Envoyer un fichier via HTTP POST avec C #
J'ai cherché et lu à ce sujet et je ne pouvais rien trouver de vraiment utile.
J'écris une petite application gagnante C # qui permet à l'utilisateur d'envoyer des fichiers à un serveur Web, pas par FTP, mais par HTTP à l'aide de POST. Pensez-y comme à un formulaire Web mais fonctionnant sous une application Windows.
J'ai mon objet HttpWebRequest créé en utilisant quelque chose comme ceci
HttpWebRequest req = WebRequest.Create(uri) as HttpWebRequest
et définissez également les propriétés Method, ContentType et ContentLength. Mais c'est loin je peux aller.
Ceci est mon morceau de code:
HttpWebRequest req = WebRequest.Create(uri) as HttpWebRequest;
req.KeepAlive = false;
req.Method = "POST";
req.Credentials = new NetworkCredential(user.UserName, user.UserPassword);
req.PreAuthenticate = true;
req.ContentType = file.ContentType;
req.ContentLength = file.Length;
HttpWebResponse response = null;
try
{
response = req.GetResponse() as HttpWebResponse;
}
catch (Exception e)
{
}
Ma question est donc de savoir comment puis-je envoyer un fichier (fichier texte, image, audio, etc.) avec C # via HTTP POST.
Merci!
Avec .NET 4.5 (ou .NET 4.0 en ajoutant le package Microsoft.Net.Http de NuGet), il existe un moyen plus simple de simuler des demandes de formulaire. Voici un exemple:
private async Task<System.IO.Stream> Upload(string actionUrl, string paramString, Stream paramFileStream, byte [] paramFileBytes)
{
HttpContent stringContent = new StringContent(paramString);
HttpContent fileStreamContent = new StreamContent(paramFileStream);
HttpContent bytesContent = new ByteArrayContent(paramFileBytes);
using (var client = new HttpClient())
using (var formData = new MultipartFormDataContent())
{
formData.Add(stringContent, "param1", "param1");
formData.Add(fileStreamContent, "file1", "file1");
formData.Add(bytesContent, "file2", "file2");
var response = await client.PostAsync(actionUrl, formData);
if (!response.IsSuccessStatusCode)
{
return null;
}
return await response.Content.ReadAsStreamAsync();
}
}
Pour envoyer le fichier brut uniquement :
using(WebClient client = new WebClient()) {
client.UploadFile(address, filePath);
}
Si vous souhaitez émuler un formulaire de navigateur avec un <input type="file"/>, alors c'est plus difficile. Voir cette réponse pour une réponse multipart/form-data.
Pour moi client.UploadFile toujours encapsulé le contenu dans une requête multipartie, je devais donc le faire comme ceci:
using (WebClient client = new WebClient())
{
client.Headers.Add("Content-Type", "application/octet-stream");
using (Stream fileStream = File.OpenRead(filePath))
using (Stream requestStream = client.OpenWrite(new Uri(fileUploadUrl), "POST"))
{
fileStream.CopyTo(requestStream);
}
}
J'avais le même problème et le code suivant répondait parfaitement à ce problème:
//Identificate separator
string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");
//Encoding
byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");
//Creation and specification of the request
HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(url); //sVal is id for the webService
wr.ContentType = "multipart/form-data; boundary=" + boundary;
wr.Method = "POST";
wr.KeepAlive = true;
wr.Credentials = System.Net.CredentialCache.DefaultCredentials;
string sAuthorization = "login:password";//AUTHENTIFICATION BEGIN
byte[] toEncodeAsBytes = System.Text.ASCIIEncoding.ASCII.GetBytes(sAuthorization);
string returnValue = System.Convert.ToBase64String(toEncodeAsBytes);
wr.Headers.Add("Authorization: Basic " + returnValue); //AUTHENTIFICATION END
Stream rs = wr.GetRequestStream();
string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}"; //For the POST's format
//Writting of the file
rs.Write(boundarybytes, 0, boundarybytes.Length);
byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(Server.MapPath("questions.pdf"));
rs.Write(formitembytes, 0, formitembytes.Length);
rs.Write(boundarybytes, 0, boundarybytes.Length);
string headerTemplate = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: {2}\r\n\r\n";
string header = string.Format(headerTemplate, "file", "questions.pdf", contentType);
byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);
rs.Write(headerbytes, 0, headerbytes.Length);
FileStream fileStream = new FileStream(Server.MapPath("questions.pdf"), FileMode.Open, FileAccess.Read);
byte[] buffer = new byte[4096];
int bytesRead = 0;
while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
{
rs.Write(buffer, 0, bytesRead);
}
fileStream.Close();
byte[] trailer = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");
rs.Write(trailer, 0, trailer.Length);
rs.Close();
rs = null;
WebResponse wresp = null;
try
{
//Get the response
wresp = wr.GetResponse();
Stream stream2 = wresp.GetResponseStream();
StreamReader reader2 = new StreamReader(stream2);
string responseData = reader2.ReadToEnd();
