git.squeep.com Git - squeep-api-dingus/blob - lib/dingus.js

   1 /* eslint-disable security/detect-object-injection */
   2 'use strict';
   3
   4 /**
   5  * A very minimal API server framework.
   6  * Just a self-contained router and some request glue.
   7  */
   8
   9 require('./patches');
  10 const { promises: fsPromises } = require('fs');
  11 const path = require('path');
  12 const querystring = require('querystring');
  13 const common = require('./common');
  14 const ContentNegotiation = require('./content-negotiation');
  15 const Enum = require('./enum');
  16 const { DingusError, ResponseError } = require('./errors');
  17 const { extensionToMime } = require('./mime-helper');
  18 const Router = require('./router');
  19 const Template = require('./template');
  20
  21 // For logging.
  22 const _fileScope = common.fileScope(__filename);
  23
  24 const defaultOptions = {
  25   ignoreTrailingSlash: false,
  26   proxyPrefix: '',
  27   strictAccept: true,
  28   selfBaseUrl: '',
  29   staticMetadata: true,
  30   staticPath: undefined, // No reasonable default
  31   trustProxy: true,
  32   querystring,
  33 };
  34
  35 class Dingus {
  36   /**
  37    * @param {Object} logger object which implements logging methods
  38    * @param {Object} options
  39    * @param {Boolean} options.ignoreTrailingSlash
  40    * @param {string} options.proxyPrefix leading part of url path to strip
  41    * @param {Boolean} options.strictAccept whether to error on unsupported Accept type
  42    * @param {string} options.selfBaseUrl for constructing links
  43    * @param {Boolean} options.staticMetadata serve static headers with static files
  44    * @param {Boolean} options.trustProxy trust some header data to be provided by proxy
  45    * @param {Object} options.querystring alternate qs parser to use
  46    */
  47   constructor(logger = console, options = {}) {
  48     common.setOptions(this, defaultOptions, options);
  49
  50     this.router = new Router(options);
  51
  52     if (!this.proxyPrefix) {
  53       this._stripPrefix = (p) => p;
  54     }
  55
  56     this.responseTypes = [
  57       Enum.ContentType.TextHTML,
  58       Enum.ContentType.TextPlain,
  59       Enum.ContentType.ApplicationJson,
  60     ];
  61
  62     this.logger = logger;
  63   }
  64
  65
  66   /**
  67    * Resolve relative and empty paths in url
  68    * @param {string} p path
  69    */
  70   _normalizePath(p) {
  71     const pathNorm = path.normalize(p); // This isn't perfectly correct, but it's easy...
  72     return this._stripPrefix(pathNorm);
  73   }
  74
  75
  76   /**
  77    * Remove a leading portion of url path
  78    * N.B. This method gets obliterated if there is no prefix defined at construction
  79    * @param {string} p path
  80    */
  81   _stripPrefix(p) {
  82     if (p.startsWith(this.proxyPrefix)) {
  83       return p.slice(this.proxyPrefix.length);
  84     }
  85     return p;
  86   }
  87
  88
  89   /**
  90    * Returns the path part, and querystring object, from a request url.
  91    * @param {string} url
  92    */
  93   _splitUrl(url) {
  94     const [ p, qs ] = common.splitFirst(url, '?');
  95     return {
  96       pathPart: this._normalizePath(p),
  97       queryParams: this.querystring.parse(qs),
  98     };
  99   }
 100
 101
 102   /**
 103    * Insert a new path handler
 104    * @param {string} method
 105    * @param {string} urlPath
 106    * @param {fn} handler
 107    */
 108   on(method, urlPath, handler, ...handlerArgs) {
 109     this.router.on(method, urlPath, handler, handlerArgs);
 110   }
 111
 112
 113   /**
 114    * Common header tagging for all requests.
 115    * Add our own identifier, and persist any external transit identifiers.
