WebApiClient与Asp.net core DI的结合
1 WebApiClient
一款基于HttpClient封装，只需要定义c#接口并修饰相关特性，即可异步调用远程http接口的客户端库
2 Http接口的注册与提供
2.1 声明远程端http接口
public interface IBaiduApi : IHttpApi
{
[HttpGet("/s")]
ITask<string> GetAsync(string word);
}
2.2 远程端http的注册
使用HttpClientFactory管理HttpClient的创建，利用AddTypedClient创建远程http接口的WebApiClient调用代理，同时给HttpApiConfig配置ServiceProvider实例。
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
services.AddHttpApiTypedClient<IBaiduApi>().ConfigureHttpApiConfig((c, p) =>
{
c.HttpHost = new Uri("http://www.baidu.com/");
});
}
/// <summary>
/// 添加HttpApiClient的别名HttpClient
/// </summary>
/// <typeparam name="TInterface">接口类型</typeparam>
/// <param name="services"></param>
/// <param name="configOptions">配置选项</param>
/// <exception cref="ArgumentNullException"></exception>
/// <returns></returns>
public static IHttpClientBuilder AddHttpApiTypedClient<TInterface>(this IServiceCollection services, Action<HttpApiConfig, IServiceProvider> configOptions)
where TInterface : class, IHttpApi
{
if (configOptions == null)
{
throw new ArgumentNullException(nameof(configOptions));
}
return services
.AddHttpClient<TInterface>()
.AddTypedClient((httpClient, provider) =>
{
var httpApiConfig = new HttpApiConfig(httpClient)
{
ServiceProvider = provider
};
configOptions.Invoke(httpApiConfig, provider);
return HttpApiClient.Create<TInterface>(httpApiConfig);
});
}
2.3 远程端http接口的提供
可以使用构造器注入IBaiduApi或[FromServices]特性得到远程接口代理实例。
public class HomeController : Controller
{
// GET: /<controller>/
public async Task<IActionResult> Index([FromServices] IBaiduApi baiduApi)
{
var html = await baiduApi.GetAsync("WebApiClient");
return Content(html);
}
}
3 WebApiClient过滤器的服务提供
3.1 在接口上使用自定义LogFilter
[LogFilter]
public interface IBaiduApi : IHttpApi
{
[HttpGet("/s")]
ITask<string> GetAsync(string word);
}
3.2 使用context.GetService获取服务实例
class LogFilter : ApiActionFilterAttribute
{
public override Task OnBeginRequestAsync(ApiActionContext context)
{
var logger = context.GetService<ILoggerFactory>().CreateLogger("Baidu");
logger.LogWarning($"request {context.ApiActionDescriptor.Name} {context.RequestMessage.RequestUri}");
return base.OnBeginRequestAsync(context);
}
}
3.3 日志服务输出日志样例
warn: Baidu[0]
request GetAsync http://www.baidu.com/s?word=WebApiClient
