SQL Operations Studio Public Preview 1 (0.23) release source code

dataprotocol-node/jsonrpc/src/messageWriter.ts

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+/* --------------------------------------------------------------------------------------------
+ * Copyright (c) Microsoft Corporation. All rights reserved.
+ * Licensed under the Source EULA. See License.txt in the project root for license information.
+ * ------------------------------------------------------------------------------------------ */
+'use strict';
+
+import { ChildProcess } from 'child_process';
+
+import { Message } from './messages';
+import { Event, Emitter } from './events';
+import * as is from './is';
+
+let ContentLength: string = 'Content-Length: ';
+let CRLF = '\r\n';
+
+export interface MessageWriter {
+	onError: Event<[Error, Message, number]>;
+	onClose: Event<void>;
+	write(msg: Message): void;
+}
+
+export abstract class AbstractMessageWriter {
+
+	private errorEmitter: Emitter<[Error, Message, number]>;
+	private closeEmitter: Emitter<void>;
+
+	constructor() {
+		this.errorEmitter = new Emitter<[Error, Message, number]>();
+		this.closeEmitter = new Emitter<void>();
+	}
+
+	public get onError(): Event<[Error, Message, number]> {
+		return this.errorEmitter.event;
+	}
+
+	protected fireError(error: any, message?: Message, count?: number): void {
+		this.errorEmitter.fire([this.asError(error), message, count]);
+	}
+
+	public get onClose(): Event<void> {
+		return this.closeEmitter.event;
+	}
+
+	protected fireClose(): void {
+		this.closeEmitter.fire(undefined);
+	}
+
+	private asError(error: any): Error {
+		if (error instanceof Error) {
+			return error;
+		} else {
+			return new Error(`Writer recevied error. Reason: ${is.string(error.message) ? error.message : 'unknown'}`);
+		}
+	}
+}
+
+export class StreamMessageWriter extends AbstractMessageWriter implements MessageWriter {
+
+	private writable: NodeJS.WritableStream;
+	private encoding: string;
+	private errorCount: number;
+
+	public constructor(writable: NodeJS.WritableStream, encoding: string = 'utf8') {
+		super();
+		this.writable = writable;
+		this.encoding = encoding;
+		this.errorCount = 0;
+		this.writable.on('error', (error) => this.fireError(error));
+		this.writable.on('close', () => this.fireClose());
+	}
+
+	public write(msg: Message): void {
+		let json = JSON.stringify(msg);
+		let contentLength = Buffer.byteLength(json, this.encoding);
+
+		let headers: string[] = [
+			ContentLength, contentLength.toString(), CRLF,
+			CRLF
+		];
+		try {
+			// Header must be written in ASCII encoding
+			this.writable.write(headers.join(''), 'ascii');
+
+			// Now write the content. This can be written in any encoding
+			this.writable.write(json, this.encoding);
+			this.errorCount = 0;
+		} catch (error) {
+			this.errorCount++;
+			this.fireError(error, msg, this.errorCount);
+		}
+	}
+}
+
+export class IPCMessageWriter extends AbstractMessageWriter implements MessageWriter {
+
+	private process: NodeJS.Process | ChildProcess;
+	private errorCount: number;
+
+	public constructor(process: NodeJS.Process | ChildProcess) {
+		super();
+		this.process = process;
+		this.errorCount = 0;
+
+		let eventEmitter: NodeJS.EventEmitter = <NodeJS.EventEmitter>this.process;
+		eventEmitter.on('error', (error) => this.fireError(error));
+		eventEmitter.on('close', () => this.fireClose);
+	}
+
+	public write(msg: Message): void {
+		try {
+			this.process.send(msg);
+			this.errorCount = 0;
+		} catch (error) {
+			this.errorCount++;
+			this.fireError(error, msg, this.errorCount);
+		}
+	}
+}