So, using vb.net, I retrieve from my server the byte data for a file that the user wishes to download. I always know what the filename and extension is, but what I don't know is how to start downloading the byte data and in the proper file format. How do I got about doing this?
EDIT: Just to clarify, I already retrieve the data in byte format in code, I just need to download it as the proper file type which is also known. I'm keeping the URL to the file hidden at all times so it's never exposed.
If you want to download the file directly to the hard drive, the easiest solution is to use WebClient.DownloadFile. The MSDN page contains a nice example.
If you want to put the file into a byte array instead of a file on disk, use WebClient.DownloadData instead:
Dim myWebClient As New WebClient()
Dim myByteArray = myWebClient.DownloadData("http://...")
Again, a larger example can be found on the MSDN page.
If you want your program to stay responsive while downloading, check out the asynchronous versions of those methods.
EDIT: I'm still having a hard time understanding your situation, but it you already have a byte array and just want to write it to the disk, you can use File.WriteAllBytes:
File.WriteAllBytes("C:\my\path\myfile.bin", myByteArray)
Okay, I figured it out. Using BinaryWrite with the other Response functions like AddHeader and ContentType I got it to work. GetMimeType is a function I made. Code below:
Response.Clear()
Response.AddHeader("Content-Disposition", "attachment; filename=" + FileName)
Response.ContentType = GetMimeType(FileName)
Response.BinaryWrite(data)
Response.End()
Response.Flush()
Thanks to those who tried to help!
Related
According to the Discord.NET documentation page for the EmbedBuilder class, the syntax (converted to VB) to add a local image to an EmbedBuilder object should look something like this:
Dim fileName = "image.png"
Dim embed = New EmbedBuilder() With {
.ImageUrl = $"attachment://{fileName}"
}.Build()
I'm trying to use something like this to add a dynamically created image to the EmbedBuilder, but I can't seem to get it to work properly. Here's basically what I've got:
Dim TweetBuilder As New Discord.EmbedBuilder
Dim DynamicImagePath As String = CreateDynamicImage()
Dim AttachURI As String = $"attachment:///" & DynamicImagePath.Replace("\", "/").Replace(" ", "%20")
With Builder
.Description = "SAMPLE DESCRIPTION"
.ImageUrl = AttachURI
End With
MyClient.GetGuild(ServerID).GetTextChannel(PostChannelID).SendMessageAsync("THIS IS A TEST", False, Builder.Build)
My CreateDynamicImage method returns the full path to the locally created image (e.g., C:\Folder\Another Folder\image.png). I've done a fair amount of "fighting"/testing with this to get past the Url must be a well-formed URI exception I was initially getting because of the [SPACE] in the path.
MyClient is a Discord.WebSocket.SocketClient object set elsewhere.
The SendMessageAsync method does send the Embed to Discord on the correct channel, but without the embedded image.
If I instead send the image using the SendFileAsync method (like so):
MyClient.GetGuild(ServerID).GetTextChannel(PostChannelID).SendFileAsync(DynamicImagePath, "THIS IS A TEST", False, Builder.Build)
the image is sent, but as a part of the message, rather than included as a part of the Embed (this is expected behavior - I only bring it up b/c it was a part of my testing to ensure that there wasn't a problem with actually sending the image to Discord).
I've tried using the file:/// scheme instead of the attachment:/// scheme, but that results in the entire post never making it to Discord at all.
Additionally, I've tried setting the ImageUrl property to a Web resource (e.g., https://www.somesite.com/someimage.png) and the Embed looks exactly as expected with the image and everything when it successfully posts to Discord.
So, I'm just wondering at this point if I'm just missing something, or if I'm just doing it completely wrong?
I cross-posted this to issue #1609 in the Discord.Net GitHub project to get a better idea of what options are available for this and received a good explanation of the issue:
The Embed (and EmbedImage) objects don't do anything with files. They simply pass the URI as configured straight into Discord. Discord then expects a URI in the form attachment://filename.ext if you want to refer to an attached image.
