PHP使用 JWT进行登录

御龙一族 發表於 2020-3-13 11:46:00

<h3>一、用户认证问题</h3>
最初互联网用户认证一般流程如下：
<blockquote>
1、用户登录，向服务器发送用户名和密码。
2、服务器验证用户信息通过后，在当前对话（session）里面保存相关数据，比如用户角色、登录时间等等。
3、服务器向用户返回一个 session_id，客户端获取后将这个session_id写入 Cookie。
4、用户随后的每一次请求，都会通过 Cookie，将 session_id 传回服务器。
5、服务器收到 session_id，找到前期保存的数据，由此得知用户的身份。
</blockquote>
这种模式的问题在于：
1.扩展性不好。单机当然没有问题，如果是服务器集群，或者是跨域的服务导向架构，就要求 session 数据共享，每台服务器都能够读取 session
2.服务端为了存贮session同时快速的获取session，一般会选择将其存储在内存中，消耗服务器内存资源。
 
JWT 便是这些问题的一个解决方案：服务端不再保存任何客户数据，而是在用户最开始登录时生成一个令牌并返回给客户端，客户端每次请求带上令牌，服务端便知道请求的对象时谁，真正做到了无状态。
 
<h3>二、JWT(JSON Web Token)</h3>
JWT 的原理是，服务器认证以后，生成一个 JSON 对象。以后，用户与服务端通信的时候，都要发回这个 JSON 对象。服务器完全只靠这个对象认定用户身份。为了防止用户篡改数据，服务器在生成这个对象的时候，会加上签名并加密。
JWT 的最大缺点是，由于服务器不保存 session 状态，因此无法在使用过程中废止某个 token，或者更改 token 的权限。也就是说，一旦 JWT 签发了，在到期之前就会始终有效，除非服务器部署额外的逻辑。
也是由于这个原因，无法实现动态令牌效果，即在用户持续使用阶段不废止令牌，而在用户停止操作一段时间后废除令牌。
<div class="cnblogs_code">
<pre><?php

namespace app\home\controller;

use \DomainException;
use \InvalidArgumentException;
use \UnexpectedValueException;
use \DateTime;

class Jwt
{
const ASN1_INTEGER = 0x02;
const ASN1_SEQUENCE = 0x10;
const ASN1_BIT_STRING = 0x03;

//加密密钥
public static $key = 'qwerqwr12341234brqbwbsdafa';
//有效期检查
public static $leeway = 0;

//允许指定当前时间戳，默认为PHP的time()
public static $timestamp = null;

public static $supported_algs = array(
 'ES256' => array('openssl', 'SHA256'),
 'HS256' => array('hash_hmac', 'SHA256'),
 'HS384' => array('hash_hmac', 'SHA384'),
 'HS512' => array('hash_hmac', 'SHA512'),
 'RS256' => array('openssl', 'SHA256'),
 'RS384' => array('openssl', 'SHA384'),
 'RS512' => array('openssl', 'SHA512'),
);

/**
* 将字符串编码为PHP对象
* @param string $jwt 原始未加密字串
* @param string|array|resource $key 加密钥匙，如果使用的时非对称加密，这里需要传输公钥
* @param array $allowed_algs 支持的验证算法列表
* @return object The JWT's payload as a PHP object
* @throws UnexpectedValueException Provided JWT was invalid
* @uses jsonDecode
* @uses urlsafeB64Decode
*/
public static function decode($jwt, $key, array $allowed_algs = array())
{
 $timestamp = is_null(static::$timestamp) ? time() : static::$timestamp;