 116    * @param {http.ClientRequest} req
 117    * @param {http.ServerResponse} res
 118    * @param {object} ctx
 119    */
 120   static tagContext(req, res, ctx) {
 121     const requestId = common.requestId();
 122     ctx.requestId = requestId;
 123     res.setHeader(Enum.Header.RequestId, requestId);
 124     [Enum.Header.XRequestId, Enum.Header.XCorrelationId].forEach((h) => {
 125       const v = req.getHeader(h);
 126       if (v) {
 127         ctx[h.replace(/-/g, '')] = v;
 128         res.setHeader(h, v);
 129       }
 130     });
 131     return requestId;
 132   }
 133
 134
 135   /**
 136    *
 137    * @param {http.ClientRequest} req
 138    */
 139   _getAddress(req) {
 140     // TODO: RFC7239 Forwarded support
 141     const address = (this.trustProxy && req?.getHeader(Enum.Header.XForwardedFor)) ||
 142       (this.trustProxy && req?.getHeader(Enum.Header.XRealIP)) ||
 143       (req?.connection?.remoteAddress) ||
 144       '';
 145     return address.split(/\s*,\s*/u)[0];
 146   }
 147
 148
 149   /**
 150    *
 151    * @param {http.ClientRequest} req
 152    */
 153   _getProtocol(req) {
 154     // TODO: RFC7239 Forwarded support
 155     const protocol = (this.trustProxy && req?.getHeader(Enum.Header.XForwardedProto)) ||
 156       ((req?.connection?.encrypted) ? 'https' : 'http');
 157     return protocol.split(/\s*,\s*/u)[0];
 158   }
 159
 160
 161   /**
 162    *
 163    * @param {http.ClientRequest} req
 164    * @param {http.ServerResponse} res
 165    * @param {object} ctx
 166    */
 167   clientAddressContext(req, res, ctx) {
 168     ctx.clientAddress = this._getAddress(req);
 169     ctx.clientProtocol = this._getProtocol(req);
 170   }
 171
 172
 173   /**
 174    * Called before every request handler.
 175    * @param {http.ClientRequest} req
 176    * @param {http.ServerResponse} res
 177    * @param {object} ctx
 178    */
 179   async preHandler(req, res, ctx) {
 180     Dingus.tagContext(req, res, ctx);
 181     this.clientAddressContext(req, res, ctx);
 182   }
 183
 184
 185   /**
 186    * Helper for collecting chunks as array of buffers.
 187    * @param {Buffer[]} chunks
 188    * @param {string|Buffer} chunk
 189    * @param {string} encoding
 190    */
 191   static pushBufChunk(chunks, chunk, encoding = 'utf8') {
 192     if (chunk) {
 193       if (typeof chunk === 'string') {
 194         chunk = Buffer.from(chunk, encoding);
 195       }
 196       chunks.push(chunk);
 197     }
 198   }
 199
 200
 201   /**
 202    * Sets ctx.responseBody and calls handler upon res.end().
 203    * @param {http.ClientRequest} req
 204    * @param {http.ServerResponse} res
 205    * @param {object} ctx
 206    * @param {*} handler fn(req, res, ctx)
 207    */
 208   static setEndBodyHandler(req, res, ctx, handler) {
 209     const origWrite = res.write.bind(res);
 210     const origEnd = res.end.bind(res);
 211     const chunks = [];
 212     res.write = function (chunk, encoding, ...rest) {
 213       Dingus.pushBufChunk(chunks, chunk, encoding);
 214       return origWrite(chunk, encoding, ...rest);
 215     };
 216     res.end = function (data, encoding, ...rest) {
 217       Dingus.pushBufChunk(chunks, data, encoding);
 218       ctx.responseBody = Buffer.concat(chunks);
 219       handler(req, res, ctx);
 220       return origEnd(data, encoding, ...rest);
 221     };
 222   }
 223
 224
 225   /**
 226    * Intercept writes for head requests, do not send to client,
 227    * but send length, and make body available in context.
 228    * N.B. If persisted, ctx.responseBody will be a raw buffer, be aware when logging.
