<?php
namespace utils;


/**
* 
*/
class Jwt
{

    public $KEY = 'hao';
    
    /**
     * [返回 hash 加密后的字符串]
     * @param  [type] $header  [description]
     * @param  [type] $payload [description]
     * @return [type]          [description]
     */
    private function hash_do($str, $type){
        $algo = 'sha256';
        if (strtoupper($type) == 'MD5'){
            $algo = 'md5';
        } else if(strtolower($type) == 'HAVAL'){
            $algo = 'haval160,4';
        }
        return hash($algo, $str);
    }


    /**
     * [create_token description]
     * @param  [type] $header  [description]
     * @param  [type] $payload [description]
     * @return [type]          [description]
     */
    public function create_token($header, $payload){
        if (!empty($header) && is_array($header) && 
                (strtoupper($header['alg'])=='HS256' || strtoupper($header['alg'])=='MD5' || strtoupper($header['alg'])=='HAVAL') &&
                 !empty($payload))
        {
            $h = base64_encode(json_encode($header));
            $p = base64_encode(json_encode($payload));
            $s = $this->hash_do($h . $p . md5($this->KEY), $header['alg']);
            $sign = $h. '.' . $p . '.' . $s;
            return $sign;
        }
        return null;
    }

    public function check_token($jwt){
        if (empty($jwt)){
            return false;
        }
        $tokens = explode('.', $jwt);
        if (count($tokens)!==3){
            return false;
        }
        list($header64, $payload64, $sign) = $tokens;

        $header = json_decode(base64_decode($header64), TRUE);
        if (!isset($header['alg'])){
            return false;
        }

        $s = $this->hash_do($header64 . $payload64 . md5($this->KEY), $header['alg']);
        if ($s !== $sign){
            return false;
        }

        $payload = json_decode(base64_decode($payload64), TRUE);
        $time = time();
        if (isset($payload['iat']) && $payload['iat'] > $time){
            return false;
        }
        if (isset($payload['exp']) && $payload['exp'] < $time){
            return false;
        }
        return true;
    }

}

使用方式：

public function auth_token(){
    $over = config('TOKEN_OVER_TIME'); // 生存时间
    $time = time();
    $time_over = $time + $over;
    $header = [
        'typ' => 'JWT',
        'alg' => 'HS256'
    ];
    $payload = [
        'iss' => 'admin_name',
        'iat' => $time,
        'exp' => $time_over,
        'uid' => 12 
    ];

    $j = new Jwt();
    $sign = $j->create_token($header, $payload);
    return $sign;
}





 public function check(){
 	$jwt = 'jwtxxxxxxxx';
    
 	$j = new Jwt();
    $b = $j->check_token($jwt);
 	dump($b);
 }