Forum OpenACS Q&A: Help for using HTMLDOC to output pdf file/download pdf file

Hi. All.

I have openacs3.x running on my dev box and am trying to figure out
how to use HTMLDOC to output pdf file.

I create a filter similar to file-storage and a proc similiar to fs-
file-downloader, which creates a link for user to download a pdf file
created by htmldoc in the /tmp directory.

The code of the proc is "

proc_doc pdf_downloader {conn key } "" {


    set_the_usual_form_variables


    if { [empty_string_p $file_name] } {

    return filter_break

    }


    set file_name_html "$file_name.html"

    set file_name_pdf "$file_name.pdf"


    if {[catch {exec htmldoc --webpage -f $file_name_pdf
$file_name_html} errmsg]} {

    ad_return_error Error $errmsg

    }


    ns_returnfile 200 "application/pdf" $file_name_pdf


    return filter_return
}

This proc is invoked by this link "/document/doc.pdf?
file_name=/tmp/docXXXXXX", which is created by another proc.
$file_name_html is already created in /tmp directory.

I put "
ns_section "ns/mimetypes"
ns_param  ".pdf"          "application/pdf"
" in nsd.tcl file.

It works well till the last step, which gives me the following error:
"Error
PAGES: 1 BYTES: 3612
".

If I reload the page, it gives me some additional info:
"
Error

PAGES: 1 BYTES: 3612

mailto:webmaster@localhost.localdomain
HTTP/1.0 200 OK MIME-Version: 1.0 Date: Fri, 03 May 2002 01:25:01 GMT
Server: AOLserver/3.4.2 Content-Type:
text/html Content-Length: 245 Connection: close Last-Modified: Fri,
03 May 2002 01:25:01 GMT Content-Type:
application/pdf Content-Length: 3612 %PDF-1.3 %âãÏ
".

Don't know exactly what the problem is. The pdf file is created in
the /tmp directory but is not returned to the browser.

I tried file-storage module to upload a pdf file and I can download
it from the link created by fs-file-downloader. But that page uses
db_blob to return the file.

Is this a problem with mime type? Ns_returnfile doesn't return that
pdf file correctly.

I tried "ns_write "output-type : application/pdf" $file_name_pdf"
and "ns_respond -status 200 -type "application/pdf" -file
$file_name_pdf" and both don't work.

Any feedback is appreciated!

Have you tried

exec htmldoc --webpage --quiet -f $file_name_pdf $file_name_html ?

Thanks. All.

"--quiet" fixes the problem.  Wow! I guess I didn't dig enough in HTMLDOC documentation.

Thanks again!

Are you using exactly the same procedure as in the original question? Then the problem might be with using set_the_usual_form_variables - I am not sure if that still works as expected under OpenACS 4.x. Try to pass the file_name directly to the proc instead, something like:

ad_proc pdf_downloader { file_name } { } {

if { [empty_string_p $file_name] } ... and so on

Running exec on htmldoc would successfully execute the shell commands, but return this error:

  child process exited abnormally

This would ruin my ns_returnfile since output was sent to the browser before the 200 header.

I discovered htmldoc returns 1 on success to stdout which is returned by catch and exec. Just catch the error and do nothing with it.

#
# Download the pdf
#
set file_name_pdf [ns_tmpnam]
append file_name_pdf ".pdf"

if {[catch {exec echo \ $html\  | /usr/share/htmldoc/htmldoc --webpage --quiet -f $file_name_pdf -} errmsg]} {
#Do nothing with the error and we're good.
}

ns_returnfile 200 application/pdf $file_name_pdf

return filter_return

Oh, and concerning the strangeness with
  echo \[space]$html\[space]
This is the only way to simulate shell quotes with exec. Curly braces and \" do not seem to work. Remember that $html must be escaped - "[{ etc!

More info on exec: http://wiki.tcl.tk/1039

Hope this helps someone.