2016-09-0210:49:20
以中邮速递API为服务接口，由于提交方式为表单提交，我要获取返回值来处理其他业务，所以一开始尝试采用Js后台获取返回值，但是涉及到跨域请求限制问题，那边服务端接口返回的是json而不能处理jsonp；所以开始着手考虑后台模拟提交表单；
网上开始查资料，对于后台提交表单的一些相关资料：
- 表单提交协议规定：
对于含文件的表单提交，要先将 HTTP 要求的 Content-Type 设为 multipart/form-data，而且要设定一个 boundary 参数，
这个参数是由应用程序自行产生，它会用来识别每一份资料的边界 (boundary)，用以产生多重信息部份 (message part)。
- 基本内容：
1. 每个信息部份都要用 --[BOUNDARY_NAME] 来包装，以分隔出信息的每个部份，而最后要再加上一个 --[BOUNDARY_NAME] 来表示结束。
2. 每个信息部份都要有一个 Content-Disposition: form-data; name=""，而 name 设定的就是 HTTP POST 的键值 (key)。
3. 声明区和值区中间要隔两个新行符号（\r\n）。
4. 中间可以夹入二进制资料，但二进制资料必须要格式化为二进制字符串。
5. 若要设定不同信息段的资料型别 (Content-Type)，则要在信息段内的声明区设定。
- 内容模板：
两个form内容模板
boundary = "----" + DateTime.Now.Ticks.ToString("x");//程序生成
1.文本内容
"\r\n--" + boundary +
"\r\nContent-Disposition: form-data; name=\"键\"; filename=\"文件名\"" +
"\r\nContent-Type: application/octet-stream" +
"\r\n\r\n";
2.文件内容
"\r\n--" + boundary +
"\r\nContent-Disposition: form-data; name=\"键\"" +
"\r\n\r\n内容";
- 单个文件或文本的实体类：
/// <summary>
/// 单个文件或键值
/// </summary>
public class FormItemModel
{
/// <summary>
/// 表单键，request["key"]
/// </summary>
public string Key { set; get; }
/// <summary>
/// 表单值,上传文件时忽略，request["key"].value
/// </summary>
public string Value { set; get; }
/// <summary>
/// 是否是文件
/// </summary>
public bool IsFile
{
get
{
if (FileContent == null || FileContent.Length == 0)
return false;
if (FileContent != null && FileContent.Length > 0 && string.IsNullOrWhiteSpace(FileName))
throw new Exception("上传文件时 FileName 属性值不能为空");
return true;
}
}
/// <summary>
/// 上传的文件名
/// </summary>
public string FileName { set; get; }
/// <summary>
/// 上传的文件内容
/// </summary>
public Stream FileContent { set; get; }
}
提交表单主逻辑实现：
/// <summary>
/// 使用Post方法获取字符串结果
/// </summary>
/// <param name="url"></param>
/// <param name="formItems">Post表单内容</param>
/// <param name="cookieContainer"></param>
/// <param name="timeOut">默认20秒</param>
/// <param name="encoding">响应内容的编码类型（默认utf-8）</param>
/// <returns></returns>
public static string FormSubmit(string url, List<FormItemModel> formItems, CookieContainer cookieContainer = null, string refererUrl = null, Encoding encoding = null, int timeOut = 20000)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
#region 初始化请求对象
request.Method = "POST";
request.Timeout = timeOut;
request.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8";
request.KeepAlive = true;
request.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.57 Safari/537.36";
if (!string.IsNullOrEmpty(refererUrl))
request.Referer = refererUrl;
if (cookieContainer != null)
request.CookieContainer = cookieContainer;
#endregion
string boundary = "----" + DateTime.Now.Ticks.ToString("x");//分隔符
request.ContentType = string.Format("multipart/form-data; boundary={0}", boundary);
//请求流
var postStream = new MemoryStream();
#region 处理Form表单请求内容
//是否用Form上传文件
var formUploadFile = formItems != null && formItems.Count > 0;
if (formUploadFile)
{
//文件数据模板
string fileFormdataTemplate =
"\r\n--" + boundary +
"\r\nContent-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"" +
"\r\nContent-Type: application/octet-stream" +
"\r\n\r\n";
//文本数据模板
string dataFormdataTemplate =
