C# Httpclient編程

今天研究了一天C#如何添加cookie到httpcient裡面，從而發請求時，能把cookie作為頭部發出，最後發現根本加不進去。

Httpclient的cookie是來自上一個請求的響應，httpclient會自動把上一個請求的響應裡面的cookie儲存起來，所以當發送幾個有關聯的request，就必須要用同一個Httpclient

樣本：

//第一個請求

            HttpClient client = new HttpClient();
            // 為JSON格式添加一個Accept前序
            //client.DefaultRequestHeaders.Accept.Add(
            //    new MediaTypeWithQualityHeaderValue("application/json"));
            string strDecodeBody = HttpUtility.UrlEncode(strBody);
            HttpContent content = new StringContent(strDecodeBody);
            content.Headers.ContentType = new MediaTypeHeaderValue("application/json");

            client.DefaultRequestHeaders.Add("user-agent", "Mozilla/5.0");
            client.DefaultRequestHeaders.Add("Authentication", "123");

            HttpResponseMessage response = null;
            response = client.PostAsync(strIP, content).Result;

            if (response != null)
            {

                if (expectCode == HttpStatusCode.OK)
                {
                    var resultValue = response.Content.ReadAsStringAsync().Result;
                    string strResponse = HttpUtility.UrlDecode(resultValue.ToString());
                    string[] strCookies = (string[])response.Headers.GetValues("Set-Cookie");
                    if(strCookies.Length>0)
                    {
                        strCookie = strCookies[0].Substring(0, strCookies[0].IndexOf(';'));
                    }

                }
            }

 

//第二個請求，在這個請求裡，沒有設定cookie，由於跟第一個請求使用相同httpclient，所以cookie會自動放入要求標頭部發給伺服器

            string strEncodeBody = HttpUtility.UrlEncode(strBody);
            HttpContent content = new StringContent(strEncodeBody);
            content.Headers.ContentType = new MediaTypeHeaderValue("application/json");

            HttpResponseMessage response = null;
            response = client.PostAsync(strIP, content).Result;

            if (response != null)
            {

                if (expectCode == HttpStatusCode.OK)
                {
                    var resultValue = response.Content.ReadAsStringAsync().Result;
                    string strResponse = HttpUtility.UrlDecode(resultValue.ToString());
                    return strResponse;
                }
            }