CODEWITHSUNDEEP
asp.netvb.netpdfitext
invernomuto
invernomuto

Reputation: 10221

Merge PDF by streams

I am in trouble with a .ashx which should merge some PDF memory-stream, in a simplest case, where I have in output only one stream, the output PDF stream are corrupted, but when I call another ashx which get in output only the single stream works, what I miss in the following code?

I collect memory-streams:

Dim streamDocument As MemoryStream = FumForm.CreatePdfDocument(context, _fumForm, _formTemplate, _match)
lReader.Add(New PdfReader(streamDocument))

then I would like append all pdf pages in an other pdf:

Dim document As Document = New Document(PageSize.A4, 0, 0, 0, 0)
Dim writer As PdfWriter = PdfWriter.GetInstance(document, context.Response.OutputStream)
document.Open()

For Each r As PdfReader In lReader
  For i As Integer = 1 To r.NumberOfPages
    Dim page As PdfImportedPage = writer.GetImportedPage(r, i)
    document.Add(Image.GetInstance(page))

  Next
Next

Dim filename = String.Format("{0}{1}.pdf", "pippo", "test")
document.Close()
context.Response.Clear()
context.Response.ContentType = "application/pdf"
context.Response.AppendHeader("content-disposition", "inline; filename=""" & filename & """")
context.Response.Flush()
context.Response.Close()
context.Response.End()

CreatePdfDocument works well, and have this signature

static public MemoryStream CreatePdfDocument(HttpContext context, 
                                             FumForm form, 
                                             FumFormTemplate formTemplate, 
                                             Match match)

Any help will be really appreciated

Upvotes: 1

Views: 619

Answers (1)

mkl
mkl

Reputation: 96064

The code first writes the whole PDF to context.Response.OutputStream

Dim document As Document = New Document(PageSize.A4, 0, 0, 0, 0)
Dim writer As PdfWriter = PdfWriter.GetInstance(document, context.Response.OutputStream)
...
document.Close()

and thereafter clears and changes headers of the context.Response

context.Response.Clear()
context.Response.ContentType = "application/pdf"
context.Response.AppendHeader("content-disposition", "inline; filename=""" & filename & """")

To work correctly, all response object clearing and header manipulations have to be finished before the data may be written to the response stream.

Upvotes: 2

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