ServiceCollectionExtension.cs

namespace Salt.HttpClient;

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using Microsoft.Extensions.DependencyInjection;
using Polly;
using Polly.Extensions.Http;

/// <summary>
/// Inject SaltHttpClients to IServiceCollection
/// </summary>
public static class ServiceCollectionExtension
{
    private static IAsyncPolicy<HttpResponseMessage> GetRetryPolicy(int times) =>
        HttpPolicyExtensions
            .HandleTransientHttpError()
            .OrResult(msg => msg.StatusCode is HttpStatusCode.NotFound)
            .WaitAndRetryAsync(times, retryAttempt => TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)));

    /// <summary>
    /// Добавление в DI типизированного httpClient
    /// </summary>
    /// <param name="serviceCollection">IServiceCollection</param>
    /// <param name="baseUrl">базовый Url конечного узла</param>
    /// <param name="timeout">Таймаут запроса</param>
    /// <param name="handlerLifetime">HttpHandler lifetime. If null, set as Timespan.FromMinutes(5)</param>
    /// <param name="baseHeaders">Базовые headers для каждого запроса</param>
    /// <param name="retryNumber">Количество попыток подключения, если в качестве ответов падают ошибки 5ХХ, 408 (timeout) или 404 (notFound)</param>
    /// <typeparam name="TRealization">Тип, наследующися от AbstractHttpClient</typeparam>
    /// <returns></returns>
    public static IServiceCollection AddSaltHttpClient<TRealization>(this IServiceCollection serviceCollection
        , Uri baseUrl
        , TimeSpan? timeout = null
        , TimeSpan? handlerLifetime = null
        , HttpHeaders baseHeaders = null
        , int retryNumber = 0)
        where TRealization : AbstractHttpClient
    {
        IHttpClientBuilder httpClientBuilder = serviceCollection.AddHttpClient<TRealization>(httpClient =>
            HttpClientConfig(httpClient, baseUrl, timeout, baseHeaders));

        HttpClientBuilderConfig(httpClientBuilder, handlerLifetime, retryNumber);

        return serviceCollection;
    }

    /// <summary>
    /// Добавление в DI типизированного httpClient
    /// </summary>
    /// <param name="serviceCollection">IServiceCollection</param>
    /// <param name="baseUrl">базовый Url конечного узла</param>
    /// <param name="timeout">Таймаут запроса</param>
    /// <param name="handlerLifetime">HttpHandler lifetime. If null, set as Timespan.FromMinutes(5)</param>
    /// <param name="baseHeaders">Базовые headers для каждого запроса</param>
    /// <param name="retryNumber">Количество попыток подключения, если в качестве ответов падают ошибки 5ХХ, 408 (timeout) или 404 (notFound)</param>
    /// <typeparam name="TClient">Тип типа клиента. Будет зарегистрирован как Transient</typeparam>
    /// <typeparam name="TRealization">Тип, наследующися от AbstractHttpClient</typeparam>
    /// <returns></returns>
    public static IServiceCollection AddSaltHttpClient<TClient, TRealization>(this IServiceCollection serviceCollection
        , Uri baseUrl
        , TimeSpan? timeout = null
        , TimeSpan? handlerLifetime = null
        , HttpHeaders baseHeaders = null
        , int retryNumber = 0)
        where TClient : class
        where TRealization : AbstractHttpClient, TClient
    {
        IHttpClientBuilder httpClientBuilder = serviceCollection.AddHttpClient<TClient, TRealization>(httpClient =>
            HttpClientConfig(httpClient, baseUrl, timeout, baseHeaders));

        HttpClientBuilderConfig(httpClientBuilder, handlerLifetime, retryNumber);
        return serviceCollection;
    }

    #region private

    /// <summary>
    /// Настроить HttpClient
    /// </summary>
    /// <param name="httpClient">Созданный httpClient</param>
    /// <param name="baseUrl">базовый Url конечного узла</param>
    /// <param name="timeout">Таймаут запроса</param>
    /// <param name="baseHeaders">Базовые headers для каждого запроса</param>
    private static void HttpClientConfig(System.Net.Http.HttpClient httpClient
        , Uri baseUrl
        , TimeSpan? timeout = null
        , HttpHeaders baseHeaders = null)
    {
        httpClient.BaseAddress = baseUrl;
        if (timeout.HasValue)
            httpClient.Timeout = timeout.Value;
        if (baseHeaders != null && baseHeaders.Any())
            foreach (KeyValuePair<string, IEnumerable<string>> header in baseHeaders)
                httpClient.DefaultRequestHeaders.Add(header.Key, header.Value);
    }

    /// <summary>
    /// Настроить IHttpClientBuilder
    /// </summary>
    /// <param name="httpClientBuilder">Созданный IHttpClientBuilder</param>
    /// <param name="handlerLifetime">HttpHandler lifetime. If null, set as Timespan.FromMinutes(5)</param>
    /// <param name="retryNumber">Количество попыток подключения, если в качестве ответов падают ошибки 5ХХ, 408 (timeout) или 404 (notFound)</param>
    private static void HttpClientBuilderConfig(IHttpClientBuilder httpClientBuilder
        , TimeSpan? handlerLifetime = null
        , int retryNumber = 0)
    {
        httpClientBuilder.SetHandlerLifetime(handlerLifetime ?? TimeSpan.FromMinutes(5));

        if (retryNumber > 0)
            httpClientBuilder.AddPolicyHandler(GetRetryPolicy(retryNumber));
    }

    #endregion
}