added event listener

src/keeper/Event.ts

@@ -0,0 +1,35 @@
+import GenericContract from "./contracts/GenericContract"
+
+export default class Event {
+
+    private poller
+    private lastBlock: number = 0
+
+    constructor(private contractName: string,
+                private eventName: string,
+                private filter: any) {
+
+    }
+
+    public stopListen() {
+        clearTimeout(this.poller)
+    }
+
+    public listen(callback: any) {
+        this.poller = setTimeout(() => this.handler(callback), 200)
+    }
+
+    private async handler(callback: any) {
+        const contract = await
+            GenericContract.getInstance(this.contractName)
+        const events = await
+            contract.getEventData(this.eventName, {
+                filter: this.filter,
+                fromBlock: this.lastBlock,
+                toBlock: "latest",
+            })
+
+        this.lastBlock = events[events.length - 1].blockNumber
+        callback(events)
+    }
+}

src/keeper/EventListener.ts

@@ -0,0 +1,25 @@
+import Event from "./Event"
+
+export default class EventListener {
+
+    private static events: Event[] = []
+
+    public subscribe(contractName: string,
+                     eventName: string,
+                     filter: any): Event {
+
+        const event = new Event(contractName, eventName, filter)
+        EventListener.events.push(event)
+
+        return event
+    }
+
+    public unsubscribe(event): boolean {
+
+        EventListener.events = EventListener.events.splice(
+            EventListener.events.findIndex((e) => e === event),
+            1)
+
+        return true
+    }
+}

test/keeper/EventListener.test.ts

@@ -0,0 +1,71 @@
+import {assert} from "chai"
+import ConfigProvider from "../../src/ConfigProvider"
+import EventListener from "../../src/keeper/EventListener"
+import Keeper from "../../src/keeper/Keeper"
+import Account from "../../src/ocean/Account"
+import Ocean from "../../src/ocean/Ocean"
+import config from "../config"
+import TestContractHandler from "./TestContractHandler"
+
+let keeper: Keeper
+let ocean: Ocean
+let accounts: Account[]
+
+describe("EventListener", () => {
+
+    before(async () => {
+        ConfigProvider.setConfig(config)
+        await TestContractHandler.prepareContracts()
+        keeper = await Keeper.getInstance()
+        assert(keeper)
+        ocean = await Ocean.getInstance(config)
+        assert(ocean)
+        accounts = await ocean.getAccounts()
+        assert(accounts)
+    })
+
+    describe("#subscribe()", () => {
+
+        it("should subscribe to an event", (done) => {
+
+            const eventListener = new EventListener()
+            const acc = accounts[1]
+
+            const event = eventListener.subscribe("OceanToken",
+                "Transfer",
+                {
+                    to: acc.getId(),
+                })
+
+            event.listen((events) => {
+
+                assert(events)
+                assert(events.length === 2)
+                done()
+            })
+
+            const {market} = keeper
+
+            market.requestTokens(400, acc.getId())
+            market.requestTokens(400, acc.getId())
+        })
+    })
+
+    describe("#unsubscribe()", () => {
+
+        it("should subscribe to an event", (done) => {
+
+            const eventListener = new EventListener()
+
+            const event = eventListener.subscribe("OceanToken",
+                "Transfer",
+                {})
+
+            const unsubscribed = eventListener.unsubscribe(event)
+            assert(unsubscribed)
+
+            done()
+        })
+    })
+
+})