I am trying to make a httplistener server in c# that sends files to the client (who is on a browser). This is my code:
static void SendFile(HttpListenerResponse response, string FileName, string ContentType) {
response.ContentType = ContentType;
// Read contents of file
var reader = new StreamReader(FileName);
var contents = reader.ReadToEnd();
reader.Close();
// Write to output stream
var writer = new StreamWriter(output);
writer.Write(contents);
// Wrap up.
writer.Close();
stream.Close();
response.Close();
}
Unfortunately, this code cannot send binary files, such as images, PDFs, and lots of other file types. How can I make this SendFile function binary-safe?
Thank you for all the comments and the gist link! The solution where you read from the file as a byte[] and write those bytes to the output stream I looked up worked, but is was kind of confusing, so I made a really short SendFile function.
static void SendFile(HttpListenerResponse response, string FileName, string ContentType) {
response.AddHeader("Content-Type", ContentType);
var output = response.OutputStream;
// Open the file
var file = new FileStream(FileName, FileMode.Open, FileAccess.Read);
// Write to output stream
file.CopyTo(output);
// Wrap up.
file.Close();
stream.Close();
response.Close();
}
This code just copies the file to the output stream.
Related
I have taken a IFormFile as an input and I need to read its content.
And, I am going to read the file content using the following code. However, File.OpenText requires a file path as input.
TextReader fileReader = File.OpenText(pathToFile)
Since I am not going to save the file in a physical location I have no file path with me at hand to pass to File.OpenText as an input.
How can I solve this ?
public async Task<string> PdfFileSave(IFormFile file, string nameOfThePerson)
{
TextReader fileReader = File.OpenText(pathToFile);
}
Try this:
using (var memoryStream = new MemoryStream())
{
await file.CopyToAsync(memoryStream);
byte[] fileBytes = memoryStream.ToArray();
string text = Encoding.UTF8.GetString(fileBytes);
}
you can use File.OpenReadStream():
public async Task<string> PdfFileSave(IFormFile file, string nameOfThePerson)
{
TextReader fileReader = new StreamReader( file.OpenReadStream() );
}
So Im trying to upload a file to my ftp server. Every things seems to work like expected but when I open the file from from the ftp I receive a I/O error. The local file works just fine. Some how the file gets corrupt after uploading. I found a similar problem here.
Here I read that you have to change the transfer mode to binary. I tried to set ftpRequest.UseBinary = true; But I still get the I/O error. Do I have to change the transfer mode somewhere els?
This is my ftp upload code:
public string upload(string remoteFile, string localFile)
{
ftpRequest = (FtpWebRequest)FtpWebRequest.Create(host + "/" + remoteFile);
ftpRequest.UseBinary = true;
ftpRequest.Credentials = new NetworkCredential(user, pass);
ftpRequest.Method = WebRequestMethods.Ftp.UploadFile;
// Copy the contents of the file to the request stream.
StreamReader sourceStream = new StreamReader(localFile);
byte[] fileContents = Encoding.UTF8.GetBytes(sourceStream.ReadToEnd());
sourceStream.Close();
ftpRequest.ContentLength = fileContents.Length;
Stream requestStream = ftpRequest.GetRequestStream();
requestStream.Write(fileContents, 0, fileContents.Length);
requestStream.Close();
FtpWebResponse response = (FtpWebResponse)ftpRequest.GetResponse();
response.Close();
return string.Format("Upload File Complete, status {0}", response.StatusDescription);
}
Using webclient I get the error:
The remote server returned an error: (553) File name not allowed.
Here is my code:
private void uploadToPDF(int fileName, string localFilePath, string ftpPath, string baseAddress)
{
WebClient webclient = new WebClient();
webclient.BaseAddress = baseAddress;
webclient.Credentials = new NetworkCredential(username, password);
webclient.UploadFile(ftpPath + fileName + ".pdf", localFilePath);
}
Your method upload most likely breaks the PDF contents because it treats it as text:
You use a StreamReader to read the PDF file. That class
Implements a TextReader that reads characters from a byte stream in a particular encoding.
(MSDN StreamReader information)
This implies that while reading the file bytes, the class interprets them according to that particular encoding (UTF-8 in your case because that's the default). But not all byte combinations do make sense as UTF-8 character combinations. Thus, this reading already is destructive.
You partially make up for this interpretation by re-encoding the characters according to UTF-8 later:
byte[] fileContents = Encoding.UTF8.GetBytes(sourceStream.ReadToEnd());
but as said before, the initial interpretation, the decoding as a UTF-8 encoded file already has destroyed the original file unless you were lucky enough and all the byte combinations made sense as UTF-8 encoded text.
For binary data (like ZIP archives, Word documents or PDF files) you should use the FileStream class, cf. its MSDN information.
Just started with writing unit tests and I am now, blocked with this situation:
I have a method which has a FileStream object and I am trying to pass a "string" to it.
So, I would like to convert my string to FileStream and I am doing this:
File.WriteAllText(string.Concat(Environment.ExpandEnvironmentVariables("%temp%"),
#"/test.txt"), testFileContent); //writes my string to a temp file!
new FileStream(string.Concat(Environment.ExpandEnvironmentVariables("%temp%"),
#"/test.txt"), FileMode.Open) //open that temp file and uses it as a fileStream!
close the file then!
But, I guess there must be some very simple alternative to convert a string to a fileStream.
Suggestions are welcome! [Note there are other answers to this question in stackoverflow but none seems to be a straight forward solution to that]
Thanks in advance!