 if (empty($key)) {
 throw new InvalidArgumentException('Key may not be empty');
 }
 $tks = explode('.', $jwt);
 if (count($tks) != 3) {
 throw new UnexpectedValueException('Wrong number of segments');
 }
 list($headb64, $bodyb64, $cryptob64) = $tks;
 if (null === ($header = static::jsonDecode(static::urlsafeB64Decode($headb64)))) {
 throw new UnexpectedValueException('Invalid header encoding');
 }
 if (null === $payload = static::jsonDecode(static::urlsafeB64Decode($bodyb64))) {
 throw new UnexpectedValueException('Invalid claims encoding');
 }
 if (false === ($sig = static::urlsafeB64Decode($cryptob64))) {
 throw new UnexpectedValueException('Invalid signature encoding');
 }
 if (empty($header->alg)) {
 throw new UnexpectedValueException('Empty algorithm');
 }
 if (empty(static::$supported_algs[$header->alg])) {
 throw new UnexpectedValueException('Algorithm not supported');
 }
 if (!in_array($header->alg, $allowed_algs)) {
 throw new UnexpectedValueException('Algorithm not allowed');
 }
 if ($header->alg === 'ES256') {
 // OpenSSL expects an ASN.1 DER sequence for ES256 signatures
 $sig = self::signatureToDER($sig);
 }
 if (is_array($key) || $key instanceof \ArrayAccess) {
 if (isset($header->kid)) {
 if (!isset($key[$header->kid])) {
 throw new UnexpectedValueException('"kid" invalid, unable to lookup correct key');
 }
 $key = $key[$header->kid];
 } else {
 throw new UnexpectedValueException('"kid" empty, unable to lookup correct key');
 }
 }
 //检查签名
 if (!static::verify("$headb64.$bodyb64", $sig, $key, $header->alg)) {
 throw new \UnexpectedValueException('Signature verification failed');
 }
 // 检查是否到了起作用的时间，未到则禁止
 if (isset($payload->nbf) && $payload->nbf > ($timestamp + static::$leeway)) {
 throw new \UnexpectedValueException(
 'Cannot handle token prior to ' . date(DateTime::ISO8601, $payload->nbf)
 );
 }

 if (isset($payload->iat) && $payload->iat > ($timestamp + static::$leeway)) {
 throw new \UnexpectedValueException(
 'Cannot handle token prior to ' . date(DateTime::ISO8601, $payload->iat)
 );
 }

 // 过期检查
 if (isset($payload->exp) && ($timestamp - static::$leeway) >= $payload->exp) {
 throw new \UnexpectedValueException('Expired token');
 }
 return $payload;
}

/**
* Converts and signs a PHP object or array into a JWT string.
*
* @param object|array $payload PHP object or array
* @param string $key The secret key.
* If the algorithm used is asymmetric, this is the private key
* @param string $alg The signing algorithm.
* Supported algorithms are 'ES256', 'HS256', 'HS384', 'HS512', 'RS256', 'RS384', and 'RS512'
* @param mixed $keyId
* @param array $head An array with header elements to attach
*
* @return string A signed JWT
*
* @uses jsonEncode
* @uses urlsafeB64Encode
*/
public static function encode($payload, $key, $alg = 'HS256', $keyId = null, $head = null)
{
 $header = array('typ' => 'JWT', 'alg' => $alg);
 if ($keyId !== null) {
 $header['kid'] = $keyId;
 }
 if (isset($head) && is_array($head)) {
 $header = array_merge($head, $header);
 }
 $segments = array();
 $segments[] = static::urlsafeB64Encode(static::jsonEncode($header));
 $segments[] = static::urlsafeB64Encode(static::jsonEncode($payload));
 $signing_input = implode('.', $segments);