 229    * @param {http.ClientRequest} req
 230    * @param {http.ServerResponse} res
 231    * @param {object} ctx
 232    * @param {Boolean} persistResponseBody
 233    */
 234   static setHeadHandler(req, res, ctx, persistResponseBody = false) {
 235     if (req.method === 'HEAD') {
 236       const origEnd = res.end.bind(res);
 237       const chunks = [];
 238       res.write = function (chunk, encoding) {
 239         Dingus.pushBufChunk(chunks, chunk, encoding);
 240         // No call to original res.write.
 241       };
 242       res.end = function (data, encoding, ...rest) {
 243         Dingus.pushBufChunk(chunks, data, encoding);
 244         const responseBody = Buffer.concat(chunks);
 245         res.setHeader(Enum.Header.ContentLength, Buffer.byteLength(responseBody));
 246         if (persistResponseBody) {
 247           ctx.responseBody = responseBody;
 248         }
 249         return origEnd(undefined, encoding, ...rest);
 250       };
 251     }
 252   }
 253
 254
 255   /**
 256    * Dispatch the handler for a request
 257    * @param {http.ClientRequest} req
 258    * @param {http.ServerResponse} res
 259    * @param {object} ctx
 260    */
 261   async dispatch(req, res, ctx = {}) {
 262     const _scope = _fileScope('dispatch');
 263
 264     const { pathPart, queryParams } = this._splitUrl(req.url);
 265     ctx.queryParams = queryParams;
 266
 267     let handler, handlerArgs = [];
 268     try {
 269       ({ handler, handlerArgs } = this.router.lookup(req.method, pathPart, ctx));
 270     } catch (e) {
 271       if (e instanceof DingusError) {
 272         switch (e.message) {
 273           case 'NoPath':
 274             handler = this.handlerNotFound.bind(this);
 275             break;
 276           case 'NoMethod':
 277             handler = this.handlerMethodNotAllowed.bind(this);
 278             break;
 279           default:
 280             this.logger.error(_scope, 'unknown dingus error', { error: e });
 281             handler = this.handlerInternalServerError.bind(this);
 282         }
 283       } else if (e instanceof URIError) {
 284         handler = this.handlerBadRequest.bind(this);
 285       } else {
 286         this.logger.error(_scope, 'lookup failure', { error: e });
 287         handler = this.handlerInternalServerError.bind(this);
 288       }
 289     }
 290
 291     try {
 292       await this.preHandler(req, res, ctx);
 293       return await handler(req, res, ctx, ...handlerArgs);
 294     } catch (e) {
 295       ctx.error = e;
 296       this.sendErrorResponse(e, req, res, ctx);
 297     }
 298   }
 299
 300
 301   /**
 302    * Return normalized type, without any parameters.
 303    * @param {http.ClientRequest} req
 304    * @returns {string}
 305    */
 306   static getRequestContentType(req) {
 307     const contentType = req.getHeader(Enum.Header.ContentType);
 308     return (contentType || '').split(';')[0].trim().toLowerCase();
 309   }
 310
 311
 312   /**
 313    * Parse rawBody as contentType into ctx.parsedBody.
 314    * @param {string} contentType
 315    * @param {object} ctx
 316    * @param {string|buffer} rawBody
 317   */
 318   parseBody(contentType, ctx, rawBody) {
 319     const _scope = _fileScope('parseBody');
 320
 321     switch (contentType) {
 322       case Enum.ContentType.ApplicationForm:
 323         ctx.parsedBody = this.querystring.parse(rawBody);
 324         break;
 325
 326       case Enum.ContentType.ApplicationJson:
 327         try {
 328           ctx.parsedBody = JSON.parse(rawBody);
 329         } catch (e) {
 330           this.logger.debug(_scope, 'JSON parse failed', { requestId: ctx.requestId, error: e });
 331           throw new ResponseError(Enum.ErrorResponse.BadRequest, e.message);
 332         }
 333         break;
 334
 335       default:
 336         this.logger.debug(_scope, 'unhandled content-type', { requestId: ctx.requestId, contentType });
 337         throw new ResponseError(Enum.ErrorResponse.UnsupportedMediaType);
 338     }
 339   }
 340
 341
 342   /**
 343    * Return all body data from a request.
