We Keep Coding

C# Uploading a memorystream object to Web API

I have an CSV file in memory that I want to upload to a Web API.
If I save the CSV file to disk and upload it, it gets accepted.
However, I want to avoid the extra work and also make the code cleaner by simply uploading the text I have as a MemoryStream Object (I think that's the correct format?).
The following code works for uploading the file:
string webServiceUrl = "XXX";
string filePath = #"C:\test.csv";
string cred = "YYY";
using (var client = new WebClient()){
client.Headers.Add("Authorization", "Basic " + cred);
byte[] rawResponse = client.UploadFile(webServiceUrl, "POST", filePath);
Console.WriteLine(System.Text.Encoding.ASCII.GetString(rawResponse));
}
How would I do if I had a string with all the contents and I want to upload it in the same way without having to save it down to a file?
WebClient.UploadData or WebClient.UploadString perhaps?
Thank you
EDIT:
I tried what you said but by using a local file (in case there was something wrong with the string), but I get the same error.
Here is what I suppose the code would be using your solution
string webServiceUrl = "XXX";
string file = #"C:\test.csv";
string cred = "YYY";
FileStream fs = new FileStream(file, FileMode.Open, FileAccess.Read);
BinaryReader r = new BinaryReader(fs);
byte[] postArray = r.ReadBytes((int)fs.Length);
using (var client = new WebClient())
{
client.Headers.Add("Authorization", "Basic " + cred);
using (var postStream = client.OpenWrite(webServiceUrl, "POST"))
{
postStream.Write(postArray, 0, postArray.Length);
}
}
Any thoughts?

Use OpenWrite() from the WebClient.
using (var postStream = client.OpenWrite(endpointUrl))
{
postStream.Write(memStreamContent, 0, memStream.Length);
}
As documentation mentioned:
The OpenWrite method returns a writable stream that is used to send data to a resource.
Update
Try to set the position of the MemoryStream to 0 before uploading.
memoryStream.Position = 0;
When you copy the file into the MemoryStream, the pointer is moved to the end of the stream, so when you then try to read it, you're getting a null byte instead of your stream data.
MSDN - CopyTo()
Copying begins at the current position in the current stream, and does not reset the position of the destination stream after the copy operation is complete.

I finally managed to solve it.
First I made a request using CURL that worked.
I analyzed the packet data and made an except copy of the packet.
I did a lot of changes, however, the final change was that using the different functions I found online it never closed the packet with a "Last-Boundary" while CURL did.
So by modifying the function, making sure it properly wrote a Last-Boundary it finally worked.
Also, another crucial thing was to set PreAuthenticate to true, the examples online didn't do that.
So, all in all:
1. Make sure that the packet is properly constructed.
2. Make sure you pre authenticate if you need to authenticate.
webrequest.PreAuthenticate = true;
webrequest.Headers[HttpRequestHeader.Authorization] = string.Format("Basic {0}", cred);
Don't forget to add SSL if using a https (which you probably do if you authenticate):
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls | SecurityProtocolType.Ssl3;
Hope this helps someone.
And thanks for the help earlier!

C# Download File from FTP AS400

we currently have a *.BAT file that contains some FTP commands to download a file from our AS400 and save into a TEXT file. The BAT works fine and the text file will show the records inside the downloaded file one under the other.
Now, we wanted to get rid of this *.BAT file and use C# to download the file for us and save into a text file. The problem now is that the file we get contains all the records in ONE single line of string! they are no longer listed under each other.
here is the code we are using:
tpWebRequest request = default(FtpWebRequest);
FtpWebResponse response = default(FtpWebResponse);
StreamWriter writer = default(StreamWriter);
request = WebRequest.Create("*******URL******") as FtpWebRequest;
request.Credentials = new NetworkCredential("user", "pass");
request.Method = WebRequestMethods.Ftp.DownloadFile;
request.UseBinary = true;
response = request.GetResponse() as FtpWebResponse;
writer = new StreamWriter(Server.MapPath("/filename.txt"));
using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.GetEncoding(37))) //37 for IBM encoding
{
writer.WriteLine(reader.ReadToEnd());
}
writer.Close();
response.Close();
Any idea why we are getting this? and why the simple DOS FTP command work better than our code?
Thanks a lot! :)

ASCII mode will add record delimiters when downloading a physical file. It is the default transfer mode of most ftp clients.
request.UseBinary = false;
Specifying false causes the FtpWebRequest to send a "Type A" command to the server.
Data Transfer Methods
Transferring QSYS.LIB files

The problem might be simple: you read the whole document at once. You need to read every line seperately:
using(StreamReader sr = new StreamReader(fs))
{
while(!sr.EndOfStream)
{
Console.WriteLine(sr.ReadLine());
}
}