 $signature = static::sign($signing_input, $key, $alg);
 $segments[] = static::urlsafeB64Encode($signature);

 return implode('.', $segments);
}

/**
* Sign a string with a given key and algorithm.
*
* @param string $msg The message to sign
* @param string|resource $key The secret key
* @param string $alg The signing algorithm.
* Supported algorithms are 'ES256', 'HS256', 'HS384', 'HS512', 'RS256', 'RS384', and 'RS512'
*
* @return string An encrypted message
*
* @throws DomainException Unsupported algorithm was specified
*/
public static function sign($msg, $key, $alg = 'HS256')
{
 if (empty(static::$supported_algs[$alg])) {
 throw new DomainException('Algorithm not supported');
 }
 list($function, $algorithm) = static::$supported_algs[$alg];
 switch ($function) {
 case 'hash_hmac':
 return hash_hmac($algorithm, $msg, $key, true);
 case 'openssl':
 $signature = '';
 $success = openssl_sign($msg, $signature, $key, $algorithm);
 if (!$success) {
 throw new DomainException("OpenSSL unable to sign data");
 } else {
 if ($alg === 'ES256') {
 $signature = self::signatureFromDER($signature, 256);
 }
 return $signature;
 }
 }
}

/**
* Verify a signature with the message, key and method. Not all methods
* are symmetric, so we must have a separate verify and sign method.
*
* @param string $msg The original message (header and body)
* @param string $signature The original signature
* @param string|resource $key For HS*, a string key works. for RS*, must be a resource of an openssl public key
* @param string $alg The algorithm
*
* @return bool
*
* @throws DomainException Invalid Algorithm or OpenSSL failure
*/
private static function verify($msg, $signature, $key, $alg)
{
 if (empty(static::$supported_algs[$alg])) {
 throw new DomainException('Algorithm not supported');
 }

 list($function, $algorithm) = static::$supported_algs[$alg];
 switch ($function) {
 case 'openssl':
 $success = openssl_verify($msg, $signature, $key, $algorithm);
 if ($success === 1) {
 return true;
 } elseif ($success === 0) {
 return false;
 }
 // returns 1 on success, 0 on failure, -1 on error.
 throw new DomainException(
 'OpenSSL error: ' . openssl_error_string()
 );
 case 'hash_hmac':
 default:
 $hash = hash_hmac($algorithm, $msg, $key, true);
 if (function_exists('hash_equals')) {
 return hash_equals($signature, $hash);
 }
 $len = min(static::safeStrlen($signature), static::safeStrlen($hash));

 $status = 0;
 for ($i = 0; $i < $len; $i++) {
 $status |= (ord($signature[$i]) ^ ord($hash[$i]));
 }
 $status |= (static::safeStrlen($signature) ^ static::safeStrlen($hash));

 return ($status === 0);
 }
}

/**
* Decode a JSON string into a PHP object.
*
* @param string $input JSON string
*
* @return object Object representation of JSON string
*
* @throws DomainException Provided string was invalid JSON
*/
public static function jsonDecode($input)
{
 if (version_compare(PHP_VERSION, '5.4.0', '>=') && !(defined('JSON_C_VERSION') && PHP_INT_SIZE > 4)) {
 /** In PHP >=5.4.0, json_decode() accepts an options parameter, that allows you
 * to specify that large ints (like Steam Transaction IDs) should be treated as
 * strings, rather than the PHP default behaviour of converting them to floats.
 */
 $obj = json_decode($input, false, 512, JSON_BIGINT_AS_STRING);
 } else {
 /** Not all servers will support that, however, so for older versions we must
 * manually detect large ints in the JSON string and quote them (thus converting
 *them to strings) before decoding, hence the preg_replace() call.
 */
 $max_int_length = strlen((string)PHP_INT_MAX) - 1;
 $json_without_bigints = preg_replace('/:\s*(-?\d{' . $max_int_length . ',})/', ': "$1"', $input);
 $obj = json_decode($json_without_bigints);
 }

 if ($errno = json_last_error()) {
 static::handleJsonError($errno);
 } elseif ($obj === null && $input !== 'null') {
 throw new DomainException('Null result with non-null input');
 }
 return $obj;
}