 344    * @param {http.ClientRequest} req
 345    * @param {Number=} maximumBodySize
 346    * @param {Boolean=} toString
 347    */
 348   async bodyData(req, maximumBodySize, toString = true) {
 349     const _scope = _fileScope('bodyData');
 350     return new Promise((resolve, reject) => {
 351       const body = [];
 352       let length = 0;
 353       req.on('data', (chunk) => {
 354         body.push(chunk);
 355         length += Buffer.byteLength(chunk);
 356         if (maximumBodySize && length > maximumBodySize) {
 357           this.logger.debug(_scope, 'body data exceeded limit', { length, maximumBodySize });
 358           reject(new ResponseError(Enum.ErrorResponse.RequestEntityTooLarge));
 359         }
 360       });
 361       req.on('end', () => {
 362         const bodyBuffer = Buffer.concat(body);
 363         resolve(toString ? bodyBuffer.toString() : bodyBuffer);
 364       });
 365       req.on('error', (e) => {
 366         this.logger.error(_scope, 'failed', { error: e });
 367         reject(e);
 368       });
 369     });
 370   }
 371
 372
 373   /**
 374    * Read and parse request body data.
 375    * @param {http.ClientRequest} req
 376    * @param {http.ServerResponse} res
 377    * @param {object} ctx
 378    * @param {object}
 379    * @param {Boolean} .parseEmptyBody
 380    * @param {Boolean} .persistRawBody
 381    */
 382   async ingestBody(req, res, ctx, { parseEmptyBody = true, persistRawBody = false, maximumBodySize } = {}) {
 383     const rawBody = await this.bodyData(req, maximumBodySize);
 384     if (persistRawBody) {
 385       ctx.rawBody = rawBody;
 386     }
 387     if (rawBody || parseEmptyBody) {
 388       const contentType = Dingus.getRequestContentType(req);
 389       this.parseBody(contentType, ctx, rawBody);
 390     }
 391   }
 392
 393
 394   /**
 395    * Return the best matching response type.
 396    * @param {string[]} responseTypes
 397    * @param {http.ClientRequest} req
 398    */
 399   static getResponseContentType(responseTypes, req) {
 400     const acceptHeader = req.getHeader(Enum.Header.Accept);
 401     return ContentNegotiation.accept(responseTypes, acceptHeader);
 402   }
 403
 404
 405   /**
 406    * Returns a list of the most-preferred content encodings for the response.
 407    * @param {string[]} responseEncodings
 408    * @param {http.ClientRequest} req
 409    */
 410   static getResponseEncoding(responseEncodings, req) {
 411     const acceptEncodingHeader = req.getHeader(Enum.Header.AcceptEncoding);
 412     return ContentNegotiation.preferred(responseEncodings, acceptEncodingHeader);
 413   }
 414
 415
 416   /**
 417    * Set the best content type for the response.
 418    * @param {string[]} responseTypes default first
 419    * @param {http.ClientRequest} req
 420    * @param {http.ServerResponse} res
 421    * @param {object} ctx
 422    */
 423   setResponseType(responseTypes, req, res, ctx) {
 424     const _scope = _fileScope('setResponseType');
 425     ctx.responseType = Dingus.getResponseContentType(responseTypes, req);
 426     if (!ctx.responseType) {
 427       if (this.strictAccept) {
 428         this.logger.debug(_scope, 'unhandled strict accept', { requestId: req.requestId });
 429         throw new ResponseError(Enum.ErrorResponse.NotAcceptable);
 430       } else {
 431         ctx.responseType = responseTypes[0];
 432       }
 433     }
 434     res.setHeader(Enum.Header.ContentType, ctx.responseType);
 435   }
 436
 437
 438   /**
 439    * Inserts an encoding
 440    * @param {http.ServerResponse} res
 441    * @param {string} encoding
 442    */
 443   static addEncodingHeader(res, encoding) {
 444     const existingEncodings = res.getHeader(Enum.Header.ContentEncoding);
 445     if (existingEncodings) {
 446       encoding = `${encoding}, ${existingEncodings}`;
 447     }
 448     res.setHeader(Enum.Header.ContentEncoding, encoding);
 449   }
 450
 451
 452   /**
 453    * Attempt to fetch both data and metadata for a file.
