116 lines
3.5 KiB
TypeScript
116 lines
3.5 KiB
TypeScript
// We can start to use deltas to express relational data in a given context
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import express from "express";
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import { bindPublish, } from "./pub-sub";
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import { deltasAccepted, deltasProposed, runDeltas } from "./deltas";
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import { Entity } from "./object-layer";
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import { Collection } from "./collection-layer";
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import { bindReply, runRequestHandlers } from "./request-reply";
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import { askAllPeersForDeltas, subscribeToSeeds } from "./peers";
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import { ENABLE_HTTP_API, HTTP_API_ADDR, HTTP_API_PORT } from "./config";
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// As an app we want to be able to write and read data.
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// The data is whatever shape we define it to be in a given context.
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// So we want access to an API that is integrated with our declarations of
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// e.g. entities and their properties.
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// This implies at least one layer on top of the underlying primitive deltas.
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type UserProperties = {
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id?: string;
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name: string;
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nameLong?: string;
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email?: string;
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age: number;
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};
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class Users {
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db = new Collection();
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create(properties: UserProperties): Entity {
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// We provide undefined for the id, to let the database generate it
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// This call returns the id
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const user = this.db.put(undefined, properties);
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console.log(`Users.create(${user.id}, ${JSON.stringify(properties)}`);
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return user;
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}
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upsert(properties: UserProperties): Entity {
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const user = this.db.put(properties.id, properties);
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console.log(`Users.upsert(${user.id}, ${JSON.stringify(properties)}`);
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return user;
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}
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getOne(id: string): Entity | undefined {
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return this.db.get(id);
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}
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getIds(): string[] {
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return this.db.getIds();
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}
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}
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(async () => {
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const users = new Users();
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const app = express()
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app.get("/ids", (req: express.Request, res: express.Response) => {
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res.json({ ids: users.getIds()});
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});
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app.get("/deltas", (req: express.Request, res: express.Response) => {
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// TODO: streaming
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res.json(deltasAccepted);
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});
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app.get("/deltas/count", (req: express.Request, res: express.Response) => {
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// TODO: streaming
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res.json(deltasAccepted.length);
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});
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if (ENABLE_HTTP_API) {
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app.listen(HTTP_API_PORT, HTTP_API_ADDR, () => {
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console.log(`HTTP API bound to http://${HTTP_API_ADDR}:${HTTP_API_PORT}`);
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});
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}
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await bindPublish();
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await bindReply();
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runDeltas();
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runRequestHandlers();
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await new Promise((resolve) => setTimeout(resolve, 500));
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subscribeToSeeds();
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await new Promise((resolve) => setTimeout(resolve, 500));
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askAllPeersForDeltas();
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await new Promise((resolve) => setTimeout(resolve, 1000));
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setInterval(() => {
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console.log('deltasProposed count', deltasProposed.length,
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'deltasAccepted count', deltasAccepted.length);
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}, 5000)
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const taliesin = users.upsert({
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// id: 'taliesin-1',
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name: 'Taliesin',
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nameLong: 'Taliesin (Ladd)',
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age: Math.floor(Math.random() * 1000)
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});
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users.db.onUpdate((u: Entity) => {
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console.log('User updated:', u);
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});
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users.db.onCreate((u: Entity) => {
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console.log('New user!:', u);
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});
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// TODO: Allow configuration regarding read/write concern i.e.
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// if we perform a read immediately do we see the value we wrote?
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// Intuition says yes, we want that-- but how do we expose the propagation status?
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const result = users.getOne(taliesin.id);
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const matches: boolean = JSON.stringify(result) === JSON.stringify(taliesin);
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console.log(`Result ${matches ? 'matches' : 'does not match'} expected.` +
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`\n\nExpected \n${JSON.stringify(taliesin)}` +
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`\nReceived\n${JSON.stringify(result)}`);
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})();
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