static-route.js

/**
 * create a static route
 *
 * License: MIT
 */
var fs = require('fs');
var path = require('path');
var url = require('url');
var util = require('util');

var he = require('he');
var mime = require('mime');

module.exports = main;
module.exports.streamfile = streamfile;

// exported function to give a static route function
function main(opts) {
  opts = opts || {};
  if (typeof opts === 'string') {
    opts = { dir: opts };
  }
  opts.tryfiles = [''].concat((opts.tryfiles || []).reverse());

  var logger = opts.logger || function() {};

  return staticroute;

  // static serving function
  function staticroute(req, res) {
    logger('%s %s', req.method, req.url);

    var parsed = url.parse(req.url, true);
    // copy the array
    var tryfiles = opts.tryfiles.slice(0);

    // decode everything, and then fight against dir traversal
    var reqfile;
    try {
      reqfile = path.normalize(decodeURIComponent(parsed.pathname));
    } catch (e) {
      res.statusCode = 400;
      res.end();
      return;
    }

    // slice off opts.slice
    if (opts.slice && reqfile.indexOf(opts.slice) === 0)
      reqfile = reqfile.substr(opts.slice.length);

    // unsupported methods
    if (['HEAD', 'GET'].indexOf(req.method) === -1) {
      res.statusCode = 501;
      res.end();
      return;
    }

    var f = path.join((opts.dir || process.cwd()), reqfile);

    tryfile();
    function tryfile() {
      var file = path.join(f, tryfiles.pop());

      // the user wants some actual data
      fs.stat(file, function(err, stats) {
        if (err) {
          logger(err.message);
          if (tryfiles.length)
            return tryfile();

          res.statusCode = (err.code === 'ENOENT') ? 404 : 500;
          res.end();
          return;
        }

        if (stats.isDirectory()) {
          // directory
          // forbidden
          if (!opts.autoindex) {
            res.statusCode = 403;
            res.end();
            return;
          }

          // json stringify the dir
          statall(file, function(e, files) {
            if (e) {
              logger(e.message);
              res.statusCode = 500;
              res.end();
              return;
            }
            files = files.map(function(_file) {
              return _file.filename + (_file.directory ? '/' : '');
            });
            files.sort(function(a, b) {
              a = a.toLowerCase();
              b = b.toLowerCase();
              var adir = a.indexOf('/') > -1;
              var bdir = b.indexOf('/') > -1;
              if (adir && !bdir)
                return -1;
              else if (bdir && !adir)
                return 1;
              return a < b ? -1 : 1;
            });
            if (hap(parsed.query, 'json')) {
              res.setHeader('Content-Type', 'application/json; charset=utf-8');
              res.write(JSON.stringify(files));
            } else {
              res.setHeader('Content-Type', 'text/html; charset=utf-8');
              writehtml(res, parsed.pathname, files);
            }
            res.end();
          });
        } else {
          streamfile(file, stats, req, res);
        }
      });
    }
  }
}

function streamfile(file, stats, req, res) {
  var rs_opts;

  var etag = util.format('"%d-%d"', stats.size, stats.mtime.getTime());
  res.setHeader('Last-Modified', stats.mtime.toUTCString());
  res.setHeader('Content-Type', mime.lookup(file));
  res.setHeader('ETag', etag);

  // check cache and range
  var range = req.headers.range;
  if (req.headers['if-none-match'] === etag) {
    // etag matched, end the request
    res.statusCode = 304;
    res.end();
  } else if (range) {
    // range transfer
    var parts = range.replace('bytes=', '').split('-');
    var partialstart = parts[0];
    var partialend = parts[1];

    var startrange = parseInt(partialstart, 10);
    var endrange = partialend ? parseInt(partialend, 10) : stats.size - 1;
    if (!startrange)
      startrange = 0;
    if (!endrange)
      endrange = stats.size - 1;
    var chunksize = endrange - startrange + 1;

    if (endrange <= startrange) {
      res.statusCode = 416;
      res.end();
      return;
    }

    res.statusCode = 206;
    res.setHeader('Content-Range', 'bytes ' + startrange + '-' + endrange + '/' + stats.size);
    res.setHeader('Accept-Ranges', 'bytes');
    res.setHeader('Content-Length', chunksize);
    if (req.method === 'HEAD') {
      res.end();
      return;
    }

    rs_opts = {
      start: startrange,
      end: endrange
    };
  } else {
    // no range
    res.setHeader('Content-Length', stats.size);
    if (req.method === 'HEAD') {
      res.end();
      return;
    }
  }

  var rs = fs.createReadStream(file, rs_opts);
  rs.pipe(res);
  rs.on('error', function (err) {
    res.statusCode = err.code === 'ENOENT' ? 404 : 500;
    res.end();
  });
  res.on('close', rs.destroy.bind(rs));
}

// stat all files in a directory (non-recursively) and call back with
// an array of all stat objects
function statall(dir, cb) {
  var files = [];
  fs.readdir(dir, function(err, d) {
    if (err) {
      cb(err);
      return;
    }
    d = ['..'].concat(d);

    var i = 0;
    d.forEach(function(file) {
      fs.stat(path.join(dir, file), function(_err, stats) {
        i++;
        if (!_err) {
          stats.filename = file;
          stats.directory = stats.isDirectory();
          files.push(stats);
        }
        if (i === d.length)
          cb(null, files);
      });
    });
  });
}

// given a `res` object, base dir, and files array, write HTML
// to the receiving end
function writehtml(res, base, files) {
  var title = he.encode(util.format('Index of %s', base));
  res.write('<!doctype html><html><head><title>\n');
  res.write(title);
  res.write('\n</title></head><body>\n');
  res.write(util.format('<h1>%s</h1>', title));
  res.write('<hr />\n');
  res.write('<ul style="list-style: none; font-family: monospace;">\n');
  files.forEach(function(file) {
    var linktext = file;
    var linkhref = path.join(base, file);
    res.write(util.format('<li><a href="%s">%s</a></li>\n',
        he.encode(linkhref), he.encode(linktext)));
  });
  res.write('</ul>\n');
  res.write('<hr />\n');
  res.write('</body></html>\n');
}

function hap(o, p) {
    return ({}).hasOwnProperty.call(o, p);
}