I was trying to test a resumable download using c#. I found that add range will help by looking at some blogs. But in the following code add range have no meaning.
Guys Suggest me how to solve the issue.
What method will be effective to make a Resumable download??
HttpWebRequest myrequest = null;
HttpWebResponse myresponse = null;
private int interval=2048;
public bool set_url(string todonwloads,string tosaves)
{
this.todownload = todonwloads;
this.tosave = tosaves;
return true;
}
public bool start_download()
{
myrequest = (HttpWebRequest)WebRequest.Create(this.todownload);
// it the following code.
//If i dont write addrange. It will download same portion of the file.
myrequest.AddRange(4000,8000);
try
{
myresponse = (HttpWebResponse)myrequest.GetResponse();
if (myresponse.StatusCode == HttpStatusCode.OK)
{
Stream ReceiveSteam = myresponse.GetResponseStream();
FileStream fs = new FileStream(
this.tosave,
FileMode.Create,
FileAccess.Write,
FileShare.None);
int reads;
byte[] buffer = new byte[this.interval];
while ((reads = ReceiveSteam.Read(
buffer,
0,
this.interval)) > 0)
{
fs.Write(buffer, 0, reads);
}
return true;
}
}
catch (WebException ex)
{
throw ex;
}
finally
{
if (myresponse != null)
{
myresponse.Close();
}
}
return false;
}
You currently create and overwrite the file every time you download a section of the file:
// Overwrites the file each time -\/
... = new FileStream(this.tosave, FileMode.Create, ...
You instead need to open or create the file using FileMode.OpenOrCreate, then seek to the last section of the file you wrote to:
// seek to the last end offset, you'll need to save this somehow
fs.Seek(lastOffset, SeekOrigin.Begin);
int reads;
byte[] buffer = new byte[this.interval];
while ((reads = ReceiveSteam.Read(buffer, 0, this.interval)) > 0)
{
fs.Write(buffer, 0, reads);
lastOffset += reads;
}
Related
I'm working on a project where I need to send large audio files via streams from a client to a server. I'm using the ASP.NET Web Api to communicate between client and server. My client has a "SendFile" method which I believe works fine, but I don't know how to make my server receive the data I'm sending via a stream. My client code looks like this so far:
private const int MAX_CHUNK_SIZE = (1024 * 5000);
private HttpWebRequest webRequest = null;
private FileStream fileReader = null;
private Stream requestStream = null;
public bool SendAudio(string uri, string file)
{
byte[] fileData;
fileReader = new FileStream(file, FileMode.Open, FileAccess.Read);
webRequest = (HttpWebRequest)WebRequest.Create(uri);
webRequest.Method = "POST";
webRequest.ContentLength = fileReader.Length;
webRequest.Timeout = 600000;
webRequest.Credentials = CredentialCache.DefaultCredentials;
webRequest.AllowWriteStreamBuffering = false;
requestStream = webRequest.GetRequestStream();
long fileSize = fileReader.Length;
long remainingBytes = fileSize;
int numberOfBytesRead = 0, done = 0;
while (numberOfBytesRead < fileSize)
{
SetByteArray(out fileData, remainingBytes);
done = WriteFileToStream(fileData, requestStream);
numberOfBytesRead += done;
remainingBytes -= done;
}
fileReader.Close();
return true;
}
public int WriteFileToStream(byte[] fileData, Stream requestStream)
{
int done = fileReader.Read(fileData, 0, fileData.Length);
requestStream.Write(fileData, 0, fileData.Length);
return done;
}
private void SetByteArray(out byte[] fileData, long bytesLeft)
{
fileData = bytesLeft < MAX_CHUNK_SIZE ? new byte[bytesLeft] : new byte[MAX_CHUNK_SIZE];
}
My server looks like this:
[HttpPost]
[ActionName("AddAudio")]
public async Task<IHttpActionResult> AddAudio([FromUri]string name)
{
try
{
isReceivingFile = true;
byte[] receivedBytes = await Request.Content.ReadAsByteArrayAsync();
if (WriteAudio(receivedBytes, name) == true)
{
isReceivingFile = false;
return Ok();
}
else
{
isReceivingFile = false;
return BadRequest("ERROR: Audio could not be saved on server.");
}
}
catch (Exception ex)
{
isReceivingFile = false;
return BadRequest("ERROR: Audio could not be saved on server.");
}
}
public bool WriteAudio(byte[] receivedBytes, string fileName)
{
string file = Path.Combine(#"C:\Users\username\Desktop\UploadedFiles", fileName);
using (FileStream fs = File.Create(file))
{
fs.Write(receivedBytes, 0, receivedBytes.Length);
}
return true;
}
The server code has the original code I wrote for it, before deciding to try and make it work with streams. The server code still works if I send a small file (under 30 MB), but if I send a large file my server gets a "outofmemoryexception". I can't figure out how to make the server take in the data via a stream. In my search for solutions I've come across a lot of examples with sockets and TCPClient, but that's not how we want to do it on this project. Can anybody help, please?
