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     console.log(`route is ${route}`)
 131     /* If the route exists, check if we are a returning host or a new client */
 132     if (route) {
 133       if (route.bind) {
 134         htArgv[0] = htArgv[0].replace(`${routeName}`,'')
 135         if (htArgv[0][0] === '/')
 136           htArgv[0] = htArgv[0].slice(1)
 137         this.serveBind(response, route.bind, htArgv)
 138       }
 139       //TODO: auth better than this (ip spoofing is easy)
 140       // but this will require a more involved host-creation process
 141       // that isn't just "give you a route if it's available" on visit
 142       /* else if (route.origin == (request.headers['x-forwarded-for'] ||
 143                          request.connection.remoteAddress))
 144         this.serveHost(response, route, htArgv)
 145       else */
 146       else {
 147         this.serveClient(request, response, route)
 148       }
 149     }
 150     /* If it's a valid routename that doesn't exist, make this client a host */
 151     else if (this.validRoutes.test(routeName)) {
 152        this.routes[routeName] = true
 153       require('get-port')()
 154         .then((port) => {
 155           this.createHost(routeName, htArgv, port, request, response)
 156         })
 157         .catch((err) => {
 158           delete this.routes[routeName]
 159           console.log(err)
 160         })
 161     }
 162     /* Try servicing files if we have a root directory for it */
 163     else if (this.httpdRoot) {
 164       let realPath = require('path').join(this.httpdRoot, htArgv[0])
 165       if (realPath == this.httpdRoot)
 166         realPath += '/index.html'
 167       if (realPath.indexOf(`${this.httpdRoot}/`) == 0) {
 168         const stat_cb = (err, stat) => {
 169           if (err) {
 170             response.writeHead(404)
 171             response.end()
 172             console.log(err)
 173           }
 174           else if (stat.isDirectory()) {
 175             realPath += '/index.html'
 176             require('fs').lstat(realPath, stat_cb)
 177           }
 178           else if (stat.isFile())
 179             this.serveFile(response, realPath)
 180           else {
 181             response.writeHead(403)
 182             response.end()
 183           }
 184         }
 185         require('fs').lstat(realPath, stat_cb)
 186       }
 187       else {
 188         response.writeHead(400)
 189         response.end()
 190       }
 191     }
 192     /* Unhandled */
 193     else {
 194       response.writeHead(404)
 195       response.end()
 196     }
 197   },
 198
 199   /** @func
 200    * @summary Serves a binding to a client
 201    * @desc    Resolves a binding and serves a response to the client
 202    * @arg     {http.ServerResponse} response - the response to use
 203    * @arg     {Object} bind - the binding to serve the client
 204    * @arg     {string[]} argv - path and arguments for the bind
 205    */
 206   serveBind: function (response, bind, argv) {
 207     dlog(`Serving binding ${bind.path}/${argv[0]}`)
 208     if (bind.dir) {
 209       if (argv[0] == '')
 210         argv[0] = 'index.html'
 211       this.serveFile(response, require('path').join(bind.path, argv[0]))
 212     }
 213     else
 214       this.serveFile(response, bind.path)
 215   },
 216
 217   /** @func
 218    * @summary Serve a route to an http client
 219    * @desc    routes may be bound to the filesystem, or to an outgoing host
 220    * @arg     {http.ClientRequest} request - request from the client
 221    * @arg     {http.ServerResponse} response - response object to use
 222    * @arg     {Object} route - route associated with client request
 223    */
 224   serveClient: function (request, response, route) {
 225     const type = request.headers['x-strapp-type']
 226     const pubKey = request.headers['x-strapp-pubkey']
 227     dlog(`Client ${type || 'HT'} request routed to ${route.name}`)
 228     switch (type) {
 229     case null:
 230     case undefined:
 231       response.writeHead(200, { 'Content-Type': 'text/html' })
 232       response.write(`${this.skelPage[0]}${this.clientJS}${this.skelPage[1]}`)
 233       response.end()
 234       break
 235     case 'ice-candidate-request':
 236     case 'ice-candidate-submission':
 237     case 'client-sdp-offer':
 238       let data = ''
 239       if (pubKey) {
 240         let data = request.headers['x-strapp-offer']
 241         route.pendingResponses.addResponse(pubKey, response)
