AutoWrapper

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AutoWrapper is a simple, yet customizable global HTTP exception handler and response wrapper for ASP.NET Core APIs. It uses an ASP.NET Core middleware to intercept incoming HTTP requests and automatically wraps the responses for you by providing a consistent response format for both successful and error results. The goal is to let you focus on your business code specific requirements and let the wrapper automatically handle the HTTP response. This can speedup the development time when building your APIs while enforcing own standards for your HTTP responses.

Main features:

• Exception handling.
• ModelState validation error handling (support both Data Annotation and FluentValidation).
• A configurable API exception.
• A consistent response format for Result and Errors.
• A detailed Result response.
• A detailed Error response.
• A configurable HTTP StatusCodes and messages.
• Add support for Swagger.
• Add Logging support for Request, Response and Exceptions.
• A configurable middleware options to configure the wrapper. See Options section below for details.
• Enable property name mappings for the default ApiResponse properties.
• Add support for implementing your own user-defined Response and Error schema / object.
• Add support for Problem Details exception format.
• Add support for ignoring action methods that don't need to be wrapped using [AutoWrapIgnore] filter attribute.
• V3.x enable backwards compatibility support for netcoreapp2.1 and netcoreapp2.2 .NET Core frameworks.
• Add ExcludePaths option to enable support for SignalR and dapr routes。

Installation

1. Download and Install the latest AutoWrapper.Core from NuGet or via CLI:

PM> Install-Package AutoWrapper.Core -Version 4.5.1

2. Declare the following namespace within Startup.cs

using AutoWrapper;

3. Register the middleware below within the Configure() method of Startup.cs "before" the UseRouting() middleware:

app.UseApiResponseAndExceptionWrapper();

That's simple! Here’s how the response is going to look like for the default ASP.NET Core API template “WeatherForecastController” API:

{
    "message": "GET Request successful.",
    "result": [
        {
            "date": "2019-09-16T23:37:51.5544349-05:00",
            "temperatureC": 21,
            "temperatureF": 69,
            "summary": "Mild"
        },
        {
            "date": "2019-09-17T23:37:51.554466-05:00",
            "temperatureC": 28,
            "temperatureF": 82,
            "summary": "Cool"
        },
        {
            "date": "2019-09-18T23:37:51.554467-05:00",
            "temperatureC": 21,
            "temperatureF": 69,
            "summary": "Sweltering"
        },
        {
            "date": "2019-09-19T23:37:51.5544676-05:00",
            "temperatureC": 53,
            "temperatureF": 127,
            "summary": "Chilly"
        },
        {
            "date": "2019-09-20T23:37:51.5544681-05:00",
            "temperatureC": 22,
            "temperatureF": 71,
            "summary": "Bracing"
        }
    ]
}

Defining Your Own Custom Message

To display a custom message in your response, use the ApiResponse object from AutoWrapper.Wrappers namespace. For example, if you want to display a message when a successful POST has been made, then you can do something like this:

[HttpPost]
public async Task<ApiResponse> Post([FromBody]CreatePersonRequest createRequest)  
{
    try
    {
        var personId = await _personManager.CreateAsync(createRequest);
        return new ApiResponse("New record has been created in the database.", personId, Status201Created);
    }
    catch (Exception ex)
    {
        //TO DO: Log ex
        throw;
    }
}

Running the code will give you the following result when successful:

{
    "message": "New record has been created in the database.",
    "result": 100
}

The ApiResponse object has the following overload constructors that you can use:

ApiResponse(string message, object result = null, int statusCode = 200, string apiVersion = "1.0.0.0")
ApiResponse(object result, int statusCode = 200)
ApiResponse(int statusCode, object apiError)
ApiResponse()

Defining Your Own Api Exception

AutoWrapper provides two flavors that you can use to define your own custom exception:

• ApiException - default
• ApiProblemDetailsException - available only in version 4 and up.

Here are a few examples for throwing your own exception message.

