ASP.NET Core AutoWrapper 自定義響應輸出
阿新 • • 發佈：2020-03-31
## 前言
AutoWrapper是一個簡單可自定義全域性異常處理程式和ASP.NET Core API響應的包裝。他使用ASP.NET Core middleware攔截傳入的HTTP請求，並將最後的結果使用統一的格式來自動包裝起來.目的主要是讓我們更多的關注業務特定的程式碼要求，並讓包裝器自動處理HTTP響應。這可以在構建API時加快開發時間，同時為HTTP響應試試我們統一的標準。
## 安裝
AutoWrapper.Core從NuGet或通過CLI下載並安裝
```
PM> Install-Package AutoWrapper.Core
```
在Startup.cs Configure方法中註冊以下內容，但是切記要放在UseRouting前
```
app.UseApiResponseAndExceptionWrapper();
```
## 啟動屬性對映
預設情況下AutoWrapper將在成功請求成功時輸出以下格式：
```
{
"message": "Request successful.",
"isError": false,
"result": [
{
"id": 7002,
"firstName": "Vianne",
"lastName": "Durano",
"dateOfBirth": "2018-11-01T00:00:00"
}
]
}
```
如果說不喜歡預設屬性命名方式，那麼我們可以通過AutoWrapperPropertyMap屬性進行對映為我們需要指定的任何名稱。例如我麼可以將result屬性的名稱更改為data。如下所示
```
public class MapResponseObject
{
[AutoWrapperPropertyMap(Prop.Result)]
public object Data { get; set; }
}
```
然後將MapResponseObject類傳遞給AutpWrapper middleware
```
app.UseApiResponseAndExceptionWrapper();
```
通過對映重新請求後，現在影響格式如下所示
```
{
"message": "Request successful.",
"isError": false,
"data": {
"id": 7002,
"firstName": "Vianne",
"lastName": "Durano",
"dateOfBirth": "2018-11-01T00:00:00"
}
}
```
可以從中看出result屬性已經更換為data屬性了
預設情況下AutoWrapper發生異常時將吐出以下響應格式
```
{
"isError": true,
"responseException": {
"exceptionMessage": "Unhandled Exception occurred. Unable to process the request."
}
}
```
而且如果在AutoWrapperOptions中設定了IsDebug，則將產生帶有堆疊跟蹤資訊的類似資訊
```
{
"isError": true,
"responseException": {
"exceptionMessage": " Input string was not in a correct format.",
"details": " at System.Number.ThrowOverflowOrFormatException(ParsingStatus status, TypeCode type)\r\n at System.Number.ParseInt32(ReadOnlySpan`1 value, NumberStyles styles, NumberFormatInfo info)\r\n …"
}
}
```
如果想將某些APIError屬性名稱更改為其他名稱，只需要在以下程式碼中新增以下對映MapResponseObject
```
public class MapResponseObject
{
[AutoWrapperPropertyMap(Prop.ResponseException)]
public object Error { get; set; }
[AutoWrapperPropertyMap(Prop.ResponseException_ExceptionMessage)]
public string Message { get; set; }
[AutoWrapperPropertyMap(Prop.ResponseException_Details)]
public string StackTrace { get; set; }
}
```
通過如下程式碼來模擬錯誤
```
int num = Convert.ToInt32("10s");
```
現在對映後的輸出如下所示
```
{
"isError": true,
"error": {
"message": " Input string was not in a correct format.",
"stackTrace": " at System.Number.ThrowOverflowOrFormatException(ParsingStatus status, TypeCode type)\r\n at System.Number.ParseInt32(ReadOnlySpan`1 value, NumberStyles styles, NumberFormatInfo info)\r\n …"
}
}
```
請注意APIError現在根據MapResponseObject類中定義的屬性更改了模型的預設屬性。
我們可以自由的選擇對映任何屬性，下面是對映屬性相對應的列表
```
[AutoWrapperPropertyMap(Prop.Version)]
[AutoWrapperPropertyMap(Prop.StatusCode)]
[AutoWrapperPropertyMap(Prop.Message)]
[AutoWrapperPropertyMap(Prop.IsError)]
[AutoWrapperPropertyMap(Prop.Result)]
[AutoWrapperPropertyMap(Prop.ResponseException)]
[AutoWrapperPropertyMap(Prop.ResponseException_ExceptionMessage)]
[AutoWrapperPropertyMap(Prop.ResponseException_Details)]
[AutoWrapperPropertyMap(Prop.ResponseException_ReferenceErrorCode)]
[AutoWrapperPropertyMap(Prop.ResponseException_ReferenceDocumentLink)]
[AutoWrapperPropertyMap(Prop.ResponseException_ValidationErrors)]
[AutoWrapperPropertyMap(Prop.ResponseException_ValidationErrors_Field)]
[AutoWrapperPropertyMap(Prop.ResponseException_ValidationErrors_Message)]
```
## 自定義錯誤架構
AutoWrapper還提供了一個APIException可用於定義自己的異常的物件，如果想丟擲自己的異常訊息，則可以簡單地執行以下操作
```
throw new ApiException("Error blah", 400, "511", "http://blah.com/error/511");
```
預設輸出格式如下所示
```
{
"isError": true,
"responseException": {
"exceptionMessage": "Error blah",
"referenceErrorCode": "511",
"referenceDocumentLink": "http://blah.com/error/511"
}
}
```
當然我們可以自定義錯誤格式
```
public class MapResponseObject
{
[AutoWrapperPropertyMap(Prop.ResponseException)]
public object Error { get; set; }
}
public class Error
{
public string Message { get; set; }
