router.js

   1 /**
   2  * @file      HTTP(S) Router that treats the first directory in a URL's path as
   3  *            a route to a host.
   4  * @author    Ken Grimes
   5  * @version   0.0.1
   6  * @license   AGPL-3.0
   7  * @copyright Strapp.io
   8  */
   9
  10 const dlog = (msg) => console.log(msg)
  11
  12 exports = {
  13   /** Regular expression for valid routes
  14    * @prop {Object.RegEx} validRoutes - matches valid route names
  15    */
  16   validRoutes: /[a-zA-Z][a-zA-Z0-9\-_]*/,
  17
  18   /** Parameters set on bootup (startHttpServer)
  19    * @prop {string[2]} skelPage - html document split in twain for JS injection
  20    * @prop {string} clientJS - jerverscripps to inject in skelPage for clients
  21    * @prop {string} hostJS - jerverscripps for the hosts
  22    * @prop {string} httpdRoot - a normalized path for http-servable files
  23    * @prop {string} bindJail - jail bindings to this path
  24    */
  25   skelPage: undefined,
  26   clientJS: undefined,
  27   hostJS: undefined,
  28   httpdRoot: undefined,
  29   bindJail: undefined,
  30
  31   /** @func
  32    * @summary Start main HTTP server
  33    * @desc    starts up an HTTP or HTTPS server used for routing
  34    * @arg     {Object} conf - object containing configuration properties
  35    * @prop    {number|string} conf.port - local system port to bind to
  36    * @prop    {string} conf.skelFile - location of the skeleton HTML page
  37    * @prop    {string} conf.clientJS - client JS file
  38    * @prop    {string} conf.hostJS - host JS file
  39    * @prop    {string} [conf.httpdRoot] - root path of http-accessible files, if
  40    *                                      undefined no files are accessible
  41    * @prop    {Object} [conf.tls] - if present, startHttpServer will use tls
  42    * @prop    {string} [conf.tls.certFile] - tls certificate file
  43    * @prop    {string} [conf.tls.keyFile] - tls public key file
  44    */
  45   startHttpServer: function (conf) {
  46     if ('httpd' in this)
  47       throw new Error('httpd already running')
  48     if (conf.tls == undefined)
  49       this.httpd = require('http').createServer(this.httpdListener)
  50     else if (!('keyFile' in conf.tls) || !('certFile' in conf.tls))
  51       throw new Error('HTTPS requires a valid key and cert')
  52     else
  53       this.syncReads([conf.tls.keyFile, conf.tls.certFile]).then((results) => {
  54         Object.defineProperty(this, 'httpsOpts', {
  55           value: {
  56             key: results[conf.tls.keyFile],
  57             cert: results[conf.tls.certFile]
  58           }
  59         })
  60         this.httpd =
  61           require('https').createServer(this.httpsOpts, this.httpdListener)
  62       })
  63     this.httpd.listen(conf.port)
  64     this.httpdRoot =
  65       conf.httpdRoot ? require('path').normalize(conf.httpdRoot) : undefined
  66     while (this.httpdRoot[this.httpdRoot.length - 1] == require('path').sep)
  67       this.httpdRoot = this.httpdRoot.slice(0,-1)
  68     this.syncReads(conf.skelFile, conf.clientJS, conf.hostJS)
  69       .then((results) => {
  70         this.skelPage = results[conf.skelFile].split('<!--STRAPP_SRC-->')
  71         this.clientJS = results[conf.clientJS]
  72         this.hostJS = results[conf.hostJS]
  73       })
  74       .catch((err) => {
  75         console.log(err)
  76       })
  77     console.log(`HTTP${(conf.tls == undefined) ? 'S' : ''} ` +
  78                 `Server Started on port ${conf.port}${this.httpdRoot ?