What you need to do is use SendFileAsync with the embed. You have two options here:
Use SendFileAsync with the Stream stream, string filename overload. I think this makes it clear what you need to do: you provide a file stream (via File.OpenRead or similar) and a filename. The provided filename does not have to match any file on disk. > So, for example:
var embed = new EmbedBuilder()
.WithImageUrl("attachment://myimage.png")
.Build();
await channel.SendFileAsync(stream, "myimage.png", embed: embed);
Alternatively, you can use SendFileAsync with the string filePath overload. Internally, this gets a stream of the file at the path, and sets filename (as sent to Discord) to the last part of the path. So it's equivalent to:
using var stream = File.OpenRead(filePath);
var filename = Path.GetFileName(filePath);
await channel.SendFileAsync(stream, filename);
From here, you can see that if you want to use the string filePath overload, you need to set embed image URI to something like $"attachment://{Path.GetFileName(filePath)}", because the attachment filename must match the one sent to Discord.
I almost had it with my code above, but I misunderstood the intention and usage of the method and property. I guess I thought the .ImageUrl property somehow "automatically" initiated a Stream in the background. Additionally, I missed one very important piece:
As it's an async method, you must await (or whatever the VB.NET equivalent is) on SendFileAsync.
So, after making my calling method into an async method, my code now looks like this:
Private Async Sub TestMessageToDiscord()
Dim Builder As New Discord.EmbedBuilder
Dim AttachmentPath As String = CreateDynamicImage() '<-- Returns the full, local path to the created file
With Builder
.Description = "SAMPLE DESCRIPTION"
.ImageUrl = $"attachment://{IO.Path.GetFileName(AttachmentPath)}"
End With
Using AttachmentStream As IO.Stream = IO.File.OpenRead(AttachmentPath)
Await MyClient.GetGuild(ServerID).GetTextChannel(PostChannelID).SendFileAsync(AttachmentStream, IO.Path.GetFileName(AttachmentPath), "THIS IS A TEST", False, Builder.Build)
End Using
End Sub
Now, everything works exactly as expected and I didn't have to resort to uploading the image to a hosting site and using the new URL (I actually had that working before I got the response on GitHub. I'm sure that code won't go to waste).
EDIT
Okay, so I still ended up going back to my separately hosted image option for one reason: I have a separate event method that modifies the original Embed object during which I want to remove the image and replace the text. However, when that event fired, while the text was replaced, the image was "moved" to the body of the Discord message. While I may have been able to figure out how to get rid of the image entirely, I decided to "drop back and punt" since I had already worked out the hosted image solution.
I've tried everyting I could, but I got stuck at the same point at where you are now.
My guesses are that Discord doesn't like the embedded images from https://cdn.discordapp.com/attachments, and only accepts the new files from https://media.discordapp.net. I might be wrong though, this is the way it worked for me.
I believe it's only a visual glitch, as I found if you send a link for an image from cdn.discordapp.com/attchments in your regular Discord client, it bugs out and shows an empty embed for some reason.
That would make sense since the default link used in an embedded image actually starts with https://cdn.discordapp.com/attachments/...
You could solve this issue by using https://media.discordapp.net, but it seems like Discord.net is configured to use the old domain.
I'm trying to get a large CSV file from S3 but the download fails with “java.net.SocketException: Connection reset”, which is probably due to the InputStream simply being open for too long (the download often takes more than an hour since I am doing multiple time-consuming processes on the streamed content). This is how I currently parse the file:
InputStream inputStream = new GZIPInputStream(s3Client.getObject("bucket", "key").getObjectContent());
Reader decoder = new InputStreamReader(inputStream, Charset.defaultCharset());
BufferedReader isr = new BufferedReader(decoder);
CSVParser csvParser = new CSVParser(isr, CSVFormat.DEFAULT);
CSVRecord nextRecord = csvParser.iterator().next();
...
I know I have to split the download into multiple short getObject-calls with a defined offset for the GetObjectRequest, but I'm wondering how to define this offset in case of a CSV, since I need complete lines.
Do I have to ditch the parser library and parse each line into an Object myself so I can keep a count of the read bytes and use it as an offset for the next batch? That doesn't seem very robust to me. Is there any best practice way to achieve "batch downloading" of CSV records?
I decided on simply using the dedicated getObject(GetObjectRequest getObjectRequest, File destinationFile) method to copy the entire CSV to a temporary file on disk. This closes the HTTP connection as soon as possible and allows me to get the InputStream from the local file with no problems. It doesn't resolve the question of the best way to download in batches, but it's a nice and simple workaround.
I need to download a file from a FTP Server.
