Merge pull request #37 from graphcool/subscriptions

feat: added subscriptions support

package.json

@@ -28,17 +28,18 @@
   "dependencies": {
     "apollo-link": "1.0.7",
     "apollo-link-http": "1.3.2",
+    "apollo-link-ws": "^1.0.4",
     "cross-fetch": "^1.1.1",
     "graphql": "0.12.3",
-    "graphql-binding": "0.2.1",
+    "graphql-binding": "0.3.0",
     "graphql-import": "0.1.9",
-    "graphql-schema-cache": "0.3.4",
-    "graphql-tools": "2.15.0",
-    "jsonwebtoken": "^8.1.0"
+    "graphql-tools": "2.16.0",
+    "jsonwebtoken": "^8.1.0",
+    "subscriptions-transport-ws": "^0.9.4"
   },
   "devDependencies": {
-    "@types/jsonwebtoken": "7.2.5",
     "@types/graphql": "0.11.7",
+    "@types/jsonwebtoken": "7.2.5",
     "@types/node": "8.5.2",
     "tslint": "5.8.0",
     "tslint-config-standard": "7.0.0",

src/Graphcool.ts

@@ -2,19 +2,28 @@ import { Binding } from 'graphql-binding'
 import { Exists, GraphcoolOptions } from './types'
 import { sign } from 'jsonwebtoken'
 import { makeGraphcoolLink } from './link'
-import { SchemaCache } from 'graphql-schema-cache'
 import { GraphQLResolveInfo, isListType, isWrappingType } from 'graphql'
 import { buildExistsInfo } from './info'
 import { importSchema } from 'graphql-import'
-import { GraphQLNamedType } from 'graphql';
+import { GraphQLNamedType, GraphQLSchema } from 'graphql'
+import { SharedLink } from './SharedLink'
+import { makeRemoteExecutableSchema } from 'graphql-tools'
 
-const schemaCache = new SchemaCache()
 const typeDefsCache: { [schemaPath: string]: string } = {}
 
+const sharedLink = new SharedLink()
+let remoteSchema: GraphQLSchema | undefined
+
 export class Graphcool extends Binding {
   exists: Exists
 
-  constructor({ typeDefs, endpoint, secret, fragmentReplacements, debug }: GraphcoolOptions) {
+  constructor({
+    typeDefs,
+    endpoint,
+    secret,
+    fragmentReplacements,
+    debug,
+  }: GraphcoolOptions) {
     if (!typeDefs) {
       throw new Error('No `typeDefs` provided when calling `new Graphcool()`')
     }
@@ -28,7 +37,7 @@ export class Graphcool extends Binding {
         endpoint = process.env.GRAPHCOOL_ENDPOINT
       } else {
         throw new Error(
-          `No Graphcool endpoint found. Either provide \`endpoint\` constructor option or set \`GRAPHCOOL_ENDPOINT\` env var.`
+          `No Graphcool endpoint found. Either provide \`endpoint\` constructor option or set \`GRAPHCOOL_ENDPOINT\` env var.`,
         )
       }
     }
@@ -42,7 +51,7 @@ export class Graphcool extends Binding {
         secret = process.env.GRAPHCOOL_SECRET
       } else {
         throw new Error(
-          `No Graphcool secret found. Either provide \`secret\` constructor option or set \`GRAPHCOOL_SECRET\` env var.`
+          `No Graphcool secret found. Either provide \`secret\` constructor option or set \`GRAPHCOOL_SECRET\` env var.`,
         )
       }
     }
@@ -54,13 +63,18 @@ export class Graphcool extends Binding {
     const token = sign({}, secret!)
     const link = makeGraphcoolLink({ endpoint: endpoint!, token, debug })
 
-    const remoteSchema = schemaCache.makeExecutableSchema({
-      link,
-      typeDefs,
-      key: endpoint!
-    })
+    if (!remoteSchema) {
+      remoteSchema = makeRemoteExecutableSchema({
+        link: sharedLink,
+        schema: typeDefs,
+      })
+    }
 
