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   /** A map of routes
  19    * @prop {Object.Map} routes - all the routes!
  20    */
  21   routes: {},
  22
  23   /** Parameters set on bootup (startHttpServer)
  24    * @prop {string[2]} skelPage - html document split in twain for JS injection
  25    * @prop {string} clientJS - jerverscripps to inject in skelPage for clients
  26    * @prop {string} hostJS - jerverscripps for the hosts
  27    * @prop {string} httpdRoot - a normalized path for http-servable files
  28    * @prop {string} bindJail - jail bindings to this path
  29    */
  30   skelPage: undefined,
  31   clientJS: undefined,
  32   hostJS: undefined,
  33   httpdRoot: undefined,
  34   bindJail: undefined,
  35
  36   /** @func
  37    * @summary Start main HTTP server
  38    * @desc    starts up an HTTP or HTTPS server used for routing
  39    * @arg     {Object} conf - object containing configuration properties
  40    * @prop    {number|string} conf.port - local system port to bind to
  41    * @prop    {string} conf.skelFile - location of the skeleton HTML page
  42    * @prop    {string} conf.clientJS - client JS file
  43    * @prop    {string} conf.hostJS - host JS file
  44    * @prop    {string} [conf.httpdRoot] - root path of http-accessible files, if
  45    *                                      undefined no files are accessible
  46    * @prop    {Object} [conf.tls] - if present, startHttpServer will use tls
  47    * @prop    {string} [conf.tls.certFile] - tls certificate file
  48    * @prop    {string} [conf.tls.keyFile] - tls public key file
  49    */
  50   startHttpServer: function (conf) {
  51     if ('httpd' in this)
  52       throw new Error('httpd already running')
  53     if (conf.tls == undefined)
  54       this.httpd = require('http').createServer((req, res) =>
  55                                                 this.httpdListener(req, res))
  56     else if (!('keyFile' in conf.tls) || !('certFile' in conf.tls))
  57       throw new Error('HTTPS requires a valid key and cert')
  58     else
  59       this.syncReads([conf.tls.keyFile, conf.tls.certFile]).then((results) => {
  60         Object.defineProperty(this, 'httpsOpts', {
  61           value: {
  62             key: results[conf.tls.keyFile],
  63             cert: results[conf.tls.certFile]
  64           }
  65         })
  66         this.httpd =
  67           require('https').createServer(this.httpsOpts, (request,response) =>
  68                                         this.httpdListener(request,response))
  69           .listen(conf.port)
  70       })
  71     if (conf.httpdRoot) {
  72       this.httpdRoot = require('path').normalize(conf.httpdRoot)
  73       while (this.httpdRoot[this.httpdRoot.length - 1] == require('path').sep)
  74         this.httpdRoot = this.httpdRoot.slice(0,-1)
  75     }
  76     this.syncReads([conf.skelFile, conf.clientJS, conf.hostJS])
  77       .then((results) => {
  78         this.skelPage = results[conf.skelFile].split('<!--STRAPP_SRC-->')
  79         this.clientJS = results[conf.clientJS]
  80         this.hostJS = results[conf.hostJS]
  81       })
  82       .catch((err) => {
  83         console.log(err)
  84       })
  85     console.log(`HTTP${(conf.tls == undefined) ? '' : 'S'} ` +
  86                 `Server Started on port ${conf.port}${this.httpdRoot ?
  87                 `, serving files from ${this.httpdRoot}`:''}`)
  88   },
  89
  90   /** @func
  91    * @summary Create a binding for the server
  92    * @desc    makes a new route which is bound to a file or a path.  routes
  93    *          bound to files always serve that file, regardless of any
  94    *          additional path parameters provided by the URI
  95    * @arg     {string} routeName - the route to create
  96    * @arg     {string} path - the path to the file or directory to bind
  97    */
  98   createBind: function (routeName, path) {
  99     dlog(`Binding ${routeName} to ${path}`)
 100     if (routeName in this.routes)
 101       throw new Error(`route ${routeName} already exists`)
 102     path = require('path').normalize(path)
 103     if (this.bindJail
 104         && path.indexOf(`${this.bindJail}/`) !== 0
 105         && this.bindJail != path)
 106       throw new Error(`${routeName}:${path} jailed to ${this.bindJail}`)
 107     if (require('fs').existsSync(path)) {
 108       this.routes[routeName] = {
 109         bind: {
 110           path: path,
 111           dir: require('fs').lstatSync(path).isDirectory()
 112         }
 113       }
 114     }
 115     else
 116       throw new Error(`${path} not found, ${routeName} not bound`)
 117   },
 118
 119   /** @func
 120    * @summary Router
 121    * @desc    listens for http client requests and services routes/files
 122    * @arg     {http.ClientRequest} request
 123    * @arg     {http.ServerResponse} response
 124    */
 125   httpdListener: function (request,response) {
 126     dlog(`Received request ${request.method} ${request.url}`)
 127     let htArgv = request.url.slice(1).split('?')
