400 lines
13 KiB
TypeScript
400 lines
13 KiB
TypeScript
import * as plugins from './plugins.js';
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import { TypedRouter } from './classes.typedrouter.js';
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export interface ICommFunctions {
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sendMethod?: (
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sendPayload: plugins.typedRequestInterfaces.IStreamRequest
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) => Promise<plugins.typedRequestInterfaces.IStreamRequest>;
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typedrouter?: TypedRouter;
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}
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/**
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* 1. A VirtualStream connects over the network
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* 2. It is always paired to one other VirtualStream
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* on the other side with the same streamId.
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* 3. It has a Readable and Writable side.
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* 4. The Writable side is Readable on the other side and vice versa.
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*/
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export class VirtualStream<T = Uint8Array> implements plugins.typedRequestInterfaces.IVirtualStream<T> {
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// STATIC
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public static encodePayloadForNetwork(
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objectPayload: any,
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commFunctions: ICommFunctions,
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originalPayload?: any,
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path = []
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): any {
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if (!objectPayload) {
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return objectPayload;
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}
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if (plugins.smartbuffer.isBufferLike(objectPayload)) {
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return objectPayload;
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}
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if (objectPayload instanceof VirtualStream) {
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if (!objectPayload.side && commFunctions.sendMethod) {
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objectPayload.side = 'requesting';
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objectPayload.sendMethod = commFunctions.sendMethod;
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}
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if (!objectPayload.side && commFunctions.typedrouter) {
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objectPayload.side = 'responding';
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objectPayload.typedrouter = commFunctions.typedrouter;
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commFunctions.typedrouter.registeredVirtualStreams.add(objectPayload);
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}
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if (!originalPayload.response || path.includes('response')) {
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objectPayload.startKeepAliveLoop();
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return {
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_isVirtualStream: true,
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streamId: objectPayload.streamId,
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};
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} else {
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return {
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_OBMITTED_VIRTUAL_STREAM: true,
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reason: 'path is under .request: obmitted for deduplication reasons in response cycle.',
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};
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}
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} else if (Array.isArray(objectPayload)) {
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// For arrays, we recurse over each item.
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return objectPayload.map((item, index) =>
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VirtualStream.encodePayloadForNetwork(
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item,
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commFunctions,
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originalPayload || objectPayload,
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path.concat(String(index)) // Convert index to string and concatenate to path
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)
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);
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} else if (objectPayload !== null && typeof objectPayload === 'object') {
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// For objects, we recurse over each key-value pair.
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return Object.entries(objectPayload).reduce((acc, [key, value]) => {
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const newPath = path.concat(key); // Concatenate the new key to the path
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acc[key] = VirtualStream.encodePayloadForNetwork(
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value,
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commFunctions,
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originalPayload || objectPayload,
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newPath
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);
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return acc;
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}, {});
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} else {
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return objectPayload;
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}
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}
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public static decodePayloadFromNetwork(objectPayload: any, commFunctions: ICommFunctions): any {
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if (
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plugins.smartbuffer.isBufferLike(objectPayload)
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|| objectPayload instanceof TypedRouter
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) {
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return objectPayload;
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}
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if (objectPayload !== null && typeof objectPayload === 'object') {
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if (objectPayload._isVirtualStream) {
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const virtualStream = new VirtualStream();
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virtualStream.streamId = objectPayload.streamId;
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if (!virtualStream.side && commFunctions.sendMethod) {
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virtualStream.side = 'requesting';
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virtualStream.sendMethod = commFunctions.sendMethod;
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}
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if (!virtualStream.side && commFunctions.typedrouter) {
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virtualStream.side = 'responding';
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virtualStream.typedrouter = commFunctions.typedrouter;
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commFunctions.typedrouter.registeredVirtualStreams.add(virtualStream);
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}
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virtualStream.startKeepAliveLoop();
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return virtualStream;
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} else if (Array.isArray(objectPayload)) {
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const returnArray = [];
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for (const item of objectPayload) {
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returnArray.push(VirtualStream.decodePayloadFromNetwork(item, commFunctions));
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}
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return returnArray;
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} else {
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return Object.keys(objectPayload).reduce((acc, key) => {
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acc[key] = VirtualStream.decodePayloadFromNetwork(objectPayload[key], commFunctions);
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return acc;
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}, {});
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}
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} else {
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return objectPayload;
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}
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}
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// INSTANCE
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public side: 'requesting' | 'responding';
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public streamId: string = plugins.isounique.uni();
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// integration with typedrequest mechanics
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public sendMethod: ICommFunctions['sendMethod'];
