import { BadState } from "./bad_state.js"; export class Client { static get _PROTOCOL() { return "fs"; } constructor(provider) { this._provider = provider; this._ws = null; this.onopen = () => { }; this.onclose = () => { }; this.onerror = () => { }; } connectTo(url) { this.disconnect(); this._ws = new WebSocket(url, Client._PROTOCOL); this._ws.onopen = this.onopen; this._ws.onclose = this.onclose; this._ws.onerror = this.onerror; this._ws.onmessage = (message) => { this._onmessage(message); }; } disconnect() { if (this._ws) { this._ws.close(); this._ws = null; } } isConnected() { return ((this._ws) && (this._ws.readyState === WebSocket.OPEN)); } _onmessage(message) { try { const request = JSON.parse(message.data); const method = request.method; const id = request.id; const params = request.params; if ("string" !== typeof(method)) { throw new Error("parse error: missing field: \"method\""); } if (!params) { throw new Error("parse error: missing field: \"params\""); } if ("number" === typeof(request.id)) { this._invoke(method, params, id); } else { this._notify(method, params); } } catch (ex) { // swallow } } _invoke(method, params, id) { this._invokeAsync(method, params). then((result) => { const response = { result, id }; this._ws.send(JSON.stringify(response)); }). catch((ex) => { const code = ex.code || BadState.BAD; const response = {error: {code}, id}; this._ws.send(JSON.stringify(response)); }); } async _invokeAsync(method, params) { switch(method) { case "lookup": return this._lookup(params); case "getattr": return this._getattr(params); case "readdir": return this._readdir(params); case "open": return this._open(params); case "read": return this._read(params); default: throw new BadState(BadState.NOT_IMPLEMENTED); } } _notify(method, params) { switch(method) { case 'close': this._close(params); break; default: throw new Error(`Invalid method: "${method}"`); } } async _lookup([parent, name]) { return this._provider.lookup(parent, name); } async _getattr([inode]) { return this._provider.getattr(inode); } async _readdir([inode]) { return this._provider.readdir(inode); } async _open([inode, mode]) { return this._provider.open(inode, mode); } _close([inode, handle, mode]) { this._provider.close(inode, handle, mode); } async _read([inode, handle, offset, length]) { const data = await this._provider.read(inode, handle, offset, length); if ("string" === typeof(data)) { return { data: btoa(data), format: "base64", count: data.length }; } else { throw new BadState(BadState.BAD); } } }