JwtToken---Token上下文，负责token的创建和验证

public class JwtToken
{
/// <summary>
/// 秘钥，可以从配置文件中获取
/// </summary>
public static string securityKey = "GQDstclechenxxxxxxxxojPOXOYg5MbeJ1XT0uxxxxxxvVBrk";

/// <summary>
/// 创建jwttoken,源码自定义
/// </summary>
/// <param name="payLoad"></param>
/// <param name="header"></param>
/// <returns></returns>
public static string CreateToken(Dictionary<string, object> payLoad, int expiresMinute, Dictionary<string, object> header = null)
{
if (header == null)
{
header = new Dictionary<string, object>(new List<KeyValuePair<string, object>>() {
new KeyValuePair<string, object>("alg", "HS256"),
new KeyValuePair<string, object>("typ", "JWT")
});
}
//添加jwt可用时间（应该必须要的）
var now = DateTime.UtcNow;
payLoad["nbf"] = ToUnixEpochDate(now);//可用时间起始
payLoad["exp"] = ToUnixEpochDate(now.Add(TimeSpan.FromMinutes(expiresMinute)));//可用时间结束

var encodedHeader = Base64UrlEncoder.Encode(JsonConvert.SerializeObject(header));
var encodedPayload = Base64UrlEncoder.Encode(JsonConvert.SerializeObject(payLoad));

var hs256 = new HMACSHA256(Encoding.ASCII.GetBytes(securityKey));
var encodedSignature = Base64UrlEncoder.Encode(hs256.ComputeHash(Encoding.UTF8.GetBytes(string.Concat(encodedHeader, ".", encodedPayload))));

var encodedJwt = string.Concat(encodedHeader, ".", encodedPayload, ".", encodedSignature);
return encodedJwt;
}

/// <summary>
/// 创建jwtToken,采用微软内部方法，默认使用HS256加密，如果需要其他加密方式，请更改源码
/// 返回的结果和CreateToken一样
/// </summary>
/// <param name="payLoad"></param>
/// <param name="expiresMinute">有效分钟</param>
/// <returns></returns>
public static string CreateTokenByHandler(Dictionary<string, object> payLoad, int expiresMinute)
{

var now = DateTime.UtcNow;

// Specifically add the jti (random nonce), iat (issued timestamp), and sub (subject/user) claims.
// You can add other claims here, if you want:
var claims = new List<Claim>();
foreach (var key in payLoad.Keys)
{
var tempClaim = new Claim(key, payLoad[key]?.ToString());
claims.Add(tempClaim);
}

// Create the JWT and write it to a string
var jwt = new JwtSecurityToken(
issuer: null,
audience: null,
claims: claims,
notBefore: now,
expires: now.Add(TimeSpan.FromMinutes(expiresMinute)),
signingCredentials: new SigningCredentials(new SymmetricSecurityKey(Encoding.ASCII.GetBytes(securityKey)), SecurityAlgorithms.HmacSha256));
var encodedJwt = new JwtSecurityTokenHandler().WriteToken(jwt);
return encodedJwt;
}

/// <summary>
/// 验证身份 验证签名的有效性,
/// </summary>
/// <param name="encodeJwt"></param>
/// <param name="validatePayLoad">自定义各类验证； 是否包含那种申明，或者申明的值， </param>
/// 例如：payLoad["aud"]?.ToString() == "roberAuddience";
/// 例如：验证是否过期 等
/// <returns></returns>
public static bool Validate(string encodeJwt, Func<Dictionary<string, object>, bool> validatePayLoad)
{
var success = true;
var jwtArr = encodeJwt.Split('.');
var header = JsonConvert.DeserializeObject<Dictionary<string, object>>(Base64UrlEncoder.Decode(jwtArr[0]));
var payLoad = JsonConvert.DeserializeObject<Dictionary<string, object>>(Base64UrlEncoder.Decode(jwtArr[1]));

var hs256 = new HMACSHA256(Encoding.ASCII.GetBytes(securityKey));
//首先验证签名是否正确（必须的）
success = success && string.Equals(jwtArr[2], Base64UrlEncoder.Encode(hs256.ComputeHash(Encoding.UTF8.GetBytes(string.Concat(jwtArr[0], ".", jwtArr[1])))));
if (!success)
{
return success;//签名不正确直接返回
}
//其次验证是否在有效期内（也应该必须）
var now = ToUnixEpochDate(DateTime.UtcNow);
success = success && (now >= long.Parse(payLoad["nbf"].ToString()) && now < long.Parse(payLoad["exp"].ToString()));

//再其次 进行自定义的验证
success = success && validatePayLoad(payLoad);

return success;
}
/// <summary>
/// 获取jwt中的payLoad
/// </summary>
/// <param name="encodeJwt"></param>
/// <returns></returns>
public static Dictionary<string, object> GetPayLoad(string encodeJwt)
{
var jwtArr = encodeJwt.Split('.');
var payLoad = JsonConvert.DeserializeObject<Dictionary<string, object>>(Base64UrlEncoder.Decode(jwtArr[1]));
return payLoad;
}
public static long ToUnixEpochDate(DateTime date) =>
(long)Math.Round((date.ToUniversalTime() - new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.Zero)).TotalSeconds);
}