public string Code { get; set; }
public InnerError InnerError { get; set; }
public Error(string message, string code, InnerError inner)
{
this.Message = message;
this.Code = code;
this.InnerError = inner;
}
}
public class InnerError
{
public string RequestId { get; set; }
public string Date { get; set; }
public InnerError(string reqId, string reqDate)
{
this.RequestId = reqId;
this.Date = reqDate;
}
}
```
然後我們可以通過如下程式碼進行引發我們錯誤
```
throw new ApiException(
new Error("An error blah.", "InvalidRange",
new InnerError("12345678", DateTime.Now.ToShortDateString())
));
```
輸出格式如下所示
```
{
"isError": true,
"error": {
"message": "An error blah.",
"code": "InvalidRange",
"innerError": {
"requestId": "12345678",
"date": "10/16/2019"
}
}
}
```
## 使用自定義API響應格式
如果對映滿足不了我們的需求。並且我們需要向API響應模型中新增其他屬性，那麼我們現在可以自定義自己的格式類，通過設定UseCustomSchema為true來實現，程式碼如下所示
```
app.UseApiResponseAndExceptionWrapper(new AutoWrapperOptions { UseCustomSchema = true });
```
現在假設我們想在主API中響應中包含一個屬性SentDate和Pagination物件，我們可能希望將API響應模型定義為以下格式
```
public class MyCustomApiResponse
{
public int Code { get; set; }
public string Message { get; set; }
public object Payload { get; set; }
public DateTime SentDate { get; set; }
public Pagination Pagination { get; set; }
public MyCustomApiResponse(DateTime sentDate, object payload = null, string message = "", int statusCode = 200, Pagination pagination = null)
{
this.Code = statusCode;
this.Message = message == string.Empty ? "Success" : message;
this.Payload = payload;
this.SentDate = sentDate;
this.Pagination = pagination;
}
public MyCustomApiResponse(DateTime sentDate, object payload = null, Pagination pagination = null)
{
this.Code = 200;
this.Message = "Success";
this.Payload = payload;
this.SentDate = sentDate;
this.Pagination = pagination;
}
public MyCustomApiResponse(object payload)
{
this.Code = 200;
this.Payload = payload;
}
}
public class Pagination
{
public int TotalItemsCount { get; set; }
public int PageSize { get; set; }
public int CurrentPage { get; set; }
public int TotalPages { get; set; }
}
```
通過如下程式碼片段進行測試結果
```
public async Task Get()
{
var data = await _personManager.GetAllAsync();
return new MyCustomApiResponse(DateTime.UtcNow, data,
new Pagination
{
CurrentPage = 1,
PageSize = 10,
TotalItemsCount = 200,
TotalPages = 20
});
}
```
執行後會得到如下影響格式
```
{
"code": 200,
"message": "Success",
"payload": [
{
"id": 1,
"firstName": "Vianne",
"lastName": "Durano",
"dateOfBirth": "2018-11-01T00:00:00"
},
{
"id": 2,
"firstName": "Vynn",
"lastName": "Durano",
"dateOfBirth": "2018-11-01T00:00:00"
},
{
"id": 3,
"firstName": "Mitch",
"lastName": "Durano",
"dateOfBirth": "2018-11-01T00:00:00"
}
],
"sentDate": "2019-10-17T02:26:32.5242353Z",
"pagination": {
"totalItemsCount": 200,
"pageSize": 10,
"currentPage": 1,
"totalPages": 20
}
}
```
但是從這裡要注意一旦我們對API響應進行自定義，那麼就代表我們完全控制了要格式化資料的方式，同時丟失了預設API響應的某些選項配置。但是我們仍然可以利用ApiException()方法引發使用者定義的錯誤訊息
如下所示
```
[Route("{id:long}")]
[HttpPut]
public async Task Put(long id, [FromBody] PersonDTO dto)
{
if (ModelState.IsValid)
{
try
{
var person = _mapper.Map(dto);
person.ID = id;
if (await _personManager.UpdateAsync(person))
return new MyCustomApiResponse(DateTime.UtcNow, true, "Update successful.");
else
throw new ApiException($"Record with id: {id} does not exist.", 400);
}
catch (Exception ex)
{
_logger.Log(LogLevel.Error, ex, "Error when trying to update with ID:{@ID}", id);
throw;
}
}
else
throw new ApiException(ModelState.AllErrors());
}
```
現在當進行模型驗證時，可以獲得預設響應格式
```
{
"isError": true,
"responseException": {
"exceptionMessage": "Request responded with validation error(s). Please correct the specified validation errors and try again.",
"validationErrors": [
{
"field": "FirstName",
"message": "'First Name' must not be empty."
}
]
}
}
```
## Reference
https://github.com/proudmonkey/AutoWrapper