src/charging-station/ui-server/UIHttpServer.ts

   1 import { IncomingMessage, RequestListener, Server, ServerResponse } from 'http';
   2
   3 import { StatusCodes } from 'http-status-codes';
   4
   5 import BaseError from '../../exception/BaseError';
   6 import { ServerOptions } from '../../types/ConfigurationData';
   7 import {
   8   ProcedureName,
   9   Protocol,
  10   ProtocolResponse,
  11   ProtocolVersion,
  12   RequestPayload,
  13   ResponsePayload,
  14   ResponseStatus,
  15 } from '../../types/UIProtocol';
  16 import Configuration from '../../utils/Configuration';
  17 import logger from '../../utils/Logger';
  18 import Utils from '../../utils/Utils';
  19 import { AbstractUIServer } from './AbstractUIServer';
  20 import UIServiceFactory from './ui-services/UIServiceFactory';
  21 import { UIServiceUtils } from './ui-services/UIServiceUtils';
  22
  23 const moduleName = 'UIHttpServer';
  24
  25 type responseHandler = { procedureName: ProcedureName; res: ServerResponse };
  26
  27 export default class UIHttpServer extends AbstractUIServer {
  28   private readonly responseHandlers: Map<string, responseHandler>;
  29
  30   public constructor(private options?: ServerOptions) {
  31     super();
  32     this.server = new Server(this.requestListener.bind(this) as RequestListener);
  33     this.responseHandlers = new Map<string, responseHandler>();
  34   }
  35
  36   public start(): void {
  37     (this.server as Server).listen(this.options ?? Configuration.getUIServer().options);
  38   }
  39
  40   public stop(): void {
  41     this.chargingStations.clear();
  42   }
  43
  44   // eslint-disable-next-line @typescript-eslint/no-unused-vars
  45   public sendRequest(request: string): void {
  46     // This is intentionally left blank
  47   }
  48
  49   public sendResponse(response: string): void {
  50     const [uuid, payload] = JSON.parse(response) as ProtocolResponse;
  51     const statusCode = this.responseStatusToStatusCode(payload.status);
  52     if (this.responseHandlers.has(uuid)) {
  53       const { res } = this.responseHandlers.get(uuid);
  54       res.writeHead(statusCode, { 'Content-Type': 'application/json' });
  55       res.write(JSON.stringify(payload));
  56       res.end();
  57       this.responseHandlers.delete(uuid);
  58     } else {
  59       logger.error(
  60         `${this.logPrefix()} ${moduleName}.sendResponse: Response received for unknown request: ${response}`
  61       );
  62     }
  63   }
  64
  65   public logPrefix(modName?: string, methodName?: string): string {
  66     const logMsg =
  67       modName && methodName ? ` UI HTTP Server | ${modName}.${methodName}:` : ' UI HTTP Server |';
  68     return Utils.logPrefix(logMsg);
  69   }
  70
  71   private requestListener(req: IncomingMessage, res: ServerResponse): void {
  72     // Expected request URL pathname: /ui/:version/:procedureName
  73     const [protocol, version, procedureName] = req.url?.split('/').slice(1) as [
  74       Protocol,
  75       ProtocolVersion,
  76       ProcedureName
  77     ];
  78     const uuid = Utils.generateUUID();
  79     this.responseHandlers.set(uuid, { procedureName, res });
  80     try {
  81       if (UIServiceUtils.isProtocolSupported(protocol, version) === false) {
  82         throw new BaseError(`Unsupported UI protocol version: '/${protocol}/${version}'`);
  83       }
  84       req.on('error', (error) => {
  85         logger.error(
  86           `${this.logPrefix(
  87             moduleName,
  88             'requestListener.req.onerror'
  89           )} Error at incoming request handling:`,
  90           error
  91         );
  92       });
  93       if (!this.uiServices.has(version)) {
  94         this.uiServices.set(version, UIServiceFactory.getUIServiceImplementation(version, this));
  95       }
  96       if (req.method === 'POST') {
  97         const bodyBuffer = [];
  98         let body: RequestPayload;
  99         req
 100           .on('data', (chunk) => {
 101             bodyBuffer.push(chunk);
 102           })
 103           .on('end', () => {
 104             body = JSON.parse(Buffer.concat(bodyBuffer).toString()) as RequestPayload;
 105             this.uiServices
 106               .get(version)
 107               .requestHandler(this.buildRequest(uuid, procedureName, body ?? {}))
 108               .catch(() => {
 109                 this.sendResponse(this.buildResponse(uuid, { status: ResponseStatus.FAILURE }));
 110               });
 111           });
 112       } else {
 113         throw new BaseError(`Unsupported HTTP method: '${req.method}'`);
 114       }
 115     } catch (error) {
 116       this.sendResponse(this.buildResponse(uuid, { status: ResponseStatus.FAILURE }));
 117     }
 118   }
 119
 120   private buildRequest(
 121     id: string,
 122     procedureName: ProcedureName,
 123     requestPayload: RequestPayload
 124   ): string {
 125     return JSON.stringify([id, procedureName, requestPayload]);
 126   }
 127
 128   private buildResponse(id: string, responsePayload: ResponsePayload): string {
 129     return JSON.stringify([id, responsePayload]);
 130   }
 131
 132   private responseStatusToStatusCode(status: ResponseStatus): StatusCodes {
 133     switch (status) {
 134       case ResponseStatus.SUCCESS:
 135         return StatusCodes.OK;
 136       case ResponseStatus.FAILURE:
 137         return StatusCodes.BAD_REQUEST;
 138       default:
 139         return StatusCodes.INTERNAL_SERVER_ERROR;
 140     }
 141   }
 142 }