 454    * @param {string} filePath
 455    */
 456   async _readFileInfo(filePath) {
 457     const _scope = _fileScope('_readFileInfo');
 458     let result;
 459     try {
 460       // eslint-disable-next-line security/detect-non-literal-fs-filename
 461       const stat = fsPromises.stat(filePath);
 462       // eslint-disable-next-line security/detect-non-literal-fs-filename
 463       const data = fsPromises.readFile(filePath);
 464       result = await Promise.all([stat, data]);
 465     } catch (e) {
 466       if (['ENOENT', 'EACCES', 'EISDIR', 'ENAMETOOLONG', 'EINVAL'].includes(e.code)) {
 467         return [null, null];
 468       }
 469       this.logger.error(_scope, 'fs error', { error: e, filePath });
 470       throw e;
 471     }
 472     return result;
 473   }
 474
 475
 476   /**
 477    * Potentially add additional headers from static file meta-file.
 478    * @param {http.ServerResponse} res
 479    * @param {string} directory
 480    * @param {string} fileName - already normalized and filtered
 481    */
 482   async _serveFileMetaHeaders(res, directory, fileName) {
 483     const _scope = _fileScope('_serveFileMetaHeaders');
 484     this.logger.debug(_scope, 'called', { directory, fileName });
 485
 486     const metaPrefix = '.';
 487     const metaSuffix = '.meta';
 488     const metaFileName = `${metaPrefix}${fileName}${metaSuffix}`;
 489     const metaFilePath = path.join(directory, metaFileName);
 490
 491     const [stat, data] = await this._readFileInfo(metaFilePath);
 492     if (!stat) {
 493       return;
 494     }
 495
 496     const lineBreakRE = /\r\n|\n|\r/;
 497     const lines = data.toString().split(lineBreakRE);
 498     common.unfoldHeaderLines(lines);
 499
 500     const headerParseRE = /^(?<name>[^:]+): +(?<value>.*)$/;
 501     lines.forEach((line) => {
 502       if (line) {
 503         const result = headerParseRE.exec(line);
 504         const { groups: header } = result;
 505         res.setHeader(header.name, header.value);
 506       }
 507     });
 508   }
 509
 510
 511   /**
 512    * Serve a file from a directory, with rudimentary cache awareness.
 513    * This will also serve pre-encoded variations if available and requested.
 514    * @param {http.ClientRequest} req
 515    * @param {http.ServerResponse} res
 516    * @param {object} ctx
 517    * @param {string} directory
 518    * @param {string} fileName
 519    */
 520   async serveFile(req, res, ctx, directory, fileName) {
 521     const _scope = _fileScope('serveFile');
 522     this.logger.debug(_scope, 'called', { req, ctx });
 523
 524     // Require a directory field.
 525     if (!directory) {
 526       this.logger.debug(_scope, 'rejected unset directory', { fileName });
 527       return this.handlerNotFound(req, res, ctx);
 528     }
 529
 530     // Normalize the supplied path, as encoded path-navigation may have been (maliciously) present.
 531     fileName = path.normalize(fileName);
 532
 533     // We will not deal with any subdirs, nor any dot-files.
 534     // (Note that we could not deal with subdirs even if we wanted, due to simple router matching scheme.)
