如何使用Dispatchproxy封装REST API，让API调用更简单。
1、创建HttpClientDispathProxy类继承自DispatchProxy
public class HttpClientDispathProxy<TInterface> : DispatchProxy
{
public Func<string> token;
public ApiClient client;
protected override object? Invoke(MethodInfo? targetMethod, object?[]? args)
{
if (targetMethod?.ReturnType == typeof(Task))
return this.InvokeAsync(targetMethod, args);
if (IsGenericTask(targetMethod?.ReturnType))
{
var method = this.GetType().GetMethod("InvokeAsyncT", BindingFlags.NonPublic | BindingFlags.Instance);
var methodInfo = method!.MakeGenericMethod(targetMethod?.ReturnType?.GenericTypeArguments ?? new Type[] { });
return methodInfo.Invoke(this, new object[] { targetMethod, args }); ;
}
if (targetMethod?.ReturnType != typeof(void))
{
var response = this.SendAsync(targetMethod, args);
var result = this.client.ReadResponse(targetMethod.ReturnType, response.Result);
return result;
}
return default;
}
protected async Task InvokeAsync(MethodInfo? method, object?[]? args)
{
await this.SendAsync(method, args);
}
protected async Task<T> InvokeAsyncT<T>(MethodInfo? method, object?[]? args)
{
var response = await this.SendAsync(method, args);
var result = this.client.ReadJson<T>(response);
return result;
}
protected virtual async Task<string> SendAsync(MethodInfo methodInfo, Object[] args)
{
var attr = methodInfo.GetCustomAttribute<ApiAttribute>();
if (attr == null)
throw new ArgumentNullException(nameof(attr));
using (HttpRequestMessage request = new())
{
request.Headers.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", token());
BuildHttpRequestMessage(methodInfo, args, attr, request);
return await client.SendAsync(request);
}
}
protected virtual void BuildHttpRequestMessage(MethodInfo method, object[] args, ApiAttribute attr, HttpRequestMessage request)
{
request.Method = _ConvertHttpMethod(attr.HttpMethod);
var parameters = this.GetParameters(method, args);
if (attr.HttpMethod == "POST" || attr.HttpMethod == "PUT" || attr.HttpMethod == "PTCH")
{
request.RequestUri = GetRequestUrl(true, attr.Url, parameters.uri);
if (parameters.forms != null)
{
JsonSerializerOptions op = new() { DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull };
var contentString = "";
if (parameters.forms.Count() == 1)
{
contentString = JsonSerializer.Serialize(parameters.forms.First().Value, op);
}
else if (parameters.forms.Count() > 1)
{
contentString = JsonSerializer.Serialize(parameters.forms, op);
}
if (!String.IsNullOrEmpty(contentString))
{
request.Content = new StringContent(contentString, Encoding.UTF8, "application/json");
}
}
}
else
{
request.RequestUri = GetRequestUrl(false, attr.Url, parameters.uri);
}
}
protected virtual Uri GetRequestUrl(Boolean isPost, String path, Dictionary<String, Object> parameters)
{
var url = $"{path.TrimEnd('/')}".ToLower();
var qMark = url.IndexOf("?") == -1 ? "?" : String.Empty;
var and = String.IsNullOrEmpty(qMark) ? "&" : String.Empty;
if (parameters != null)
{
List<String> parsedParam = new();
foreach (var kv in parameters)
{
var holder = "{" + kv.Key.ToLower() + "}";
if (url.Contains(holder))
{
if (kv.Value == null)
{
throw new ArgumentNullException(kv.Key, "Parameter in uri can not be null.");
}
String tempValue;
if (kv.Value is Enum enumValue)
{
tempValue = enumValue.ToString();//enumValue.GetEnumDescription();
}
else
tempValue = kv.Value.ToString();
url = url.Replace(holder, tempValue);
parsedParam.Add(kv.Key);
}
}
var leftParams = parameters.Where(i => !parsedParam.Contains(i.Key));
if (leftParams.Any())
{
List<String> tempParamsList = new();
foreach (var item in leftParams)
{
var value = item.Value?.ToString();
if (string.IsNullOrEmpty(value))
{
if (item.Value is GraphQuery query)
{
if (query.Top != 0)
{
tempParamsList.Add("$top=" + query.Top);
}
if (string.IsNullOrEmpty(query.Expand))
{
tempParamsList.Add("$expand=" + query.Expand);
}
if (string.IsNullOrEmpty(query.Select))
{
tempParamsList.Add("$select=" + query.Select);
}
if (string.IsNullOrEmpty(query.Orderby))
{
tempParamsList.Add("$orderby=" + query.Orderby);
}
if (string.IsNullOrEmpty(query.Filter))
{
tempParamsList.Add("$filter=" + query.Filter);
}
if (query.Skip != 0)
{
tempParamsList.Add("$skip=" + query.Skip);
}
if (query.Count)
{
tempParamsList.Add("$count=true");
}
}
else
{
tempParamsList.Add($"{item.Key}={HttpUtility.UrlEncode(item.Value.ToString()).Replace("+", "%20")}");
}
}
}
url = $"{url}{qMark}{and}{String.Join("&", tempParamsList.ToArray())}";
}
}
return new Uri(url);
}
protected virtual (Dictionary<string, object> uri, Dictionary<string, object> forms) GetParameters(MethodInfo method, object[] args)
{
var uri = new Dictionary<string, object>();
var forms = new Dictionary<string, object>();
if (args != null && args.Any())
{
var parameters = method.GetParameters();
foreach (var param in parameters)
{
var customAttributes = param.GetCustomAttributes();
foreach (var customAttribute in customAttributes)
{
if (customAttribute is ApiParameterAttribute attribute)
{
if (attribute.IsRequestUri)
if (!string.IsNullOrEmpty(attribute.Endpoint))
uri.Add(attribute.Name ?? "endpoint", new Uri(attribute.Endpoint));
else
uri.Add(attribute.Name, args[param.Position]);
else
forms.Add(attribute.Name, args[param.Position]);
}
else
forms.Add(param.Name, args[param.Position]);
}
}
}
return (uri, forms);
}
private static HttpMethod _ConvertHttpMethod(string method)
=> method.ToLowerInvariant() switch
{
"get" => HttpMethod.Get,
"post" => HttpMethod.Post,
"put" => HttpMethod.Put,
"delete" => HttpMethod.Delete,
"patch" => HttpMethod.Patch,
_ => throw new ArgumentOutOfRangeException($"The method type is not supported. method: {method}.")
