C#高效使用HttpClient

Question

我有一段从网页下载内容的代码，如下：

public class Downloader
{
    private readonly HttpClient _client = new HttpClient();

    public async Task<(HttpStatusCode, string)> GetContent(Uri site)
    {
        HttpStatusCode status = HttpStatusCode.Unused;
        try
        {
            var response = await _client.GetAsync(site);
            status = response.StatusCode;

            var content = await response.Content.ReadAsStringAsync();

            return (status, content);
        }
        catch (Exception e)
        {
            ...
        }
    }
}

请注意，我有一个 HttpClient class 的只读实例。我的应用程序只有一个 Downloader 实例。就是上面展示的HttpClient的初始化，比每次调用GetContent创建一个实例更高效的初始化HttpClient的方式，如下：

public class Downloader
{
    public async Task<(HttpStatusCode, string)> GetContent(Uri site)
    {
        HttpStatusCode status = HttpStatusCode.Unused;
        try
        {
            using var client = new HttpClient();
            var response = await client.GetAsync(site);
            status = response.StatusCode;

            var content = await response.Content.ReadAsStringAsync();

            return (status, content);
        }
        catch (Exception e)
        {
            ...
        }
    }
}

在此先感谢您的建议！

注意：对于此示例或依赖项注入，我对 HttpClientFactory 不感兴趣。

Answer 1

静态HttpClient（或单例上的实例字段，本质上是同一件事）是proper way to go for modern versions of .NET Core. The SocketsHttpHandler in .NET Core 2.1 and newer handles the DNS problems inherent in the singleton HttpClient approach。

C#高效使用HttpClient

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