如何在ASP.NET Core中缓存请求

Question

我正在寻找如何在ASP.NET Core 2.x中缓存请求？

我有API代理，它总是使用相同的请求返回不同的响应(同义词组合使用AI，因此这就是我不想缓存响应的原因(。

我想缓存请求，因为它总是相同的(总是相同的基本身份验证和参数来戳我代理的另一个API(。

由于请求使用文件input.xml作为参数，我想知道在哪里可以缓存该文件以及

我的控制器：

[Route("api/v1/[controller]")]
public class CompositionController : Controller
{
[HttpGet]
public async Task<string> Get(string transformation = "xml")
{
var httpClient = new HttpClient();
const string authScheme = @"Basic";
const string name = @"myUserName";
const string password = @"myPassword";
var authBytes = Encoding.ASCII.GetBytes($@"{name}:{password}");
var auth64BaseString = Convert.ToBase64String(authBytes);
httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue(authScheme, auth64BaseString);
const string fileName = @"input.xml";
var inputBytes = File.ReadAllBytes(fileName);
var byteArrayContent = new ByteArrayContent(inputBytes);
const string formDataKey = @"""file""";
const string formDataValue = @"""input.xml""";
var multipartFormDataContent = new MultipartFormDataContent()
{
{ byteArrayContent, formDataKey, formDataValue }
};
const string url = @"http://baseurl:port/my/resource/is/there.do?transformation=" + transformation;
var response = await httpClient.PostAsync(url, multipartFormDataContent);
return await response.Content.ReadAsStringAsync();
}
}

Answer 1

您真的不应该每次调用端点都构造HttpClient。

这就是我要做的：

//create a service that caches HttpClient based on url
public interface IHttpClientService
{
IHttpClient GetClient(string baseHref);
void AddClient(HttpClient client, string baseHref);
}
//implement your interface
public class HttpClientService : IHttpClientService
{
private readonly ConcurrentDictionary<string, IHttpClient> _httpClients;
public HttpClientService()
{
_httpClients = new ConcurrentDictionary<string, IHttpClient>();
}
public void AddClient(HttpClient client, string baseHref)
{
_httpClients.
.AddOrUpdate(baseHref, client, (key, existingHttpClient) => existingHttpClient);
}
public IHttpClient GetClient(string baseHref)
{
if (_httpClients.TryGetValue(baseHref, out var client))
return client;
return null;
}
}
//register as singleton Startup.cs
services.AddSingleton<IHttpClientService, HttpClientService>();
//inject into Controller
[HttpGet]
public async Task<string> Get(string transformation = "xml")
{
const string url = @"http://baseurl:port/my/resource/is/there.do?transformation=" + transformation;

var httpClient = _httpService.GetClient(url);
if(httpClient == null)
{
httpClient = new HttpClient(url);
const string authScheme = @"Basic";
const string name = @"myUserName";
const string password = @"myPassword";
var authBytes = Encoding.ASCII.GetBytes($@"{name}:{password}");
var auth64BaseString = Convert.ToBase64String(authBytes);
httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue(authScheme, auth64BaseString);
const string fileName = @"input.xml";
var inputBytes = File.ReadAllBytes(fileName);
var byteArrayContent = new ByteArrayContent(inputBytes);
const string formDataKey = @"""file""";
const string formDataValue = @"""input.xml""";
var multipartFormDataContent = new MultipartFormDataContent()
{
{ byteArrayContent, formDataKey, formDataValue }
};
_httpClient.AddClient(httpClient, url);
}
else
{
//You can cache your MultipartFormDataContent in MemoryCache or same cache as HttpClient
//Get MultipartFormDataContent from cache and
}
var response = await httpClient.PostAsync(url, multipartFormDataContent);
return await response.Content.ReadAsStringAsync();
}