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.net core异常中间件的使用

程序员文章站 2022-04-14 18:56:14
正文这样写入中间件哈，那么在env环境下就会去执行usedeveloperexceptionpage。那么我们应该去看developerexceptionpagemiddleware中间件哈。那么这里...

正文

if (env.isdevelopment())
{
	app.usedeveloperexceptionpage();
}

这样写入中间件哈，那么在env环境下就会去执行usedeveloperexceptionpage。

public static iapplicationbuilder usedeveloperexceptionpage(this iapplicationbuilder app)
{
	if (app == null)
	{
		throw new argumentnullexception(nameof(app));
	}

	return app.usemiddleware<developerexceptionpagemiddleware>();
}

那么我们应该去看developerexceptionpagemiddleware中间件哈。

那么这里介绍它是如何能够捕获其他中间件的异常的哈。

里面的invoke:

其实它的操作是很简单的，直接在外面套了try catch。

里面的异常处理怎么处理的可以直接去看developerexceptionpagemiddleware 中间件，里面的操作也比较简单处理。

测试:

[httpget]
public int getservice([fromservices]iselfservice selfservice)
{
	throw new system.exception("错误");
	return 1;
}

结果:

.net core异常中间件的使用

因为上面说了，这个是dev环境下，那么生产环境不能直接给用户看到错误信息。

正式环境:

app.useexceptionhandler("/error");

将错误转移到/error 处理。具体useexceptionhandler细节篇里面介绍，有许多可以借鉴的地方。

[apicontroller]
[route("[controller]")]
public class errorcontroller : controller
{
	public ilogger<errorcontroller> _logger;
	public errorcontroller(ilogger<errorcontroller> logger)
	{
		this._logger = logger;
	}

	public iactionresult index()
	{
		var exceptionhandlerpathfeature = httpcontext.features.get<iexceptionhandlerpathfeature>();

		var ex = exceptionhandlerpathfeature?.error;

		var knownexception = ex as iknownexception;

		if (knownexception == null)
		{
			_logger.logerror(ex, ex.message);
			knownexception = knownexception.unknow;
		}
		else
		{
			knownexception = knownexception.fromknowexception(knowexception);
		}

		return view(knownexception);
	}
}

视图:

<html>
<head>

</head>
<body>
<div>
    错误码: @model.errorcode
</div>
<div>
    错误信息: @model.message
</div>
</body>
</html>

iknownexception:

public interface iknownexception
{
	public string message { get; }

	public int errorcode { get; }

	public object[] errordata { get; }
}

knownexception:

public class knownexception : iknownexception
{
	public string message
	{
		get; private set;
	}

	public int errorcode
	{
		get; private set;
	}

	public object[] errordata
	{
		get;
		private set;
	}

	public readonly static iknownexception unknow = new knownexception { message = "未知错误", errorcode = 99 };

	public static iknownexception fromknowexception(iknownexception exception)
	{
		return new knownexception{message = exception.message, errorcode = exception.errorcode, errordata = exception.errordata};
	}
}

测试1：

[httpget]
public int getservice([fromservices]iselfservice selfservice)
{
	throw new system.exception("错误");
	return 1;
}

这种属于未知异常，结果:

.net core异常中间件的使用

现在弄一个支付异常:

public class payerrorexception : exception, iknownexception
{
	public payerrorexception(string message, int errorcode, params object[] errordata): base(message)
	{
		this.errorcode = errorcode;
		this.errordata = errordata;
	}

	public int errorcode { get;private set; }

	public object[] errordata { get;private set; }
}

测试2:

[httpget]
public int getservice([fromservices]iselfservice selfservice)
{

	throw new payerrorexception("支付错误",405,null);
	return 1;
}

.net core异常中间件的使用

将异常处理放入到中间件分支中。

app.useexceptionhandler(errapp =>
{
	errapp.run(async context =>
	{
		var exceptionhandlerpathfeature = context.features.get<iexceptionhandlerpathfeature>();
		iknownexception knownexception = exceptionhandlerpathfeature.error as iknownexception;
		if (knownexception == null)
		{
			var logger = context.requestservices.getservice<ilogger<myexceptionfilterattribute>>();
			logger.logerror(exceptionhandlerpathfeature.error, exceptionhandlerpathfeature.error.message);
			knownexception = knownexception.unknown;
			context.response.statuscode = statuscodes.status500internalservererror;
		}
		else
		{
			knownexception = knownexception.fromknownexception(knownexception);
			context.response.statuscode = statuscodes.status200ok;
		}
		var jsonoptions = context.requestservices.getservice<ioptions<jsonoptions>>();
		context.response.contenttype = "application/json; charset=utf-8";
		await context.response.writeasync(system.text.json.jsonserializer.serialize(knownexception, jsonoptions.value.jsonserializeroptions));
	});
});

效果一样就不演示了。如果是已知异常错误码应该为200，一个是500异常是系统无法处理，系统错误，但是已知错误是属于系统正常处理。另一个是监控系统，认为报500错误，是会持续放出系统警告。

还有一种局部异常，只在mvc中生效，而不是全局生效:

public class myexceptionfilter : iexceptionfilter
{
	public void onexception(exceptioncontext context)
	{
		iknownexception knownexception = context.exception as iknownexception;
		if (knownexception == null)
		{
			var logger = context.httpcontext.requestservices.getservice<ilogger<myexceptionfilterattribute>>();
			logger.logerror(context.exception, context.exception.message);
			knownexception = knownexception.unknown;
			context.httpcontext.response.statuscode = statuscodes.status500internalservererror;
		}
		else
		{
			knownexception = knownexception.fromknownexception(knownexception);
			context.httpcontext.response.statuscode = statuscodes.status200ok;
		}
		context.result = new jsonresult(knownexception)
		{
			contenttype = "application/json; charset=utf-8"
		};
	}
}

在mvc 中注册:

services.addmvc(mvcoptions =>
{
	mvcoptions.filters.add<myexceptionfilter>();
}).addjsonoptions(jsonoptions =>
{
	jsonoptions.jsonserializeroptions.encoder = system.text.encodings.web.javascriptencoder.unsaferelaxedjsonescaping;
});

最后介绍一种，只作用于某个控制器，或者action:

public class myexceptionfilterattribute : exceptionfilterattribute
{
	public override void onexception(exceptioncontext context)
	{
		iknownexception knownexception = context.exception as iknownexception;
		if (knownexception == null)
		{
			var logger = context.httpcontext.requestservices.getservice<ilogger<myexceptionfilterattribute>>();
			logger.logerror(context.exception, context.exception.message);
			knownexception = knownexception.unknown;
			context.httpcontext.response.statuscode = statuscodes.status500internalservererror;
		}
		else
		{
			knownexception = knownexception.fromknownexception(knownexception);
			context.httpcontext.response.statuscode = statuscodes.status200ok;
		}
		context.result = new jsonresult(knownexception)
		{
			contenttype = "application/json; charset=utf-8"
		};
	}
}

查看一下exceptionfilterattribute头部:

[attributeusage(attributetargets.class | attributetargets.method, allowmultiple = true, inherited = true)]
public abstract class exceptionfilterattribute : attribute, iasyncexceptionfilter, iexceptionfilter, iorderedfilter

上面标志了可以放于类上也可以放于方法上。所以可以放至在controller上，也可以action上，看需求了。

结

以上就是.net core异常中间件的使用的详细内容，更多关于.net core异常中间件的资料请关注其它相关文章！

相关标签： .net core 异常 中间件

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