c# 爬虫（三）文件上传 -云博客

c# 爬虫（三）文件上传

# windos 2024-05-05 09:13 0 108 来源：云博客

在上一篇中，我们说了模拟登录，

下面我们说说附件上传。

据说，最早的http协议是不支持附件上传的，后来有添加了一个RFC 2045 协议，才支持附件上传，关于附件上传，请参见

http://www.cnblogs.com/greenerycn/archive/2010/05/15/csharp_http_post.html

好了，其实用C#模拟上传附件，主要的难点就在于如何构建此协议的格式以及编码。

作为备忘，我这里只放一段成品代码了。

参数：URL,上传控件的id，附件的本地全路径，传输的Key-value数据

 public
 string
 HttpWebUpload(
 string
 url, 
 string
 fileControlID, 
 string
 fileFullPath, Dictionary<
 string
 , 
 string
 > dic) 
         
 { 
             
 string
 fileContentType = 
 "application/octet-stream"
 ;
 //"application/octet-stream";//"text/plain";//image/jpeg 
            
             
 int
 index = fileFullPath.LastIndexOf(
 ‘\\‘
 ); 
             
 string
 filename = fileFullPath.Substring(index+1); 
               
             
 var
 boundary = DateTime.Now.Ticks.ToString(
 "x"
 ); 
             
 var
 beginBoundary = 
 "--"
 + boundary; 
             
 var
 reqContentType = 
 "multipart/form-data; boundary="
 + boundary; 
   
             
 var
 memStream = 
 new
 MemoryStream(); 
             
 var
 fileStream = 
 new
 FileStream(fileFullPath, FileMode.Open, FileAccess.Read); 
             
 int
 fsLen = (
 int
 )fileStream.Length; 
             
 byte
 [] btfileValue = 
 new
 byte
 [fsLen]; 
             
 int
 r = fileStream.Read(btfileValue, 0, btfileValue.Length); 
   
             
 StringBuilder fileHeader = 
 new
 StringBuilder(); 
             
 fileHeader.AppendLine(beginBoundary); 
             
 fileHeader.AppendLine(
 string
 .Format(
 "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\""
 , fileControlID, filename)); 
             
 fileHeader.AppendLine(
 string
 .Format(
 "Content-Type: {0}"
 , fileContentType)); 
             
 fileHeader.AppendLine(); 
             
 var
 btfileKey = Encoding.UTF8.GetBytes(fileHeader.ToString()); 
   
             
 StringBuilder dicData = 
 new
 StringBuilder(); 
             
 dicData.AppendLine(); 
             
 foreach
 (
 var
 item 
 in
 dic) 
             
 { 
   
                 
 dicData.AppendLine(beginBoundary); 
                 
 dicData.AppendLine(
 string
 .Format(
 "Content-Disposition:form-data; name=\"{0}\""
 , item.Key)); 
                 
 dicData.AppendLine(); 
                 
 dicData.AppendLine(item.Value); 
             
 } 
   
             
 dicData.AppendLine(beginBoundary + 
 "--"
 ); 
             
 var
 btDic = Encoding.UTF8.GetBytes(dicData.ToString()); 
   
             
 HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url); 
             
 req.Method = 
 "POST"
 ; 
             
 req.AllowAutoRedirect = 
 false
 ; 
             
 req.ContentType = reqContentType; 
             
 if
 (!
 string
 .IsNullOrEmpty(UserAgent)) 
             
 { 
                 
 req.UserAgent = 
 this
 .UserAgent; 
             
 } 
   
             
 if
 (!
 string
 .IsNullOrEmpty(Cookie)) 
             
 { 
                 
 req.CookieContainer = 
 new
 CookieContainer(); 
                 
 req.CookieContainer.SetCookies(req.RequestUri, 
 this
 .Cookie); 
             
 } 
   
             
 req.ContentLength = btfileKey.Length + btfileValue.Length + btDic.Length; 
             
 Stream postDataStream = req.GetRequestStream(); 
             
 postDataStream.Write(btfileKey, 0, btfileKey.Length); 
             
 postDataStream.Write(btfileValue, 0, btfileValue.Length); 
             
 postDataStream.Write(btDic, 0, btDic.Length); 
             
 postDataStream.Close(); 
   
             
 HttpWebResponse resp = (HttpWebResponse)req.GetResponse(); 
             
 string
 html = 
 new
 StreamReader(resp.GetResponseStream()).ReadToEnd(); 
             
 return
 html; 
         
 }  

　　注意，这里如果需要cookie,则添加对应的cookie。

调用方法

 string
 controlid = 
 "fupCert"
 ; 
 string
 filefullPath = 
 "f:\\3.pdf"
 ; 
 string
 url = 
 "http://10.35.3.240/NT_HandbookExtend/FrmCertificate.aspx?type=N&zdtype=J&DELEGATENO=SBWJ16100001&ID=SB20161018000001%2c3206960757&Action=Modify&manualRecordID=SL20161018000001&tm=0.17032586549994377"
 ; 
   
 var
 hiddenVal = web.GetDoNetHiddenValuesByUrl(url);
 //获取__VIEWSTATE，与__EVENTVALIDATION隐藏域值 
   
 Dictionary<
 string
 , 
 string
 > dic = 
 new
 Dictionary<
 string
 , 
 string
 >(); 
 dic.Add(
 "__EVENTARGUMENT"
 , 
 ""
 ); 
 dic.Add(
 "__EVENTTARGET"
 , 
 "btnUpload"
 ); 
 dic.Add(
 "__EVENTVALIDATION"
 , hiddenVal.Eventvalidation); 
 dic.Add(
 "__PREVIOUSPAGE"
 , 
 "EncayjCF95BJXxMazWGgd9UdPYeLp64GjuJlZ-rvnQ5n34-y7KQYllE35nAdVFvk0"
 ); 
 dic.Add(
 "__VIEWSTATE"
 , hiddenVal.Vievstate); 
 dic.Add(
 "__VIEWSTATEENCRYPTED"
 , 
 ""
 ); 
 dic.Add(
 "grdNavigatorPRE_EMS3_CUS_IMG$ctl06"
 , 
 ""
 ); 
 dic.Add(
 "grdNavigatorPRE_EMS3_CUS_IMG$ctl07"
 , 
 "15"
 ); 
 dic.Add(
 "grdNavigatorPRE_EMS3_CUS_IMG$labelRowCount"
 , 
 "8"
 ); 
 dic.Add(
 "hfERP"
 , 
 "http://www.nteport.gov.cn/cerp/platform/erp/documentManagement/documentDocking.jsp"
 ); 
 dic.Add(
 "hidFileType"
 , 
 "333"
 ); 
 dic.Add(
 "hidID"
 , 
 ""
 ); 
 //web.UserAgent = "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0)"; 
 string
 html = web.HttpWebUpload(url, controlid, filefullPath, dic); 