usage.md

Usage  _{^{Quick overview of how to use redbean-jwt}}

Assuming the jwt.lua is added to the .lua directory in the redbean.

Add the module to the Lua script:

local jwt = require("jwt")

The minimal table required to create a JWT is the following:

local jwtTable = {
    ["header"] = {
        ["alg"] = "HS256"
    },
    ["payload"] = {}
} 

Normally the payload is filled an "iat" (Issued At) claim.
And if some data is to be transferred, the payload segment is the place to store it.

So we can make a JWT table with the data

local jwtTable = {
    ["header"] = {
        ["alg"] = "HS256"
    }, 
    payload = {
        ["iat"] = 1643673600, 
        ["data"] = "Valid JWT with data"
    }
}

The function: jwt.DefaultTable() is an easy way to get a basic JWT table

Using the jwtTable with JWT.Encode a JWT string is created

local serverSecret = "SuperSecretKey"
local token = jwt.Encode(jwtTable, serverSecret) 

print(token)

Console output:

eyJhbGciOiJIUzI1NiJ9.eyJkYXRhIjoiVmFsaWQgSldUIHdpdGggZGF0YSIsImlhdCI6MTY0MzY3MzYwMH0.x1S6pFtQEpBYaAt-eKrRXKQQAQR-HGE1uPRrhIPtP20

It can be verified that this token contains the data we expect by pasting it into jwt.io

The created token can also be decoded by jwt.Decode.
However this does not verify the data by recreating the signature.

To also verify the signature jwt.DecodeAndVerify should be used.

-- token and serverSecret defined in example above
local decodedTable = jwt.DecodeAndVerify(token, serverSecret)

print(decodedTable.payload.data)

Console output:

Valid JWT with data

More about JWT

jwt.io/introduction