adding subscription handling to dwn server. #68
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,175 @@ | ||
| import type { Dwn, SubscriptionFilter } from '@tbd54566975/dwn-sdk-js'; | ||
| import type { EventMessage, PermissionsGrant } from '@tbd54566975/dwn-sdk-js'; | ||
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| import type { JsonRpcSuccessResponse } from './lib/json-rpc.js'; | ||
| import { SubscriptionRequest } from '@tbd54566975/dwn-sdk-js'; | ||
| import type { SubscriptionRequestReply } from '@tbd54566975/dwn-sdk-js'; | ||
| import type WebSocket from 'ws'; | ||
| import { WebSocketServer } from 'ws'; | ||
| import { v4 as uuidv4 } from 'uuid'; | ||
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| export class Subscription { | ||
| from?: string; | ||
| subscriptionId: string; | ||
| createdAt: string; | ||
| description: string; | ||
| filters?: SubscriptionFilter[]; | ||
| permissionGrant: PermissionsGrant; | ||
| connection: WebSocket; | ||
| } | ||
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| export interface SubscriptionController { | ||
| clear(): Promise<void>; | ||
| close(): Promise<void>; | ||
| start(): Promise<void>; | ||
| subscribe( | ||
| request: RegisterSubscriptionRequest, | ||
| ): Promise<RegisterSubscriptionReply>; | ||
| } | ||
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| export type RegisterSubscriptionRequest = { | ||
| from: string; // from connection | ||
| socket: WebSocket; // socket connection | ||
| filters?: SubscriptionFilter[]; // filters, if applicable | ||
| permissionGrant?: PermissionsGrant; //permission grant, if applicable | ||
| request: SubscriptionRequest; // subscription request | ||
| }; | ||
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| export type RegisterSubscriptionReply = { | ||
| reply?: SubscriptionRequestReply; | ||
| subscriptionId?: string; | ||
| }; | ||
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| export type defaultSubscriptionChannel = 'event'; | ||
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| export type SubscriptionManagerOptions = { | ||
| wss?: WebSocketServer; | ||
| dwn: Dwn; | ||
| tenant: string; | ||
| }; | ||
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| export class SubscriptionManager { | ||
| private wss: WebSocketServer; | ||
| private dwn: Dwn; | ||
| private connections: Map<string, Subscription>; | ||
|
There was a problem hiding this comment. keep track of all the subscriptions here. IMPORTANT is to close the subscription when it's finished. |
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| options: SubscriptionManagerOptions; | ||
| #open: boolean; | ||
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| constructor(options?: SubscriptionManagerOptions) { | ||
| this.wss = options?.wss || new WebSocketServer(); | ||
| this.connections = new Map(); | ||
| this.dwn = options?.dwn; | ||
| this.options = options; | ||
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| this.wss.on('connection', (socket: WebSocket) => { | ||
| socket.on('message', async (data) => { | ||
| await this.handleSubscribe(socket, data); | ||
| }); | ||
| }); | ||
| } | ||
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| async clear(): Promise<void> { | ||
| this.wss.removeAllListeners(); | ||
| this.connections.clear(); | ||
| } | ||
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| async close(): Promise<void> { | ||
| this.#open = false; | ||
| this.connections.clear(); | ||
| this.wss.close(); | ||
| } | ||
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| async open(): Promise<void> { | ||
| this.#open = true; | ||
| } | ||
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| async start(): Promise<void> { | ||
| this.open(); | ||
| } | ||
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| private async createSubscription( | ||
| from: string, | ||
| request: RegisterSubscriptionRequest, | ||
| ): Promise<Subscription> { | ||
| return { | ||
| from, | ||
| subscriptionId: uuidv4(), | ||
| createdAt: new Date().toISOString(), | ||
| description: 'subscription', | ||
| filters: request.filters, | ||
| permissionGrant: request.permissionGrant, | ||
| connection: request.socket, | ||
| }; | ||
| } | ||
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| async handleSubscribe( | ||
| socket: WebSocket, | ||
| data: any, | ||
| ): Promise<RegisterSubscriptionReply> { | ||
| // parse message | ||
| const req = await SubscriptionRequest.parse(data); | ||
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| return await this.subscribe({ | ||
| request: req, | ||
| socket: socket, | ||
| from: req.author, | ||
| }); | ||
| } | ||
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| createJSONRPCEvent(e: EventMessage): JsonRpcSuccessResponse { | ||
| return { | ||
| id: uuidv4(), | ||
| jsonrpc: '2.0', | ||
| result: e, | ||
| }; | ||
| } | ||
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| async subscribe( | ||
| req: RegisterSubscriptionRequest, | ||
| ): Promise<RegisterSubscriptionReply> { | ||
| const subscriptionReply = await this.dwn.handleSubscriptionRequest( | ||
| req.from, | ||
| req.request.message, | ||
| ); | ||
| if (subscriptionReply.status.code !== 200) { | ||
| return { reply: subscriptionReply }; | ||
| } | ||
| const subscription = await this.createSubscription(req.from, req); | ||
| this.registerSubscription(subscription); | ||
| // set up forwarding. | ||
| // console.log('---------', subscriptionReply.subscription.emitter); | ||
| subscriptionReply.subscription.emitter.on( | ||
| async (e: EventMessage): Promise<void> => { | ||
| // console.log('got a record', e); | ||
| const jsonRpcResponse = this.createJSONRPCEvent(e); | ||
| const str = JSON.stringify(jsonRpcResponse); | ||
| return req.socket.send(Buffer.from(str)); | ||
| }, | ||
| ); | ||
| return { | ||
| reply: subscriptionReply, | ||
| subscriptionId: subscription?.subscriptionId, | ||
| } as RegisterSubscriptionReply; | ||
| } | ||
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| private async registerSubscription( | ||
| subscription: Subscription, | ||
| ): Promise<void> { | ||
| if (!this.#open) { | ||
| throw new Error("Can't register subscription. It's not opened."); | ||
| } | ||
| if (this.connections.has(subscription.subscriptionId)) { | ||
| throw new Error( | ||
| 'Failed to add connection to controller. ID already exists.', | ||
| ); | ||
| } | ||
| this.connections.set(subscription.subscriptionId, subscription); | ||
| subscription.connection.on('close', () => { | ||
| this.deleteSubscription(subscription.subscriptionId); | ||
| }); | ||
| } | ||
|
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| private async deleteSubscription(id: string): Promise<void> { | ||
| this.connections.delete(id); | ||
| } | ||
| } | ||
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please change the environment variable to
DWN_SUBSCRIPTIONS. I realize not all environment variables currently follow that convention, but I would like to move in that direction.