C#如何解析http報文

更新時間：2015年08月04日 11:35:27 投稿：mrr

這篇文章如果講解了用C#如何解析http報文，要解析http報文，需要哪些操作呢？下面小編給大家整理相關資料，需要的朋友可以參考下

下面通過一段內(nèi)容有文字說明有代碼分析，并附有展示圖供大家學習。

要解析HTTP報文，需要實現(xiàn)以下操作：

讀取HTTP報頭提供的各種屬性
分析屬性值，從中獲取內(nèi)容編碼和字符集編碼
將報頭數(shù)據(jù)和內(nèi)容進行分離
判斷內(nèi)容是否文本還是二進制，如果是二進制的則不進行處理
如果內(nèi)容是文本，按報頭中提供的內(nèi)容編碼和字符集編碼進行解壓縮和解碼
目前沒有找到.Net框架內(nèi)置的解析方法，理論上HttpClient等類在內(nèi)部應該已經(jīng)實現(xiàn)了解析，但不知為何沒有公開這些處理方法。（亦或是我沒找到）

那么只能自己來解析這些數(shù)據(jù)了。

我們先來看看這個經(jīng)過gzip壓縮的文本內(nèi)容的HTTP報文：

這里提供一個老外寫的簡陋的解析類（已經(jīng)過修改，原代碼中存在一些嚴重BUG）：

public enum HTTPHeaderField
{
 Accept = 0,
 Accept_Charset = 1,
 Accept_Encoding = 2,
 Accept_Language = 3,
 Accept_Ranges = 4,
 Authorization = 5,
 Cache_Control = 6,
 Connection = 7,
 Cookie = 8,
 Content_Length = 9,
 Content_Type = 10,
 Date = 11,
 Expect = 12,
 From = 13,
 Host = 14,
 If_Match = 15,
 If_Modified_Since = 16,
 If_None_Match = 17,
 If_Range = 18,
 If_Unmodified_Since = 19,
 Max_Forwards = 20,
 Pragma = 21,
 Proxy_Authorization = 22,
 Range = 23,
 Referer = 24,
 TE = 25,
 Upgrade = 26,
 User_Agent = 27,
 Via = 28,
 Warn = 29,
 Age = 30,
 Allow = 31,
 Content_Encoding = 32,
 Content_Language = 33,
 Content_Location = 34,
 Content_Disposition = 35,
 Content_MD5 = 36,
 Content_Range = 37,
 ETag = 38,
 Expires = 39,
 Last_Modified = 40,
 Location = 41,
 Proxy_Authenticate = 42,
 Refresh = 43,
 Retry_After = 44,
 Server = 45,
 Set_Cookie = 46,
 Trailer = 47,
 Transfer_Encoding = 48,
 Vary = 49,
 Warning = 50,
 WWW_Authenticate = 51
};
class HTTPHeader
{
 #region PROPERTIES
 private string[] m_StrHTTPField = new string[52];
 private byte[] m_byteData = new byte[4096];
 public string[] HTTPField
 {
  get { return m_StrHTTPField; }
  set { m_StrHTTPField = value; }
 }
 public byte[] Data
 {
  get { return m_byteData; }
  set { m_byteData = value; }
 }
 #endregion
 // convertion
 System.Text.ASCIIEncoding encoding = new System.Text.ASCIIEncoding();
 #region CONSTRUCTEUR
 /// <summary>
 /// Constructeur par défaut - non utilisé
 /// </summary>
 private HTTPHeader()
 { }
 public HTTPHeader(byte[] ByteHTTPRequest)
 {
  string HTTPRequest = encoding.GetString(ByteHTTPRequest);
  try
  {
   int IndexHeaderEnd;
   string Header;
   // Si la taille de requête est supérieur ou égale à 1460, alors toutes la chaine est l'entête http
   if (HTTPRequest.Length <= 1460)
    Header = HTTPRequest;
   else
   {
    IndexHeaderEnd = HTTPRequest.IndexOf("\r\n\r\n");
    Header = HTTPRequest.Substring(0, IndexHeaderEnd);
    Data = ByteHTTPRequest.Skip(IndexHeaderEnd + 4).ToArray();
   }
   HTTPHeaderParse(Header);
  }
  catch (Exception)
  { }
 }
 #endregion
 #region METHODES
 private void HTTPHeaderParse(string Header)
 {
  #region HTTP HEADER REQUEST & RESPONSE
  HTTPHeaderField HHField;
  string HTTPfield, buffer;
  int Index;
  foreach (int IndexHTTPfield in Enum.GetValues(typeof(HTTPHeaderField)))
  {
   HHField = (HTTPHeaderField)IndexHTTPfield;
   HTTPfield = "\n" + HHField.ToString().Replace('_', '-') + ": "; //Ajout de \n devant pour éviter les doublons entre cookie et set_cookie
   // Si le champ n'est pas présent dans la requête, on passe au champ suivant
   Index = Header.IndexOf(HTTPfield);
   if (Index == -1)
    continue;
   buffer = Header.Substring(Index + HTTPfield.Length);
   Index = buffer.IndexOf("\r\n");
   if (Index == -1)
    m_StrHTTPField[IndexHTTPfield] = buffer.Trim();
   else
    m_StrHTTPField[IndexHTTPfield] = buffer.Substring(0, Index).Trim();
   //Console.WriteLine("Index = " + IndexHTTPfield + " | champ = " + HTTPfield.Substring(1) + " " + m_StrHTTPField[IndexHTTPfield]);
  }
  // Affichage de tout les champs
  /*for (int j = 0; j < m_StrHTTPField.Length; j++)
  {
   HHField = (HTTPHeaderField)j;
   Console.WriteLine("m_StrHTTPField[" + j + "]; " + HHField + " = " + m_StrHTTPField[j]);
  }
  */
  #endregion
 }
 #endregion
}

編寫以下代碼以實現(xiàn)解析文件：

class Program
{
 static void Main(string[] args)
 {
  SRART: Console.WriteLine("輸入待解析的HTTP報文數(shù)據(jù)文件完整路徑：");
  var filename = Console.ReadLine();
  try
  {
   FileStream fs = new FileStream(filename, FileMode.Open);
   BinaryReader br = new BinaryReader(fs);
   var data = br.ReadBytes((int)fs.Length);
   var header = new HTTPHeader(data);
   var x = 0;
   foreach (var f in header.HTTPField)
   {
    if (!String.IsNullOrEmpty(f))
    {
     Console.WriteLine($"[{x:00}] - {(HTTPHeaderField) x} : {f}");
    }
    x++;
   }
   Console.WriteLine($"總數(shù)據(jù)尺寸{fs.Length}字節(jié)，實際數(shù)據(jù)尺寸{header.Data.Length}字節(jié)");
   Console.WriteLine(Encoding.UTF8.GetString(header.Data));
   Console.WriteLine();
   br.Close();
   fs.Close();  
  }
  catch (Exception e)
  {
   Console.WriteLine(e);
  }
  goto SRART;
 }
}

這里還未實現(xiàn)gzip解壓縮和字符解碼，直接用UTF8解碼輸出的。（需要時再寫吧，都是體力活兒~）

效果圖展示：