Capturing ModelState Validation Errors

if (!ModelState.IsValid)
{
    throw new ApiException(ModelState.AllErrors());
}

The format of the exception result would look something like this when validation fails:

{
    "isError": true,
    "responseException": {
        "exceptionMessage": "Request responded with one or more validation errors occurred.",
        "validationErrors": [
            {
                "name": "LastName",
                "reason": "'Last Name' must not be empty."
            },
            {
                "name": "FirstName",
                "reason": "'First Name' must not be empty."
            },
            {
                "name": "DateOfBirth",
                "reason": "'Date Of Birth' must not be empty."
            }
        ]
    }
}

To use Problem Details as an error format, just set UseApiProblemDetailsException to true:

app.UseApiResponseAndExceptionWrapper(new AutoWrapperOptions { UseApiProblemDetailsException = true }); 

Then you can use the ApiProblemDetailsException object like in the following:

if (!ModelState.IsValid)
{
    throw new ApiProblemDetailsException(ModelState);
}

The format of the exception result would now look something like this when validation fails:

{
    "isError": true,
    "type": "https://httpstatuses.com/422",
    "title": "Unprocessable Entity",
    "status": 422,
    "detail": "Your request parameters didn't validate.",
    "instance": null,
    "extensions": {},
    "validationErrors": [
        {
            "name": "LastName",
            "reason": "'Last Name' must not be empty."
        },
        {
            "name": "FirstName",
            "reason": "'First Name' must not be empty."
        },
        {
            "name": "DateOfBirth",
            "reason": "'Date Of Birth' must not be empty."
        }
    ]
}

You can see how the validationErrors property is automatically populated with the violated name from your model.

Throwing Your Own Exception Message

An example using ApiException:

throw new ApiException($"Record with id: {id} does not exist.", Status404NotFound);

The result would look something like this:

{
    "isError": true,
    "responseException": {
        "exceptionMessage": "Record with id: 1001 does not exist.",
    }
}

An example using ApiProblemDetailsException:

throw new ApiProblemDetailsException($"Record with id: {id} does not exist.", Status404NotFound);  

The result would look something like this:

{
    "isError": true,
    "type": "https://httpstatuses.com/404",
    "title": "Record with id: 1001 does not exist.",
    "status": 404,
    "detail": null,
    "instance": null,
    "extensions": {}
}

The ApiException object contains the following overload constructors that you can use to define an exception:

ApiException(string message, int statusCode = 400, string errorCode = "", string refLink = "")
ApiException(IEnumerable<ValidationError> errors, int statusCode = 400)
ApiException(System.Exception ex, int statusCode = 500)
ApiException(object custom, int statusCode = 400)

The ApiProblemDetailsException object contains the following overload constructors that you can use to define an exception:

ApiProblemDetailsException(int statusCode)
ApiProblemDetailsException(string title, int statusCode)
ApiProblemDetailsException(ProblemDetails details)
ApiProblemDetailsException(ModelStateDictionary modelState, int statusCode = Status422UnprocessableEntity)

For more information, checkout the links below at the Samples section.

Implement Model Validations

Model validations allows you to enforce pre-defined validation rules at a class/property level. You'd normally use this validation technique to keep a clear separation of concerns, so your validation code becomes much simpler to write, maintain, and test.

As you have already known, starting ASP.NET Core 2.1, it introduced the ApiController attribute which performs automatic model state validation for 400 Bad Request error. When the Controller is decorated with ApiController attribute, the framework will automatically register a ModelStateInvalidFilter which runs on the OnActionExecuting event. This checks for the Model State validity and returns the response accordingly. This is a great feature, but since we want to return a custom response object instead of the 400 Bad Request error, we will disable this feature in our case.

To disable the automatic model state validation, just add the following code at ConfigureServices() method in Startup.cs file:

public void ConfigureServices(IServiceCollection services) {  
    services.Configure<ApiBehaviorOptions>(options =>
    {
        options.SuppressModelStateInvalidFilter = true;
    });

}

Enable Property Mappings

Note: Property Mappings is not available for Problem Details attributes.

