今天调用某API时，对于文档中的传入参数：File[] 类型，感觉很陌生，无从下手！ 按通常的方式在json参数中加入file的二进制数据提交，一直报错（参数错误）！后来经过多方咨询，是要换一种
表单提交方式，即：模拟提交带附件的表单！在网上扒出了一个用于提交带附件表单的类！使用方法如下：
使用 参考代码（工具类代码在下面）：
//构造文件 FormUpload.FileParameter file = new FormUpload.FileParameter(File.ReadAllBytes("D://TestAdvertiserFile.jpg"), "TestAdvertiserFile.jpg"); //构造参数 Dictionary<string, object> postParams = new Dictionary<string, object>(); postParams.Add("demoId", 3); postParams.Add("token", "TnQqQSDFSDI#2121231"); postParams.Add("advertiserId", input.SinaInput.Id); postParams.Add("name", input.SinaInput.Name); postParams.Add("industry",input.SinaInput.Industry); //文件作为参数加入，如果有多个文件，可以参照加入多个 postParams.Add("qualificationFiles", file); //提交请求，获得返回结果 var httpWebResp = FormUpload.MultipartFormDataPost("http://amp.ad.sina.com.cn/sax/interface/advertiser/upload.action", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.19 (KHTML, like Gecko) Chrome/18.0.1025.3 Safari/535.19", postParams); Stream instream = httpWebResp.GetResponseStream(); StreamReader sr = new StreamReader(instream,Encoding.UTF8); //返回结果网页(html)代码 string response = sr.ReadToEnd(); sr.Close();
工具类如下：
// Implements multipart/form-data POST in C# http://www.ietf.org/rfc/rfc2388.txt
// http://www.briangrinstead.com/blog/multipart-form-post-in-c
public static class FormUpload
{
private static readonly Encoding encoding = Encoding.UTF8;
public static HttpWebResponse MultipartFormDataPost(string postUrl, string userAgent, Dictionary<string, object> postParameters)
{
string formDataBoundary = String.Format("----------{0:N}", Guid.NewGuid());
string contentType = "multipart/form-data; boundary=" + formDataBoundary;
byte[] formData = GetMultipartFormData(postParameters, formDataBoundary);
return PostForm(postUrl, userAgent, contentType, formData);
}
private static HttpWebResponse PostForm(string postUrl, string userAgent, string contentType, byte[] formData)
{
HttpWebRequest request = WebRequest.Create(postUrl) as HttpWebRequest;
if (request == null)
{
throw new NullReferenceException("request is not a http request");
}
// Set up the request properties.
request.Method = "POST";
request.ContentType = contentType;
request.UserAgent = userAgent;
request.CookieContainer = new CookieContainer();
request.ContentLength = formData.Length;
// You could add authentication here as well if needed:
// request.PreAuthenticate = true;
// request.AuthenticationLevel = System.Net.Security.AuthenticationLevel.MutualAuthRequested;
// request.Headers.Add("Authorization", "Basic " + Convert.ToBase64String(System.Text.Encoding.Default.GetBytes("username" + ":" + "password")));
// Send the form data to the request.
using (Stream requestStream = request.GetRequestStream())
{
requestStream.Write(formData, 0, formData.Length);
requestStream.Close();
}
return request.GetResponse() as HttpWebResponse;
}
private static byte[] GetMultipartFormData(Dictionary<string, object> postParameters, string boundary)
{
Stream formDataStream = new System.IO.MemoryStream();
bool needsCLRF = false;
foreach (var param in postParameters)
{
// Thanks to feedback from commenters, add a CRLF to allow multiple parameters to be added.
// Skip it on the first parameter, add it to subsequent parameters.
if (needsCLRF)
formDataStream.Write(encoding.GetBytes("
"), 0, encoding.GetByteCount("
"));
needsCLRF = true;
if (param.Value is FileParameter)
{
FileParameter fileToUpload = (FileParameter)param.Value;
// Add just the first part of this param, since we will write the file data directly to the Stream
string header = string.Format("--{0}
Content-Disposition: form-data; name="{1}"; filename="{2}";
Content-Type: {3}
",
boundary,
param.Key,
fileToUpload.FileName ?? param.Key,
fileToUpload.ContentType ?? "application/octet-stream");
formDataStream.Write(encoding.GetBytes(header), 0, encoding.GetByteCount(header));
// Write the file data directly to the Stream, rather than serializing it to a string.
formDataStream.Write(fileToUpload.File, 0, fileToUpload.File.Length);
}
else
{
string postData = string.Format("--{0}
Content-Disposition: form-data; name="{1}"
{2}",
boundary,
param.Key,
param.Value);
formDataStream.Write(encoding.GetBytes(postData), 0, encoding.GetByteCount(postData));
}
}
// Add the end of the request. Start with a newline
string footer = "
--" + boundary + "--
";
formDataStream.Write(encoding.GetBytes(footer), 0, encoding.GetByteCount(footer));
// Dump the Stream into a byte[]
formDataStream.Position = 0;
byte[] formData = new byte[formDataStream.Length];
formDataStream.Read(formData, 0, formData.Length);
formDataStream.Close();
return formData;
}
public class FileParameter
{
public byte[] File { get; set; }
public string FileName { get; set; }
public string ContentType { get; set; }
public FileParameter(byte[] file) : this(file, null) { }
public FileParameter(byte[] file, string filename) : this(file, filename, null) { }
public FileParameter(byte[] file, string filename, string contenttype)
{
File = file;
FileName = filename;
ContentType = contenttype;
}
}
}