pgjwt: JSON Web Tokens

The pgjwt (Postgres JSON Web Token) extension allows you to create and parse JSON Web Tokens (JWTs) within a Postgres database. JWTs are commonly used for authentication and authorization in web applications and services.

Enable the extension#

API#

• sign(payload json, secret text, algorithm text default 'HSA256'): Signs a JWT containing payload with secret using algorithm.
• verify(token text, secret text, algorithm text default 'HSA256'): Decodes a JWT token that was signed with secret using algorithm.

Where:

• payload is an encrypted JWT represented as a string.
• secret is the private/secret passcode which is used to sign the JWT and verify its integrity.
• algorithm is the method used to sign the JWT using the secret.
• token is an encrypted JWT represented as a string.

Usage#

Once the extension is installed, you can use its functions to create and parse JWTs. Here's an example of how you can use the sign function to create a JWT:

1
2
3
4
5
6
select  extensions.sign(    payload   := '{"sub":"1234567890","name":"John Doe","iat":1516239022}',    secret    := 'secret',    algorithm := 'HS256'  );

The pgjwt_encode function returns a string that represents the JWT, which can then be safely transmitted between parties.

1
2
3
4
5
6
7
8
sign--------------------------------- eyJhbGciOiJIUzI1NiIsInR5cCI6IkpX VCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiw ibmFtZSI6IkpvaG4gRG9lIiwiaWF0Ijo xNTE2MjM5MDIyfQ.XbPfbIHMI6arZ3Y9 22BhjWgQzWXcXNrz0ogtVhfEd2o(1 row)

To parse a JWT and extract its claims, you can use the verify function. Here's an example:

1
2
3
4
5
6
select  extensions.verify(    token := 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJuYW1lIjoiRm9vIn0.Q8hKjuadCEhnCPuqIj9bfLhTh_9QSxshTRsA5Aq4IuM',    secret    := 'secret',    algorithm := 'HS256'  );

Which returns the decoded contents and some associated metadata.

1
2
3
4
header            |    payload     | valid-----------------------------+----------------+------- {"alg":"HS256","typ":"JWT"} | {"name":"Foo"} | t(1 row)

Resources#

• Official pgjwt documentation