ASP.NET Core集成微信登录

工具：

Visual Studio 2015 update 3

Asp.Net Core 1.0

1 准备工作

申请微信公众平台接口测试帐号，申请网址：（http://mp.weixin.qq.com/debug/cgi-bin/sandbox?t=sandbox/login）。申请接口测试号无需公众帐号，可以直接体验和测试公众平台所有高级接口。

1.1 配置接口信息

1.2 修改网页授权信息

点击“修改”后在弹出页面填入你的网站域名：

2  新建网站项目

2.1 选择ASP.NET Core Web Application 模板

2.2 选择Web 应用程序，并更改身份验证为个人用户账户

3 集成微信登录功能

3.1添加引用

打开project.json文件，添加引用Microsoft.AspNetCore.Authentication.OAuth

3.2 添加代码文件

在项目中新建文件夹，命名为WeChatOAuth，并添加代码文件（本文最后附全部代码）。

3.3 注册微信登录中间件

打开Startup.cs文件，在Configure中添加代码：

app.UseWeChatAuthentication(new WeChatOptions()
{
    AppId = "******",
    AppSecret = "******"
});

注意该代码的插入位置必须在app.UseIdentity()下方。

4 代码

 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

 using System;
 using Microsoft.AspNetCore.Authentication.WeChat;
 using Microsoft.Extensions.Options;

 namespace Microsoft.AspNetCore.Builder
 {
     /// <summary>
     /// Extension methods to add WeChat authentication capabilities to an HTTP application pipeline.
     /// </summary>
     public static class WeChatAppBuilderExtensions
     {
         /// <summary>
         /// Adds the <see cref="WeChatMiddleware"/> middleware to the specified <see cref="IApplicationBuilder"/>, which enables WeChat authentication capabilities.
         /// </summary>
         /// <param name="app">The <see cref="IApplicationBuilder"/> to add the middleware to.</param>
         /// <returns>A reference to this instance after the operation has completed.</returns>
         public static IApplicationBuilder UseWeChatAuthentication(this IApplicationBuilder app)
         {
             if (app == null)
             {
                 throw new ArgumentNullException(nameof(app));
             }

             return app.UseMiddleware<WeChatMiddleware>();
         }

         /// <summary>
         /// Adds the <see cref="WeChatMiddleware"/> middleware to the specified <see cref="IApplicationBuilder"/>, which enables WeChat authentication capabilities.
         /// </summary>
         /// <param name="app">The <see cref="IApplicationBuilder"/> to add the middleware to.</param>
         /// <param name="options">A <see cref="WeChatOptions"/> that specifies options for the middleware.</param>
         /// <returns>A reference to this instance after the operation has completed.</returns>
         public static IApplicationBuilder UseWeChatAuthentication(this IApplicationBuilder app, WeChatOptions options)
         {
             if (app == null)
             {
                 throw new ArgumentNullException(nameof(app));
             }
             if (options == null)
             {
                 throw new ArgumentNullException(nameof(options));
             }

             return app.UseMiddleware<WeChatMiddleware>(Options.Create(options));
         }
     }
 }

WeChatAppBuilderExtensions.cs

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

namespace Microsoft.AspNetCore.Authentication.WeChat
{
    public static class WeChatDefaults
    {
        public const string AuthenticationScheme = "WeChat";

        public static readonly string AuthorizationEndpoint = "https://open.weixin.qq.com/connect/oauth2/authorize";

        public static readonly string TokenEndpoint = "https://api.weixin.qq.com/sns/oauth2/access_token";

        public static readonly string UserInformationEndpoint = "https://api.weixin.qq.com/sns/userinfo";
    }
}

WeChatDefaults.cs

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using Microsoft.AspNetCore.Authentication.OAuth;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http.Authentication;
using Microsoft.AspNetCore.Http.Extensions;
using Microsoft.Extensions.Primitives;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Security.Claims;
using System.Text;
using Microsoft.AspNetCore.Mvc;
using System.Threading.Tasks;

namespace Microsoft.AspNetCore.Authentication.WeChat
{
    internal class WeChatHandler : OAuthHandler<WeChatOptions>
    {
        public WeChatHandler(HttpClient httpClient)
            : base(httpClient)
        {
        }

