@erez213/sagecell-node-client/lib/sagecell.js

SageCell js client

'use strict';

var utils = require('./utils');
var axios = require('axios').default;
var SockJS = require('sockjs-client');

class SageClient {
	constructor(config) {
		this.config = {};

		this.connected = false;

		this.config.onstatuschange = null;
		this.config.onmessage = null;
		this.config.onerror = null;
		this.config.server = "https://sagecell.sagemath.org";
		this.config.timeout = 60;

		if (config.server) this.config.server = config.server;
		if (config.timeout) this.config.timeout = config.timeout;
		if (config.onstatuschange) this.config.onstatuschange = config.onstatuschange;
		if (config.onmessage) this.config.onmessage = config.onmessage;
		if (config.onerror) this.config.onerror = config.onerror;
	}

	//Connect to kernel
	connect() {
		this.cellSessionID = utils.uuid();
		this.connected = false;
		this.sessionID = null;
		this.listners = {};

		axios({
			method: 'post',
			url: this.getKernelUrl(),
			responseType: 'json',
			data: { "accepted_tos": true }
		}).then((response) => {
			this.sessionID = response.data.id;
			this.wsURL = response.data.ws_url;

			this.sock = new SockJS(this.getSockUrl());
			this.sock.onopen = () => {
				this.connected = true;
				this.sendStatusChangeEvent("connected");
			};

			this.sock.onmessage = (e) => {
				var data = JSON.parse(e.data.replace(this.sessionID + "/channels,", ""));
				if (data.msg_type == "execute_result" && data.content.data['text/plain'] != null) {
					var res = { from: data.parent_header.msg_id, type: "text", data: data.content.data['text/plain'], raw: data };
					this.sendDataEvent(res);
					this.listners[data.parent_header.msg_id]("done", res);
				}
				if (data.msg_type == "display_data" && data.content.data['text/plain'] != null) {
					var res = { from: data.parent_header.msg_id, type: "image", data: this.getImageUrl(data.content.data['text/image-filename']), raw: data };
					this.sendDataEvent(res);
					this.listners[data.parent_header.msg_id]("done", res);
				}
				if (data.header.msg_type == "status" && data.content.execution_state && data.content.execution_state == "dead") {
					if (this.connected) {
						this.connected = false;
						this.sendStatusChangeEvent("closed");
						this.disconnect();
					}
				}
				if (data.msg_type == "error") {
					this.sendErrorEvent("sage", data.content);
					this.listners[data.parent_header.msg_id]("error", data.content);
				}
			};

			this.sock.onerror = (e) => {
				this.sendErrorEvent("sockjs", e);
			}

			this.sock.onclose = (e) => {
				if (this.connected) {
					this.connected = false;
					this.sendStatusChangeEvent("closed");
					this.disconnect();
				}
			}
		}).catch((err) => {
			this.sendErrorEvent("kernel_connect", err);
		});
	}

	//Close connection
	disconnect() {
		this.connected = false;
		this.sessionID = null;
		this.sock.close();
		this.sock = null;
	}

	//Close and then re-open connection
	reconnect() {
		this.disconnect();
		this.connect();
	}

	//Send formula to server
	sendCommand(id, command) {
		return this.send(id, "execute_request", this.getCodeContent(command));
	}

	//Send raw command. Return promise of the response
	send(id, op, msg) {
		return new Promise((resolve, reject) => {
			if (!this.connected) {
				this.sendErrorEvent("sending_error", { error: "not connected" });
				reject({ error: "not connected" });
				return;
			}
			if (!this.sock) {
				this.sendErrorEvent("sending_error", { error: "no socket" });
				reject({ error: "no socket" });
				return;
			}

			if (!id) id = utils.uuid();

			this.listners[id] = (status, data) => {
				if (status == "done") {
					resolve(data);
				} else {
					reject(data);
				}
			}
			this.sock.send(this.getMsgData(id, op, msg));
		});
	}

	//Get URLs
	getKernelUrl() {
		return this.config.server + "/kernel?timeout=" + this.config.timeout + "&CellSessionID=" + this.cellSessionID;
	}
	getSockUrl() {
		return this.config.server + "/sockjs" + '?CellSessionID=' + this.cellSessionID
	}
	getImageUrl(f) {
		return this.config.server + "/kernel/" + this.sessionID + "/files/" + f;
	}

	//Event listners
	sendErrorEvent(from, err) {
		if (this.config.onerror) this.config.onerror(from, err);
	}
	sendStatusChangeEvent(status) {
		if (this.config.onstatuschange) this.config.onstatuschange(status);
	}
	sendDataEvent(msg) {
		if (this.config.onmessage) this.config.onmessage(msg);
	}

	//Helpers methods
	getMsgData(id, msg_type, content) {
		return this.sessionID + '/channels' + "," + JSON.stringify(

			{
				header: {
					msg_id: id,
					session: this.cellSessionID,
					msg_type: msg_type,
					username: "username",
					version: "5.2"
				},
				content: content,
				parent_header: {},
				metadata: {},
				buffers: [],
				channel: "shell"
			}
		);
	}
	getCodeContent(code) {
		return {
			code: code,
			silent: false,
			store_history: false,
			user_expressions: {
				"_sagecell_files": "sys._sage_.new_files()"
			},
			allow_stdin: false
		};
	}
}

module.exports = SageClient;