 242         route.socket.send(`${pubKey} ${type} ${data}`)
 243       }
 244       else {
 245         response.writeHead(401)
 246         response.end()
 247       }
 248       break
 249     default:
 250       response.writeHead(400)
 251       response.end()
 252     }
 253   },
 254
 255   /** @func
 256    * @summary Create a new route for a host
 257    * @desc    makes a new route for the given route name
 258    * @arg     {string} routeName - name of the new route
 259    * @arg     {string[]} argv - Origin address from the request that made this
 260    *                          route (for security verification on the socket)
 261    * @arg     {number|string} port - the port to listen on for websocket
 262    * @arg     {http.ClientRequest} request - host's request
 263    * @arg     {http.ServerResponse} response - responder
 264    */
 265   createHost: function (routeName, argv, port, request, response) {
 266     const origin = (request.headers['x-forwarded-for'] ||
 267                     request.connection.remoteAddress)
 268     dlog(`New ${this.httpsOpts?'TLS ':''}route ${routeName}:${port}=>${origin}`)
 269     const httpd = this.httpsOpts
 270           ? require('https').createServer(this.httpsOpts)
 271           : require('http').createServer()
 272     const route = {
 273       pendingResponses: new Map([]),
 274       origin: origin,
 275       httpd: httpd,
 276       name: routeName,
 277       port: port,
 278       wsd: undefined,
 279       socket: undefined
 280     }
 281     route.httpd.listen(port)
 282     route.wsd = new (require('ws').Server)({ server: httpd })
 283       .on('connection', (socket) => {
 284         route.socket = socket
 285         socket.on('message', (msg) =>
 286                   this.hostMessage(msg,route))
 287       })
 288     route.pendingResponses.addResponse = function (key, response_p) {
 289       let responses = this.get(key) || []
 290       responses.push(response_p)
 291       this.set(key, responses)
 292     }
 293     this.routes[routeName] = route
 294     this.serveHost(response, route, argv)
 295   },
 296
 297   /** @func
 298    * @summary Serve a route to an authorized http host
 299    * @desc    services host application to the client, establishing a socket
 300    * @arg     {http.ServerResponse} response - response object to use
 301    * @arg     {Object} route - the route that belongs to this host
 302    * @arg     {string[]} argv - vector of arguments sent to the host
 303    */
 304   serveHost: function (response, route, argv) {
 305     dlog(`Serving host ${route.origin}`)
 306     response.writeHead(200, { 'Content-Type': 'text/html' })
 307     response.write(`${this.skelPage[0]}` +
 308                    `\tconst _strapp_port = ${route.port}\n` +
 309                    `\tconst _strapp_protocol = ` +
 310                    `'${this.httpsOpts ? 'wss' : 'ws'}'\n` +
 311                    `${this.hostJS}\n${this.skelPage[1]}`)
 312     response.end()
 313   },
 314
 315   /** @func
 316    * @summary handle host message
 317    * @desc    receives a message from a host, handles the command (first character),
 318    *          and responds to either the host or the client, or both.  Commands
 319    *          are whitespace separated strings.
 320    *            Commands:
 321    *              Forward Payload to Client)
 322    *              < clientKey payload [header]
 323    *                Route 'payload' to the client identified by 'clientKey'.
 324    *                The optional 'header' argument is a stringified JSON object,
 325    *                which will be written to the HTTP response header
 326    *                  In case of multiple requests from a single client, the
 327    *                  oldest request will be serviced on arrival of message
 328    *              Translate SDP and Forward to Client)
 329    *              ^ clientKey sdp [header]
 330    *                Route the JSON object 'sdp' to the client, after translating
 331    *                for interop between browsers using planB or Unified.  Other
 332    *                than the interop step, this is identical to the '<' command
 333    *              Error)
 334    *              ! errorMessage errorCode [offendingMessage]
 335    *                Notify host that an error has occured, providing a message
 336    *                and error code.  'offendingMessage', if present, is the
 337    *                message received from the remote that triggered the error.