        protected override async Task<AuthenticateResult> HandleRemoteAuthenticateAsync()
        {
            AuthenticationProperties properties = null;
            var query = Request.Query;

            var error = query["error"];
            if (!StringValues.IsNullOrEmpty(error))
            {
                var failureMessage = new StringBuilder();
                failureMessage.Append(error);
                var errorDescription = query["error_description"];
                if (!StringValues.IsNullOrEmpty(errorDescription))
                {
                    failureMessage.Append(";Description=").Append(errorDescription);
                }
                var errorUri = query["error_uri"];
                if (!StringValues.IsNullOrEmpty(errorUri))
                {
                    failureMessage.Append(";Uri=").Append(errorUri);
                }

                return AuthenticateResult.Fail(failureMessage.ToString());
            }

            var code = query["code"];
            var state = query["state"];
            var oauthState = query["oauthstate"];

            properties = Options.StateDataFormat.Unprotect(oauthState);

            if (state != Options.StateAddition || properties == null)
            {
                return AuthenticateResult.Fail("The oauth state was missing or invalid.");
            }

            // OAuth2 10.12 CSRF
            if (!ValidateCorrelationId(properties))
            {
                return AuthenticateResult.Fail("Correlation failed.");
            }

            if (StringValues.IsNullOrEmpty(code))
            {
                return AuthenticateResult.Fail("Code was not found.");
            }

            //获取tokens
            var tokens = await ExchangeCodeAsync(code, BuildRedirectUri(Options.CallbackPath));

            var identity = new ClaimsIdentity(Options.ClaimsIssuer);

            AuthenticationTicket ticket = null;

            if (Options.WeChatScope == Options.InfoScope)
            {
                //获取用户信息
                ticket = await CreateTicketAsync(identity, properties, tokens);
            }
            else
            {
                //不获取信息，只使用openid
                identity.AddClaim(new Claim(ClaimTypes.NameIdentifier, tokens.TokenType, ClaimValueTypes.String, Options.ClaimsIssuer));
                ticket = new AuthenticationTicket(new ClaimsPrincipal(identity), properties, Options.AuthenticationScheme);
            }

            if (ticket != null)
            {
                return AuthenticateResult.Success(ticket);
            }
            else
            {
                return AuthenticateResult.Fail("Failed to retrieve user information from remote server.");
            }
        }

        /// <summary>
        /// OAuth第一步,获取code
        /// </summary>
        /// <param name="properties"></param>
        /// <param name="redirectUri"></param>
        /// <returns></returns>
        protected override string BuildChallengeUrl(AuthenticationProperties properties, string redirectUri)
        {
            //加密OAuth状态
            var oauthstate = Options.StateDataFormat.Protect(properties);

            //
            redirectUri = $"{redirectUri}?{nameof(oauthstate)}={oauthstate}";

            var queryBuilder = new QueryBuilder()
            {
                { "appid", Options.ClientId },
                { "redirect_uri", redirectUri },
                { "response_type", "code" },
                { "scope", Options.WeChatScope },
                { "state",  Options.StateAddition },
            };
            return Options.AuthorizationEndpoint + queryBuilder.ToString();
        }

        /// <summary>
        /// OAuth第二步,获取token
        /// </summary>
        /// <param name="code"></param>
        /// <param name="redirectUri"></param>
        /// <returns></returns>
        protected override  async Task<OAuthTokenResponse> ExchangeCodeAsync(string code, string redirectUri)
        {
            var tokenRequestParameters = new Dictionary<string, string>()
            {
                { "appid", Options.ClientId },
                { "secret", Options.ClientSecret },
                { "code", code },
                { "grant_type", "authorization_code" },
            };

            var requestContent = new FormUrlEncodedContent(tokenRequestParameters);

            var requestMessage = new HttpRequestMessage(HttpMethod.Post, Options.TokenEndpoint);
            requestMessage.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
            requestMessage.Content = requestContent;
            var response = await Backchannel.SendAsync(requestMessage, Context.RequestAborted);
            if (response.IsSuccessStatusCode)
            {
                var payload = JObject.Parse(await response.Content.ReadAsStringAsync());

                string ErrCode = payload.Value<string>("errcode");
                string ErrMsg = payload.Value<string>("errmsg");

                if (!string.IsNullOrEmpty(ErrCode) | !string.IsNullOrEmpty(ErrMsg))
                {
                    return OAuthTokenResponse.Failed(new Exception($"ErrCode:{ErrCode},ErrMsg:{ErrMsg}"));
                }

                var tokens = OAuthTokenResponse.Success(payload);