  79                 `, serving files from ${this.httpdRoot}`:''}`)
  80   },
  81
  82   /** @func
  83    * @summary Create a binding for the server
  84    * @desc    makes a new route which is bound to a file or a path.  routes
  85    *          bound to files always serve that file, regardless of any
  86    *          additional path parameters provided by the URI
  87    * @arg     {string} routeName - the route to create
  88    * @arg     {string} path - the path to the file or directory to bind
  89    */
  90   createBind: function (routeName, path) {
  91     dlog(`Binding ${routeName} to ${path}`)
  92     if (routeName in this.routes)
  93       throw new Error(`route ${routeName} already exists`)
  94     path = require('path').normalize(path)
  95     if (this.bindJail
  96         && path.indexOf(`${this.bindJail}/`) !== 0
  97         && this.bindJail != path)
  98       throw new Error(`${routeName}:${path} jailed to ${this.bindJail}`)
  99     if (require('fs').existsSync(path)) {
 100       this.route[routeName] = {
 101         bind: {
 102           path: path,
 103           dir: require('fs').lstatSync(path).isDirectory()
 104         }
 105       }
 106     }
 107     else
 108       throw new Error(`${path} not found, ${routeName} not bound`)
 109   },
 110
 111   /** @func
 112    * @summary Router
 113    * @desc    listens for http client requests and services routes/files
 114    * @arg     {http.ClientRequest} request
 115    * @arg     {http.ServerResponse} response
 116    */
 117   httpdListener: function (request,response) {
 118     dlog(`Received request ${request.method} ${request.url}`)
 119     let htArgv = request.url.slice(1).split('?')
 120     const routeName = htArgv[0].split('/')[0]
 121     const route = this.routes[routeName]
 122     /* If the route exists, check if we are a returning host or a new client */
 123     if (route) {
 124       if (route.bind) {
 125         htArgv[0] = htArgv[0].replace(`${routeName}`,'')
 126         if (htArgv[0][0] === '/')
 127           htArgv[0] = htArgv[0].slice(1)
 128         this.serveBind(response, route.bind, htArgv)
 129       }
 130       //TODO: auth better than this (ip spoofing is easy)
 131       else if (route.host == (request.headers['x-forwarded-for'] ||
 132                          request.connection.remoteAddress))
 133         this.serveHost(response, route, htArgv)
 134       else
 135         this.serveClient(request, response, route)
 136     }
 137     /* If it's a valid routename that doesn't exist, make this client a host */
 138     else if (this.validRoutes.test(routeName)) {
 139       route = this.createRoute(routeName, this.httpsOpts)
 140       this.serveHost(response, route, htArgv)
 141     }
 142     /* Try servicing files if we have a root directory for it */
 143     else if (this.httpdRoot) {
 144       let realPath = require('path').join(this.httpdRoot, htArgv[0])
 145       if (realPath == this.httpdRoot)
 146         realPath += '/index.html'
 147       if (realPath.indexOf(`${this.httpdRoot}/`) == 0) {
 148         const stat_cb = (err, stat) => {
 149           if (err) {
 150             response.writeHead(404)
 151             response.end()
 152             console.log(err)
 153           }
 154           else if (stat.isDirectory()) {
 155             realPath += '/index.html'
 156             require('fs').lstat(realPath, stat_cb)
 157           }
 158           else if (stat.isFile())
 159             this.serveFile(response, realPath)
 160           else {
 161             response.writeHead(403)
 162             response.end()
 163           }
 164         }
 165         require('fs').lstat(realPath, stat_cb)
 166       }
 167       else {
 168         response.writeHead(400)
 169         response.end()
 170       }
 171     }
 172     /* Unhandled */
 173     else {
 174       response.writeHead(404)
 175       response.end()
 176     }
 177   },
 178
 179   /** @func
 180    * @summary Serves a binding to a client
 181    * @desc    Resolves a binding and serves a response to the client
 182    * @arg     {http.ServerResponse} response - the response to use
 183    * @arg     {Object} bind - the binding to serve the client
 184    * @arg     {string[]} argv - path and arguments for the bind
 185    */
 186   serveBind: function (response, bind, argv) {
 187     dlog(`Serving binding ${bind.path}/${argv[0]}`)
 188     if (bind.dir) {
 189       if (argv[0] == '')
 190         argv[0] = 'index.html'
 191       this.serveFile(response, require('path').join(bind.path, argv[0]))
 192     }
 193     else
 194       this.serveFile(response, bind.path)
 195   },
 196
 197   /** @func