};
private static Boolean IsGenericTask(Type? type)
{
if ((type?.IsGenericType ?? false) && type?.GetGenericTypeDefinition() == typeof(Task<>))
return true;
return false;
}
}
dispachproxy
2、创建HttpClientProxy类继承自HttpClientDispathProxy，用于创建泛型Interface实例
public class HttpClientProxy<TInterface>: HttpClientDispathProxy<TInterface>
{
public static TInterface Create(ApiClient client, Func<string> func)
{
Object proxy = Create<TInterface, HttpClientDispathProxy<TInterface>>()!;
((HttpClientDispathProxy<TInterface>)proxy).token = func;
((HttpClientDispathProxy<TInterface>)proxy).client = client;
return (TInterface)proxy;
}
}
proxy
3、创建ApiClient 类调用interface实例方法
public partial class ApiClient
{
public T GetApiService<T>(Func<string> token) where T : IApiService
{
return HttpClientProxy<T>.Create(this, token);
}
}
APIClient
这里指定partial class，原因是方便扩展
public partial class ApiClient
{
private readonly IHttpClientFactory _httpClient;
public ApiClient(IHttpClientFactory httpClient)
{
this._httpClient = httpClient;
}
internal async Task<string> SendAsync(HttpRequestMessage request)
{
using var response = await this._httpClient.CreateClient().SendAsync(request);
var content = await response.Content.ReadAsStringAsync();
if (response.IsSuccessStatusCode)
return content;
throw new ApiClientException(response.StatusCode, content);
}
internal Object ReadResponse(Type type, String content)
{
if (!string.IsNullOrEmpty(content) && type != typeof(void))
{
try
{
return System.Text.Json.JsonSerializer.Deserialize(content, type);
}
catch (Exception ex)
{
throw new ApiClientException(ex.Message);
}
}
return default;
}
internal T ReadJson<T>(String content)
{
if(!string.IsNullOrEmpty(content))
try
{
return (T)this.ReadResponse(typeof(T), content);
}
catch (Exception ex)
{
throw new ApiClientException(ex.Message);
}
return default;
}
}
APIClient
4、创建接口，添加对应attribute
public interface IApiService
{
[Api(HttpMethod = "GET", Url = "{endpoint}WeatherForecast")]
Task<IEnumerable<WeatherForecast>> GetAsync(
[ApiParameter(Endpoint = "https://localhost:7101", IsRequestUri = true)] string endpoint = default
);
}
interface
ApiAttribute
[AttributeUsage(AttributeTargets.Method)]
public class ApiAttribute : Attribute
{
public string HttpMethod { get; set; }
public string Url { get; set; }
}
api attribute
ApiParameterAttribute
public class ApiParameterAttribute: Attribute
{
public string Name { get; set; }
public bool IsRequestUri { get; set; }
public string Endpoint { get; set; }
public ApiParameterAttribute()
{
}
public ApiParameterAttribute(string name)
{
Name = name;
}
}
api parameter attribute
5、exception
public class ApiClientException : Exception
{
public HttpStatusCode StatusCode { get; set; }
public ApiClientException(HttpStatusCode httpStatusCode, string message)
: base(message)
{
StatusCode = httpStatusCode;
}
public ApiClientException(string message)
: base(message)
{
}
}
exception
6、demo controller
[ApiExplorerSettings(GroupName = "demo1")]
[ApiController]
[Route("[controller]")]
public class SwagggerDemoController : ControllerBase
{
private readonly ApiClient _apiClient;
public SwagggerDemoController(ApiClient apiClient)
{
this._apiClient = apiClient;
}
[HttpGet("getdispatchproxydemo"), Authorize]
public IEnumerable<WeatherForecast> DispatchProxyDemo(string token)
{
var client = _apiClient.GetApiService<IApiService>(() => token);
var response = client.GetAsync().GetAwaiter().GetResult();
return response;
}
}
controller
7、验证，正确取到数据
Notes:这里加了authentication验证，之前blog中有提过，可以参考。
OK 搞定！
标签：return,string,NetCore,args,DispatchProxy,var,new,public From： https://www.cnblogs.com/qindy/p/17102811.html