Use the AutoWrapperPropertyMap attribute to map the AutoWrapper default property to something else. For example, let's say you want to change the name of the result property to something else like data, then you can simply define your own schema for mapping it like in the following:

public class MapResponseObject  
{
    [AutoWrapperPropertyMap(Prop.Result)]
    public object Data { get; set; }
}

You can then pass the MapResponseObject class to the AutoWrapper middleware like this:

app.UseApiResponseAndExceptionWrapper<MapResponseObject>();  

On successful requests, your response should now look something like this after mapping:

{
    "message": "Request successful.",
    "isError": false,
    "data": {
        "id": 7002,
        "firstName": "Vianne",
        "lastName": "Durano",
        "dateOfBirth": "2018-11-01T00:00:00"
    }
}

Notice that the default result attribute is now replaced with the data attribute.

Keep in mind that you are free to choose whatever property that you want to map. Here is the list of default properties that you can map:

[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)]

Using Your Own Error Schema

You can define your own Error object and pass it to the ApiException() method. For example, if you have the following Error model with mapping configured:

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;
    }
}

You can then throw an error like this:

throw new ApiException(  
      new Error("An error blah.", "InvalidRange",
      new InnerError("12345678", DateTime.Now.ToShortDateString())
));

The format of the output will now look like this:

{
    "isError": true,
    "error": {
        "message": "An error blah.",
        "code": "InvalidRange",
        "innerError": {
            "requestId": "12345678",
            "date": "10/16/2019"
        }
    }
}

Using Your Own API Response Schema

If mapping wont work for you and you need to add additional attributes to the default API response schema, then you can use your own custom schema/model to achieve that by setting the UseCustomSchema to true in AutoWrapperOptions as shown in the following code below:

app.UseApiResponseAndExceptionWrapper(new AutoWrapperOptions { UseCustomSchema = true }); 

Now let's say for example you wanted to have an attribute SentDate and Pagination object as part of your main API response, you might want to define your API response schema to something like this:

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; }
}

To test the result, you can create a GET method to something like this:

public async Task<MyCustomApiResponse> Get()  
{
    var data = await _personManager.GetAllAsync();

    return new MyCustomApiResponse(DateTime.UtcNow, data,
        new Pagination
        {
            CurrentPage = 1,
            PageSize = 10,
            TotalItemsCount = 200,
            TotalPages = 20
        });
}

Running the code should give you now the following response format:

{
    "code": 200,
    "message": "Success",
    "payload": [
        {
            "id": 1,
            "firstName": "Vianne Maverich",
            "lastName": "Durano",
            "dateOfBirth": "2018-11-01T00:00:00"
        },
        {
            "id": 2,
            "firstName": "Vynn Markus",
            "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
    }
}

That’s it. One thing to note here is that once you use your own schema for your API response, you have the full ability to control how you would want to format your data, but at the same time losing some of the option configurations for the default API Response. The good thing is you can still take advantage of the ApiException() method to throw a user-defined error message.

Options

The following properties are the available options that you can set:

Version 4.5.x Additions

• ExcludePaths

Version 4.3.x Additions

• ShouldLogRequestData
• ShowIsErrorFlagForSuccessfulResponse

Version 4.2.x Additions

• IgnoreWrapForOkRequests

Version 4.1.0 Additions

• LogRequestDataOnException

Version 4.0.0 Additions

• UseApiProblemDetailsException
• UseCustomExceptionFormat

Version 3.0.0 Additions

• BypassHTMLValidation
• ReferenceLoopHandling

Version 2.x.x Additions

• EnableResponseLogging
• EnableExceptionLogging

Version 2.0.x Additions

• IgnoreNullValue
• UseCamelCaseNamingStrategy
• UseCustomSchema

Version 1.x.x Additions

• IsApiOnly
• WrapWhenApiPathStartsWith

Version 1.0.0

• ApiVersion
• ShowApiVersion
• ShowStatusCode
• IsDebug

ShowApiVersion

if you want to show the API version in the response, then you can do:

app.UseApiResponseAndExceptionWrapper(new AutoWrapperOptions { ShowApiVersion = true });

The default API version format is set to "1.0.0.0"

