Cookie Signature#

And lastly, with an introduction of Cookie Schema, and t.Cookie type. We are able to create a unified type for handling sign/verify cookie signature automatically.

Cookie signature is a cryptographic hash appended to a cookie's value, generated using a secret key and the content of the cookie to enhance security by adding a signature to the cookie.

This make sure that the cookie value is not modified by malicious actor, helps in verifying the authenticity and integrity of the cookie data.

Using Cookie Signature#

By provide a cookie secret, and sign property to indicate which cookie should have a signature verification.

new Teasim().get(
  "/",
  ({ cookie: { profile } }) => {
    profile.value = {
      id: 617,
      name: "Summoning 101",
    };
  },
  {
    cookie: t.Cookie(
      {
        profile: t.Object({
          id: t.Numeric(),
          name: t.String(),
        }),
      },
      {
        secret: "Fischl von Luftschloss Narfidort",
        sign: ["profile"],
      }
    ),
  }
);

Teasim then sign and unsign cookie value automatically.

Constructor#

You can use Teasim constructor to set global cookie secret, and sign value to apply to all route globally instead of inlining to every route you need.

new Teasim({
  cookie: {
    secret: "Fischl von Luftschloss Narfidort",
    sign: ["profile"],
  },
}).get(
  "/",
  ({ cookie: { profile } }) => {
    profile.value = {
      id: 617,
      name: "Summoning 101",
    };
  },
  {
    cookie: t.Cookie({
      profile: t.Object({
        id: t.Numeric(),
        name: t.String(),
      }),
    }),
  }
);

Cookie Rotation#

Teasim handle Cookie's secret rotation automatically.

Cookie Rotation is a migration technique to sign a cookie with a newer secret, while also be able to verify the old signature of the cookie.

new Teasim({
  cookie: {
    secret: ["Vengeance will be mine", "Fischl von Luftschloss Narfidort"],
  },
});

Config#

Below is a cookie config accepted by Teasim.

secret#

The secret key for signing/un-signing cookies.

If an array is passed, will use Key Rotation.

Key rotation is when an encryption key is retired and replaced by generating a new cryptographic key.

Below is a config that extends from cookie

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.

encode#

@default encodeURIComponent

Specifies a function that will be used to encode 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 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.

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.

httpOnly#

@default false

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.

maxAge#

@default undefined

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.

path#

Specifies the value for the Path Set-Cookie attribute.

By default, the path handler is considered the default path.

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 boolean or string to be the value for the SameSite Set-Cookie attribute. true will set the SameSite attribute to Strict for strict same-site enforcement. false will not set the SameSite attribute. '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.

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.