From 3c140656ebe6ed34dda9356a01dbff205651e641 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Thu, 14 Feb 2019 23:05:04 +0800
Subject: Develop user token interface.

---
 Timeline/Services/JwtService.cs | 74 ++++++++++++++++++++++++++++++++++++++---
 1 file changed, 70 insertions(+), 4 deletions(-)

(limited to 'Timeline/Services/JwtService.cs')

diff --git a/Timeline/Services/JwtService.cs b/Timeline/Services/JwtService.cs
index 1b465dd9..a01f3f2b 100644
--- a/Timeline/Services/JwtService.cs
+++ b/Timeline/Services/JwtService.cs
@@ -1,17 +1,22 @@
-using Microsoft.Extensions.Options;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
 using Microsoft.IdentityModel.Tokens;
 using System;
-using System.Collections.Generic;
 using System.IdentityModel.Tokens.Jwt;
 using System.Linq;
 using System.Security.Claims;
 using System.Text;
-using System.Threading.Tasks;
 using Timeline.Configs;
 using Timeline.Entities;
 
 namespace Timeline.Services
 {
+    public class TokenValidationResult
+    {
+        public bool IsValid { get; set; }
+        public UserInfo UserInfo { get; set; }
+    }
+
     public interface IJwtService
     {
         /// <summary>
@@ -21,16 +26,34 @@ namespace Timeline.Services
         /// <param name="user">The user to generate token.</param>
         /// <returns>The generated token or null if <paramref name="user"/> is null.</returns>
         string GenerateJwtToken(User user);
+
+        /// <summary>
+        /// Validate a JWT token.
+        /// Return null is <paramref name="token"/> is null.
+        /// If token is invalid, return a <see cref="TokenValidationResult"/> with
+        /// <see cref="TokenValidationResult.IsValid"/> set to false and
+        /// <see cref="TokenValidationResult.UserInfo"/> set to null.
+        /// If token is valid, return a <see cref="TokenValidationResult"/> with
+        /// <see cref="TokenValidationResult.IsValid"/> set to true and
+        /// <see cref="TokenValidationResult.UserInfo"/> filled with the user info
+        /// in the token.
+        /// </summary>
+        /// <param name="token">The token string to validate.</param>
+        /// <returns>Null if <paramref name="token"/> is null. Or the result.</returns>
+        TokenValidationResult ValidateJwtToken(string token);
+
     }
 
     public class JwtService : IJwtService
     {
         private readonly IOptionsMonitor<JwtConfig> _jwtConfig;
         private readonly JwtSecurityTokenHandler _tokenHandler = new JwtSecurityTokenHandler();
+        private readonly ILogger<JwtService> _logger;
 
-        public JwtService(IOptionsMonitor<JwtConfig> jwtConfig)
+        public JwtService(IOptionsMonitor<JwtConfig> jwtConfig, ILogger<JwtService> logger)
         {
             _jwtConfig = jwtConfig;
+            _logger = logger;
         }
 
         public string GenerateJwtToken(User user)
@@ -42,6 +65,7 @@ namespace Timeline.Services
 
             var identity = new ClaimsIdentity();
             identity.AddClaim(new Claim(ClaimTypes.NameIdentifier, user.Id.ToString()));
+            identity.AddClaim(new Claim(identity.NameClaimType, user.Username));
             identity.AddClaims(user.Roles.Select(role => new Claim(identity.RoleClaimType, role)));
 
             var tokenDescriptor = new SecurityTokenDescriptor()
@@ -60,5 +84,47 @@ namespace Timeline.Services
 
             return tokenString;
         }
+
+
+        public TokenValidationResult ValidateJwtToken(string token)
+        {
+            if (token == null)
+                return null;
+
+            var config = _jwtConfig.CurrentValue;
+
+            try
+            {
+                var principal = _tokenHandler.ValidateToken(token, new TokenValidationParameters
+                {
+                    ValidateIssuer = true,
+                    ValidateAudience = true,
+                    ValidateIssuerSigningKey = true,
+                    ValidateLifetime = true,
+                    ValidIssuer = config.Issuer,
+                    ValidAudience = config.Audience,
+                    IssuerSigningKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes(config.SigningKey))
+                }, out SecurityToken validatedToken);
+
+                var identity = principal.Identity as ClaimsIdentity;
+
+                var userInfo = new UserInfo
+                {
+                    Username = identity.FindAll(identity.NameClaimType).Select(claim => claim.Value).Single(),
+                    Roles = identity.FindAll(identity.RoleClaimType).Select(claim => claim.Value).ToArray()
+                };
+
+                return new TokenValidationResult
+                {
+                    IsValid = true,
+                    UserInfo = userInfo
+                };
+            }
+            catch (Exception e)
+            {
+                _logger.LogInformation(e, "Token validation failed! Token is {} .", token);
+                return new TokenValidationResult { IsValid = false };
+            }
+        }
     }
 }
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