西红柿炒荷花

.Net模拟提交表单

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;
            }

     

posted on 2016-09-02 11:09  西红柿炒荷花  阅读(603)  评论(0编辑  收藏  举报

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