                //借用TokenType属性保存openid
                tokens.TokenType = payload.Value<string>("openid");

                return tokens;
            }
            else
            {
                var error = "OAuth token endpoint failure";
                return OAuthTokenResponse.Failed(new Exception(error));
            }
        }

        /// <summary>
        /// OAuth第四步，获取用户信息
        /// </summary>
        /// <param name="identity"></param>
        /// <param name="properties"></param>
        /// <param name="tokens"></param>
        /// <returns></returns>
        protected override async Task<AuthenticationTicket> CreateTicketAsync(ClaimsIdentity identity, AuthenticationProperties properties, OAuthTokenResponse tokens)
        {
            var queryBuilder = new QueryBuilder()
            {
                { "access_token", tokens.AccessToken },
                { "openid",  tokens.TokenType },//在第二步中，openid被存入TokenType属性
                { "lang", "zh_CN" }
            };

            var infoRequest = Options.UserInformationEndpoint + queryBuilder.ToString();

            var response = await Backchannel.GetAsync(infoRequest, Context.RequestAborted);
            if (!response.IsSuccessStatusCode)
            {
                throw new HttpRequestException($"Failed to retrieve WeChat user information ({response.StatusCode}) Please check if the authentication information is correct and the corresponding WeChat Graph API is enabled.");
            }

            var user = JObject.Parse(await response.Content.ReadAsStringAsync());
            var ticket = new AuthenticationTicket(new ClaimsPrincipal(identity), properties, Options.AuthenticationScheme);
            var context = new OAuthCreatingTicketContext(ticket, Context, Options, Backchannel, tokens, user);

            var identifier = user.Value<string>("openid");
            if (!string.IsNullOrEmpty(identifier))
            {
                identity.AddClaim(new Claim(ClaimTypes.NameIdentifier, identifier, ClaimValueTypes.String, Options.ClaimsIssuer));
            }

            var nickname = user.Value<string>("nickname");
            if (!string.IsNullOrEmpty(nickname))
            {
                identity.AddClaim(new Claim(ClaimTypes.Name, nickname, ClaimValueTypes.String, Options.ClaimsIssuer));
            }

            var sex = user.Value<string>("sex");
            if (!string.IsNullOrEmpty(sex))
            {
                identity.AddClaim(new Claim("urn:WeChat:sex", sex, ClaimValueTypes.String, Options.ClaimsIssuer));
            }

            var country = user.Value<string>("country");
            if (!string.IsNullOrEmpty(country))
            {
                identity.AddClaim(new Claim(ClaimTypes.Country, country, ClaimValueTypes.String, Options.ClaimsIssuer));
            }

            var province = user.Value<string>("province");
            if (!string.IsNullOrEmpty(province))
            {
                identity.AddClaim(new Claim(ClaimTypes.StateOrProvince, province, ClaimValueTypes.String, Options.ClaimsIssuer));
            }

            var city = user.Value<string>("city");
            if (!string.IsNullOrEmpty(city))
            {
                identity.AddClaim(new Claim("urn:WeChat:city", city, ClaimValueTypes.String, Options.ClaimsIssuer));
            }

            var headimgurl = user.Value<string>("headimgurl");
            if (!string.IsNullOrEmpty(headimgurl))
            {
                identity.AddClaim(new Claim("urn:WeChat:headimgurl", headimgurl, ClaimValueTypes.String, Options.ClaimsIssuer));
            }

            var unionid = user.Value<string>("unionid");
            if (!string.IsNullOrEmpty(unionid))
            {
                identity.AddClaim(new Claim("urn:WeChat:unionid", unionid, ClaimValueTypes.String, Options.ClaimsIssuer));
            }

            await Options.Events.CreatingTicket(context);
            return context.Ticket;
        }
    }
}