if I send a large file my server gets a "outofmemoryexception"
Well, it's reading the entire stream into memory right here:
byte[] receivedBytes = await Request.Content.ReadAsByteArrayAsync();
What you want to do is copy the stream from one location to another, without loading it all into memory at once. Something like this should work:
[HttpPost]
[ActionName("AddAudio")]
public async Task<IHttpActionResult> AddAudio([FromUri]string name)
{
try
{
string file = Path.Combine(#"C:\Users\username\Desktop\UploadedFiles", fileName);
using (FileStream fs = new FileStream(file, FileMode.Create, FileAccess.Write,
FileShare.None, 4096, useAsync: true))
{
await Request.Content.CopyToAsync(fs);
}
return Ok();
}
catch (Exception ex)
{
return BadRequest("ERROR: Audio could not be saved on server.");
}
}
I have a C# windows form application which downloads file from a url(asp.net application) but it is not returning full image lets say image is of 780kb the file that windows form creates is 381 bytes exactly.
I am not able to figure out the issue. Please help.
The code i am using for download is:
public bool getFileFromURL(string url, string filename)
{
long contentLength = 0;
Stream stream = null;
try
{
WebRequest req = WebRequest.Create(url);
WebResponse response = req.GetResponse();
stream = response.GetResponseStream();
contentLength = response.ContentLength;
// Transfer the file
byte[] buffer = new byte[10 * 1024]; // 50KB at a time
int numBytesRead = 0;
long totalBytesRead = 0;
using (FileStream fileStream = new FileStream(filename, FileMode.Create))
{
using (BinaryWriter fileWriter = new BinaryWriter(fileStream))
{
while (stream.CanRead)
{
numBytesRead = stream.Read(buffer, 0, buffer.Length);
if (numBytesRead == 0) break;
totalBytesRead += numBytesRead;
fileWriter.Write(buffer, 0, numBytesRead);
}
fileWriter.Close();
}
fileStream.Close();
}
stream.Close();
response.Close();
req.Abort();
return true;
}
catch (Exception)
{
return false;
}
}
This is my asp.net app code:
using (PortalEntities db = new PortalEntities())
{
PortalModel.Command command = db.Commands.SingleOrDefault(c => c.id == id);
var filePath = Server.MapPath("~/Uploads/"+command.arguments);
if (!File.Exists(filePath))
return;
var fileInfo = new System.IO.FileInfo(filePath);
Response.ContentType = "image/jpg";
Response.AddHeader("Content-Disposition", String.Format("attachment;filename=\"{0}\"", filePath));
Response.AddHeader("Content-Length", fileInfo.Length.ToString());
Response.WriteFile(filePath);
Response.End();
}
That's an awful lot of code to write some bytes out to a file from a web response. How about something like this (.NET 4+):
public static bool GetFileFromURL(string url, string filename)
{
try
{
var req = WebRequest.Create(url);
using (Stream output = File.OpenWrite(filename))
using (WebResponse res = req.GetResponse())
using (Stream s = res.GetResponseStream())
s.CopyTo(output);
return true;
}
catch
{
return false;
}
}
You can download image in more elegant way, it was discussed before here Unable to locate FromStream in Image class
And use File.WriteAllBytes Method to save the byte array as a file, more info at
http://msdn.microsoft.com/en-us/library/system.io.file.writeallbytes(v=vs.110).aspx
So all your client code can be replaced with
public void getFileFromURL(string url, string filename)
{
using (var webClient = new WebClient())
{
File.WriteAllBytes(filename,webClient.DownloadData(url));
}
}
Dude, why are you not using WebClient.DownloadFileAsync?
private void DownloadFile(string url, string path)
{
using (var client = new System.Net.WebClient())
{
client.DownloadFileAsync(new Uri(url), path);
}
}
That's pretty much it, but this method can't download over 2GB. But i don't think the image is that big xD.
