C# HTTP請求GET，POST

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轉自原文 【C#】HTTP請求GET，POST

 

HTTP定義了與伺服器互動的不同方法，基本方法有GET，POST，PUT，DELETE，分別對於查，該，增，刪。一般情況下我們只用到GET和POST，其他兩種都也可以用GET和POST來實現，很多瀏覽器也只實現了GET和POST兩種方法

　　GET：使用者擷取資訊

　　　　安全的：不會對伺服器上的資料進行修改，和破壞

　　　　等冪的：相同的請求所返回的結果相同

　　　　參數是通過Url來傳輸，接在Url後面中間用?分開，不同參數之間用&分開，下面表示傳遞兩個參數param1和param2，值為value1和value2

　　　　　　http://songurl/index.htm?param1=value1&param2=value2

　　　　通過上面可以看到，GET請求資料在隱私方面又是不安全的，因為Url上的資訊可以直接讓使用者看到，這樣不利於隱私保護

　　POST：用於更新資料

　　　　傳遞的資料對使用者隱藏，封裝在包裡，具體看示範

　　　　有時候請求會重新導向，但我們就需要從重新導向url擷取東西，這時可以設定重新導向禁用，你就可以從headers的Location屬性中擷取重新導向地址

　　　　　　request.AllowAutoRedirect = false;

　　　　　　string[] values = request.Headers.GetValues("Location");

下面是輔助類的定義

 

public class HttpHelper        {            /// <summary>              /// 建立GET方式的HTTP請求              /// </summary>              public static HttpWebResponse CreateGetHttpResponse(string url, int timeout, string userAgent, CookieCollection cookies)            {                HttpWebRequest request = null;                if (url.StartsWith("https", StringComparison.OrdinalIgnoreCase))                {                    //對服務端認證進行有效性校正（非第三方權威機構頒發的認證，如自己產生的，不進行驗證，這裡返回true）                    ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);                    request = WebRequest.Create(url) as HttpWebRequest;                    request.ProtocolVersion = HttpVersion.Version10;    //http版本，預設是1.1,這裡設定為1.0                }                else                {                    request = WebRequest.Create(url) as HttpWebRequest;                }                request.Method = "GET";                                //設定代理UserAgent和逾時                //request.UserAgent = userAgent;                //request.Timeout = timeout;                if (cookies != null)                {                    request.CookieContainer = new CookieContainer();                    request.CookieContainer.Add(cookies);                }                return request.GetResponse() as HttpWebResponse;            }                        /// <summary>              /// 建立POST方式的HTTP請求              /// </summary>              public static HttpWebResponse CreatePostHttpResponse(string url, IDictionary<string, string> parameters, int timeout, string userAgent, CookieCollection cookies)            {                HttpWebRequest request = null;                //如果是發送HTTPS請求                  if (url.StartsWith("https", StringComparison.OrdinalIgnoreCase))                {                    //ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);                    request = WebRequest.Create(url) as HttpWebRequest;                    //request.ProtocolVersion = HttpVersion.Version10;                }                else                {                    request = WebRequest.Create(url) as HttpWebRequest;                }                request.Method = "POST";                request.ContentType = "application/x-www-form-urlencoded";                //設定代理UserAgent和逾時                //request.UserAgent = userAgent;                //request.Timeout = timeout;                 if (cookies != null)                {                    request.CookieContainer = new CookieContainer();                    request.CookieContainer.Add(cookies);                }                //發送POST資料                  if (!(parameters == null || parameters.Count == 0))                {                    StringBuilder buffer = new StringBuilder();                    int i = 0;                    foreach (string key in parameters.Keys)                    {                        if (i > 0)                        {                            buffer.AppendFormat("&{0}={1}", key, parameters[key]);                        }                        else                        {                            buffer.AppendFormat("{0}={1}", key, parameters[key]);                            i++;                        }                    }                    byte[] data = Encoding.ASCII.GetBytes(buffer.ToString());                    using (Stream stream = request.GetRequestStream())                    {                        stream.Write(data, 0, data.Length);                    }                }                string[] values = request.Headers.GetValues("Content-Type");                return request.GetResponse() as HttpWebResponse;            }            /// <summary>            /// 擷取請求的資料            /// </summary>            public static string GetResponseString(HttpWebResponse webresponse)            {                using (Stream s = webresponse.GetResponseStream())                {                    StreamReader reader = new StreamReader(s, Encoding.UTF8);                    return reader.ReadToEnd();                }            }                        /// <summary>            /// 驗證認證            /// </summary>            private static bool CheckValidationResult(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)            {                if (errors == SslPolicyErrors.None)                    return true;                return false;            }          }

 

C# HTTP請求GET，POST