微信相关配置请参考 [微信公众平台](https://mp.weixin.qq.com/wiki?t=resource/res_main&id=mp1421140842) 的这篇文章。注意授权回调域名一定要修改正确。
微信网页授权是通过OAuth2.0机制实现的，所以我们可以使用 [https://github.com/china-live/QQConnect](https://github.com/china-live/QQConnect) 这个开源项目提供的中间件来实现微信第三方登录的流程。
### 开发流程
1、新建一个.net core webapi 项目。在NuGet中查找并安装 ```AspNetCore.Authentication.WeChat``` 包。
2、修改 ```appsettings.json``` 配置文件，增加以下配置：
```
"Authentication": {
"WeChat": {
"AppId": "微信AppID",
"AppSecret": "微信AppSecret"
}
},
"Logging": {
"LogLevel": {
"Default": "Debug", //日志级别从低到高，依次为：Debug,Information,Warning,Error,None
"Microsoft.EntityFrameworkCore": "Error",
"System": "Error"
}
}
```
3、修改 ```Startup```
```
services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
services.AddAuthentication()
.AddWeChat(wechatOptions =>
{
wechatOptions.AppId = Configuration["Authentication:WeChat:AppId"];
wechatOptions.AppSecret = Configuration["Authentication:WeChat:AppSecret"];
wechatOptions.UseCachedStateDataFormat = true;
});
```
4、新增 ```AccountController```
```
[Route("api/[controller]")]
[ApiController]
public class AccountController : ControllerBase
{
private const string LoginProviderKey = "LoginProvider";
private const string Provider_WeChat = "WeChat";
private readonly ILogger _logger;
private readonly IHttpContextAccessor _contextAccessor;
public AccountController(ILogger<AccountController> logger,
IHttpContextAccessor contextAccessor)
{
_logger = logger;
_contextAccessor = contextAccessor;
}
/// <summary>
/// 微信登录
/// </summary>
/// <param>授权成功后的跳转地址</param>
/// <returns></returns>
[HttpGet("LoginByWeChat")]
public IActionResult LoginByWeChat(string redirectUrl)
{
var request = _contextAccessor.HttpContext.Request;
var url = $"{request.Scheme}://{request.Host}{request.PathBase}{request.Path}Callback?provider={Provider_WeChat}&redirectUrl={redirectUrl}";
var properties = new AuthenticationProperties { RedirectUri = url };
properties.Items[LoginProviderKey] = Provider_WeChat;
return Challenge(properties, Provider_WeChat);
}
/// <summary>
/// 微信授权成功后自动回调的地址
/// </summary>
/// <param></param>
/// <param>授权成功后的跳转地址</param>
/// <returns></returns>
[HttpGet("LoginByWeChatCallback")]
public async Task<IActionResult> LoginByWeChatCallbackAsync(string provider = null, string redirectUrl = "")
{
var authenticateResult = await _contextAccessor.HttpContext.AuthenticateAsync(provider);
if (!authenticateResult.Succeeded) return Redirect(redirectUrl);
var openIdClaim = authenticateResult.Principal.FindFirst(ClaimTypes.NameIdentifier);
if (openIdClaim == null || openIdClaim.Value.IsNullOrWhiteSpace())
return Redirect(redirectUrl);
//TODO 记录授权成功后的微信信息
var city = authenticateResult.Principal.FindFirst("urn:wechat:city")?.Value;
var country = authenticateResult.Principal.FindFirst(ClaimTypes.Country)?.Value;
var headimgurl = authenticateResult.Principal.FindFirst(ClaimTypes.Uri)?.Value;
var nickName = authenticateResult.Principal.FindFirst(ClaimTypes.Name)?.Value;
var openId = authenticateResult.Principal.FindFirst(ClaimTypes.NameIdentifier)?.Value;
var privilege = authenticateResult.Principal.FindFirst("urn:wechat:privilege")?.Value;
var province = authenticateResult.Principal.FindFirst("urn:wechat:province")?.Value;
var sexClaim = authenticateResult.Principal.FindFirst(ClaimTypes.Gender);
int sex = 0;
if (sexClaim != null && !sexClaim.Value.IsNullOrWhiteSpace())
sex = int.Parse(sexClaim.Value);
var unionId = authenticateResult.Principal.FindFirst("urn:wechat:unionid")?.Value;
_logger.LogDebug($"WeChat Info=> openId: {openId},nickName: {nickName}");
return Redirect($"{redirectUrl}?openId={openIdClaim.Value}");
}
}
```
5、将网站发布到外网，请求```https://你的授权域名/api/account/LoginByWeChat?redirectUrl=授权成功后要跳转的页面```即可调起微信授权页面。
### 注意
> 微信授权必须使用https
> 微信开放平台和微信公众平台都有提供网站用微信登录的接口，前者适用于任何网站，后者只适用于微信服务号的内嵌网站。