WebApiClientCore使用說明

前言

我是WebApiClient庫的作者，目前在開發其.netcore版本，在整理其readme後，想想一來這部分內容可能對大家有用，二來興許能給WebApiClient帶人更多人氣，所以將readme作為部落格在此發表。

WebApiClientCore

WebApiClient.JIT的.netcore版本，基於HttpClient的高效能與高可擴充套件性於一體的宣告式Http客戶端庫，特別適用於微服務的restful資源請求，也適用於各種非標準的http介面請求。

PackageReference

<PackageReference Include="WebApiClientCore" Version="1.0.0-beta1" />

專案原因

1. WebApiClient很優秀，它將不同框架不同平臺都實現了統一的api
2. WebApiClient不夠優秀，它在.netcore下完全可以更好，但它不得不相容.net45開始所有框架而有所犧牲

相對變化

• 使用System.Text.Json替換Json.net，提升序列化效能
• 移除HttpApiFactory和HttApiConfig功能，使用Microsoft.Extensions.Http的HttpClientFactory
• 移除AOT功能，僅保留依賴於Emit的執行時代理
• 高效的ActionInvoker，對返回Task<>和ITask<>作不同處理
• 所有特性都都變成中介軟體，基於管道編排各個特性並生成Action執行委託
• 良好設計的HttpContext、ApiRequestContext、ApiParameterContext和ApiResponseContext

Benchmark

WebApiClientCore、WebApiClient.JIT與原生HttpClient的效能比較，相比原生的HttpClient，WebApiClientCore幾乎沒有效能損耗。

BenchmarkDotNet=v0.12.1, OS=Windows 10.0.18362.778 (1903/May2019Update/19H1)
Intel Core i3-4150 CPU 3.50GHz (Haswell), 1 CPU, 4 logical and 2 physical cores
.NET Core SDK=3.1.202
[Host] : .NET Core 3.1.4 (CoreCLR 4.700.20.20201, CoreFX 4.700.20.22101), X64 RyuJIT
DefaultJob : .NET Core 3.1.4 (CoreCLR 4.700.20.20201, CoreFX 4.700.20.22101), X64 RyuJIT

Method	Mean	Error	StdDev
WebApiClient_GetAsync	279.479 us	22.5466 us	64.3268 us
WebApiClientCore_GetAsync	25.298 us	0.4953 us	0.7999 us
HttpClient_GetAsync	2.849 us	0.0568 us	0.1393 us
WebApiClient_PostAsync	25.942 us	0.3817 us	0.3188 us
WebApiClientCore_PostAsync	13.462 us	0.2551 us	0.6258 us
HttpClient_PostAsync	4.515 us	0.0866 us	0.0926 us

宣告式介面定義

• 支援Task、Task<>和ITask<>三種非同步返回
• 支援模型自動轉換為Xml、Json、Form、和FormData共4種請求格式的內容
• 支援HttpResponseMessage、byte[]、string和Stream原生型別返回內容
• 支援原生HttpContent(比如StringContent)型別直接做為請求引數
• 內建豐富的能滿足各種環境的常用特性(ActionAttribute和ParameterAttribute)
• 內建常用的FormDataFile等引數型別，同時支援自定義IApiParameter引數型別作為引數值
• 支援使用者自定義IApiActionAttribute、IApiParameterAttribue、IApiReturnAttribute和IApiFilterAttribute

以下宣告的程式碼為使用WebApiClientCore.Extensions.OpenApi工具將openApi文件反向生成得到

namespace Petstore
{
    /// <summary>
    /// Everything about your Pets
    /// </summary>
    [LoggingFilter]
    [HttpHost("https://petstore.swagger.io/v2/")]
    public interface IPetApi : IHttpApi
    {
        /// <summary>
        /// Add a new pet to the store
        /// </summary>
        /// <param name="body">Pet object that needs to be added to the store</param>
        [HttpPost("pet")]
        Task AddPetAsync([Required] [JsonContent] Pet body, CancellationToken token = default);

        /// <summary>
        /// Update an existing pet
        /// </summary>
        /// <param name="body">Pet object that needs to be added to the store</param>
        [HttpPut("pet")]
        Task<HttpResponseMessage> UpdatePetAsync([Required] [JsonContent] Pet body, CancellationToken token = default);

        /// <summary>
        /// Finds Pets by status
        /// </summary>
        /// <param name="status">Status values that need to be considered for filter</param>
        /// <returns>successful operation</returns>
        [HttpGet("pet/findByStatus")]
        ITask<List<Pet>> FindPetsByStatusAsync([Required] IEnumerable<Anonymous> status);

        /// <summary>
        /// Finds Pets by tags
        /// </summary>
        /// <param name="tags">Tags to filter by</param>
        /// <returns>successful operation</returns>
        [Obsolete]
        [HttpGet("pet/findByTags")]
        ITask<List<Pet>> FindPetsByTagsAsync([Required] [PathQuery] IEnumerable<string> tags);

        /// <summary>
        /// Find pet by ID
        /// </summary>
        /// <param name="petId">ID of pet to return</param>
        /// <returns>successful operation</returns>
        [HttpGet("pet/{petId}")]
        ITask<Pet> GetPetByIdAsync([Required] long petId);

        /// <summary>
        /// Updates a pet in the store with form data
        /// </summary>
        /// <param name="petId">ID of pet that needs to be updated</param>
        /// <param name="name">Updated name of the pet</param>
        /// <param name="status">Updated status of the pet</param>
        [HttpPost("pet/{petId}")]
        Task UpdatePetWithFormAsync([Required] long petId, [FormContent] string name, [FormContent] string status);

