My requirement is to use Web API to send across the network, a zip file (consisting a bunch of files in turn) which should not be written anywhere locally (not written anywhere on the server/client disk). For zipping, I am using DotNetZip - Ionic.Zip.dll
Code at Server:
public async Task<IHttpActionResult> GenerateZip(Dictionary<string, StringBuilder> fileList)
{
// fileList is actually a dictionary of “FileName”,”FileContent”
byte[] data;
using (ZipFile zip = new ZipFile())
{
foreach (var item in filelist.ToArray())
{
zip.AddEntry(item.Key, item.Value.ToString());
}
using (MemoryStream ms = new MemoryStream())
{
zip.Save(ms);
data = ms.ToArray();
}
}
var result = new HttpResponseMessage(HttpStatusCode.OK);
MemoryStream streams = new MemoryStream(data);
//, 0, data.Length-1, true, false);
streams.Position = 0;
//Encoding UTFEncode = new UTF8Encoding();
//string res = UTFEncode.GetString(data);
//result.Content = new StringContent(res, Encoding.UTF8, "application/zip");
<result.Content = new StreamContent(streams);
result.Content.Headers.ContentType = new MediaTypeHeaderValue("application/zip");
//result.Content.Headers.ContentLength = data.Length;
result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment");
result.Content.Headers.ContentDisposition.FileName = "test.zip";
return this.Ok(result);
}
The issue I am facing is that after the zip file downloaded at client end when modified as a test.bin has its stream contents (byte[] data in this example’s contents) missing. (I am getting back a test.zip file. When I change the file locally from test.zip to test.bin, I am seeing that the File’s contents as shown below. It does not contain the Response.Content values. P.S. I have also tried the MIME type “application/octet-stream” as well. No luck!)
Test.zip aka test.bin’s contents:
{"version":{"major":1,"minor":1,"build":-1,"revision":-1,"majorRevision":-1,"minorRevision":-1},
"content":{"headers":[{"key":"Content-Type","value":["application/zip"]},
{"key":"Content-Disposition","value":["attachment; filename=test.zip"]}]},
"statusCode":200,"reasonPhrase":"OK","headers":[],"isSuccessStatusCode":true}
Can someone please help me on how we can set result.Content with a MemoryStream object (I have seen example of “FileStream” at other places on google to set “result.Content” but I want to use MemoryStream object only!). I am highlighting this because I think the problem lies with setting the MemoryStream object to the result.Content (in order to properly save the streams content into the result.Content object)
P.S. I have also gone thru Uploading/Downloading Byte Arrays with AngularJS and ASP.NET Web API (and a bunch of other links) but it did not help me much… :(
Any help is greatly appreciated. Thanks a lot in advance :)
I got my issue solved!!
All I did was to change the Response Type to HttpResponseMessage and use "return result" in the last line rather than Ok(result) { i.e. HttpResponseMessage Type rather than OKNegiotatedContentResult Type)
Related
I am unable to download a PDF file, fetched from Sql Database. Bytes value has been fetched, Function doesn't throw any error, but the PDF is not downloaded.
Code:
public ActionResult PrintPDF(string projectSelection)
{
byte[] extract = (byte[])_selectionManager.FindPdf();
MemoryStream pdfStream = new MemoryStream();
pdfStream.Write(extract, 0, extract.Length);
pdfStream.Position = 0;
HttpContext.Response.AddHeader("content-disposition",
"attachment; filename=form.pdf");
return new FileStreamResult(pdfStream, "application/pdf");
}
Since you already have the file content as bytes, why converting it to stream ?
Please check if this works
byte[] extract = (byte[])_selectionManager.FindPdf();
return File(
extract, System.Net.Mime.MediaTypeNames.Application.Pdf, "form.pdf");
I am trying to download a 1GB file from blob storage into the client. I used before Memory Stream and I get OutOfMemory exception.
now I am trying to open a read stream from the blob and send it directly to the client.
[HttpGet]
[ResponseType(typeof(HttpResponseMessage))]
public async Task<HttpResponseMessage> DownloadAsync(string file)
{
HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
var stream = await blob.OpenReadAsync("container", file);
result.Content = new StreamContent(stream);
return result;
}
The file is downloaded correctly, but the problem is: The code download the complete stream in the client, then the client sees the downloaded file.
I wanted the client to see the file as being downloaded, so the user knows that he is downloading something. Not just blocking the request and wait till it finished.
I am using FileSaver in Angular2:
this.controller.download('data.zip').subscribe(
data => {
FileSaver.saveAs(data, 'data.zip');
});
Has anybody an idea how to fix it?
Thank you!
To fix it you'd need to use the following javascript code instead:
var fileUri = "http://localhost:56676/api/blobfile"; //replace with your web api endpoint
var link = document.createElement('a');
document.body.appendChild(link);
link.href = fileUri;
link.click();
And then in your backend, make it like so:
HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
var stream = await blob.OpenReadAsync("container", file);
result.Content = new StreamContent(stream);
result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
{
FileName = "data.zip"
};
result.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
return result;
I had the same problem.
The Solution I sorted out was -
First thing, the expected behaviour can occur only when client tries to download the file from blob and usually I prefer downloading the file from the client itself.
As in your case, try to get file blob uri and do some operations as below to open file in browser using Angular Router or simply window.location.href.
window.location.href = “https://*/filename.xlsx”
This worked for me.
I have an endpoint that needs to accept a file upload and also some other information from the client request. With the following code I can upload the file successfully but can't seem to figure out how to read the other info.
