.NetCore Flurl.Http 集成 Microsoft.Extensions.ServiceDiscovery-优快云博客

本文链接：https://blog.youkuaiyun.com/hefeng_aspnet/article/details/144910862

.Net8.0及以上版本，微软官方提供了服务发现Nuget包Microsoft.Extensions.ServiceDiscovery，能够对 HttpClient 请求服务进行服务发现和解析，对于轻量级Flurl.Http 来说，也可以进行集成，主要思路是通过HttpClientFactory 构建HttpClient 实例，调用new FlurlClient(httpClientFactory.CreateClient()) 实现，以下具体介绍集成过程同时与常规的 HttpClient 写法做一个比较。

服务发现
引入依赖包

Microsoft.Extensions.ServiceDiscovery 当前对应版本为9.0.0。可以通过Nuget 管理器引入到项目中。

dotnet add package Microsoft.Extensions.ServiceDiscovery

基础配置服务

主类中主体结构如下：
public class Program
{
public static void Main(string[] args)
{
var builder = WebApplication.CreateBuilder(args);

// 注册服务
IServiceCollection services = builder.Services;

// 添加服务发现
services.AddServiceDiscovery();

// 设置httpclient构建添加服务发现
services.ConfigureHttpClientDefaults(static http =>
{
// Turn on service discovery by default
http.AddServiceDiscovery();
});

// 注册请求服务
services.AddSingleton<MapClientService>();

var app = builder.Build();

app.MapControllers();

app.Run();
}

其中，AddServiceDiscovery() 注册服务发现。

builder.Services.AddServiceDiscovery();

MapClientService 实际请求处理类。

// 注册请求服务
services.AddSingleton<MapClientService>();
ConfigureHttpClientDefaults(static http =>{})添加全局HttpClient 实例应用服务发现。

// 设置httpclient构建添加服务发现
services.ConfigureHttpClientDefaults(static http =>
{
// Turn on service discovery by default
http.AddServiceDiscovery();
});

添加服务发现配置appsettings.json 根层级。

{
   "Services": {
   "mapservice": { // 服务名称
   "http": [ // http请求
   "192.168.31.116:6003" // 服务实际服务地址和端口
   ]
}
}
}

请求实现类
普通工厂创建实例

private readonly MapOptions _options;
private readonly IDistributedCache _cache;
private readonly IHttpClientFactory _httpClientFactory;
public MapClientService(IOptions<MapOptions> map,IDistributedCache cache,IHttpClientFactory httpClientFactory)
{
_options = map?.Value;
_cache = cache;
_httpClientFactory = httpClientFactory;
}
// 请求服务地址(期望通过服务发现进行解析)
private const string _url = "http://mapservice";
public const string token = "/api/identity/token";
public async Task<string> Token()
{
string key = _cache.GetString(token);
if (key == null) {
var data = new
{
grantType = "password",
account = _options.Uname,
password = _options.Pwd
};
// 构建请求--------------------------------------------------
HttpClient httpClient = _httpClientFactory.CreateClient();
httpClient.DefaultRequestHeaders.Add("Authorization", $"Bearer {token}");
HttpRequestMessage httpRequest = new HttpRequestMessage();
httpRequest.Method = HttpMethod.Post;
httpRequest.RequestUri = new Uri($"{_url}{updateMapState}");
httpRequest.Content = new StringContent(JsonSerializer.Serialize(data));
httpRequest.Content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
HttpResponseMessage httpResponse = await httpClient.SendAsync(httpRequest);
var msg = await httpResponse.Content.ReadAsStringAsync();
AjaxResult<TokenResult> result = JsonSerializer.Deserialize<AjaxResult<TokenResult>>(msg);
if (result.Type == 200)
{
key = result.Data.AccessToken;
_cache.SetString(token, key,new DistributedCacheEntryOptions { AbsoluteExpirationRelativeToNow = TimeSpan.FromSeconds(300)});
}
}
return key;
}

运行输入日志如下：

info: System.Net.Http.HttpClient.Default.LogicalHandler[100]
Start processing HTTP request POST http://mapservice/api/urlmap/updateurlmapstate
info: System.Net.Http.HttpClient.Default.ClientHandler[100]
Sending HTTP request POST http://192.168.31.116:6003/api/urlmap/updateurlmapstate

使用Flurl.Http请求

直接使用Flurl.Http 对之前的HttpClientFactory 进行改造。

using Flurl.Http;

private readonly MapOptions _options;
private readonly IDistributedCache _cache;
private readonly IFlurlClient _flurlClient;
public MapClientService(IOptions<MapOptions> map,IDistributedCache cache)
{
_options = map?.Value;
_cache = cache;
}
// 请求服务地址(期望通过服务发现进行解析)
private const string _url = "http://mapservice";
public const string token = "/api/identity/token";
public async Task<string> Token()
{
string key = _cache.GetString(token);
if (key == null) {
var data = new
{
grantType = "password",
account = _options.Uname,
password = _options.Pwd
};
// 构建请求--------------------------------------------------
var result = await $"{_url}{token}".PostJsonAsync(data).ReceiveJson<AjaxResult<TokenResult>>();

if (result.Type == 200)
{
key = result.Data.AccessToken;
_cache.SetString(token, key,new DistributedCacheEntryOptions { AbsoluteExpirationRelativeToNow = TimeSpan.FromSeconds(300)});
}
}
return key;
}

通过FlurlClient并支持服务发现

private readonly MapOptions _options;
private readonly IDistributedCache _cache;
private readonly IFlurlClient _flurlClient;
public MapClientService(IOptions<MapOptions> map,IDistributedCache cache,IHttpClientFactory httpClientFactory)
{
_options = map?.Value;
_cache = cache;
_flurlClient = new FlurlClient(httpClientFactory.CreateClient());
}
// 请求服务地址(期望通过服务发现进行解析)
private const string _url = "http://mapservice";
public const string token = "/api/identity/token";
public async Task<string> Token()
{
string key = _cache.GetString(token);
if (key == null) {
var data = new
{
grantType = "password",
account = _options.Uname,
password = _options.Pwd
};
// 构建请求--------------------------------------------------
var result = await _flurlClient.Request($"{_url}{token}").PostJsonAsync(data).ReceiveJson<AjaxResult<TokenResult>>();

if (result.Type == 200)
{
key = result.Data.AccessToken;
_cache.SetString(token, key,new DistributedCacheEntryOptions { AbsoluteExpirationRelativeToNow = TimeSpan.FromSeconds(300)});
}
}
return key;
}

运行项目，程序输入如下，与HttpClientFactory 构建实例发起请求输出一致。

info: System.Net.Http.HttpClient.Default.LogicalHandler[100]
Start processing HTTP request POST http://mapservice/api/identity/token2
info: System.Net.Http.HttpClient.Default.ClientHandler[100]
Sending HTTP request POST http://192.168.31.116:6003/api/identity/token2

可以发现，对应请求日志输出，两者并无差异，也能够成功解析，表示通过IHttpClientFactory 构建实例能够与Flurl.Http 中进行集成。既简化了简单的接口请求，又能够使用HttpClient 官方提供的一些扩展功能。

参考文章：Flurl.Http集成Microsoft.Extensions.ServiceDiscovery - 关关长语 - 博客园

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