}
catch (Exception ex)
{
string s = ex.Message;
}
finally
{
if (wresp != null)
{
wresp.Close();
wresp = null;
}
wr = null;
}
Vous devez écrire votre fichier dans le flux de demande:
using (var reqStream = req.GetRequestStream())
{
reqStream.Write( ... ) // write the bytes of the file
}
Pour poster des fichiers à partir de tableaux d'octets:
private static string UploadFilesToRemoteUrl(string url, IList<byte[]> files, NameValueCollection nvc) {
string boundary = "----------------------------" + DateTime.Now.Ticks.ToString("x");
var request = (HttpWebRequest) WebRequest.Create(url);
request.ContentType = "multipart/form-data; boundary=" + boundary;
request.Method = "POST";
request.KeepAlive = true;
var postQueue = new ByteArrayCustomQueue();
var formdataTemplate = "\r\n--" + boundary + "\r\nContent-Disposition: form-data; name=\"{0}\";\r\n\r\n{1}";
foreach (string key in nvc.Keys) {
var formitem = string.Format(formdataTemplate, key, nvc[key]);
var formitembytes = Encoding.UTF8.GetBytes(formitem);
postQueue.Write(formitembytes);
}
var headerTemplate = "\r\n--" + boundary + "\r\n" +
"Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\n" +
"Content-Type: application/Zip\r\n\r\n";
var i = 0;
foreach (var file in files) {
var header = string.Format(headerTemplate, "file" + i, "file" + i + ".Zip");
var headerbytes = Encoding.UTF8.GetBytes(header);
postQueue.Write(headerbytes);
postQueue.Write(file);
i++;
}
postQueue.Write(Encoding.UTF8.GetBytes("\r\n--" + boundary + "--"));
request.ContentLength = postQueue.Length;
using (var requestStream = request.GetRequestStream()) {
postQueue.CopyToStream(requestStream);
requestStream.Close();
}
var webResponse2 = request.GetResponse();
using (var stream2 = webResponse2.GetResponseStream())
using (var reader2 = new StreamReader(stream2)) {
var res = reader2.ReadToEnd();
webResponse2.Close();
return res;
}
}
public class ByteArrayCustomQueue {
private LinkedList<byte[]> arrays = new LinkedList<byte[]>();
/// <summary>
/// Writes the specified data.
/// </summary>
/// <param name="data">The data.</param>
public void Write(byte[] data) {
arrays.AddLast(data);
}
/// <summary>
/// Gets the length.
/// </summary>
/// <value>
/// The length.
/// </value>
public int Length { get { return arrays.Sum(x => x.Length); } }
/// <summary>
/// Copies to stream.
/// </summary>
/// <param name="requestStream">The request stream.</param>
/// <exception cref="System.NotImplementedException"></exception>
public void CopyToStream(Stream requestStream) {
foreach (var array in arrays) {
requestStream.Write(array, 0, array.Length);
}
}
}
public string SendFile(string filePath)
{
WebResponse response = null;
try
{
string sWebAddress = "Https://www.address.com";
string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");
byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");
HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(sWebAddress);
wr.ContentType = "multipart/form-data; boundary=" + boundary;
wr.Method = "POST";
wr.KeepAlive = true;
wr.Credentials = System.Net.CredentialCache.DefaultCredentials;
Stream stream = wr.GetRequestStream();
string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";
stream.Write(boundarybytes, 0, boundarybytes.Length);
byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(filePath);
stream.Write(formitembytes, 0, formitembytes.Length);
stream.Write(boundarybytes, 0, boundarybytes.Length);
string headerTemplate = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: {2}\r\n\r\n";
string header = string.Format(headerTemplate, "file", Path.GetFileName(filePath), Path.GetExtension(filePath));
byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);
stream.Write(headerbytes, 0, headerbytes.Length);
FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);
byte[] buffer = new byte[4096];
int bytesRead = 0;
while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
stream.Write(buffer, 0, bytesRead);
fileStream.Close();
byte[] trailer = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");
stream.Write(trailer, 0, trailer.Length);
stream.Close();
response = wr.GetResponse();
Stream responseStream = response.GetResponseStream();
StreamReader streamReader = new StreamReader(responseStream);
string responseData = streamReader.ReadToEnd();
return responseData;
}
catch (Exception ex)
{
return ex.Message;
}
finally
{
if (response != null)
response.Close();
}
}
Utilisation de .NET 4.5 pour essayer d’effectuer le transfert du fichier POST). Nous avons essayé la plupart des méthodes ci-dessus mais en vain. Nous avons trouvé la solution ici https: //www.c-sharpcorner. com/article/upload-any-file-using-http-post-multipart-form-data
Mais je ne suis pas enthousiaste car je ne comprends pas pourquoi nous avons encore besoin de traiter avec une programmation aussi bas niveau dans ces usages courants (devrait être gérée correctement par framework)