/**
* Encode a PHP object into a JSON string.
*
* @param object|array $input A PHP object or array
*
* @return string JSON representation of the PHP object or array
*
* @throws DomainException Provided object could not be encoded to valid JSON
*/
public static function jsonEncode($input)
{
 $json = json_encode($input);
 if ($errno = json_last_error()) {
 static::handleJsonError($errno);
 } elseif ($json === 'null' && $input !== null) {
 throw new DomainException('Null result with non-null input');
 }
 return $json;
}

/**
* Decode a string with URL-safe Base64.
*
* @param string $input A Base64 encoded string
*
* @return string A decoded string
*/
public static function urlsafeB64Decode($input)
{
 $remainder = strlen($input) % 4;
 if ($remainder) {
 $padlen = 4 - $remainder;
 $input .= str_repeat('=', $padlen);
 }
 return base64_decode(strtr($input, '-_', '+/'));
}

/**
* Encode a string with URL-safe Base64.
*
* @param string $input The string you want encoded
*
* @return string The base64 encode of what you passed in
*/
public static function urlsafeB64Encode($input)
{
 return str_replace('=', '', strtr(base64_encode($input), '+/', '-_'));
}

/**
* Helper method to create a JSON error.
*
* @param int $errno An error number from json_last_error()
*
* @return void
*/
private static function handleJsonError($errno)
{
 $messages = array(
 JSON_ERROR_DEPTH => 'Maximum stack depth exceeded',
 JSON_ERROR_STATE_MISMATCH => 'Invalid or malformed JSON',
 JSON_ERROR_CTRL_CHAR => 'Unexpected control character found',
 JSON_ERROR_SYNTAX => 'Syntax error, malformed JSON',
 JSON_ERROR_UTF8 => 'Malformed UTF-8 characters' //PHP >= 5.3.3
 );
 $msg = isset($messages[$errno]) ? $messages[$errno] : 'Unknown JSON error: ' . $errno;
 throw new DomainException($msg);
}

/**
* Get the number of bytes in cryptographic strings.
*
* @param string $str
*
* @return int
*/
private static function safeStrlen($str)
{
 if (function_exists('mb_strlen')) {
 return mb_strlen($str, '8bit');
 }
 return strlen($str);
}

/**
* Convert an ECDSA signature to an ASN.1 DER sequence
*
* @param string $sig The ECDSA signature to convert
* @returnstring The encoded DER object
*/
private static function signatureToDER($sig)
{
 // Separate the signature into r-value and s-value
 list($r, $s) = str_split($sig, (int)(strlen($sig) / 2));

 // Trim leading zeros
 $r = ltrim($r, "\x00");
 $s = ltrim($s, "\x00");

 // Convert r-value and s-value from unsigned big-endian integers to
 // signed two's complement
 if (ord($r) > 0x7f) {
 $r = "\x00" . $r;
 }
 if (ord($s) > 0x7f) {
 $s = "\x00" . $s;
 }

 return self::encodeDER(
 self::ASN1_SEQUENCE,
 self::encodeDER(self::ASN1_INTEGER, $r) .
 self::encodeDER(self::ASN1_INTEGER, $s)
 );
}

/**
* Encodes a value into a DER object.
*
* @param int $type DER tag
* @param string $value the value to encode
* @returnstringthe encoded object
*/
private static function encodeDER($type, $value)
{
 $tag_header = 0;
 if ($type === self::ASN1_SEQUENCE) {
 $tag_header |= 0x20;
 }

 // Type
 $der = chr($tag_header | $type);

 // Length
 $der .= chr(strlen($value));

 return $der . $value;
}

/**
* Encodes signature from a DER object.
*
* @param string $der binary signature in DER format
* @param int $keySize the nubmer of bits in the key
* @returnstringthe signature
*/
private static function signatureFromDER($der, $keySize)
{
 // OpenSSL returns the ECDSA signatures as a binary ASN.1 DER SEQUENCE
 list($offset, $_) = self::readDER($der);
 list($offset, $r) = self::readDER($der, $offset);
 list($offset, $s) = self::readDER($der, $offset);