Hope it helps!
I am attempting to create a Save/Load class that has the option for saving & load files compressed files. Below is what I have so far. Stepping through it seems to work just fine, except that I get a "The magic number in GZip header is not correct" exception. I don't understand how this can be as I am checking to make sure that the number is there before I pass it over, and I have verified via an external program that it is a GZip file.
Any assistance in finding out where I went wrong would be appreciated. Constructive criticism of my code is always welcome - Thanks!
public static class SaveLoad
{
public static void Save(string fileName, object savefrom, bool compress)
{
FileStream stream = new FileStream(fileName, FileMode.Create);
BinaryFormatter formatter = new BinaryFormatter();
if (compress)
{
GZipStream compressor = new GZipStream(stream, CompressionMode.Compress);
formatter.Serialize(compressor, savefrom);
compressor.Close();
}
else { formatter.Serialize(stream, savefrom); }
stream.Close();
}
public static object Load(string fileName)
{
object loadedObject = null;
try
{
FileStream stream = new FileStream(fileName, FileMode.Open);
BinaryFormatter formatter = new BinaryFormatter();
if (stream.Length > 4)
{
byte[] data = new byte[4];
stream.Read(data, 0, 4);
if (BitConverter.ToUInt16(data, 0) == 0x8b1f) //GZIP_LEAD_BYTES == 0x8b1f
{
GZipStream decompressor = new GZipStream(stream, CompressionMode.Decompress);
loadedObject = formatter.Deserialize(decompressor); //Exception
decompressor.Close();
}
else { loadedObject = formatter.Deserialize(stream); }
}
stream.Close();
}
catch (Exception e)
{
Logger.StaticLog.AddEvent(new Logger.lEvent(null, Logger.lEvent.EventTypes.Warning, "Failed to load file: " + fileName, e)
{
SendingObject = "SaveLoad"
});
Logger.StaticLog.WriteLog();
throw;
}
return loadedObject;
}
}
It seems that you read the magic number before passing the stream to decompressor (which won't read the magic number then, because you've already read it).
Use stream.Seek(0,SeekOrigin.Begin) before you decompress.
public byte[] GetFile(string filename)
{
FileStream aStream = File.Open(filename, FileMode.Open, FileAccess.Read);
BinaryReader binReader = new BinaryReader(aStream);
binReader.BaseStream.Position = 0;
byte[] binFile = binReader.ReadBytes(Convert.ToInt32(binReader.BaseStream.Length));
binReader.Close();
return binFile;
}
I run this method for a number of filepaths, problem is whenever a file cannot be accessed with File.Open (because it is used by another process) I get:
'aStream.Position' threw an exception of type 'System.ObjectDisposedException'
on the following line:
binReader.BaseStream.Position = 0;
And seldom I get
{System.IO.IOException: The process can not access the file '\folder\file.txt' because it is being used by another process.}
This is the exception I want. So why is the object disposed most of the times?
Note: I first had the FileStream line in a using statement but removed it because I thought that might have disposed the object. But the problem remains.
Edit: Using Compact Framework, which doesn't have ReadAllBytes.
Maybe that part of the time your FileStream is throwing the IOException whenever your file is in use, and at other times, perhaps, you are getting the ObjectDisposedException because your array is not initialized.
Obviously, I can not test this theory.
See if you can copy-n-paste this one with good results:
public byte[] GetFile(string filename)
{
byte[] binFile = null;
try
{
using (var aStream = File.Open(filename, FileMode.Open, FileAccess.Read))
{
BinaryReader binReader = new BinaryReader(aStream);
binFile = new byte[binReader.BaseStream.Length];
binReader.BaseStream.Position = 0; // <= this step should not be necessary
binFile = binReader.ReadBytes(binReader.BaseStream.Length);
binReader.Close();
}
} catch (IOException err) {
// file is being used by another process.
} catch (ObjectDisposedException err) {
// I am guessing you would never see this because your binFile is not disposed
}
return binFile;
}
Be sure to check for null return variables!
EDIT:
I wrote (what I think is) a simpler version. I tested it, and it seems to work OK. I also prefer Read() overload to ReadBytes(), because I know how much data was pulled in.