-    super({ schema: remoteSchema, fragmentReplacements })
+    const before = () => {
+      sharedLink.setInnerLink(link)
+    }
+
+    super({ schema: remoteSchema, fragmentReplacements, before })
 
     this.exists = new Proxy({}, new ExistsHandler())
   }
@@ -74,9 +88,11 @@ export class Graphcool extends Binding {
     context: {
       [key: string]: any
     },
-    info?: GraphQLResolveInfo | string
+    info?: GraphQLResolveInfo | string,
   ): Promise<boolean> {
-    return super.delegate(operation, fieldName, args, context, info).then(res => res.length > 0)
+    return super
+      .delegate(operation, fieldName, args, context, info)
+      .then(res => res.length > 0)
   }
 }
 
@@ -86,19 +102,13 @@ class ExistsHandler implements ProxyHandler<Graphcool> {
       const rootFieldName: string = this.findRootFieldName(target, typeName)
       const args = { where }
       const info = buildExistsInfo(rootFieldName, target.schema)
-      return target.existsDelegate(
-        'query',
-        rootFieldName,
-        args,
-        {},
-        info
-      )
+      return target.existsDelegate('query', rootFieldName, args, {}, info)
     }
   }
 
   findRootFieldName(target: Graphcool, typeName: string): string {
     const fields = target.schema.getQueryType().getFields()
-    
+
     // Loop over all query root fields
     for (const field in fields) {
       const fieldDef = fields[field]

src/SharedLink.ts

@@ -0,0 +1,26 @@
+import {
+  ApolloLink,
+  Operation,
+  NextLink,
+  Observable,
+  FetchResult,
+} from 'apollo-link'
+
+export class SharedLink extends ApolloLink {
+  private innerLink?: ApolloLink
+
+  setInnerLink(innerLink: ApolloLink) {
+    this.innerLink = innerLink
+  }
+
+  request(
+    operation: Operation,
+    forward?: NextLink,
+  ): Observable<FetchResult> | null {
+    if (!this.innerLink) {
+      throw new Error('No inner link set')
+    }
+
+    return this.innerLink.request(operation, forward)
+  }
+}

src/link.ts

@@ -1,7 +1,10 @@
 import { createHttpLink } from 'apollo-link-http'
 import * as fetch from 'cross-fetch'
-import { print } from 'graphql'
-import { ApolloLink } from 'apollo-link'
+import { print, OperationDefinitionNode } from 'graphql'
+import { ApolloLink, Operation, split } from 'apollo-link'
+import { WebSocketLink } from 'apollo-link-ws'
+import { SubscriptionClient } from 'subscriptions-transport-ws'
+import * as ws from 'ws'
 
 export function makeGraphcoolLink({
   endpoint,
@@ -18,6 +21,17 @@ export function makeGraphcoolLink({
     fetch,
   })
 
+  // also works for https/wss
+  const wsEndpoint = endpoint.replace(/^http/, 'ws')
+  const subscriptionClient = new SubscriptionClient(
+    wsEndpoint,
+    { reconnect: true },
+    ws,
+  )
+  const wsLink = new WebSocketLink(subscriptionClient)
+
+  const backendLink = split(op => isSubscription(op), wsLink, httpLink)
+
   const reportErrors = new ApolloLink((operation, forward) => {
     const observer = forward!(operation)
     observer.subscribe({
@@ -49,8 +63,31 @@ export function makeGraphcoolLink({
       })
     })
 
-    return ApolloLink.from([debugLink, reportErrors, httpLink])
+    return ApolloLink.from([debugLink, reportErrors, backendLink])
   } else {
-    return ApolloLink.from([reportErrors, httpLink])
+    return ApolloLink.from([reportErrors, backendLink])
+  }
+}
+
+function isSubscription(operation: Operation): boolean {
+  const selectedOperation = getSelectedOperation(operation)
+  if (selectedOperation) {
+    return selectedOperation.operation === 'subscription'
   }
+  return false
+}
+
+function getSelectedOperation(
+  operation: Operation,
+): OperationDefinitionNode | undefined {
+  if (operation.query.definitions.length === 1) {
+    return operation.query.definitions[0] as OperationDefinitionNode
+  }
+
+  return operation.query.definitions.find(
+    d =>
+      d.kind === 'OperationDefinition' &&
+      !!d.name &&
+      d.name.value === operation.operationName,
+  ) as OperationDefinitionNode
 }