学步园

在http请求时如果要附带上附件，不可避免的需要用到multipart的content-type。具体使用是在http中把content-type改成相应的multipart类型，并且加上boundry标记作为分隔符。
需要注意两点(搞了我好久)..
如果
ContentType = "multipart/related; boundary= BOUNDARY";
除了最后一个boudry,其他的boundry格式如下
--BOUNDARY/r/n  //注意前面的"--"还有/r/n
最后一个分隔符如下
--BOUNDARY--/r/n //注意前后“--”还有/r/n

再写每一段的Content-Type等信息的时候，需要注意用逗号隔开,并且最后要空两行
如
streamWriter.Write("Content-Type: application/atom+xml/r/n/r/n");  //注意空了两行。
举个c#写的用来上传google picsaca的例子
具体reference是
http://code.google.com/apis/picasaweb/gdata.html

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.IO;
namespace WindowsApplication3
...{
    public partial class Form1 : Form
    ...{
        public Form1()
        ...{
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        ...{
            WebRequest req = WebRequest.Create("https://www.google.com/accounts/ClientLogin");
            req.Method = "POST";
            req.ContentType = "application/x-www-form-urlencoded";

            Stream stream = req.GetRequestStream();
            StreamWriter streamWriter = new StreamWriter(stream, Encoding.ASCII);
            streamWriter.Write("accountType=HOSTED_OR_GOOGLE");
            streamWriter.Write("&Email=binwind1984@gmail.com");//帐号换成你自己的
            streamWriter.Write("&Passwd=XXX");//密码换成你自己的
            streamWriter.Write("&service=lh2");
            streamWriter.Write("&source=bin-test-1.0");
            streamWriter.Close();
            stream.Close();

            WebResponse rep = req.GetResponse();

           
            Stream responseStream = rep.GetResponseStream();
            StreamReader responseReader = new StreamReader(responseStream, Encoding.ASCII);

            string a = responseReader.ReadToEnd();
            TokenCollection tokens = new TokenCollection(a, '=', true, 2);
            string token = TokenCollection.FindToken(tokens, "Auth");
            responseReader.Close();
            responseStream.Close();

            req = WebRequest.Create("http://picasaweb.google.com/data/feed/api/user/binwind1984/album/UntitledAlbum");
           //binwind1984替换为相应的帐号，UntitledAlbum替换为相应的相册名字
            string boundry = "-----xxxxxxxBOUNDERxxxxdxx";
           req.ContentType = "multipart/related; boundary="" + boundry + """;
            //req.ContentType = "image/jpeg";
            HttpWebRequest httpReq = req as HttpWebRequest;
           httpReq.AllowAutoRedirect = false;
            req.Method = "POST";
            


            req.Headers.Add("Authorization: GoogleLogin auth=" + token);
           req.Headers.Add("MIME-version: 1.0");

          
            stream = req.GetRequestStream();
          streamWriter = new StreamWriter(stream, Encoding.ASCII);

          streamWriter.WriteLine("Media multipart posting");

          streamWriter.Write("--" + boundry + " ");
          streamWriter.Write("Content-Type: application/atom+xml ");
          //streamWriter.WriteLine("<?xml version='1.0' encoding='UTF-8'?>");
          streamWriter.WriteLine("<entry xmlns="http://www.w3.org/2005/Atom">");
          streamWriter.WriteLine("<title>test document</title>");
          streamWriter.WriteLine("<summary>Darcy on the beach</summary>");
          streamWriter.WriteLine("<category scheme="http://schemas.google.com/g/2005#kind" term="http://schemas.google.com/photos/2007#photo"/>");

          streamWriter.WriteLine("</entry>");
          streamWriter.Write("--" + boundry + " ");
          streamWriter.Write("Content-Type: image/jpeg ");
          streamWriter.Flush();
            FileStream fs = new FileStream("C:/s.jpg", FileMode.Open);//这里假设上传c:s.jpg文件.
            byte[] bytes = new byte[1024];
            while (fs.CanRead)
            ...{
                int read = fs.Read(bytes, 0, 1024);

                stream.Write(bytes, 0, read);
                if (read == 0)
                ...{
                    break;
                }
            }
            fs.Close();
           stream.Flush();
           streamWriter.Write("--" + boundry + "--" + " ");

          streamWriter.Close();
            stream.Close();
            try
            ...{
                rep = req.GetResponse();
            }
            catch (Exception ex)
            ...{
                MessageBox.Show(ex.ToString());
            }

        }
    }

    public class TokenCollection : IEnumerable
    ...{
        private string[] elements;

        /**//// <summary>Constructor, takes a string and a delimiter set</summary> 
        public TokenCollection(string source, char[] delimiters)
        ...{

            if (source != null)
            ...{
                this.elements = source.Split(delimiters);
            }
        }

        /**//// <summary>Constructor, takes a string and a delimiter set</summary> 
        public TokenCollection(string source, char delimiter,
                               bool seperateLines, int resultsPerLine)
        ...{
            if (source != null)
            ...{
                if (seperateLines == true)
                ...{
                    // first split the source into a line array
                    string[] lines = source.Split(new char[] ...{ ' ' });
                    int size = lines.Length * resultsPerLine;
                    this.elements = new string[size];
                    size = 0;
                    foreach (String s in lines)
                    ...{
                        // do not use Split(char,int) as that one
                        // does not exist on .NET CF
                        string[] temp = s.Split(delimiter);
                        int counter = temp.Length < resultsPerLine ? temp.Length : resultsPerLine;

                        for (int i = 0; i < counter; i++)
                        ...{
                            this.elements[size++] = temp[i];
                        }
                        for (int i = resultsPerLine; i < temp.Length; i++)
                        ...{
                            this.elements[size - 1] += delimiter + temp[i];
                        }

                    }
                }
                else