Issues with webscraping in C#: Downloading and parsing zipped text files

I am writing an webscraper, to do the download content from a website.
Traversing to the website/URL, triggers the creation of a temporary URL. This new URL has a zipped text file. This zipped file has to be downloaded and parsed.
I have written a scraper in C# using WebClient and its function DownloadFileAsync(). The zipped file is read from the designated location on a trapped DownloadFileCompleted event.
My issue is The Windows Open/Save dialog are triggered. This requires user input and the automation is disrupted.
Can you suggest a way to bypass the issue ? I am cool with rewriting the code using any alternate libraries. :)
Thanks for reading

You can use 'HttpWebRequest' to perform the request and save the streamed bytes to disk.
var request = WebRequest.Create(#"your url here");
request.Method=WebRequestMethods.Http.Get;
var response = request.GetResponse();
using (var writeStream = new FileStream(#"path", FileMode.Create))
{
using (var readStream = response.GetResponseStream())
{
var buffer = new byte[1024];
var readCount = readStream.Read(buffer,0,buffer.Length);
while (readCount > 0)
{
writeStream.Write(buffer,0,buffer.Length);
readCount= readStream.Read(buffer,0,buffer.Length);
}
}
}

FileStream with querystring in filename?

I have a need to be able to open a file on disk but pass in parameters to that file via a querystring. It's a .SWF file, so I'm passing in the parameter necessary to get it to load correctly.
The code I'm using to do so is:
FileStream fs = new FileStream(#"C:\test\file.swf?key=value", FileMode.Open, FileAccess.Read);
I'm getting an error opening the file: "Invalid characters in path" because of the "?" in the filename. Is there any way to load a file from disk into a FileStream object using a querystring in the filename?

I think you can't do what you're trying to do. When you load a file from disk the querystring does not exist as a concept. It will only return the bytes contained in the SWF file.
The querystring matters at the execution level.

So I solved this problem by putting my two SWF files on a web server and using the following code. Not exactly production ready code, but it illustrates the concept.
private static FileStream GetFileStream()
{
string url = #"http://www.someurl.com/shell.swf?Filename=actualfile.swf";
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
WebResponse response = request.GetResponse();
byte[] result = null;
int byteCount = Convert.ToInt32(response.ContentLength);
using (BinaryReader reader = new BinaryReader(response.GetResponseStream()))
result = reader.ReadBytes(byteCount);
return new FileStream(result);
}

How to check if a file exists on a server using c# and the WebClient class

In my application I use the WebClient class to download files from a Webserver by simply calling the DownloadFile method. Now I need to check whether a certain file exists prior to downloading it (or in case I just want to make sure that it exists). I've got two questions with that:
What is the best way to check whether a file exists on a server without transfering to much data across the wire? (It's quite a huge number of files I need to check)
Is there a way to get the size of a given remote file without downloading it?
Thanks in advance!

WebClient is fairly limited; if you switch to using WebRequest, then you gain the ability to send an HTTP HEAD request. When you issue the request, you should either get an error (if the file is missing), or a WebResponse with a valid ContentLength property.
Edit: Example code:
WebRequest request = WebRequest.Create(new Uri("http://www.example.com/"));
request.Method = "HEAD";
using(WebResponse response = request.GetResponse()) {
Console.WriteLine("{0} {1}", response.ContentLength, response.ContentType);
}

When you request file using the WebClient Class, the 404 Error (File Not Found) will lead to an exception. Best way is to handle that exception and use a flag which can be set to see if the file exists or not.
The example code goes as follows:
System.Net.HttpWebRequest request = null;
System.Net.HttpWebResponse response = null;
request = (System.Net.HttpWebRequest)System.Net.HttpWebRequest.Create("www.example.com/somepath");
request.Timeout = 30000;
try
{
response = (System.Net.HttpWebResponse)request.GetResponse();
flag = 1;
}
catch
{
flag = -1;
}
if (flag==1)
{
Console.WriteLine("File Found!!!");
}
else
{
Console.WriteLine("File Not Found!!!");
}
You can put your code in respective if blocks.
Hope it helps!

What is the best way to check whether a file exists on a server
without transfering to much data across the wire?
You can test with WebClient.OpenRead to open the file stream without reading all the file bytes:
using (var client = new WebClient())
{
Stream stream = client.OpenRead(url);
// ^ throws System.Net.WebException: 'Could not find file...' if file is not present
stream.Close();
}
This will indicate if the file exists at the remote location or not.
To fully read the file stream, you would do:
using (var client = new WebClient())
{
Stream stream = client.OpenRead(url);
StreamReader sr = new StreamReader(stream);
Console.WriteLine(sr.ReadToEnd());
stream.Close();
}

In case anyone stuck with ssl certificate issue
ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback
(
delegate { return true; }
);
WebRequest request = WebRequest.Create(new Uri("http://.com/flower.zip"));
request.Method = "HEAD";
using (WebResponse response = request.GetResponse())
{
Console.WriteLine("{0} {1}", response.ContentLength, response.ContentType);
}