 338    * @arg     {string} message - raw string from the host
 339    * @arg     {Object} route - the route over
 340    */
 341   hostMessage: function (message, route) {
 342     const argv = message.split(' ')
 343     const command = argv[0][0]
 344     argv = argv.slice(1)
 345     dlog(`Received host message from ${route.name}: ${command}`)
 346     switch (command) {
 347     case '^':
 348       if (argv.length < 2) {
 349         dlog(`Malformed '${command}' command from ${route.origin}`)
 350         route.socket.send(`! "Insufficient arguments" 0 ${message}`)
 351         break
 352       }
 353       argv[1] = JSON.parse(argv[1])
 354       //TODO: interop step
 355       argv[1] = JSON.stringify(argv[1])
 356       //TODO: argv[1] = encryptForClient(argv[0], argv[1])
 357       /* Fallthrough to '<' behavior after translating argv[1] */
 358     case '<':
 359       const response = route.pendingResponses.get(argv[0]).shift()
 360       if (!response)
 361         route.socket.send(`! "No pending responses for client ${argv[0]}" 0 `
 362                           + message)
 363       else if (argv.length === 2 || argv.length === 3) {
 364         const header = argv.length === 3 ? JSON.parse(argv[2]) : {}
 365         if (!('Content-Type' in header))
 366           header['Content-Type'] = 'application/octet-stream'
 367         response.writeHead(200, header)
 368         response.write(argv[1])
 369         response.end()
 370       }
 371       else
 372         route.socket.send(`! "Insufficient arguments" 0 ${message}`)
 373       break
 374     case '!':
 375       if (argv.length === 3)
 376         argv[0] += `\nIn message: ${argv[2]}`
 377       console.log(`Error[${route.origin}|${argv[1]}]:${argv[0]}`)
 378       break
 379     default:
 380       route.socket.send(`! "Unknown command '${command}'" 0 ${message}`)
 381       dlog(`Host ${route.origin} send unknown command: ${message}`)
 382       break
 383     }
 384   },
 385
 386   /** @func
 387    * @summary Serve a file to an http client after a request
 388    * @desc    reads files from the system to be distributed to clients, and
 389    *          buffers recently accessed files
 390    * @arg     {http.ServerResponse} response - the response object to use
 391    * @arg     {string} filePath - relative location of the file
 392    */
 393   serveFile: function (response, filePath, rootPath) {
 394     //TODO: Make a buffer to hold recently used files, and only read if we
 395     // have to (don't forget to preserve mimetype)
 396     require('fs').readFile(filePath, { encoding: 'utf8' }, (err, data) => {
 397       if (err || data == undefined)
 398         response.writeHead(404)
 399       else {
 400         response.writeHead(200, {
 401           'Content-Type': require('mime').lookup(filePath)
 402         })
 403         response.write(data)
 404       }
 405       response.end()
 406     })
 407   },
 408
 409   /** @func
 410    * @summary Synchronize Reading Multiple Files
 411    * @desc    reads an array of files into an object, whose keys are the
 412    *          input filenames, and values are the data read
 413    * @arg     {string[]} files - array of file names to read
 414    * @arg     {Object} [readOpts] - options to pass to fs.readFile()
 415    */
 416   syncReads: (files, readOpts) => new Promise((resolve,reject) => {
 417     dlog(`syncing reads from ${files}`)
 418     let count = 0
 419     let results = {}
 420     const read_cb = (fileName) => (err, data) => {
 421       if (err)
 422         reject(err)
 423       else
 424         results[fileName] = data
 425       if (++count === files.length)
 426         resolve(results)
 427     }
 428     if (readOpts == undefined)
 429       readOpts = { encoding: 'utf8' }
 430     files.forEach((file) =>
 431                   require('fs').readFile(file, readOpts, read_cb(file)))
 432   })
 433 }
 434
 435 module.exports = exports