I make a test request from Postman with the following form data:
image -- myimage.jpg -- of type File
email -- a#b.com -- of type Text
The backend code looks like this:
[HttpPost]
public async Task<HttpResponseMessage> SharePhoto()
{
try
{
var provider = new MultipartMemoryStreamProvider();
var data = await Request.Content.ReadAsMultipartAsync(provider);
// this is how I get the image which I am succesfully passing to EmailService
var item = (StreamContent)provider.Contents[0];
using (var stream = new MemoryStream())
{
await item.CopyToAsync(stream);
String emailAddress;
EmailService.SendSharedPhoto(emailAddress, stream);
return Request.CreateResponse();
}
}
catch
{
// do stuff
}
}
In this example I am able to access provider.Contents[1] but can't seem to be able to get the value from it into emailAddress. I'm thinking it may be possible to use the same trick as the await item.CopyToASync(stream) from the image upload, but I'm hoping I can get a simpler solution to that. Any ideas?
I just barely answered a very similar question to this yesterday. See my answer here complete with sample controller code.
The method I ended up using is:
If the form elements are strings (and it worked for me since the mobiel frontend took responsability for input data) you can do this:
var streamContent = (StreamContent)provider.Contents[1];
var memStream = new MemoryStream();
await streamContent.CopyToAsync(memStream);
var actualString = Encoding.UTF8.GetString(x.ToArray());
If however the field needs to represent a collection of items, like for example the email list: ["a#b.com", "x#c.com"], etc a JavaScriptSerializer can be user, like so:
var streamContent = (StreamContent)provider.Contents[1];
var emailAddresses = await str.ReadAsStringAsync();
var jsSerializer = new JavaScriptSerializer();
var deserializedData = jsSerializer.Deserialize<string[]>(emailAddresses);
Note that this is nowhere near safe, though it is few lines of code and happens to work.
I am generating pdf using itexsharp.
I am creating MemoryStream, then when i am trying t write MemoryStream bytes in to response but no luck. When i am executing this code in my controller the pdf not coming in response. Memory stream is populaitng correctly i can see this in debugger, but for some reason this number of butes not coming in response.
Here is my code:
HttpContext.Current.Response.ContentType = "application/pdf";
...
using (Stream inputPdfStream = new FileStream(pdfFilePath, FileMode.Open, FileAccess.Read, FileShare.Read))
using (Stream outputPdfStream = new MemoryStream())
{
PdfReader reader = new PdfReader(inputPdfStream);
PdfStamper stamper = new PdfStamper(reader, outputPdfStream);
....
//try one
outputPdfStream.WriteTo(HttpContext.Current.Response.OutputStream); // NOT POPULATING Response
//try two
HttpContext.Current.Response.BinaryWrite(outputPdfStream.ToArray()); // NOT POPULATING Response Too
HttpContext.Current.Response.End();
}
May be some one have any ideas?
Could you not use
Response.ContentType = "application/pdf"
Response.AddHeader("Content-Type", "application/pdf")
Response.WriteFile(pdfFilePath)
Response.End()
You should use the FileContentResult Controller.File(byte[] content, string contentType) method:
public ActionResult GeneratePDF()
{
var outputStream = new MemoryStream(); // This will hold the pdf you want to send in the response
/*
* ... code here to create the pdf in the outputStrem
*/
return File(outputStream.ToArray(), "application/pdf");
}
Source: Building PDFs in Asp.Net MVC 2.
Probably the memorystream is still set at the position after the last written byte. It will write all bytes from the current position (which is none). If you do a outputPdfStream.Seek(0) it will set the position back to the first byte, and will write the contents of the whole stream to the response output.
Anyway, like Dean says, you should just use the Reponse.WriteFile method.
I am writing a program that will be executing on the cloud. The program will generate an output that should be written on to a file and the file should be saved on the blob container.
I don't have a idea of how to do that
Will this code
FileStream fs = new FileStream(file, FileMode.Create);
StreamWriter sw = new StreamWriter(fs);
generate a file named "file" on the cloud...
Oh.. then how to store the content to the blob..
Are you attempting to upload a Page blob or a Block blob? Usually block blobs are what are required, unless you are going to create a VM from the blob image, then a page blob is needed.
Something like this works however. This snippet taken from the most excellent Blob Transfer Utility Check it out for all your upload and download blob needs. (Just change the type from Block To Page if you need a VHD)
public void UploadBlobAsync(ICloudBlob blob, string LocalFile)
{
// The class currently stores state in class level variables so calling UploadBlobAsync or DownloadBlobAsync a second time will cause problems.
// A better long term solution would be to better encapsulate the state, but the current solution works for the needs of my primary client.
// Throw an exception if UploadBlobAsync or DownloadBlobAsync has already been called.
lock (WorkingLock)
{
if (!Working)
Working = true;
else
throw new Exception("BlobTransfer already initiated. Create new BlobTransfer object to initiate a new file transfer.");
}
// Attempt to open the file first so that we throw an exception before getting into the async work
using (FileStream fstemp = new FileStream(LocalFile, FileMode.Open, FileAccess.Read)) { }
// Create an async op in order to raise the events back to the client on the correct thread.
asyncOp = AsyncOperationManager.CreateOperation(blob);
TransferType = TransferTypeEnum.Upload;
m_Blob = blob;
m_FileName = LocalFile;
var file = new FileInfo(m_FileName);
long fileSize = file.Length;
FileStream fs = new FileStream(m_FileName, FileMode.Open, FileAccess.Read, FileShare.Read);
ProgressStream pstream = new ProgressStream(fs);
pstream.ProgressChanged += pstream_ProgressChanged;
pstream.SetLength(fileSize);
m_Blob.ServiceClient.ParallelOperationThreadCount = 10;
asyncresult = m_Blob.BeginUploadFromStream(pstream, BlobTransferCompletedCallback, new BlobTransferAsyncState(m_Blob, pstream));
}