ApiVersion

If you wish to specify a different version format, then you can do:

app.UseApiResponseAndExceptionWrapper(new AutoWrapperOptions { ShowApiVersion = true, ApiVersion = "2.0" });

ShowStatusCode

if you want to show the StatusCode in the response, then you can do:

app.UseApiResponseAndExceptionWrapper(new AutoWrapperOptions { ShowStatusCode = true });

IsDebug

By default, AutoWrapper suppresses stack trace information. If you want to see the actual details of the error from the response during the development stage, then simply set the AutoWrapperOptions IsDebug to true:

app.UseApiResponseAndExceptionWrapper(new AutoWrapperOptions { IsDebug = true }); 

IsApiOnly

AutoWrapper is meant to be used for ASP.NET Core API project templates only. If you are combining API Controllers within your front-end projects like Angular, MVC, React, Blazor Server and other SPA frameworks that supports .NET Core, then use this property to enable it.

app.UseApiResponseAndExceptionWrapper(new AutoWrapperOptions { IsApiOnly = false} );

WrapWhenApiPathStartsWith

If you set the IsApiOnly option to false, you can also specify the segment of your API path for validation. By default it is set to "/api". If you want to set it to something else, then you can do:

app.UseApiResponseAndExceptionWrapper( new AutoWrapperOptions { 
          IsApiOnly = false, 
          WrapWhenApiPathStartsWith = "/myapi" 
});

This will activate the AutoWrapper to intercept HTTP responses when a request contains the WrapWhenApiPathStartsWith value.

Note that I would still recommend you to implement your API Controllers in a separate project to value the separation of concerns and to avoid mixing route configurations for your SPAs and APIs.

IgnoreWrapForOkRequests

If you want to completely ignore wrapping the response for successful requests to just output directly the data, you simply set the IgnoreWrapForOkRequests to true like in the following:

app.UseApiResponseAndExceptionWrapper(new AutoWrapperOptions {  
    IgnoreWrapForOkRequests = true,
});

AutoWrapIgnore Attribute

You can use the [AutoWrapIgnore] filter attribute for endpoints that you don't need to be wrapped.

For example:

[HttpGet]
[AutoWrapIgnore]
public async Task<IActionResult> Get()  
{
    var data = await _personManager.GetAllAsync();
    return Ok(data);
}

or

[HttpGet]
[AutoWrapIgnore]
public async Task<IEnumerable<Person>> Get()  
{
    return await _personManager.GetAllAsync();
}

RequestDataLogIgnore Attribute

You can use the [RequestDataLogIgnore] if you don't want certain endpoints to log the data in the requests:

[HttpGet]
[RequestDataLogIgnore]
public async Task<ApiResponse> Post([FromBody] CreatePersonRequest personRequest)  
{
    //Rest of the code here
}

You can use the [AutoWrapIgnore] attribute and set ShouldLogRequestData property to false if you have an endpoint that don't need to be wrapped and also don't want to log the data in the requests:

[HttpGet]
[AutoWrapIgnore(ShouldLogRequestData = false)]
public async Task<IEnumerable<PersonResponse>> Get()  
{
     //Rest of the code here
}

Support for Logging

Another good thing about AutoWrapper is that logging is already pre-configured. .NET Core apps has built-in logging mechanism by default, and any requests and responses that has been intercepted by the wrapper will be automatically logged (thanks to Dependency Injection!). .NET Core supports a logging API that works with a variety of built-in and third-party logging providers. Depending on what supported .NET Core logging provider you use and how you configure the location to log the data (e.g text file, Cloud , etc. ), AutoWrapper will automatically write the logs there for you.

You can turn off the default Logging by setting EnableResponseLogging and EnableExceptionLogging options to false.

For example:

app.UseApiResponseAndExceptionWrapper(new AutoWrapperOptions {  
    EnableResponseLogging = false, 
    EnableExceptionLogging = false 
});

You can set the LogRequestDataOnException option to false if you want to exclude the request body data in the logs when an exception occurs.

app.UseApiResponseAndExceptionWrapper(new AutoWrapperOptions {  
    LogRequestDataOnException = false 
});

Support for Swagger

Swagger provides an advance documentation for your APIs where it allows developers to reference the details of your API endpoints and test them when necessary. This is very helpful especially when your API is public and you expect many developers to use it.