 535     if (fileName.indexOf(path.sep) >= 0
 536     ||  fileName.startsWith('.')) {
 537       this.logger.debug(_scope, 'rejected filename', { fileName });
 538       return this.handlerNotFound(req, res, ctx);
 539     }
 540
 541     const filePath = path.join(directory, fileName);
 542
 543     // File must exist, before any alternate static encodings will be considered.
 544     let [stat, data] = await this._readFileInfo(filePath);
 545     if (!stat) {
 546       return this.handlerNotFound(req, res, ctx);
 547     }
 548
 549     // If encodings were requested, check for static versions to serve.
 550     // Update stat and data if matching version is found.
 551     ctx.availableEncodings = Dingus.getResponseEncoding(Object.values(Enum.EncodingType), req);
 552     if (ctx.availableEncodings.length === 0) {
 553       // Identity encoding was specifically denied, and nothing else available.
 554       this.logger.debug(_scope, 'no suitable encodings', { ctx });
 555       return this.handlerMethodNotAllowed(req, res, ctx);
 556     }
 557     for (const encoding of ctx.availableEncodings) {
 558       if (encoding === Enum.EncodingType.Identity) {
 559         break;
 560       }
 561       const suffix = Enum.EncodingTypeSuffix[encoding];
 562       if (!suffix) {
 563         this.logger.error(_scope, 'supported encoding missing mapped suffix', { ctx, encoding });
 564         continue;
 565       }
 566       const encodedFilePath = `${filePath}${suffix}`;
 567       const [ encodedStat, encodedData ] = await this._readFileInfo(encodedFilePath);
 568       if (encodedStat) {
 569         ([ stat, data ] = [ encodedStat, encodedData ]);
 570         ctx.selectedEncoding = encoding;
 571         Dingus.addEncodingHeader(res, encoding);
 572         res.setHeader(Enum.Header.Vary, Enum.Header.AcceptEncoding);
 573         this.logger.debug(_scope, 'serving encoded version', { ctx, encodedFilePath });
 574       }
 575       break;
 576     }
 577
 578     const lastModifiedDate = new Date(stat.mtimeMs);
 579     res.setHeader(Enum.Header.LastModified, lastModifiedDate.toGMTString());
 580
 581     const eTag = common.generateETag(filePath, stat, data);
 582     res.setHeader(Enum.Header.ETag, eTag);
 583
 584     if (common.isClientCached(req, stat.mtimeMs, eTag)) {
 585       this.logger.debug(_scope, 'client cached file', { filePath });
 586       res.statusCode = 304; // Not Modified
 587       res.end();
 588       return;
 589     }
 590
 591     // Set the type based on extension of un-encoded filename.
 592     const ext = path.extname(filePath).slice(1); // Drop the dot
 593     const contentType = extensionToMime(ext);
 594     res.setHeader(Enum.Header.ContentType, contentType);
 595
 596     // We presume static files are relatively cacheable.
 597     res.setHeader(Enum.Header.CacheControl, 'public');
 598
 599     if (this.staticMetadata) {
 600       await this._serveFileMetaHeaders(res, directory, fileName);
 601     }
 602
 603     this.logger.debug(_scope, 'serving file', { filePath, contentType });
 604     res.end(data);
 605   }
 606
 607
 608   /**
 609    * Return a content-type appropriate rendering of an errorResponse object.
 610    * @param {string} type content-type of response
 611    * @param {object} err either an Error object, or an error response
 612    * @param {number} err.statusCode
 613    * @param {string} err.errorMessage
 614    * @param {string|string[]} err.details
 615    */
 616   // eslint-disable-next-line class-methods-use-this
 617   renderError(contentType, err) {
 618     switch (contentType) {
 619       case Enum.ContentType.ApplicationJson:
 620         return JSON.stringify(err);
 621
 622       case Enum.ContentType.TextHTML:
 623         return Template.errorHTML(err);
 624
 625       case Enum.ContentType.TextPlain:
 626       default:
 627         return [err.errorMessage, err.details].join('\r\n');
 628     }
 629   }
 630
 631
 632   /**
 633    * Send an error response.  Terminal.
