c# webrequest multpart 多文件上传

c# webrequest multpart 多文件上传

c#中通常使用 HttpWebRequest 进行HTTP网络请求, HttpWebRequest 只对Http请求进行了最简单的封装。如果要利用Http协议实现多文件上传,则必须使用 POST方法 multipart/form-data 格式。为了重复使用,我封装了几个方法,实现了多参数文件上传。

添加引用

使用WebRequest需要添加引用 System.Web ,否则引入出错。

参数封装

方便起见,我把请求参数进行了封装,代码如下:

namespace EasyHttp.Net.Core
{    public class KeyValue
    {        public string Key;        public string Value;        public string FilePath;        public string ContentType="*/*";        public KeyValue(string key, string value, string filePath, string contentType)
        {
            Key = key;
            Value = value;
            FilePath = filePath;
            ContentType = contentType;
        }        public KeyValue() { }        public KeyValue(string key, string value, string filePath)
        {
            Key = key;
            Value = value;
            FilePath = filePath;
        }        public KeyValue(string key, string value)
        {
            Key = key;
            Value = value;
        }
    }
}

KeyValue 代表了广义的参数,可以是普通的键值对,也可以是文件参数。

多文件上传封装

public static void ExecuteMultipartRequest(HttpWebRequest request, List<KeyValue> nvc)
        {
            Console.WriteLine(request.Headers);            //   log.Debug(string.Format("Uploading {0} to {1}", file, url));
            string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");            byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");

            HttpWebRequest wr = request;
            wr.ContentType = "multipart/form-data; boundary=" + boundary;
            wr.Method = "POST";
            wr.KeepAlive = true;
            wr.Credentials = System.Net.CredentialCache.DefaultCredentials;            using (var rs = wr.GetRequestStream())
            {                // 普通参数模板
                string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";                //带文件的参数模板
                string headerTemplate = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: {2}\r\n\r\n";                foreach (KeyValue keyValue in nvc)
                {                    //如果是普通参数
                    if (keyValue.FilePath == null)
                    {
                        rs.Write(boundarybytes, 0, boundarybytes.Length);                        string formitem = string.Format(formdataTemplate, keyValue.Key, keyValue.Value);                        byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(formitem);
                        rs.Write(formitembytes, 0, formitembytes.Length);
                    }                    //如果是文件参数,则上传文件
                    else
                    {
                        rs.Write(boundarybytes, 0, boundarybytes.Length);                        string header = string.Format(headerTemplate, keyValue.Key, keyValue.FilePath, keyValue.ContentType);                        byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);
                        rs.Write(headerbytes, 0, headerbytes.Length);                        using (var fileStream = new FileStream(keyValue.FilePath, FileMode.Open, FileAccess.Read))
                        {                            byte[] buffer = new byte[4096];                            int bytesRead = 0;                            long total = 0;                            while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
                            {

                                rs.Write(buffer, 0, bytesRead);
                                total += bytesRead;
                            }
                        }
                    }
                    
                }                byte[] trailer = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");
                rs.Write(trailer, 0, trailer.Length);

            }

        }

使用

static void Main(string[] args)
        {    var request = WebRequest.Create("http://localhost:8080/test/upload") as HttpWebRequest;
            List<KeyValue> keyValues = new List<KeyValue>();
            keyValues.Add(new KeyValue("key1","param1"));
            keyValues.Add(new KeyValue("key2", "param2"));
            keyValues.Add(new KeyValue("file","test1.png","image/png"));
            keyValues.Add(new KeyValue("file", "test2.png", "image/png"));

            EasyHttp.ExecuteMultipartRequest(request,keyValues);
        }


回复列表



回复操作

正在加载验证码......

请先拖动验证码到相应位置

发布时间:2016-09-12 12:00:45

修改时间:2016-09-12 12:00:45

查看次数:316

评论次数:0

TA的文章总数

44