[英]Access HttpContextAccessor from startup.cs in .net Core WebApi
我正在asp.net核心中记录数据库的异常。 MyDbContext接受HttpContextAccessor参数。因此,我将HttpContextAccessor发送到MyDbContext.cs以访问我的JWT。 但是,我无法从Startup.cs访问我的HttpContextAccessor。 我怎样才能做到这一点?
Startup.cs
public void ConfigureServices(IServiceCollection services)
{
services.AddHttpContextAccessor();
services.AddMvc();
services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
services.AddDbContext<MyDbContext>();
services.AddTransient<IUnitOfWork, UnitOfWork>();
}
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
app.UseExceptionHandler(builder => builder.Run(async context =>
{
var error = context.Features.Get<IExceptionHandlerFeature>();
context.Response.AddApplicationError(error,???????);//I want access HttpContextAccessor
await context.Response.WriteAsync(error.Error.Message);
}));
app.UseHttpsRedirection();
app.UseMvc();
}
ExceptionHelper.cs
public static class ExceptionHelper
{
public static async Task AddApplicationError(this HttpResponse response, IExceptionHandlerFeature error, IHttpContextAccessor httpContextAccessor)
{
Log log = new Log();
log.Message = error.Error.Message;
MyDbContext context = new MyDbContext(null, httpContextAccessor);
UnitOfWork uow = new UnitOfWork(context);
uow.LogRepo.AddOrUpdate(log);
await uow.CompleteAsync(false);
}
}
MyDbContext
public class MyDbContext : DbContext
{
private readonly IHttpContextAccessor _httpContextAccessor;
public MyDbContext(DbContextOptions<MyDbContext> options, IHttpContextAccessor httpContextAccessor)
: base(GetOptions())
{
_httpContextAccessor = httpContextAccessor;
}
private static DbContextOptions GetOptions()
{
return SqlServerDbContextOptionsExtensions.UseSqlServer(new DbContextOptionsBuilder(), "server=asd; database=; user id=asd; password=1234").Options;
}
public override async Task<int> SaveChangesAsync(CancellationToken cancellationToken = default(CancellationToken))
{
var token = _httpContextAccessor.HttpContext.Request.Headers["Authorization"];
var audits = AuditHelper.AddAuditLog(base.ChangeTracker, token);
return (await base.SaveChangesAsync(true, cancellationToken));
}
}
您可以在Configure
方法中注入所需的任何内容。 您已使用以下行将其添加到服务集合中:
services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
所以你需要做的就是将它添加到方法的参数列表中,如下所示:
public void Configure(IApplicationBuilder app, IHostingEnvironment env, IHttpContextAccessor accessor)
{
// make use of it here
}
DbContext
说一下:我还要指出,当您使用依赖注入时,您在静态帮助器类中手动创建DbContext
的实例时会产生一些代码味道。
更新以回应评论
为了整理一下,我会先改变你的启动来配置DbContext,如下所示:
public class Startup
{
private readonly IConfiguration configuration;
public Startup(IConfiguration configuration)
{
this.configuration = configuration;
}
public void ConfigureServices(IServiceCollection services)
{
// register other things here...
services.AddDbContext<DataContext>(o => o.UseSqlServer(
config.GetConnectionString("MyConnectionString") // from appsettings.json
));
}
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
// set up app here...
}
}
然后,您可以从MyDbContext
删除.GetOptions()
方法,并将构造函数更改为:
public MyDbContext(DbContextOptions<MyDbContext> options, IHttpContextAccessor httpContextAccessor)
: base(options)
{
_httpContextAccessor = httpContextAccessor;
}
然后将MyDbContext
的实例注入任何需要访问它的类。 问题是(据我所知)DI不适用于静态类/方法,并且您在HttpResponse
上使用扩展方法来记录您的错误。
在我看来,最好创建一个负责记录错误的类,并依赖于MyDbContext
并将其注入到Configure
方法中:
public class ErrorLogger
{
private MyDataContext db;
public ErrorLogger(MyDataContext db) => this.db = db;
public void LogError(IExceptionHandlerFeature error)
{
Log log = new Log();
log.Message = error.Error.Message;
UnitOfWork uow = new UnitOfWork(this.db);
uow.LogRepo.AddOrUpdate(log);
await uow.CompleteAsync(false);
}
}
像对待其他东西一样将它注册到DI容器,然后将其注入Configure
而不是HTTP访问器:
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ErrorLogger logger)
{
app.UseExceptionHandler(builder => builder.Run(async context =>
{
var error = context.Features.Get<IExceptionHandlerFeature>();
logger.LogError(error);
await context.Response.WriteAsync(error.Error.Message);
}));
}
我没有对此进行测试,并且我不熟悉.UseExceptionHandler(...)
因为我使用应用程序洞察来记录异常等(如果你没有看到它,请看看它)。 需要注意的一件事是依赖关系的范围; 你的DbContext默认是Scoped
(我认为你应该这样离开),这意味着你不能将它注入Singleton
对象。
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