        /// <summary>
        /// Deletes a pet
        /// </summary>
        /// <param name="api_key"></param>
        /// <param name="petId">Pet id to delete</param>
        [HttpDelete("pet/{petId}")]
        Task DeletePetAsync([Header("api_key")] string api_key, [Required] long petId);

        /// <summary>
        /// uploads an image
        /// </summary>
        /// <param name="petId">ID of pet to update</param>
        /// <param name="additionalMetadata">Additional data to pass to server</param>
        /// <param name="file">file to upload</param>
        /// <returns>successful operation</returns>
        [LoggingFilter(Enable = false)]
        [HttpPost("pet/{petId}/uploadImage")]
        ITask<ApiResponse> UploadFileAsync([Required] long petId, [FormDataContent] string additionalMetadata, FormDataFile file);
    }
}

另一個例子是WebApiClientCore.Extensions.OAuths.IOAuthClient介面宣告

using System;
using System.ComponentModel.DataAnnotations;
using System.Diagnostics.CodeAnalysis;
using System.Threading.Tasks;
using WebApiClientCore.Attributes;

namespace WebApiClientCore.Extensions.OAuths
{
    /// <summary>
    /// 定義Token客戶端的介面
    /// </summary>
    [LoggingFilter]
    [XmlReturn(Enable = false)]
    [JsonReturn(EnsureMatchAcceptContentType = false, EnsureSuccessStatusCode = false)]
    public interface IOAuthClient
    {
        /// <summary>
        /// 以client_credentials授權方式獲取token
        /// </summary>
        /// <param name="endpoint">token請求地址</param>
        /// <param name="credentials">身份資訊</param>
        /// <returns></returns>
        [HttpPost]
        [FormField("grant_type", "client_credentials")]
        Task<TokenResult> RequestTokenAsync([Required, Uri] Uri endpoint, [Required, FormContent] ClientCredentials credentials);

        /// <summary>
        /// 以password授權方式獲取token
        /// </summary>
        /// <param name="endpoint">token請求地址</param>
        /// <param name="credentials">身份資訊</param>
        /// <returns></returns>
        [HttpPost]
        [FormField("grant_type", "password")]
        Task<TokenResult> RequestTokenAsync([Required, Uri] Uri endpoint, [Required, FormContent] PasswordCredentials credentials);

        /// <summary>
        /// 重新整理token
        /// </summary>
        /// <param name="endpoint">token請求地址</param>
        /// <param name="credentials">身份資訊</param>
        /// <returns></returns>
        [HttpPost]
        [FormField("grant_type", "refresh_token")]
        Task<TokenResult> RefreshTokenAsync([Required, Uri] Uri endpoint, [Required, FormContent] RefreshTokenCredentials credentials);
    }
}

服務註冊與獲取

服務註冊

var services = new ServiceCollection();

services.AddHttpApi<IPetApi>(o =>
{
    o.UseParameterPropertyValidate = true;
    o.UseReturnValuePropertyValidate = false;
    o.KeyValueSerializeOptions.IgnoreNullValues = true;
    o.HttpHost = new Uri("http://localhost:6000/");
});

服務獲取

public class MyService
{
    private readonly IpetApi petApi;
    
    // 構造器注入IpetApi
    public MyService(IpetApi petApi)
    {
        tihs.petApi = petApi;
    }
}

請求和響應日誌

在整個Interface或某個Method上宣告[LoggingFilter]，即可把請求和響應的內容輸出到LoggingFactory中。

如果要排除某個Method不列印日誌（比如大流量傳輸介面），在方法上宣告[LoggingFilter(Enable = false)]，即可將本Method排除。

Accpet ContentType

這個用於控制客戶端希望伺服器返回什麼樣的內容格式，比如json或xml，預設的配置值是Accept: application/json; q=0.01, application/xml; q=0.01

如果想json優先，可以在Interface或Method上宣告[JsonReturn]，請求變為Accept: application/json, application/xml; q=0.01

如果想禁用其中一種，比如禁用xml，可以在Interface或Method上宣告[XmlReturn(Enable = false)]，請求變為Accept: application/json; q=0.01

請求條件重試

使用ITask<>非同步宣告，就有Retry的擴充套件，Retry的條件可以為捕獲到某種Exception或響應模型符合某種條件。

var result = await youApi.GetModelAsync(id: "id001")
    .Retry(maxCount: 3)
    .WhenCatch<Exception>()
    .WhenResult(r => r.ErrorCode > 0);

OAuths&Token

使用WebApiClientCore.Extensions.OAuths擴充套件，輕鬆支援token的獲取、重新整理與應用

1 註冊相應型別的TokenProvider

// 為介面註冊與配置token提者選項
services.AddClientCredentialsTokenProvider<IpetApi>(o =>
{
    o.Endpoint = new Uri("http://localhost:6000/api/tokens");
    o.Credentials.Client_id = "clientId";
    o.Credentials.Client_secret = "xxyyzz";
});

2 宣告對應的Token特性

/// <summary>
/// 使用者操作介面
/// </summary>
[ClientCredentialsToken]
public interface IpetApi
{
    ...
}

3 其它操作

清空Token，未過期的token也強制重新整理

var providers = serviceProvider.GetServices<ITokenProvider>();
foreach(var item in providers)
{
    // 強制清除token以支援下次獲取到新的token
    item.ClearToken();
}

自定義Token應用，得到token值，怎麼用自己說了算

class MyTokenAttribute : ClientCredentialsTokenAttribute
{
    protected override void UseTokenResult(ApiRequestContext context, TokenResult tokenResult)
    {
        context.HttpContext.RequestMessage.Headers.TryAddWithoutValidation("xxx-header", tokenResult.Access_token);
    }
}

/// <summary>
/// 使用者操作介面
/// </summary>
[MyToken]
public interface IpetApi
{
    ...
}