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public typedrouter: TypedRouter;
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// wether to keep the stream alive
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private keepAlive = true;
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private lastKeepAliveEvent: number;
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// backpressured arrays
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private sendBackpressuredArray =
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new plugins.lik.BackpressuredArray<T>(
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16
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);
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private receiveBackpressuredArray =
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new plugins.lik.BackpressuredArray<T>(
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16
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);
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constructor() {}
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/**
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* takes care of sending
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*/
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private async workOnQueue() {
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if(this.side === 'requesting') {
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let thisSideIsBackpressured = !this.receiveBackpressuredArray.checkSpaceAvailable();
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let otherSideHasNext = false;
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let otherSideIsBackpressured = false;
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// helper functions
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const getFeedback = async () => {
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const streamTr = await this.sendMethod({
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method: '##VirtualStream##',
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request: {
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streamId: this.streamId,
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cycleId: plugins.isounique.uni(),
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cycle: 'request',
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mainPurpose: 'feedback',
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next: this.sendBackpressuredArray.data.length > 0,
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backpressure: !this.receiveBackpressuredArray.checkSpaceAvailable(),
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},
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response: null,
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}).catch(() => {
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console.log('stream ended immaturely');
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this.keepAlive = false;
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});
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if (streamTr && streamTr.response) {
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otherSideIsBackpressured = streamTr.response.backpressure
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otherSideHasNext = streamTr.response.next;
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}
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}
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await getFeedback();
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// do work loop
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while (this.sendBackpressuredArray.data.length > 0 || otherSideHasNext) {
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if (otherSideIsBackpressured) {
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while (otherSideIsBackpressured) {
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await plugins.smartdelay.delayFor(50);
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await getFeedback();
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}
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}
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let dataArg: typeof this.sendBackpressuredArray.data[0];
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if (this.sendBackpressuredArray.data.length > 0) {
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dataArg = this.sendBackpressuredArray.shift();
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}
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let streamTr: plugins.typedRequestInterfaces.IStreamRequest;
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streamTr = await this.sendMethod({
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method: '##VirtualStream##',
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request: {
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streamId: this.streamId,
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cycleId: plugins.isounique.uni(),
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cycle: 'request',
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mainPurpose: dataArg ? 'chunk' : 'read',
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backpressure: thisSideIsBackpressured,
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next: this.sendBackpressuredArray.data.length > 0,
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...dataArg ? { chunkData: dataArg } : {},
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},
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response: null,
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}).catch(() => {
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console.log('stream ended immaturely');
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this.keepAlive = false;
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return null;
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});
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if (streamTr && streamTr.response && streamTr.response.chunkData) {
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this.receiveBackpressuredArray.push(streamTr.response.chunkData);
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}
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otherSideIsBackpressured = streamTr && streamTr.response && streamTr.response.backpressure;
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thisSideIsBackpressured = !this.receiveBackpressuredArray.checkSpaceAvailable();
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// lets care about looping
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otherSideHasNext = streamTr && streamTr.response && streamTr.response.next;
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}
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}
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}
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/**
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* This method handles the stream only on the responding side
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* @param streamTrArg
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* @returns
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*/
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public async handleStreamTr(streamTrArg: plugins.typedRequestInterfaces.IStreamRequest) {
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if (streamTrArg.request.keepAlive === true && this.keepAlive === true) {
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this.lastKeepAliveEvent = Date.now();
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} else if (streamTrArg.request.keepAlive === false) {
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this.keepAlive = false;
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}
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// keepAlive handling
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if (streamTrArg.request.mainPurpose === 'keepAlive') {
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// if the main purpose is keepAlive, we answer with a keepAlive
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streamTrArg.response = {
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streamId: this.streamId,
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cycleId: streamTrArg.request.cycleId,
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cycle: 'response',
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mainPurpose: 'keepAlive',
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keepAlive: this.keepAlive,
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next: this.sendBackpressuredArray.data.length > 0,
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backpressure: !this.receiveBackpressuredArray.checkSpaceAvailable(),
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};
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}
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// feedback handling
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if (streamTrArg.request.mainPurpose === 'feedback') {
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streamTrArg.response = {
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streamId: this.streamId,
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cycleId: streamTrArg.request.cycleId,
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cycle: 'response',
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mainPurpose: 'feedback',
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next: this.sendBackpressuredArray.data.length > 0,
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backpressure: !this.receiveBackpressuredArray.checkSpaceAvailable(),
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};
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}
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// chunk handling
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if (streamTrArg.request.mainPurpose === 'chunk') {