 634    * Logs any non-error-response errors as such.
 635    * @param {object} err either an Error object, or an error response
 636    * @param {http.ClientRequest} req
 637    * @param {http.ServerResponse} res
 638    * @param {object} ctx
 639    */
 640   sendErrorResponse(err, req, res, ctx) {
 641     const _scope = _fileScope('sendErrorResponse');
 642     let body;
 643
 644     // Default to a content type if one is not yet present
 645     if (!res.hasHeader(Enum.Header.ContentType)) {
 646       res.setHeader(Enum.Header.ContentType, Enum.ContentType.TextPlain);
 647     }
 648
 649     if (err?.statusCode) {
 650       res.statusCode = err.statusCode;
 651       body = this.renderError(res.getHeader(Enum.Header.ContentType), err);
 652       this.logger.debug(_scope, 'handler error', { err, req, res, ctx });
 653     } else {
 654       res.statusCode = 500;
 655       body = this.renderError(res.getHeader(Enum.Header.ContentType), Enum.ErrorResponse.InternalServerError);
 656       this.logger.error(_scope, 'handler exception', { err, req, res, ctx });
 657     }
 658     res.end(body);
 659   }
 660
 661
 662   /**
 663    * @param {http.ClientRequest} req
 664    * @param {http.ServerResponse} res
 665    * @param {object} ctx
 666    * @param {String} file - override ctx.params.file
 667    */
 668   async handlerGetStaticFile(req, res, ctx, file) {
 669     Dingus.setHeadHandler(req, res, ctx);
 670
 671     // Set a default response type to handle any errors; will be re-set to serve actual static content type.
 672     this.setResponseType(this.responseTypes, req, res, ctx);
 673
 674     await this.serveFile(req, res, ctx, this.staticPath, file || ctx.params.file);
 675   }
 676
 677
 678   /**
 679    * @param {http.ClientRequest} req
 680    * @param {http.ServerResponse} res
 681    * @param {Object} ctx
 682    * @param {String} newPath
 683    * @param {Number} statusCode
 684   */
 685   async handlerRedirect(req, res, ctx, newPath, statusCode = 307) {
 686     this.setResponseType(this.responseTypes, req, res, ctx);
 687     res.setHeader(Enum.Header.Location, newPath);
 688     res.statusCode = statusCode;
 689     res.end();
 690   }
 691
 692
 693   /**
 694    * @param {http.ClientRequest} req
 695    * @param {http.ServerResponse} res
 696    * @param {object} ctx
 697    */
 698   async handlerMethodNotAllowed(req, res, ctx) {
 699     this.setResponseType(this.responseTypes, req, res, ctx);
 700     throw new ResponseError(Enum.ErrorResponse.MethodNotAllowed);
 701   }
 702
 703
 704   /**
 705    * @param {http.ClientRequest} req
 706    * @param {http.ServerResponse} res
 707    * @param {object} ctx
 708    */
 709   async handlerNotFound(req, res, ctx) {
 710     this.setResponseType(this.responseTypes, req, res, ctx);
 711     throw new ResponseError(Enum.ErrorResponse.NotFound);
 712   }
 713
 714
 715   /**
 716    * @param {http.ClientRequest} req
 717    * @param {http.ServerResponse} res
 718    * @param {object} ctx
 719    */
 720   async handlerBadRequest(req, res, ctx) {
 721     this.setResponseType(this.responseTypes, req, res, ctx);
 722     throw new ResponseError(Enum.ErrorResponse.BadRequest);
 723   }
 724
 725
 726   /**
 727    * @param {http.ClientRequest} req
 728    * @param {http.ServerResponse} res
 729    * @param {object} ctx
 730    */
 731   async handlerInternalServerError(req, res, ctx) {
 732     this.setResponseType(this.responseTypes, req, res, ctx);
 733     throw new ResponseError(Enum.ErrorResponse.InternalServerError);
 734   }
 735
 736 }
 737
 738 module.exports = Dingus;