Connect

Logger

Log requests with the given options or a format string.

Options

  • format Format string, see below for tokens
  • stream Output stream, defaults to stdout
  • buffer Buffer duration, defaults to 1000ms when true
  • immediate Write log line on request instead of response (for response times)

Tokens

  • :req[header] ex: :req[Accept]
  • :res[header] ex: :res[Content-Length]
  • :http-version
  • :response-time
  • :remote-addr
  • :date
  • :method
  • :url
  • :referrer
  • :user-agent
  • :status

Formats

Pre-defined formats that ship with connect:

  • default ':remote-addr - - [:date] ":method :url HTTP/:http-version" :status :res[content-length] ":referrer" ":user-agent"'
  • short ':remote-addr - :method :url HTTP/:http-version :status :res[content-length] - :response-time ms'
  • tiny ':method :url :status :res[content-length] - :response-time ms'
  • dev concise output colored by response status for development use

Examples

 connect.logger() // default
 connect.logger('short')
 connect.logger('tiny')
 connect.logger({ immediate: true, format: 'dev' })
 connect.logger(':method :url - :referrer')
 connect.logger(':req[content-type] -> :res[content-type]')
 connect.logger(function(req, res){ return 'some format string' })

Defining Tokens

To define a token, simply invoke connect.logger.token() with the
name and a callback function. The value returned is then available
as ":type" in this case.

 connect.logger.token('type', function(req, res){ return req.headers['content-type']; })

Defining Formats

All default formats are defined this way, however it's public API as well:

  connect.logger.format('name', 'string or function')

Source

exports = module.exports = function logger(options) {
  if ('object' == typeof options) {
    options = options || {};
  } else if (options) {
    options = { format: options };
  } else {
    options = {};
  }

  // output on request instead of response
  var immediate = options.immediate;

  // format name
  var fmt = exports[options.format] || options.format || exports.default;

  // compile format
  if ('function' != typeof fmt) fmt = compile(fmt);

  // options
  var stream = options.stream || process.stdout
    , buffer = options.buffer;

  // buffering support
  if (buffer) {
    var realStream = stream
      , interval = 'number' == typeof buffer
        ? buffer
        : defaultBufferDuration;

    // flush interval
    setInterval(function(){
      if (buf.length) {
        realStream.write(buf.join(''));
        buf.length = 0;
      }
    }, interval); 

    // swap the stream
    stream = {
      write: function(str){
        buf.push(str);
      }
    };
  }

  return function logger(req, res, next) {
    req._startTime = new Date;

    // immediate
    if (immediate) {
      var line = fmt(exports, req, res);
      if (null == line) return;
      stream.write(line + '\n');
    // proxy end to output logging
    } else {
      var end = res.end;
      res.end = function(chunk, encoding){
        res.end = end;
        res.end(chunk, encoding);
        var line = fmt(exports, req, res);
        if (null == line) return;
        stream.write(line + '\n');
      };
    }


    next();
  };
};

compile()

Compile fmt into a function.

Source

function compile(fmt) {
  fmt = fmt.replace(/"/g, '\\"');
  var js = '  return "' + fmt.replace(/:([-\w]{2,})(?:\[([^\]]+)\])?/g, function(_, name, arg){
    return '"\n    + (tokens["' + name + '"](req, res, "' + arg + '") || "-") + "';
  }) + '";'
  return new Function('tokens, req, res', js);
};

exports.token()

Define a token function with the given name,
and callback fn(req, res).

Source

exports.token = function(name, fn) {
  exports[name] = fn;
  return this;
};

exports.format()

Define a fmt with the given name.

Source

exports.format = function(name, str){
  exports[name] = str;
  return this;
};

Default format.

Source

exports.format('default', ':remote-addr - - [:date] ":method :url HTTP/:http-version" :status :res[content-length] ":referrer" ":user-agent"');

Short format.

Source

exports.format('short', ':remote-addr - :method :url HTTP/:http-version :status :res[content-length] - :response-time ms');

Tiny format.

Source

exports.format('tiny', ':method :url :status :res[content-length] - :response-time ms');

dev (colored)

Source

exports.format('dev', function(tokens, req, res){
  var status = res.statusCode
    , len = parseInt(res.getHeader('Content-Length'), 10)
    , color = 32;

  if (status >= 500) color = 31
  else if (status >= 400) color = 33
  else if (status >= 300) color = 36;

  len = isNaN(len)
    ? ''
    : len = ' - ' + bytes(len);

  return '\033[90m' + req.method
    + ' ' + req.originalUrl + ' '
    + '\033[' + color + 'm' + res.statusCode
    + ' \033[90m'
    + (new Date - req._startTime)
    + 'ms' + len
    + '\033[0m';
});

request url

Source

exports.token('url', function(req){
  return req.originalUrl || req.url;
});

request method

Source

exports.token('method', function(req){
  return req.method;
});

response time in milliseconds

Source

exports.token('response-time', function(req){
  return new Date - req._startTime;
});

UTC date

Source

exports.token('date', function(){
  return new Date().toUTCString();
});

response status code

Source

exports.token('status', function(req, res){
  return res.statusCode;
});

normalized referrer

Source

exports.token('referrer', function(req){
  return req.headers['referer'] || req.headers['referrer'];
});

remote address

Source

exports.token('remote-addr', function(req){
  return req.socket && (req.socket.remoteAddress || (req.socket.socket && req.socket.socket.remoteAddress));
});

HTTP version

Source

exports.token('http-version', function(req){
  return req.httpVersionMajor + '.' + req.httpVersionMinor;
});

UA string

Source

exports.token('user-agent', function(req){
  return req.headers['user-agent'];
});

request header

Source

exports.token('req', function(req, res, field){
  return req.headers[field.toLowerCase()];
});

response header

Source

exports.token('res', function(req, res, field){
  return (res._headers || {})[field.toLowerCase()];
});