Convert Byte Array back to PDF in blazor-CodePudding

I'm trying to download a PDF file from blazor sent by my WebAPI as byte[] (byteArray). I know that my PDF is working because when I send it as filestreamResult and retrieve it directly from my WebAPI (using swagger for example), I get the correct PDF file.

My WebAPI:

var response = await GetResponse(new Query(request.AnalysisDate), ct);
string html = await _templateService.PerformanceReport(response);
MemoryStream stream = _pdfService.GeneratePdf(html);            
return await stream.ToArray(); // as byte[]

Blazor Side:

var bytes = await _http.GetByteArrayAsync(endpoint);  
await JsRuntime.InvokeVoidAsync("BlazorDownloadFile", "file.pdf", "application/pdf", bytes);

JS:

function BlazorDownloadFile(filename, contentType, content) {
// Create the URL
const file = new File([content], filename, { type: contentType });
const exportUrl = URL.createObjectURL(file);

// Create the <a> element and click on it
const a = document.createElement("a");
document.body.appendChild(a);
a.href = exportUrl;
a.download = filename;
a.target = "_self";
a.click();

// We don't need to keep the object url, let's release the memory
// On Safari it seems you need to comment this line... (please let me know if you know why)
URL.revokeObjectURL(exportUrl);
}

I Correctly download a PDF file named file.pdf but it looks corrupted.

Is this the correct approach with .NET 6?

Should I send a FileStreamResult from the Web API (I Like the fact that I can get the file directly from swagger)?

I can't really find a good example for blazor on how to do this. Any help would be appreciated.

CodePudding user response：

I am using another aproach. I send base64String. I convert byte array to base64 string then i pass the string to javascript function

Server side call:

js.InvokeVoidAsync("jsSaveAsFile",
                    filename,
                    Convert.ToBase64String(GetFileByteArrayFunction())
                    );

javascript function:

function jsSaveAsFile(filename, byteBase64) {
    var link = document.createElement('a');
    link.download = filename;
    link.href = "data:application/octet-stream;base64,"   byteBase64;
    document.body.appendChild(link);
   link.click();
   document.body.removeChild(link);}

js -> using Microsoft.JSInterop.

CodePudding user response：

You should send your file like this:

app.MapGet("/download", () => 
{
    //...
    Results.File("myfile.pdf");
});

there are some overloads of this method you can pick up the one that fit your requirements.