 198    * @summary Serve a route to an http client
 199    * @desc    routes may be bound to the filesystem, or to an outgoing host
 200    * @arg     {http.ClientRequest} request - request from the client
 201    * @arg     {http.ServerResponse} response - response object to use
 202    * @arg     {Object} route - route associated with client request
 203    */
 204   serveClient: function (request, response, route) {
 205     const type = request.headers['x-strapp-type']
 206     const pubKey = request.headers['x-strapp-pubkey']
 207     dlog(`Client ${type || 'HT'} request routed to ${route.name}`)
 208     switch (type) {
 209     case null:
 210     case undefined:
 211       response.writeHead(200, { 'Content-Type': 'text/html' })
 212       response.write(`${this.skelPage[0]}${this.clientJS}${this.skelPage[1]}`)
 213       response.end()
 214       break
 215     case 'ice-candidate-request':
 216     case 'ice-candidate-submission':
 217     case 'client-sdp-offer':
 218       let data = ''
 219       if (pubKey) {
 220         route.pendingResponses.addResponse(pubKey, response)
 221         request.on('data', (chunk) => data += chunk)
 222         request.on('end', () => route.socket.send(`${pubKey} ${type} ${data}`))
 223       }
 224       else {
 225         response.writeHead(401)
 226         response.end()
 227       }
 228       break
 229     default:
 230       response.writeHead(400)
 231       response.end()
 232     }
 233   },
 234
 235   /** @func
 236    * @summary Serve a route to an authorized http host
 237    * @desc    services host application to the client, establishing a socket
 238    * @arg     {http.ServerResponse} response - response object to use
 239    * @arg     {Object} route - the route that belongs to this host
 240    * @arg     {string[]} argv - vector of arguments sent to the host
 241    */
 242   serveHost: function (response, route, argv) {
 243     response.writeHead(200, { 'Content-Type': 'text/html' })
 244     response.write(`${this.skelPage[0]}` +
 245                    `\tconst _strapp_port = ${route.port}\n` +
 246                    `\tconst _strapp_protocol = ` +
 247                    `${this.httpsOpts ? 'wss' : 'ws'}'\n` +
 248                    `${this.hostJS}\n${this.skelPage[1]}`)
 249     response.end()
 250   },
 251
 252   /** @func
 253    * @summary Create a new route
 254    * @desc    makes a new route for the given route name
 255    * @arg     {string} routeName - name of the new route
 256    * @arg     {string} host - Origin address from the request that made this
 257    *                          route (for security verification on the socket)
 258    * @arg     {Object} [httpsOpts] - key and cert for tls
 259    * @returns {Object} a route object containing host, socket, and servers
 260    */
 261   createRoute: function (routeName, host, httpsOpts) {
 262     dlog(`Creating ${httpsOpts ? 'TLS ' : ''}route ${routeName} from ${host}`)
 263     if (routeName in this.routes)
 264       throw new Error(`route ${routeName} already exists`)
 265     const httpd = httpsOpts
 266           ? require('https').createServer(httpsOpts)
 267           : require('http').createServer()
 268     const route = {
 269       pendingResponses: new Map([]),
 270       host: host,
 271       httpd: httpd,
 272       name: routeName,
 273       port: undefined,
 274       wsd: undefined,
 275       socket: undefined
 276     }
 277     require('get-port')().then((port) => {
 278       route.port = port
 279       route.httpd.listen(port)
 280       route.wsd = new require('ws').Server({
 281         server:route.httpd,
 282         verifyClient: (info) =>
 283           info.origin == host && (info.secure || !httpsOpts)
 284       })
 285       route.wsd.on('connection', (socket) =>
 286                    socket.on('message', (msg) =>
 287                              this.hostMessage(msg,route)))
 288     })
 289     route.pendingResponses.addResponse = function (key, response) {
 290       let responses = this.get(key) || []
 291       this.set(key, responses.push(response))
 292     }
 293     this.routes[routeName] = route
 294     return route
 295   },
 296
 297   /** @func
 298    * @summary handle host message
 299    * @desc    receives a message from a host, handles the command (first character),
 300    *          and responds to either the host or the client, or both.  Commands
 301    *          are whitespace separated strings.
 302    *            Commands:
 303    *              Forward Payload to Client)
 304    *              < clientKey payload [header]
 305    *                Route 'payload' to the client identified by 'clientKey'.
