70,7 @@
   "dependencies": {
     "@apollographql/graphql-playground-html": "^1.6.24",
     "@hapi/accept": "^3.2.4",
+    "@types/graphql-upload": "^8.0.0",
     "apollo-server-core": "^2.10.0",
     "dataloader": "^2.0.0",
     "graphql-subscriptions": "^1.1.0",

src/service.js

@@ -133,6 +133,7 @@ module.exports = function(mixinOptions) {
 					nullIfError = false,
 					params: staticParams = {},
 					rootParams = {},
+					fileUploadArg = null,
 				} = def;
 				const rootKeys = Object.keys(rootParams);
 
@@ -189,6 +190,27 @@ module.exports = function(mixinOptions) {
 							return Array.isArray(dataLoaderKey)
 								? await dataLoader.loadMany(dataLoaderKey)
 								: await dataLoader.load(dataLoaderKey);
+						} else if (fileUploadArg != null && args[fileUploadArg] != null) {
+							if (Array.isArray(args[fileUploadArg])) {
+								return await Promise.all(
+									args[fileUploadArg].map(async uploadPromise => {
+										const {
+											createReadStream,
+											...$fileInfo
+										} = await uploadPromise;
+										const stream = createReadStream();
+										return context.ctx.call(actionName, stream, {
+											meta: { $fileInfo },
+										});
+									})
+								);
+							}
+
+							const { createReadStream, ...$fileInfo } = await args[fileUploadArg];
+							const stream = createReadStream();
+							return await context.ctx.call(actionName, stream, {
+								meta: { $fileInfo },
+							});
 						} else {
 							const params = {};
 							if (root && rootKeys) {
@@ -411,7 +433,10 @@ module.exports = function(mixinOptions) {
 										const name = this.getFieldName(mutation);
 										mutations.push(mutation);
 										resolver.Mutation[name] = this.createActionResolver(
-											action.name
+											action.name,
+											{
+												fileUploadArg: def.fileUploadArg,
+											}
 										);
 									});
 								}