In previous
post we talked about sending emails with attachments from the Google App Engine.
But how do we get files from a client to the cloud?
Here is a sample code in C#:
public static string UploadFilesToRemoteUrl(string url, string[] files, NameValueCollection nvc, string cookie)
{
string boundary = "----------------------------" +
DateTime.Now.Ticks.ToString("x");
HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(url);
httpWebRequest.ContentType = "multipart/form-data; boundary=" + boundary;
httpWebRequest.Method = "POST";
httpWebRequest.KeepAlive = true;
httpWebRequest.Headers["Cookie"] = cookie;
httpWebRequest.Credentials = System.Net.CredentialCache.DefaultCredentials;
Stream memStream = new MemoryStream();
byte[] boundarybytes = Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");
string formdataTemplate = "\r\n--" + boundary +
"\r\nContent-Disposition: form-data; name=\"{0}\";\r\n\r\n{1}";
foreach (string key in nvc.Keys)
{
string formitem = string.Format(formdataTemplate, key, nvc[key]);
byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(formitem);
memStream.Write(formitembytes, 0, formitembytes.Length);
}
memStream.Write(boundarybytes, 0, boundarybytes.Length);
string headerTemplate = "Content-Disposition: form-data; name=\"{0}\";filename=\"{1}\"\r\n\r\n";
for (int i = 0; i < files.Length; i++)
{
string header = string.Format(headerTemplate, "file" + i, files[i]);
byte[] headerbytes = Encoding.UTF8.GetBytes(header);
memStream.Write(headerbytes, 0, headerbytes.Length);
FileStream fileStream = new FileStream(files[i],
FileMode.Open, FileAccess.Read);
byte[] buffer = new byte[1024];
int bytesRead = 0;
while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
{
memStream.Write(buffer, 0, bytesRead);
}
memStream.Write(boundarybytes, 0, boundarybytes.Length);
fileStream.Close();
}
httpWebRequest.ContentLength = memStream.Length;
Stream requestStream = httpWebRequest.GetRequestStream();
memStream.Position = 0;
byte[] tempBuffer = new byte[memStream.Length];
memStream.Read(tempBuffer, 0, tempBuffer.Length);
memStream.Close();
requestStream.Write(tempBuffer, 0, tempBuffer.Length);
requestStream.Close();
WebResponse webResponse = httpWebRequest.GetResponse();
Stream stream = webResponse.GetResponseStream();
StreamReader reader = new StreamReader(stream);
string responseFromServer = reader.ReadToEnd();
webResponse.Close();
reader.Close();
stream.Close();
httpWebRequest = null;
webResponse = null;
return responseFromServer;
}
The method above has a cookie as a parameter. Here is an excellent site by Dale Lane where you can see how to access authenticated Google App Engine service from a C# client.