 306    *                The optional 'header' argument is a stringified JSON object,
 307    *                which will be written to the HTTP response header
 308    *                  In case of multiple requests from a single client, the
 309    *                  oldest request will be serviced on arrival of message
 310    *              Translate SDP and Forward to Client)
 311    *              ^ clientKey sdp [header]
 312    *                Route the JSON object 'sdp' to the client, after translating
 313    *                for interop between browsers using planB or Unified.  Other
 314    *                than the interop step, this is identical to the '<' command
 315    *              Error)
 316    *              ! errorMessage errorCode [offendingMessage]
 317    *                Notify host that an error has occured, providing a message
 318    *                and error code.  'offendingMessage', if present, is the
 319    *                message received from the remote that triggered the error.
 320    * @arg     {string} message - raw string from the host
 321    * @arg     {Object} route - the route over
 322    */
 323   hostMessage: function (message, route) {
 324     const argv = message.split(' ')
 325     const command = argv[0][0]
 326     argv = argv.slice(1)
 327     dlog(`Received host message from ${route.name}: ${command}`)
 328     switch (command) {
 329     case '^':
 330       if (argv.length < 2) {
 331         dlog(`Malformed '${command}' command from ${route.host}`)
 332         route.socket.send(`! "Insufficient arguments" 0 ${message}`)
 333         break
 334       }
 335       argv[1] = JSON.parse(argv[1])
 336       //TODO: interop step
 337       argv[1] = JSON.stringify(argv[1])
 338       //TODO: argv[1] = encryptForClient(argv[0], argv[1])
 339       /* Fallthrough to '<' behavior after translating argv[1] */
 340     case '<':
 341       const response = route.pendingResponses.get(argv[0]).shift()
 342       if (!response)
 343         route.socket.send(`! "No pending responses for client ${argv[0]}" 0 `
 344                           + message)
 345       else if (argv.length === 2 || argv.length === 3) {
 346         const header = argv.length === 3 ? JSON.parse(argv[2]) : {}
 347         if (!('Content-Type' in header))
 348           header['Content-Type'] = 'application/octet-stream'
 349         response.writeHead(200, header)
 350         response.write(argv[1])
 351         response.end()
 352       }
 353       else
 354         route.socket.send(`! "Insufficient arguments" 0 ${message}`)
 355       break
 356     case '!':
 357       if (argv.length === 3)
 358         argv[0] += `\nIn message: ${argv[2]}`
 359       console.log(`Error[${route.host}|${argv[1]}]:${argv[0]}`)
 360       break
 361     default:
 362       route.socket.send(`! "Unknown command '${command}'" 0 ${message}`)
 363       dlog(`Host ${route.host} send unknown command: ${message}`)
 364       break
 365     }
 366   },
 367
 368   /** @func
 369    * @summary Serve a file to an http client after a request
 370    * @desc    reads files from the system to be distributed to clients, and
 371    *          buffers recently accessed files
 372    * @arg     {http.ServerResponse} response - the response object to use
 373    * @arg     {string} filePath - relative location of the file
 374    */
 375   serveFile: function (response, filePath, rootPath) {
 376     //TODO: Make a buffer to hold recently used files, and only read if we
 377     // have to (don't forget to preserve mimetype)
 378     require('fs').readFile(filePath, { encoding: 'utf8' }, (err, data) => {
 379       if (err || data == undefined)
 380         response.writeHead(404)
 381       else {
 382         response.writeHead(200, {
 383           'Content-Type': require('mime').lookup(filePath)
 384         })
 385         response.write(data)
 386       }
 387       response.end()
 388     })
 389   },
 390
 391   /** @func
 392    * @summary Synchronize Reading Multiple Files
 393    * @desc    reads an array of files into an object, whose keys are the
 394    *          input filenames, and values are the data read
 395    * @arg     {string[]} files - array of file names to read
 396    * @arg     {Object} [readOpts] - options to pass to fs.readFile()
 397    */
 398   syncReads: (files, readOpts) => new Promise((resolve,reject) => {
 399     dlog(`syncReads: ${files}`)
 400     let count = 0
 401     let results = {}
 402     const read_cb = (fileName) => (err, data) => {
 403       if (err)
 404         reject(err)
 405       else
 406         results[fileName] = data
 407       if (++count === files.length)
 408         resolve(results)
 409     }
 410     if (readOpts == undefined)
 411       readOpts = { encoding: 'utf8' }
 412     files.forEach((file) =>
 413                   require('fs').readFile(file, readOpts, read_cb(file)))
 414   })
 415
 416 }