cookie

Basic HTTP cookie parser and serializer for HTTP servers.

Installation

$ npm install cookie

API

const cookie = require("cookie");

cookie.parse(str, options)

Parse an HTTP Cookie header string and returning an object of all cookie name-value pairs. The str argument is the string representing a Cookie header value and options is an optional object containing additional parsing options.

const cookies = cookie.parse("foo=bar; equation=E%3Dmc%5E2");
// { foo: 'bar', equation: 'E=mc^2' }

Options

cookie.parse accepts these properties in the options object.

decode

Specifies a function that will be used to decode a cookie's value. Since the value of a cookie has a limited character set (and must be a simple string), this function can be used to decode a previously-encoded cookie value into a JavaScript string.

The default function is the global decodeURIComponent, which will decode any URL-encoded sequences into their byte representations.

If an error is thrown from this function, the original, non-decoded cookie value will be returned as the cookie's value.

cookie.serialize(name, value, options)

Serialize a cookie name-value pair into a Set-Cookie header string. The name argument is the name for the cookie, the value argument is the value to set the cookie to, and the options argument is an optional object containing additional serialization options.

const setCookie = cookie.serialize("foo", "bar");
// foo=bar

Options

cookie.serialize accepts these properties in the options object.

encode

Specifies a function that will be used to encode a cookie's value. Since value of a cookie has a limited character set (and must be a simple string), this function can be used to encode a value into a string suited for a cookie's value.

The default function is the global encodeURIComponent, which will encode a JavaScript string into UTF-8 byte sequences and then URL-encode any that fall outside of the cookie range.

maxAge

Specifies the number (in seconds) to be the value for the Max-Age Set-Cookie attribute. The given number will be converted to an integer by rounding down. By default, no maximum age is set.

The cookie storage model specification states that if both expires and maxAge are set, then maxAge takes precedence, but it is possible not all clients by obey this, so if both are set, they should point to the same date and time.

expires

Specifies the Date object to be the value for the Expires Set-Cookie attribute. By default, no expiration is set, and most clients will consider this a "non-persistent cookie" and will delete it on a condition like exiting a web browser application.

The cookie storage model specification states that if both expires and maxAge are set, then maxAge takes precedence, but it is possible not all clients by obey this, so if both are set, they should point to the same date and time.

domain

Specifies the value for the Domain Set-Cookie attribute. By default, no domain is set, and most clients will consider the cookie to apply to only the current domain.

path

Specifies the value for the Path Set-Cookie attribute. By default, the path is considered the "default path".

httpOnly

Specifies the boolean value for the HttpOnly Set-Cookie attribute. When truthy, the HttpOnly attribute is set, otherwise it is not. By default, the HttpOnly attribute is not set.

Be careful when setting this to true, as compliant clients will not allow client-side JavaScript to see the cookie in document.cookie.

secure

Specifies the boolean value for the Secure Set-Cookie attribute. When truthy, the Secure attribute is set, otherwise it is not. By default, the Secure attribute is not set.

Be careful when setting this to true, as compliant clients will not send the cookie back to the server in the future if the browser does not have an HTTPS connection.

partitioned

Specifies the boolean value for the Partitioned Set-Cookie attribute. When truthy, the Partitioned attribute is set, otherwise it is not. By default, the Partitioned attribute is not set.

This is an attribute that has not yet been fully standardized, and may change in the future. This also means many clients may ignore this attribute until they understand it. More information about can be found in the proposal.

priority

Specifies the string to be the value for the Priority Set-Cookie attribute.

• 'low' will set the Priority attribute to Low.
• 'medium' will set the Priority attribute to Medium, the default priority when not set.
• 'high' will set the Priority attribute to High.

More information about the different priority levels can be found in the specification.

sameSite

Specifies the value for the SameSite Set-Cookie attribute.

• true will set the SameSite attribute to Strict for strict same site enforcement.
• 'lax' will set the SameSite attribute to Lax for lax same site enforcement.
• 'none' will set the SameSite attribute to None for an explicit cross-site cookie.
• 'strict' will set the SameSite attribute to Strict for strict same site enforcement.

More information about the different enforcement levels can be found in the specification.