WeChatHandler.cs

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.Globalization;
using System.Text.Encodings.Web;
using Microsoft.AspNetCore.Authentication.OAuth;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.DataProtection;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;

namespace Microsoft.AspNetCore.Authentication.WeChat
{
    /// <summary>
    /// An ASP.NET Core middleware for authenticating users using WeChat.
    /// </summary>
    public class WeChatMiddleware : OAuthMiddleware<WeChatOptions>
    {
        /// <summary>
        /// Initializes a new <see cref="WeChatMiddleware"/>.
        /// </summary>
        /// <param name="next">The next middleware in the HTTP pipeline to invoke.</param>
        /// <param name="dataProtectionProvider"></param>
        /// <param name="loggerFactory"></param>
        /// <param name="encoder"></param>
        /// <param name="sharedOptions"></param>
        /// <param name="options">Configuration options for the middleware.</param>
        public WeChatMiddleware(
            RequestDelegate next,
            IDataProtectionProvider dataProtectionProvider,
            ILoggerFactory loggerFactory,
            UrlEncoder encoder,
            IOptions<SharedAuthenticationOptions> sharedOptions,
            IOptions<WeChatOptions> options)
            : base(next, dataProtectionProvider, loggerFactory, encoder, sharedOptions, options)
        {
            if (next == null)
            {
                throw new ArgumentNullException(nameof(next));
            }

            if (dataProtectionProvider == null)
            {
                throw new ArgumentNullException(nameof(dataProtectionProvider));
            }

            if (loggerFactory == null)
            {
                throw new ArgumentNullException(nameof(loggerFactory));
            }

            if (encoder == null)
            {
                throw new ArgumentNullException(nameof(encoder));
            }

            if (sharedOptions == null)
            {
                throw new ArgumentNullException(nameof(sharedOptions));
            }

            if (options == null)
            {
                throw new ArgumentNullException(nameof(options));
            }

            if (string.IsNullOrEmpty(Options.AppId))
            {
                throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, nameof(Options.AppId)));
            }

            if (string.IsNullOrEmpty(Options.AppSecret))
            {
                throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, nameof(Options.AppSecret)));
            }
        }

        /// <summary>
        /// Provides the <see cref="AuthenticationHandler{T}"/> object for processing authentication-related requests.
        /// </summary>
        /// <returns>An <see cref="AuthenticationHandler{T}"/> configured with the <see cref="WeChatOptions"/> supplied to the constructor.</returns>
        protected override AuthenticationHandler<WeChatOptions> CreateHandler()
        {
            return new WeChatHandler(Backchannel);
        }
    }
}

WeChatMiddleware.cs

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System.Collections.Generic;
using Microsoft.AspNetCore.Authentication.WeChat;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Identity;

namespace Microsoft.AspNetCore.Builder
{
    /// <summary>
    /// Configuration options for <see cref="WeChatMiddleware"/>.
    /// </summary>
    public class WeChatOptions : OAuthOptions
    {
        /// <summary>
        /// Initializes a new <see cref="WeChatOptions"/>.
        /// </summary>
        public WeChatOptions()
        {
            AuthenticationScheme = WeChatDefaults.AuthenticationScheme;
            DisplayName = AuthenticationScheme;
            CallbackPath = new PathString("/signin-wechat");
            StateAddition = "#wechat_redirect";
            AuthorizationEndpoint = WeChatDefaults.AuthorizationEndpoint;
            TokenEndpoint = WeChatDefaults.TokenEndpoint;
            UserInformationEndpoint = WeChatDefaults.UserInformationEndpoint;
            //SaveTokens = true;           

            //BaseScope （不弹出授权页面，直接跳转，只能获取用户openid），
            //InfoScope （弹出授权页面，可通过openid拿到昵称、性别、所在地。并且，即使在未关注的情况下，只要用户授权，也能获取其信息）
            WeChatScope = InfoScope;
        }

        // WeChat uses a non-standard term for this field.
        /// <summary>
        /// Gets or sets the WeChat-assigned appId.
        /// </summary>
        public string AppId
        {
            get { return ClientId; }
            set { ClientId = value; }
        }

        // WeChat uses a non-standard term for this field.
        /// <summary>
        /// Gets or sets the WeChat-assigned app secret.
        /// </summary>
        public string AppSecret
        {
            get { return ClientSecret; }
            set { ClientSecret = value; }
        }

        public string StateAddition { get; set; }
        public string WeChatScope { get; set; }

        public string BaseScope = "snsapi_base";

        public string InfoScope = "snsapi_userinfo";
    }
}

WeChatOptions.cs