"\r\n--" + boundary +
"\r\nContent-Disposition: form-data; name=\"{0}\"" +
"\r\n\r\n{1}";
foreach (var item in formItems)
{
string formdata = null;
if (item.IsFile)
{
//上传文件
formdata = string.Format(
fileFormdataTemplate,
item.Key, //表单键
item.FileName);
}
else
{
//上传文本
formdata = string.Format(
dataFormdataTemplate,
item.Key,
item.Value);
}
//统一处理
byte[] formdataBytes = null;
//第一行不需要换行
if (postStream.Length == 0)
formdataBytes = Encoding.UTF8.GetBytes(formdata.Substring(2, formdata.Length - 2));
else
formdataBytes = Encoding.UTF8.GetBytes(formdata);
postStream.Write(formdataBytes, 0, formdataBytes.Length);
//写入文件内容
if (item.FileContent != null && item.FileContent.Length > 0)
{
using (var stream = item.FileContent)
{
byte[] buffer = new byte[1024];
int bytesRead = 0;
while ((bytesRead = stream.Read(buffer, 0, buffer.Length)) != 0)
{
postStream.Write(buffer, 0, bytesRead);
}
}
}
}
//结尾
var footer = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n");
postStream.Write(footer, 0, footer.Length);
}
else
{
request.ContentType = "application/x-www-form-urlencoded";
}
#endregion
request.ContentLength = postStream.Length;
#region 输入二进制流
if (postStream != null)
{
postStream.Position = 0;
//直接写入流
Stream requestStream = request.GetRequestStream();
byte[] buffer = new byte[1024];
int bytesRead = 0;
while ((bytesRead = postStream.Read(buffer, 0, buffer.Length)) != 0)
{
requestStream.Write(buffer, 0, bytesRead);
}
postStream.Close();//关闭文件访问
}
#endregion
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
if (cookieContainer != null)
{
response.Cookies = cookieContainer.GetCookies(response.ResponseUri);
}
using (Stream responseStream = response.GetResponseStream())
{
using (StreamReader myStreamReader = new StreamReader(responseStream, encoding ?? Encoding.UTF8))
{
string retString = myStreamReader.ReadToEnd();
return retString;
}
}
}
public static Stream FileToStream(string fileName)
{
// 打开文件
FileStream fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read);
// 读取文件的 byte[]
byte[] bytes = new byte[fileStream.Length];
fileStream.Read(bytes, 0, bytes.Length);
fileStream.Close();
// 把 byte[] 转换成 Stream
Stream stream = new MemoryStream(bytes);
return stream;
}
- 调用实例，请求中邮速递API
public static string FormSubmitDemo() { //中邮速递API var url = "http://captureupload.30post.cn/capture/index/idcard_upload"; var log1 = @"C:\Users\fmh\Desktop\图片\1.jpg"; var log2 = @"C:\Users\fmh\Desktop\图片\2.jpg"; var formDatas = new List<FormItemModel>(); //添加文件 formDatas.Add(new FormItemModel() { Key = "card_photo", Value = "", FileName = "1.jpg", FileContent = FileToStream(log1) }); formDatas.Add(new FormItemModel() { Key = "card_photob", Value = "", FileName = "2.jpg", FileContent = FileToStream(log2) }); //添加文本 formDatas.Add(new FormItemModel() { Key = "name", Value = "测试" }); formDatas.Add(new FormItemModel() { Key = "id_card", Value = "371916199103191319" }); formDatas.Add(new FormItemModel() { Key = "mobile", Value = "18722354113" }); formDatas.Add(new FormItemModel() { Key = "order_no", Value = "371916199103191319" }); //提交表单 var result = FormSubmit(url, formDatas); return result; }