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Creating JWT Tokens

The JWT Wrapper makes it easy to create JWT tokens with proper claim structures. This document explains how to create tokens using the library.

Basic Token Creation​

Creating a JWT token is a two-step process:

  1. Create JWT Data: Generate the payload data with standard JWT claims
  2. Generate Token: Convert the data into a signed JWT token string

Step 1: Initialize JwtWrapper​

First, initialize the JWT wrapper with your server name and key:

Initialize JwtWrapper
// Using HMAC
$server = "example.com";  // Your server name (issuer)
$secret = new \ByJG\JwtWrapper\JwtHashHmacSecret(base64_encode("your_secret_key"));
$jwtWrapper = new \ByJG\JwtWrapper\JwtWrapper($server, $secret);

// Or using OpenSSL
$server = "example.com";
$jwtKey = new \ByJG\JwtWrapper\JwtOpenSSLKey($privateKeyString, $publicKeyString);
$jwtWrapper = new \ByJG\JwtWrapper\JwtWrapper($server, $jwtKey);

Step 2: Create JWT Data​

Use the createJwtData method to create a payload with standard JWT claims:

Create JWT Data
$jwtData = $jwtWrapper->createJwtData(
    [
        "userId" => 123,
        "role" => "admin"
    ],
    3600,        // Expiration time in seconds (default: 60)
    0,           // Not Before time offset in seconds (default: 0)
    "payload"    // Optional key to wrap your data (default: "data")
);

The resulting $jwtData will be an array containing:

JWT Data Structure
[
    "iat" => 1234567890,              // Issued At timestamp
    "jti" => "base64_random_token_id", // JWT ID
    "iss" => "example.com",           // Issuer (your server name)
    "nbf" => 1234567890,              // Not Before timestamp
    "exp" => 1234571490,              // Expiration timestamp
    "payload" => [                    // Your custom data
        "userId" => 123,
        "role" => "admin"
    ]
]

If you set the $payloadKey parameter to null, your data will not be wrapped:

JWT Data Without Wrapping
$jwtData = $jwtWrapper->createJwtData(
    [
        "userId" => 123,
        "role" => "admin"
    ],
    3600,
    0,
    null  // No wrapping key
);

This will result in:

Unwrapped JWT Data Structure
[
    "iat" => 1234567890,
    "jti" => "base64_random_token_id",
    "iss" => "example.com",
    "nbf" => 1234567890,
    "exp" => 1234571490,
    "userId" => 123,
    "role" => "admin"
]

Step 3: Generate Token​

Convert the JWT data into a signed token string:

Generate Token
$token = $jwtWrapper->generateToken($jwtData);

The $token is now a string that can be sent to clients, stored in cookies, etc.

Complete Example​

Complete Token Creation Example
<?php
// Initialize the wrapper
$server = "example.com";
$secret = new \ByJG\JwtWrapper\JwtHashHmacSecret(base64_encode("your_secret_key"));
$jwtWrapper = new \ByJG\JwtWrapper\JwtWrapper($server, $secret);

// Create JWT data
$jwtData = $jwtWrapper->createJwtData(
    [
        "userId" => 123,
        "email" => "[email protected]"
    ],
    3600,   // Expire in 1 hour
    30      // Not valid before 30 seconds from now
);

// Generate token
$token = $jwtWrapper->generateToken($jwtData);

// The token can now be sent to the client
echo $token;

See Also​