First, is the test function that calls the method for every image in my Pictures folder:
public void Test() {
DirectoryInfo dir = new DirectoryInfo(Environment.GetFolderPath(Environment.SpecialFolder.Personal));
foreach (var subDir in dir.GetDirectories()) {
if (-1 < subDir.Name.ToLower().IndexOf("pictures")) {
foreach (var file in subDir.GetFiles()) {
byte[] data = GetFile(file.FullName);
if (data != null) {
Console.WriteLine(data.Length);
}
}
}
}
}
public byte[] GetFile(string filename) {
byte[] result = null;
try {
if (File.Exists(filename)) {
int len = 0;
FileInfo file = new FileInfo(filename);
byte[] data = new byte[file.Length];
using (BinaryReader br = new BinaryReader(file.Open(FileMode.Open, FileAccess.Read))) {
len = br.Read(data, 0, data.Length);
br.Close();
}
if (0 < len) {
if (len == data.Length) {
return data;
} else {
// this section of code was never triggered in my tests;
// however, it is good to keep it as a backup.
byte[] dat2 = new byte[len];
Array.Copy(data, dat2, len);
return dat2;
}
}
}
} catch (IOException err) {
// file is being used by another process.
} catch (ObjectDisposedException err) {
// I am guessing you would never see this because your binFile is not disposed
}
return result;
}
I don't see any reason why these would not work - unless you are having an int overflow.
Just use this:
byte[] contents = File.ReadAllBytes(filename);
Why don't you simply use
public byte[] GetFile(string filename)
{
try { return File.ReadAllBytes(filename); }
catch { return null; }
}
Just for fun, you could even define an extension method
public static class Extensions
{
public static byte[] GetFile(this string filename)
{
try { return File.ReadAllBytes(filename); }
catch { return null; }
}
}
so you could do byte[] myfile = filename.GetFile();.
Remember you must check that return is not null before proceed:
if (myfile != null)
{
// Do what you need
}
I'm saving an image from a web request and something really weird is happening. On roughly half of the 8,000 images I'm downloading I get IOEXCEPTION errors:
ERROR_ACCESS_DENIED (5)
INVALID_PARAMETER (87)
Before I save the file using file.open, I check to make sure the file does not exist. The exception is thrown at this line of code:
fileStream = File.Open(destination, FileMode.Create, FileAccess.Write, FileShare.None);
Below is the code:
public static bool DownloadFile(string url, string destination)
{
bool success = false;
System.Net.HttpWebRequest request = null;
System.Net.WebResponse response = null;
Stream responseStream = null;
FileStream fileStream = null;
try
{
request = (System.Net.HttpWebRequest)System.Net.WebRequest.Create(url);
request.Method = "GET";
request.Timeout = 100000; // 100 seconds
request.Proxy = System.Net.GlobalProxySelection.GetEmptyWebProxy();
response = request.GetResponse();
responseStream = response.GetResponseStream();
fileStream = File.Open(destination, FileMode.Create, FileAccess.Write, FileShare.None);
//fileStream = File.Create(destination);
// read up to ten kilobytes at a time
int maxRead = 10240;
byte[] buffer = new byte[maxRead];
int bytesRead = 0;
int totalBytesRead = 0;
// loop until no data is returned
while ((bytesRead = responseStream.Read(buffer, 0, maxRead)) > 0)
{
totalBytesRead += bytesRead;
fileStream.Write(buffer, 0, bytesRead);
}
// we got to this point with no exception. Ok.
success = true;
}
catch (System.Net.WebException we)
{
// something went terribly wrong.
success = false;
//MessageBox.Show(exp.ToString());
writeErrFile(we.ToString(), url);
//Debug.WriteLine(exp);
}
catch (System.IO.IOException ie)
{
// something went terribly wrong.
success = false;
//MessageBox.Show(ie.InnerException.ToString());
writeErrFile(ie.ToString(), destination + " -- " + url);
//Debug.WriteLine(exp);
}
catch (Exception exp)
{
// something went terribly wrong.
success = false;
//MessageBox.Show(exp.ToString());
writeErrFile(exp.ToString(), destination + " -- " + url);
//Debug.WriteLine(exp);
}
finally
{
// cleanup all potentially open streams.
if (null != responseStream)
responseStream.Close();
if (null != response)
response.Close();
if (null != fileStream)
fileStream.Close();
}
// if part of the file was written and the transfer failed, delete the partial file
if (!success && File.Exists(destination))
File.Delete(destination);
return success;
}
I've been stuck on this for a couple of days. Any help would be appreciated in unimaginable orders of magnitude.
Use file.exists() to check if the file exists and file.create or file.openwrite to write the file.
From your code I can't see how you are checking the file exists.