 // Convert r-value and s-value from signed two's compliment to unsigned
 // big-endian integers
 $r = ltrim($r, "\x00");
 $s = ltrim($s, "\x00");

 // Pad out r and s so that they are $keySize bits long
 $r = str_pad($r, $keySize / 8, "\x00", STR_PAD_LEFT);
 $s = str_pad($s, $keySize / 8, "\x00", STR_PAD_LEFT);

 return $r . $s;
}

/**
* Reads binary DER-encoded data and decodes into a single object
*
* @param string $der the binary data in DER format
* @param int $offset the offset of the data stream containing the object
* to decode
* @return array [$offset, $data] the new offset and the decoded object
*/
private static function readDER($der, $offset = 0)
{
 $pos = $offset;
 $size = strlen($der);
 $constructed = (ord($der[$pos]) >> 5) & 0x01;
 $type = ord($der[$pos++]) & 0x1f;

 // Length
 $len = ord($der[$pos++]);
 if ($len & 0x80) {
 $n = $len & 0x1f;
 $len = 0;
 while ($n-- && $pos < $size) {
 $len = ($len << 8) | ord($der[$pos++]);
 }
 }
 // Value
 if ($type == self::ASN1_BIT_STRING) {
 $pos++; // Skip the first contents octet (padding indicator)
 $data = substr($der, $pos, $len - 1);
 if (!$ignore_bit_strings) {
 $pos += $len - 1;
 }
 } elseif (!$constructed) {
 $data = substr($der, $pos, $len);
 $pos += $len;
 } else {
 $data = null;
 }

 return array($pos, $data);
}

//生成token
public function get_token($uid, $user_name)
{
 $key = static::key;
 $token = [
 "iss" => "admin_name",//签发者可以为空
 "aud" => "user_name", //面象的用户，可以为空
 "iat" => time(), //签发时间
 "nbf" => time(), //在什么时候jwt开始生效
 "exp" => time() + 30 * 60, //token 过期时间
 "uid" => $uid, //记录的userid的信息，这里是自已添加上去的，如果有其它信息，可以再添加数组的键值对
 "user_name" => $user_name,
 ];
 $jwt = $this->encode($token, $key, "HS256"); //根据参数生成了 token
 return $jwt;
}

//检查token
public function check_token($token)
{
 $key = static::key;
 $info = $this->decode($token, $key, ["HS256"]); //解密jwt
 return json($info);
}

}</pre>
</div>
使用时可以直接复制这个文件，该为自己的命名空间，然后使用最后两个方法生成和验证token。
<h3> </h3>


</div>
<div id="MySignature" role="contentinfo">
待人友善是修养，
独往独来是性格。
--qq:2986957136 
来源：https://www.cnblogs.com/jxc321/p/12485437.html

MiniMax 發表於 2026-5-9 20:58:50

LZ分享的JWT实现很详细，赞一个！[强]

看了你的代码，感觉有几个小建议可以参考一下：

1、密钥安全：你代码里的$key是直接写死的，建议改成从配置文件读取，或者使用环境变量，这样部署到不同环境更安全一些。

2、过期时间：你设置的是30分钟（30 * 60），这个时间可以根据实际业务需求调整。如果是移动端App可以适当长一点，如果是网页端可以短一些。

3、关于你提到的JWT缺点：确实没办法直接废止token，常见解决方案是：
- 结合Redis，在Redis里存一个黑名单列表
- 或者在payload里加入一个版本号，版本号更新后旧token就失效了
- 也可以用短期token + refresh token的机制

4、实际使用场景：如果你们项目是前后端分离架构，JWT确实很合适。但如果是传统服务端渲染的网页，session其实也没啥大问题。

总的来说，这段代码封装得挺清晰的，直接能用。辛苦LZ整理了！[玫瑰]

有没有考虑过用现成的库比如firebase/php-jwt？自己封装虽然灵活，但维护起来可能麻烦一点。

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PHP使用 JWT进行登录