 128     const routeName = htArgv[0].split('/')[0]
 129     let route = this.routes[routeName]
 130     /* If the route exists, check if we are a returning host or a new client */
 131     if (route) {
 132       if (route.bind) {
 133         htArgv[0] = htArgv[0].replace(`${routeName}`,'')
 134         if (htArgv[0][0] === '/')
 135           htArgv[0] = htArgv[0].slice(1)
 136         this.serveBind(response, route.bind, htArgv)
 137       }
 138       //TODO: auth better than this (ip spoofing is easy)
 139       // but this will require a more involved host-creation process
 140       // that isn't just "give you a route if it's available" on visit
 141       /* else if (route.origin == (request.headers['x-forwarded-for'] ||
 142                          request.connection.remoteAddress))
 143         this.serveHost(response, route, htArgv) */
 144       else
 145         this.serveClient(request, response, route)
 146     }
 147     /* If it's a valid routename that doesn't exist, make this client a host */
 148     else if (this.validRoutes.test(routeName)) {
 149        this.routes[routeName] = true
 150       require('get-port')()
 151         .then((port) => {
 152           this.createHost(routeName, htArgv, port, request, response)
 153         })
 154         .catch((err) => {
 155           delete this.routes[routeName]
 156           console.log(err)
 157         })
 158     }
 159     /* Try servicing files if we have a root directory for it */
 160     else if (this.httpdRoot) {
 161       let realPath = require('path').join(this.httpdRoot, htArgv[0])
 162       if (realPath == this.httpdRoot)
 163         realPath += '/index.html'
 164       if (realPath.indexOf(`${this.httpdRoot}/`) == 0) {
 165         const stat_cb = (err, stat) => {
 166           if (err) {
 167             response.writeHead(404)
 168             response.end()
 169             console.log(err)
 170           }
 171           else if (stat.isDirectory()) {
 172             realPath += '/index.html'
 173             require('fs').lstat(realPath, stat_cb)
 174           }
 175           else if (stat.isFile())
 176             this.serveFile(response, realPath)
 177           else {
 178             response.writeHead(403)
 179             response.end()
 180           }
 181         }
 182         require('fs').lstat(realPath, stat_cb)
 183       }
 184       else {
 185         response.writeHead(400)
 186         response.end()
 187       }
 188     }
 189     /* Unhandled */
 190     else {
 191       response.writeHead(404)
 192       response.end()
 193     }
 194   },
 195
 196   /** @func
 197    * @summary Serves a binding to a client
 198    * @desc    Resolves a binding and serves a response to the client
 199    * @arg     {http.ServerResponse} response - the response to use
 200    * @arg     {Object} bind - the binding to serve the client
 201    * @arg     {string[]} argv - path and arguments for the bind
 202    */
 203   serveBind: function (response, bind, argv) {
 204     dlog(`Serving binding ${bind.path}/${argv[0]}`)
 205     if (bind.dir) {
 206       if (argv[0] == '')
 207         argv[0] = 'index.html'
 208       this.serveFile(response, require('path').join(bind.path, argv[0]))
 209     }
 210     else
 211       this.serveFile(response, bind.path)
 212   },
 213
 214   /** @func
 215    * @summary Serve a route to an http client
 216    * @desc    routes may be bound to the filesystem, or to an outgoing host
 217    * @arg     {http.ClientRequest} request - request from the client
 218    * @arg     {http.ServerResponse} response - response object to use
 219    * @arg     {Object} route - route associated with client request
 220    */
 221   serveClient: function (request, response, route) {
 222     const type = request.headers['x-strapp-type']
 223     const pubKey = request.headers['x-strapp-pubkey']
 224     dlog(`Client ${type || 'HT GET'} request routed to ${route.name}`)
 225     switch (type) {
 226     case null:
 227     case undefined:
 228       response.writeHead(200, { 'Content-Type': 'text/html' })
 229       response.write(`${this.skelPage[0]}${this.clientJS}${this.skelPage[1]}`)
 230       response.end()
 231       break
 232     case 'ice-candidate-request':
 233     case 'ice-candidate-submission':
 234     case 'client-sdp-offer':
 235       let data = ''
 236       if (pubKey) {
 237         let data = request.headers['x-strapp-offer']
 238         route.pendingResponses.addResponse(pubKey, response)
 239         dlog(`${route.origin}=>\n${pubKey}\n${type}`)
 240         dlog(JSON.parse(data))
 241         route.socket.send(`${pubKey} ${type} ${data}`)
 242       }
 243       else {
 244         response.writeHead(401)
 245         response.end()
 246       }
 247       break
 248     default:
 249       response.writeHead(400)
 250       response.end()
 251     }
 252   },
 253
 254   /** @func
 255    * @summary Create a new route for a host
 256    * @desc    makes a new route for the given route name
 257    * @arg     {string} routeName - name of the new route
 258    * @arg     {string[]} argv - Origin address from the request that made this
 259    *                          route (for security verification on the socket)
 260    * @arg     {number|string} port - the port to listen on for websocket
 261    * @arg     {http.ClientRequest} request - host's request
 262    * @arg     {http.ServerResponse} response - responder
 263    */
 264   createHost: function (routeName, argv, port, request, response) {
 265     const origin = (request.headers['x-forwarded-for'] ||
 266                     request.connection.remoteAddress)
 267     dlog(`New ${this.httpsOpts?'TLS ':''}route ${routeName}:${port}=>${origin}`)
 268     const httpd = this.httpsOpts
 269           ? require('https').createServer(this.httpsOpts)
 270           : require('http').createServer()
 271     const route = {
 272       pendingResponses: new Map([]),
 273       origin: origin,
 274       httpd: httpd,
 275       name: routeName,
 276       port: port,
 277       wsd: undefined,
 278       socket: undefined
 279     }
 280     route.httpd.listen(port)
 281     route.wsd = new (require('ws').Server)({ server: httpd })
 282       .on('connection', (socket) => {
 283         route.socket = socket
 284         socket.on('message', (msg) =>
 285                   this.hostMessage(msg,route))
 286       })
 287     route.pendingResponses.addResponse = function (key, response_p) {
 288       let responses = this.get(key) || []
 289       responses.push(response_p)
 290       this.set(key, responses)
 291     }
 292     this.routes[routeName] = route
 293     this.serveHost(response, route, argv)
 294   },
 295
 296   /** @Func
 297    * @summary Serve a route to an authorized http host
 298    * @desc    services host application to the client, establishing a socket
 299    * @arg     {http.ServerResponse} response - response object to use
 300    * @arg     {Object} route - the route that belongs to this host
 301    * @arg     {string[]} argv - vector of arguments sent to the host
 302    */
 303   serveHost: function (response, route, argv) {
 304     dlog(`Serving host ${route.origin}`)
 305     response.writeHead(200, { 'Content-Type': 'text/html' })
 306     response.write(`${this.skelPage[0]}` +
 307                    `\tconst _strapp_port = ${route.port}\n` +
 308                    `\tconst _strapp_protocol = ` +
 309                    `'${this.httpsOpts ? 'wss' : 'ws'}'\n` +
 310                    `${this.hostJS}\n${this.skelPage[1]}`)
 311     response.end()
 312   },
 313
 314   /** @func
 315    * @summary handle host message
 316    * @desc    receives a message from a host, handles the command (first character),
 317    *          and responds to either the host or the client, or both.  Commands
 318    *          are whitespace separated strings.
 319    *            Commands:
 320    *              Forward Payload to Client)
 321    *              < clientKey payload [header]
 322    *                Route 'payload' to the client identified by 'clientKey'.