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this.receiveBackpressuredArray.push(streamTrArg.request.chunkData);
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if (this.sendBackpressuredArray.data.length > 0 && streamTrArg.response.backpressure === false) {
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const dataArg = this.sendBackpressuredArray.shift();
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streamTrArg.response = {
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streamId: this.streamId,
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cycleId: streamTrArg.request.cycleId,
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cycle: 'response',
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mainPurpose: 'chunk',
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next: this.sendBackpressuredArray.data.length > 1,
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backpressure: !this.receiveBackpressuredArray.checkSpaceAvailable(),
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chunkData: this.sendBackpressuredArray.shift(),
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};
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} else {
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streamTrArg.response = {
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streamId: this.streamId,
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cycleId: streamTrArg.request.cycleId,
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cycle: 'response',
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mainPurpose: 'feedback',
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next: this.sendBackpressuredArray.data.length > 0,
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backpressure: !this.receiveBackpressuredArray.checkSpaceAvailable(),
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};
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}
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streamTrArg.request = null;
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}
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return streamTrArg;
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}
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// lifecycle methods
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/**
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* closes the virtual stream
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*/
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public async cleanup() {
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if (this.typedrouter) {
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this.typedrouter.registeredVirtualStreams.remove(this);
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}
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}
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/**
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* a keepAlive loop that works across technologies
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*/
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private async startKeepAliveLoop() {
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// initially wait for a second
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if (this.side === 'responding') {
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return;
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}
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await plugins.smartdelay.delayFor(0);
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console.log(`starting keepalive loop on side ${this.side}`);
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let counter = 0;
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keepAliveLoop: while (this.keepAlive) {
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await this.triggerKeepAlive();
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await plugins.smartdelay.delayFor(1000);
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}
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await plugins.smartdelay.delayFor(1000);
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await this.cleanup();
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console.log(`cleaned up for stream ${this.streamId}`);
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}
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private async triggerKeepAlive() {
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if (this.side === 'requesting') {
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console.log(`keepalive sent.`);
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const streamTr = await this.sendMethod({
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method: '##VirtualStream##',
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request: {
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streamId: this.streamId,
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cycleId: plugins.isounique.uni(),
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cycle: 'request',
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mainPurpose: 'keepAlive',
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keepAlive: this.keepAlive,
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},
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response: null,
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}).catch(() => {
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this.keepAlive = false;
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});
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// lets handle keepAlive
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if (streamTr && streamTr.response && streamTr.response.keepAlive === false) {
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this.keepAlive = false;
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} else {
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this.lastKeepAliveEvent = Date.now();
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}
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if (streamTr && streamTr.response && streamTr.response.next) {
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this.workOnQueue();
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}
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}
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if (Date.now() - this.lastKeepAliveEvent > 10000) {
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console.log(`closing stream for ${this.streamId}`);
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this.keepAlive = false;
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}
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}
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// Data sending and receiving
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public async sendData(dataArg: T): Promise<void> {
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this.sendBackpressuredArray.push(dataArg);
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this.workOnQueue();
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await this.sendBackpressuredArray.waitForSpace();
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}
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public async fetchData(): Promise<T> {
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if (this.receiveBackpressuredArray.hasSpace) {
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// do something maybe?
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}
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await this.receiveBackpressuredArray.waitForItems();
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const dataPackage = this.receiveBackpressuredArray.shift();
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return dataPackage;
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}
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/**
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* reads from a Readable and sends it to the other side
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* @param readableStreamArg
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*/
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public async readFromWebstream(readableStreamArg: ReadableStream<T>, closeAfterReading = true) {
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const reader = readableStreamArg.getReader();
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let streamIsDone = false;
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while(!streamIsDone) {
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const { value, done } = await reader.read();
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if(value) {
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await this.sendData(value);
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}
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streamIsDone = done;
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}
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if (closeAfterReading) {
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await this.close();
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}
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}
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public async writeToWebstream(writableStreamArg: WritableStream<T>) {
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const writer = writableStreamArg.getWriter();
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while(this.keepAlive || this.receiveBackpressuredArray.checkHasItems()) {
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await writer.write(await this.fetchData());
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}
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}
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public async close() {
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this.keepAlive = false;
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}
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}
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