Example

The following example uses this module in conjunction with the Node.js core HTTP server to prompt a user for their name and display it back on future visits.

var cookie = require("cookie");
var escapeHtml = require("escape-html");
var http = require("http");
var url = require("url");

function onRequest(req, res) {
  // Parse the query string
  var query = url.parse(req.url, true, true).query;

  if (query && query.name) {
    // Set a new cookie with the name
    res.setHeader(
      "Set-Cookie",
      cookie.serialize("name", String(query.name), {
        httpOnly: true,
        maxAge: 60 * 60 * 24 * 7, // 1 week
      }),
    );

    // Redirect back after setting cookie
    res.statusCode = 302;
    res.setHeader("Location", req.headers.referer || "/");
    res.end();
    return;
  }

  // Parse the cookies on the request
  var cookies = cookie.parse(req.headers.cookie || "");

  // Get the visitor name set in the cookie
  var name = cookies.name;

  res.setHeader("Content-Type", "text/html; charset=UTF-8");

  if (name) {
    res.write("<p>Welcome back, <b>" + escapeHtml(name) + "</b>!</p>");
  } else {
    res.write("<p>Hello, new visitor!</p>");
  }

  res.write('<form method="GET">');
  res.write(
    '<input placeholder="enter your name" name="name"> <input type="submit" value="Set Name">',
  );
  res.end("</form>");
}

http.createServer(onRequest).listen(3000);

Testing

npm test

Benchmark

npm run bench

     name                   hz     min     max    mean     p75     p99    p995    p999     rme  samples
   · simple       8,566,313.09  0.0000  0.3694  0.0001  0.0001  0.0002  0.0002  0.0003  ±0.64%  4283157   fastest
   · decode       3,834,348.85  0.0001  0.2465  0.0003  0.0003  0.0003  0.0004  0.0006  ±0.38%  1917175
   · unquote      8,315,355.96  0.0000  0.3824  0.0001  0.0001  0.0002  0.0002  0.0003  ±0.72%  4157880
   · duplicates   1,944,765.97  0.0004  0.2959  0.0005  0.0005  0.0006  0.0006  0.0008  ±0.24%   972384
   · 10 cookies     675,345.67  0.0012  0.4328  0.0015  0.0015  0.0019  0.0020  0.0058  ±0.75%   337673
   · 100 cookies     61,040.71  0.0152  0.4092  0.0164  0.0160  0.0196  0.0228  0.2260  ±0.71%    30521   slowest
   ✓ parse top-sites (15) 22945ms
     name                                  hz     min     max    mean     p75     p99    p995    p999     rme   samples
   · parse accounts.google.com   7,164,349.17  0.0000  0.0929  0.0001  0.0002  0.0002  0.0002  0.0003  ±0.09%   3582184
   · parse apple.com             7,817,686.84  0.0000  0.6048  0.0001  0.0001  0.0002  0.0002  0.0003  ±1.05%   3908844
   · parse cloudflare.com        7,189,841.70  0.0000  0.0390  0.0001  0.0002  0.0002  0.0002  0.0003  ±0.06%   3594921
   · parse docs.google.com       7,051,765.61  0.0000  0.0296  0.0001  0.0002  0.0002  0.0002  0.0003  ±0.06%   3525883
   · parse drive.google.com      7,349,104.77  0.0000  0.0368  0.0001  0.0001  0.0002  0.0002  0.0003  ±0.05%   3674553
   · parse en.wikipedia.org      1,929,909.49  0.0004  0.3598  0.0005  0.0005  0.0007  0.0007  0.0012  ±0.16%    964955
   · parse linkedin.com          2,225,658.01  0.0003  0.0595  0.0004  0.0005  0.0005  0.0005  0.0006  ±0.06%   1112830
   · parse maps.google.com       4,423,511.68  0.0001  0.0942  0.0002  0.0003  0.0003  0.0003  0.0005  ±0.08%   2211756
   · parse microsoft.com         3,387,601.88  0.0002  0.0725  0.0003  0.0003  0.0004  0.0004  0.0005  ±0.09%   1693801
   · parse play.google.com       7,375,980.86  0.0000  0.1994  0.0001  0.0001  0.0002  0.0002  0.0003  ±0.12%   3687991
   · parse support.google.com    4,912,267.94  0.0001  2.8958  0.0002  0.0002  0.0003  0.0003  0.0005  ±1.28%   2456134
   · parse www.google.com        3,443,035.87  0.0002  0.2783  0.0003  0.0003  0.0004  0.0004  0.0007  ±0.51%   1721518
   · parse youtu.be              1,910,492.87  0.0004  0.3490  0.0005  0.0005  0.0007  0.0007  0.0011  ±0.46%    955247
   · parse youtube.com           1,895,082.62  0.0004  0.7454  0.0005  0.0005  0.0006  0.0007  0.0013  ±0.64%    947542   slowest
   · parse example.com          21,582,835.27  0.0000  0.1095  0.0000  0.0000  0.0001  0.0001  0.0001  ±0.13%  10791418

References

• RFC 6265: HTTP State Management Mechanism
• Same-site Cookies

License

MIT