ASP.NET Core 2.1 中使用jwt从原理到精通
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来源:roberg
cnblogs.com/lechengbo/p/9860711.html
原理
jwt对所有语言都是通用的,只要知道秘钥,另一一种语言有可以对jwt的有效性进行判断;
jwt的组成;Header部分Base64转化.Payload部分Base64转化.使用HS256方式根据秘钥对前面两部分进行加密后再Base64转化,其中使用的hs256加密是header部分指定的,也可以通过官网的查看,如下图:
原理就这么简单,那究竟用怎样使用C#来实现呢,又怎么确定它的正确性呢?,请继续
使用C#实现
我们定义一个今天方法,其中需要使用到Microsoft.IdentityModel.Tokens.dll,asp.net core 2.1再带,如果其他版本,没有自带,需要nuget 一下这个类库
/// <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;
}
public static long ToUnixEpochDate(DateTime date) =>
(long)Math.Round((date.ToUniversalTime() - new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.Zero)).TotalSeconds);
该方法很简单,只需要传入header键值对和payLoad键值对,然后根据原理进行Base64转换和hs256加密,接下来我们来使用一个测试类对其进行测试,代码如下:
[TestMethod]
public void TokenValidateTest()
{
Dictionary<string, object> payLoad = new Dictionary<string, object>();
payLoad.Add("sub", "rober");
payLoad.Add("jti", "09e572c7-62d0-4198-9cce-0915d7493806");
payLoad.Add("nbf", null);
payLoad.Add("exp", null);
payLoad.Add("iss", "roberIssuer");
payLoad.Add("aud", "roberAudience");
payLoad.Add("age", 30);
var encodeJwt = TokenContext.CreateToken(payLoad, 30);
var result = TokenContext.Validate(encodeJwt, (load) => { return true; });
Assert.IsTrue(result);
}
先不管后面的验证,我们先看看其中生成的encodeJwt的值:eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJyb2JlciIsImp0aSI6IjY0OWMyYjUxLTE4ZGQtNDEzYy05Yzc5LTI4NWNhMDAxODU2NSIsIm5iZiI6MTU0MDYxMDY2NSwiZXhwIjoxNTQwNjEyNDY1LCJpc3MiOiJyb2Jlcklzc3VlciIsImF1ZCI6InJvYmVyQXVkaWVuY2UiLCJhZ2UiOjMwfQ.7Is2KYHAtSr5fW2gPU1jGeHPzz2ULCZJGcWb40LSYyw
第一部分和第二部分,并不是加密,只是Base64转换,我们可以通过其他语言轻松转换回来,如下使用javascript进行转,window.atob(base64加密) window.btoa(base64解密)
var header=JSON.parse(window.atob('eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9'))
如下图:
我再对payLoa进行转换回来, var payLoad=JSON.parse(window.atob('eyJzdWIiOiJyb2JlciIsImp0aSI6IjY0OWMyYjUxLTE4ZGQtNDEzYy05Yzc5LTI4NWNhMDAxODU2NSIsIm5iZiI6MTU0MDYxMDY2NSwiZXhwIjoxNTQwNjEyNDY1LCJpc3MiOiJyb2Jlcklzc3VlciIsImF1ZCI6InJvYmVyQXVkaWVuY2UiLCJhZ2UiOjMwfQ')) ,如下图:
所以,从这里可以看出来,Base64并不是属于加密,只是简单转换,因此,不能在payLoad中存放重要内容,比如密码等。
使用aspnetcore 中自带的类生成jwt
aspnet core中自带了一个jwt帮助类,其实原理一样,对上面做了封装,丰富了一个内容,我们继续使用一个静态方法,如下
/// <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;
}
它效果和上面一模一样,如果使用同样的header 、payload、秘钥,生成的jwt肯定一样,这里就不演示了,感兴趣的可以自行尝试;
aspnetcore中如何使用自定义jwt验证
上面讲了那么多,只是为了大家更好的理解如何使用jwt进行验证,那是jwt是如何进行验证的呢?,如果一个http请求过来,一般jwt携带在http请求头部的Authorization中;先不看如何获取,先看看他是如何验证的,我们再定义个静态方法,如下:
/// <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;
}
其中 validatePayLoad 参数是一个自定义的验证的Fun,执行该Fun方法时会把解密后的payload作为参数传入进去
我们验证通过分为两部分,
我们来通过一个测试类验证
[TestMethod]
public void TokenCustomerValidateTest()
{
Dictionary<string, object> payLoad = new Dictionary<string, object>();
payLoad.Add("sub", "rober");
payLoad.Add("jti", Guid.NewGuid().ToString());
payLoad.Add("nbf", null);
payLoad.Add("exp", null);
payLoad.Add("iss", "roberIssuer");
payLoad.Add("aud", "roberAudience");
payLoad.Add("age", 30);
var encodeJwt = TokenContext.CreateToken(payLoad, 30);
var result = TokenContext.Validate(encodeJwt, (load) => {
var success = true;
//验证是否包含aud 并等于 roberAudience
success = success&& load["aud"]?.ToString() == "roberAudience";
//验证age>20等
int.TryParse(load["age"].ToString(), out int age);
Assert.IsTrue(age > 30);
//其他验证 jwt的标识 jti是否加入黑名单等
return success;
});
Assert.IsTrue(result);
}
如上面,我们可以把jwt中的payload解析出来,然后进行各种复杂的想要的验证;
其实,aspnet core中的基于角色,用户、策略,自定义策略的验证就相当这里的自定义验证,一下章将详细说明和对比,这里暂时不讲解
看完上面,是不是觉得jwt很简单就,主要就两部
1、创建jwt;
2、验证jwt;
完整代码如下:
/// <summary>
/// Token上下文,负责token的创建和验证
/// </summary>
public class TokenContext
{
/// <summary>
/// 秘钥,可以从配置文件中获取
/// </summary>
public static string securityKey = "GQDstclechengroberbojPOXOYg5MbeJ1XT0uFiwDVvVBrk";
/// <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);
}
以上就是jwt的基本内容,它确实很简单,不要被aspnet core中的各种写法给搞晕了,只要是jwt相关的验证都是基于上面这些东西
下一章节将讲述:
1、在aspnet core中,自定义jwt管道验证;
2、在aspnet core中,自定义策略验证CommonAuthorizeHandler : AuthorizationHandler<CommonAuthorize>
3、自定义jwt逻辑验证和原生的角色,用户,策略,等进行对比
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