HttpClient 使用

Api支持

HttpClient 是基于Task的异步方法组，支持取消、超时异步特性，其可以分类为以下：

Restful: GetAsync,PostAsync,DeleteAsync,PutAsync

HttpHeaders属性：DefaultRequestHeaders

Timeout属性：Timeout，相比HttpRequest的参数，更加地智能，用TimeSpan替换了int。

Get扩展（本质上是封装了GetAsync()）：GetStringAsync，GetStreamAsync，

GetByteArrayAsync

SendAsync：Restful的实现应该是封装了此方法。需要一个HttpRequestMessage作为参数。

HttpContent

使用post方式请求示例：

public static async Task<string> CreateUrlAsync(string url, Dictionary<string, string> parameters, string accessToken, int timeount = 10)
{
    HttpClient httpClient = new HttpClient(new MyHttpClientHandlerProxy(accessToken));
    httpClient.DefaultRequestHeaders.Add("Authorization", "Bearer " + accessToken);
    httpClient.Timeout = TimeSpan.FromSeconds(timeount);

    FormUrlEncodedContent content = new FormUrlEncodedContent(parameters);
    var response = await httpClient.PostAsync(url, content);
    var str = await response.Content.ReadAsStringAsync();

    return str;
}

其他的Content类型：

StreamContent，StringContent，MutilpartContent，MultipartFormDataContent

HttpClientHandler

作为一个代理角色，可以支持自定义的处理方式。

public class MyHttpClientHandlerProxy : HttpClientHandler
{
    private string accessToken;
    public MyHttpClientHandlerProxy(string accessToken)
    {
        this.accessToken = accessToken;
    }

    protected async override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken)
    {
        //处理Headers
        request.Headers.Referrer = new Uri("www.imctf.com");
        request.Headers.Add("Authorization", "Bearer " + accessToken);
        request.Headers.Add("UserAgent", "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727)");

        //执行
        var response = await base.SendAsync(request, cancellationToken);

        //处理编码
        var contentType = response.Content.Headers.ContentType;
        if (string.IsNullOrEmpty(contentType.CharSet))
        {
            contentType.CharSet = "GBK";
        }

        return response;
    }
}

使用：

HttpClient httpClient = new HttpClient(new MyHttpClientHandlerProxy(accessToken));