AutoWrapper omit any request with “/swagger” in the URL so you can still be able to navigate to the Swagger UI for your API documentation.

Exclude Paths

The ExcludePaths option enables you to set a collection of API paths to be ignored. This feature was added by chen1tian. Thank you so much for this great contribution! Here's how it works:

Excluding Api paths/routes that do not need to be wrapped support three ExcludeMode:

Strict: The request path must be exactly the same as the configured path. StartWith: The request path starts at the configuration path. Regex: If the requested path match the configured path regular expression, it will be excluded. The following is a quick example:

Support for SignalR

If you have the following SignalR endpoint：

app.UseEndpoints(endpoints =>
{
    endpoints.MapControllers();
    endpoints.MapHub<NoticeHub>("/notice");
});

then you can use the ExcludePaths and set the the "/notice" path as AutoWrapperExcludePaths for the SignalR endpoint to work. For example:

app.UseApiResponseAndExceptionWrapper(new AutoWrapperOptions
{
    ExcludePaths = new AutoWrapperExcludePath[] {
        new AutoWrapperExcludePath("/notice/.*|/notice", ExcludeMode.Regex)            
    }
});

Support for Dapr

Prior to 4.5.x version, the Dapr Pubsub request cannot reach the configured Controller Action after being wrapped by AutoWrapper. The series path starting with "/dapr/" needs to be excluded to make the dapr request take effect:

app.UseApiResponseAndExceptionWrapper(new AutoWrapperOptions
{
    ExcludePaths = new AutoWrapperExcludePath[] {
        new AutoWrapperExcludePath("/dapr", ExcludeMode.StartWith)          
    }
});

Support for NetCoreApp2.1 and NetCoreApp2.2

AutoWrapper version 2.x - 3.0 also supports both .NET Core 2.1 and 2.2. You just need to install the Nuget package Newtonsoft.json first before AutoWrapper.Core.

Unwrapping the Result from .NET Client

AutoWrapper.Server is simple library that enables you unwrap the Result property of the AutoWrapper's ApiResponse object in your C# .NET Client code. The goal is to deserialize the Result object directly to your matching Model without having you to create the ApiResponse schema.

For example:

[HttpGet]
public async Task<IEnumerable<PersonDTO>> Get()
{
    var client = HttpClientFactory.Create();
    var httpResponse = await client.GetAsync("https://localhost:5001/api/v1/persons");

    IEnumerable<PersonDTO> persons = null;
    if (httpResponse.IsSuccessStatusCode)
    {
        var jsonString = await httpResponse.Content.ReadAsStringAsync();
        persons = Unwrapper.Unwrap<IEnumerable<PersonDTO>>(jsonString);
    }

    return persons;
}

For more information, see: AutoWrapper.Server

Samples

• AutoWrapper: Prettify Your ASP.NET Core APIs with Meaningful Responses
• AutoWrapper: Customizing the Default Response Output
• AutoWrapper Now Supports Problem Details For Your ASP.NET Core APIs
• AutoWrapper.Server: Sample Usage

Feedback and Give a Star! ⭐

I’m pretty sure there are still lots of things to improve in this project. Try it out and let me know your thoughts.

Feel free to submit a ticket if you find bugs or request a new feature. Your valuable feedback is much appreciated to better improve this project. If you find this useful, please give it a star to show your support for this project.

Contributors

• Vincent Maverick Durano - Blog
• Huei Feng - Github Profile
• ITninja04 - Github Profile
• Rahmat Slamet - Github Profile
• abelfiore - Github Profile
• chen1tian - Github Profile

Want to contribute? Please read the CONTRIBUTING docs here.

Release History

See: Release Log

License

This project is licensed under the MIT License - see the LICENSE.md file for details.

Donate

If you find this project useful — or just feeling generous, consider buying me a beer or a coffee. Cheers! 🍻 ☕

Thank you!