The path and the file name is
ftp://10.17.20.60/ata0b/OpconData/StationData/Station.dat
When i want to see all Files in the StationData directory i use
Dim request As Net.FtpWebRequest = Net.FtpWebRequest.Create("ftp://10.17.20.60/%2F/ata0b/OpconData/StationData/")
request.Method = Net.WebRequestMethods.Ftp.ListDirectory
request.Credentials = New Net.NetworkCredential(form1.txtFTPUser.Text, form1.txtFTPPasswort.Text)
Dim response As Net.FtpWebResponse = request.GetResponse()
With this i get the content of the directory. Of course i see the Station.dat file. I was able to make it work since i use the %2F parameter to change the directory to ata0b.
So far so good!
Now i want to download the Station.dat file. But i always get an error (550) File unavailable (e.g., file not found, no access) at the last line in code below.
My code looks like this:
'Create Request To Download File'
Dim wrDownload As FtpWebRequest = WebRequest.Create("ftp://10.17.20.60/%2F/ata0b/OpconData/StationData/Station.dat")
'Specify That You Want To Download A File'
wrDownload.Method = WebRequestMethods.Ftp.DownloadFile
'Specify Username & Password'
wrDownload.Credentials = New NetworkCredential("opconadmin", "OpconAdmin")
'Response Object'
Dim rDownloadResponse As FtpWebResponse = wrDownload.GetResponse()
What's my failure? In my point of view the file must be at the given path. I really hope somebody can give me a hint.
BR
Steffen
The error means what it says.But let me explain why this might occur :
1 • The file might be unavailable/not present on the server
2 • You might face 'Security Problem on file' issue .
There could be other causes like server timeout or other..
However,you need to find out what the error message really is.TO do this, you can use a TRY-CATCH statement. E.g.
Try
'YOur code here
Catch e as WebException
Msgbox(e.Message) 'you can use e.tostring for more details
After you find out what exactly is the problem,then you'ld be able to solve it.Take a look at these :
http://www.dreamincode.net/forums/topic/76361-file-upload-to-server/
https://nickstips.wordpress.com/2010/10/25/c-ftp-upload-error-the-remote-server-returned-an-error-550-file-unavailable-e-g-file-not-found-no-access/
https://forums.asp.net/t/1777881.aspx
But one thing i'ld like to suggest is to check whether you have any Permission/Security issues or not.And after you get the exact error message,it may(or may not) turn out to be that you don't have enough disk space.However,try my solution and leave a reply for further assistance.
UPDATE
Try replacing the FTP link with this : ftp://10.17.20.60//ata0b/OpconData/StationData/Station.da
I have a WCF written in vb.net that I want to return a zip file from. Now I can get that working, but I can't figure out how to set the suggested name the file should be saved as (it defaults to the Operation Name with no extension). When I save the file and then rename it with a .zip extension it is the zip file I expect.
So I'd like to be able to set the file extension, I guess I'm not that bothered by the file name.
Here is my example code:
<WebGet(UriTemplate:="Export/", ResponseFormat:=WebMessageFormat.Xml, BodyStyle:=WebMessageBodyStyle.Bare)>
Public Function ModelVersionExport() As System.IO.Stream
WebOperationContext.Current.OutgoingResponse.ContentType = "application/octet-stream"
'then I call my code that creates the io.stream of the zip file (that works fine)
End Function
I thought maybe I could set something on the OutGoingResponse but nothing looks right.
This fixes the issue:
WebOperationContext.Current.OutgoingResponse.ContentType = "application/zip"
Should have been fairly obvious but all examples I'd seen used the WebOperationContext.Current.OutgoingResponse.ContentType = "application/octet-stream" setting
I had a question when using android-async-http. After reading the source code, I knew about how to add a File or InputStream as a parameter into RequestParam. Then the RequestParam would be transferred into an AsyncHttpClient which would use RequestParam to get/put/post....Just like this:
String url = ...;
File file = ...;
ResponseHandlerInterface respHandler = ...;
AsyncHttpClient client = new AsyncHttpClient();
RequestParams params = new RequestParams();
params.add("upload_file", file);
client.get(url, params, respHandler);
As we all know, Files of any types are bits essentially. So when delivered over the internet, files could be transferred into a byte stream. But I didn't find any codes about this conversion. So, I wonder how android-async-http completes this, or did I miss something when reading source codes?
I thought I found the way android-async-http handled with files/inputstreams. Uploading a file depends on the call of put(?)/post(?), but not get(?). By searching the overwrited methods of put(?)/post(?), you will find paramsToEntity(RequestParams, ResponseHandlerInterface) which will return a HttpEntity. And then, HttpPost/HttpPut will setEntity(HttpEntity). Because get(?)s don't support uploading files, then you can't find operations about uploading files in get(?)s.