 323    *                The optional 'header' argument is a stringified JSON object,
 324    *                which will be written to the HTTP response header
 325    *                  In case of multiple requests from a single client, the
 326    *                  oldest request will be serviced on arrival of message
 327    *              Translate SDP and Forward to Client)
 328    *              ^ clientKey sdp [header]
 329    *                Route the JSON object 'sdp' to the client, after translating
 330    *                for interop between browsers using planB or Unified.  Other
 331    *                than the interop step, this is identical to the '<' command
 332    *              Error)
 333    *              ! errorMessage errorCode [offendingMessage]
 334    *                Notify host that an error has occured, providing a message
 335    *                and error code.  'offendingMessage', if present, is the
 336    *                message received from the remote that triggered the error.
 337    * @arg     {string} message - raw string from the host
 338    * @arg     {Object} route - the route over
 339    */
 340   hostMessage: function (message, route) {
 341     let argv = message.split(' ')
 342     const command = argv[0][0]
 343     argv = argv.slice(1)
 344     dlog(`Received host message from ${route.name}: ${command}`)
 345     switch (command) {
 346     case '^':
 347       if (argv.length < 2) {
 348         dlog(`Malformed '${command}' command from ${route.origin}`)
 349         route.socket.send(`! "Insufficient arguments" 0 ${message}`)
 350         break
 351       }
 352       argv[1] = JSON.parse(argv[1])
 353       //TODO: interop step
 354       argv[1] = JSON.stringify(argv[1])
 355       //TODO: argv[1] = encryptForClient(argv[0], argv[1])
 356       /* Fallthrough to '<' behavior after translating argv[1] */
 357     case '<':
 358       const response = route.pendingResponses.get(argv[0]).shift()
 359       if (!response)
 360         route.socket.send(`! "No pending responses for client ${argv[0]}" 0 `
 361                           + message)
 362       else if (argv.length === 2 || argv.length === 3) {
 363         const header = argv.length === 3 ? JSON.parse(argv[2]) : {}
 364         if (!('Content-Type' in header))
 365           header['Content-Type'] = 'application/octet-stream'
 366         response.writeHead(200, header)
 367         response.write(argv[1])
 368         response.end()
 369       }
 370       else
 371         route.socket.send(`! "Insufficient arguments" 0 ${message}`)
 372       break
 373     case '!':
 374       if (argv.length === 3)
 375         argv[0] += `\nIn message: ${argv[2]}`
 376       console.log(`Error[${route.origin}|${argv[1]}]:${argv[0]}`)
 377       break
 378     default:
 379       route.socket.send(`! "Unknown command '${command}'" 0 ${message}`)
 380       dlog(`Host ${route.origin} send unknown command: ${message}`)
 381       break
 382     }
 383   },
 384
 385   /** @func
 386    * @summary Serve a file to an http client after a request
 387    * @desc    reads files from the system to be distributed to clients, and
 388    *          buffers recently accessed files
 389    * @arg     {http.ServerResponse} response - the response object to use
 390    * @arg     {string} filePath - relative location of the file
 391    */
 392   serveFile: function (response, filePath, rootPath) {
 393     //TODO: Make a buffer to hold recently used files, and only read if we
 394     // have to (don't forget to preserve mimetype)
 395     require('fs').readFile(filePath, { encoding: 'utf8' }, (err, data) => {
 396       if (err || data == undefined)
 397         response.writeHead(404)
 398       else {
 399         response.writeHead(200, {
 400           'Content-Type': require('mime').lookup(filePath)
 401         })
 402         response.write(data)
 403       }
 404       response.end()
 405     })
 406   },
 407
 408   /** @func
 409    * @summary Synchronize Reading Multiple Files
 410    * @desc    reads an array of files into an object, whose keys are the
 411    *          input filenames, and values are the data read
 412    * @arg     {string[]} files - array of file names to read
 413    * @arg     {Object} [readOpts] - options to pass to fs.readFile()
 414    */
 415   syncReads: (files, readOpts) => new Promise((resolve,reject) => {
 416     dlog(`syncing reads from ${files}`)
 417     let count = 0
 418     let results = {}
 419     const read_cb = (fileName) => (err, data) => {
 420       if (err)
 421         reject(err)
 422       else
 423         results[fileName] = data
 424       if (++count === files.length)
 425         resolve(results)
 426     }
 427     if (readOpts == undefined)
 428       readOpts = { encoding: 'utf8' }
 429     files.forEach((file) =>
 430                   require('fs').readFile(file, readOpts, read_cb(file)))
 431   })
 432 }
 433
 434 module.exports = exports