First of all change your method to allow Stream instead of FileStream. FileStream is an implementation which, as I remember, does not add any methods or properties, just implement abstract class Stream. And then using below code you can convert string to Stream:
public Stream GenerateStreamFromString(string s)
{
MemoryStream stream = new MemoryStream();
StreamWriter writer = new StreamWriter(stream);
writer.Write(s);
writer.Flush();
stream.Position = 0;
return stream;
}
As FileStream class provides a stream for a file and hence it's constructor requires the path of the file,mode, permission parameter etc. to read the file into stream and hence it is used to read the text from file into stream. If we need to convert string to stream first we need to convert string to bytes array as stream is a sequence of bytes. Below is the code.
//Stream is a base class it holds the reference of MemoryStream
Stream stream = new MemoryStream();
String strText = "This is a String that needs to beconvert in stream";
byte[] byteArray = Encoding.UTF8.GetBytes(strText);
stream.Write(byteArray, 0, byteArray.Length);
//set the position at the beginning.
stream.Position = 0;
using (StreamReader sr = new StreamReader(stream))
{
string strData;
while ((strData= sr.ReadLine()) != null)
{
Console.WriteLine(strData);
}
}
I have a PDF which is hosted in say http://test.com/mypdf.pdf.
How can I convert the PDF to Stream and then using this Stream convert it back to PDF.
I tried the following but got an exception(see image):
private static Stream ConvertToStream(string fileUrl)
{
HttpWebResponse aResponse = null;
try
{
HttpWebRequest aRequest = (HttpWebRequest)WebRequest.Create(fileUrl);
aResponse = (HttpWebResponse)aRequest.GetResponse();
}
catch (Exception ex)
{
}
return aResponse.GetResponseStream();
}
This will work:
private static Stream ConvertToStream(string fileUrl)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(fileUrl);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
try {
MemoryStream mem = new MemoryStream();
Stream stream = response.GetResponseStream();
stream.CopyTo(mem,4096);
return mem;
} finally {
response.Close();
}
}
However you are entirely responsible for the lifetime of the returned memory stream.
A better approach is:
private static void ConvertToStream(string fileUrl, Stream stream)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(fileUrl);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
try {
Stream response_stream = response.GetResponseStream();
response_stream.CopyTo(stream,4096);
} finally {
response.Close();
}
}
You can then do something like:
using (MemoryStream mem = new MemoryStream()) {
ConvertToStream('http://www.example.com/',mem);
mem.Seek(0,SeekOrigin.Begin);
... Do something else ...
}
You may also be able to return the response stream directly but you'd have to check on the lifetime of that, releasing the response may release the stream, hence the mem copy.
You may want to take a look at WebClient.DownloadFile.
You give it a URL and local file name and it saves the file straight to disk. Might save you a step or two.
You could also try WebClient.DownloadData which saves the file to an in-memory byte[].
EDIT
You did not specify the protocol of the web-service you are posting the file to. The simplest form (RESTful) would be just to POST the file to data to another URL. Here is how you would do that.
using (WebClient wc = new WebClient())
{
// copy data to byte[]
byte[] data = wc.DownloadData("http://somesite.com/your.pdf");
// POST data to another URL
wc.Headers.Add("Content-Type","application/pdf");
wc.UploadData("http://anothersite.com/your.pdf", data);
}
If you are using SOAP, you would have to convert the file to a Base64 string, but hopefully you are using a generated client which takes care of that for you. If you could elaborate on the type of web-service you are sending the file to, I could probably provide some more information..
I'm trying to convert a .db file to binary so I can stream it across a web server. I'm pretty new to C#. I've gotten as far as looking at code snippets online but I'm not really sure if the code below puts me on the right track. How I can write the data once I read it? Does BinaryReader automatically open up and read the entire file so I can then just write it out in binary format?
class Program
{
static void Main(string[] args)
{
using (FileStream fs = new FileStream("output.bin", FileMode.Create))
{
using (BinaryWriter bw = new BinaryWriter(fs))
{
long totalBytes = new System.IO.FileInfo("input.db").Length;
byte[] buffer = null;
BinaryReader binReader = new BinaryReader(File.Open("input.db", FileMode.Open));
}
}
}
}
Edit: Code to stream the database:
[WebGet(UriTemplate = "GetDatabase/{databaseName}")]
public Stream GetDatabase(string databaseName)
{
string fileName = "\\\\computer\\" + databaseName + ".db";
if (File.Exists(fileName))
{
FileStream stream = File.OpenRead(fileName);
if (WebOperationContext.Current != null)
{
WebOperationContext.Current.OutgoingResponse.ContentType = "binary/.bin";
}
return stream;
}
return null;
}
When I call my server, I get nothing back. When I use this same type of method for a content-type of image/.png, it works fine.
All the code you posted will actually do is copy the file input.db to the file output.bin. You could accomplish the same using File.Copy.
BinaryReader will just read in all of the bytes of the file. It is a suitable start to streaming the bytes to an output stream that expects binary data.
Once you have the bytes corresponding to your file, you can write them to the web server's response like this:
using (BinaryReader binReader = new BinaryReader(File.Open("input.db",
FileMode.Open)))
{
byte[] bytes = binReader.ReadBytes(int.MaxValue); // See note below
Response.BinaryWrite(bytes);
Response.Flush();
Response.Close();
Response.End();
}
Note: The code binReader.ReadBytes(int.MaxValue) is for demonstrating the concept only. Don't use it in production code as loading a large file can quickly lead to an OutOfMemoryException. Instead, you should read in the file in chunks, writing to the response stream in chunks.
See this answer for guidance on how to do that
https://stackoverflow.com/a/8613300/141172