perl wkhtmltopdf Error: Unable to write to destination

djlerman has asked for the wisdom of the Perl Monks concerning the following question:

Hello Wise Monks...

I have the following code running as CGI. It starts to run and returns an empty PDF file to the browser and writes an error message to the error_log.

Do you have any wisdom on how to solve this?

linux: Linux version 2.6.35.6-48.fc14.i686.PAE (...) (gcc version 4.5.
+1 20100924 (Red Hat 4.5.1-4) (GCC) ) #1 SMP Fri Oct 22 15:27:53 UTC 2
+010

wkhtmltopdf: wkhtmltopdf 0.10.0 rc2

perl: This is perl 5, version 12, subversion 2 (v5.12.2) built for i38
+6-linux-thread-multi
[download]

Thank You in Advance. ~Donavon

perl CODE:

#!/usr/bin/perl
#### takes string containing HTML and outputs PDF to browser to downlo
+ad
#### (otherwise would output to STDOUT)

print "Content-Disposition: attachment; filename='testPDF.pdf'\n";
print "Content-type: application/octet-stream\n\n";

my $htmlToPrint = "<html>a bunch of html</html>";

### open a filehandle and pipe it to wkhtmltopdf
### *the arguments "- -" tell wkhtmltopdf to get
###  input from STDIN and send output to STDOUT*
open(my $makePDF, "|-", "/usr/local/bin/wkhtmltopdf", "-", "-") || die
+("$!");
print $makePDF $htmlToPrint;  ## sends my HTML to wkhtmltopdf which st
+reams immediately to STDOUT
[download]

error_log message:

Loading pages (1/6)
QPainter::begin(): Returned false============================] 100%
Error: Unable to write to destination
[download]

Comment on perl wkhtmltopdf Error: Unable to write to destination Select or Download Code

Replies are listed 'Best First'.
Re: perl wkhtmltopdf Error: Unable to write to destination by RichardK (Parson) on May 07, 2014 at 16:25 UTC
'\|-' means open a command and pipe data to it, & the help for open says :- `You are not allowed to "open" to a command that pipes both in and out, + but see IPC::Open2, IPC::Open3,...` [download] So it's no great surprise that it doesn't work.	[reply] [d/l]
Re^2: perl wkhtmltopdf Error: Unable to write to destination by djlerman (Sexton) on May 07, 2014 at 18:22 UTC
Thank you for your response. I will try it with IPC::Open3. I'm trying to create a simple example for IPC::Open3. Should I create a separate post relating to getting Open3 to work? Below is code I am trying and here is the output I get: OUTPUT: `err-> /bin/ls: write error: Bad file descriptor retval-> 512` [download] CODE: `#!/usr/bin/perl use warnings; use strict; use IPC::Open3; print "Content-type: text/html\n\n"; print ' <!DOCTYPE HTML> <html lang="en"> <head> <title>IPC::Open3 Example</title> </head> <body>'; my $cmd = '/bin/ls -la'; my $pid = open3(\WRITER, \READER, \*ERROR, $cmd); while( my $output = <READER> ) { print "output-> $output\n"; } while(my $errout = <ERROR> ) { print "err-> $errout\n"; } waitpid($pid, 0 ) or die "$!\n"; my $retval = $?; print "retval-> $retval\n"; print " </body> </html>";` [download]	[reply] [d/l] [select]
Re^3: perl wkhtmltopdf Error: Unable to write to destination by djlerman (Sexton) on May 09, 2014 at 18:25 UTC
Here is the final working solution I came up with. If there is anything I missed please let me know. I don't know if I am using "gensym()" correctly. The main thing that was an issue was rights on the server side. #!/usr/bin/perl use warnings; use strict; use IPC::Open3; use Symbol; my $cmd = '/usr/local/bin/wkhtmltopdf - -'; my $err = gensym(); my $in = gensym(); my $out = gensym(); my $pdf = ''; my $pid = open3($in, $out, $err, $cmd) or die "could not run cmd : $c +md : $!\n"; my $string = '<html><head></head><body>Hello World!!!<br /><br /><br / +> IMG: <img id="image" src="data:image/gif;base64,R0lGODlhFwAPAKEAAP///w +AAAMzMzLi3tywAAAAAFwAPAAACQIyPqQjtD98RIVpJ66g3hgEYDdVhjThyXSA4aLq2rgp +78hxlyY0/ICAIBhu/HrEEKIZUyk4R1Sz9RFEkaIHNFgAAOw==" /> </body></html>'; print $in $string; close($in); while( <$out> ) { $pdf .= $_ } # for trouble shooting while( <$err> ) { # print "err-> $_<br />\n"; } # for trouble shooting waitpid($pid, 0 ) or die "$!\n"; my $retval = $?; # print "retval-> $retval<br />\n"; print "Content-Disposition: attachment; filename='testPDF.pdf'\n"; print "Content-type: application/octet-stream\n\n"; print $pdf; [download]	[reply] [d/l]
Re: perl wkhtmltopdf Error: Unable to write to destination by choroba (Cardinal) on May 07, 2014 at 16:19 UTC
Crossposted at StackOverflow. It is considered polite to inform about crossposting, so people not attending both sites don't waste their time hacking a solution to a problem already solved at the other end of the Internets. Also, googling for the error message brings up this link. Is it helpful? لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply]
Re^2: perl wkhtmltopdf Error: Unable to write to destination by djlerman (Sexton) on May 07, 2014 at 17:02 UTC
Thank you. I did not know about the rule about cross posting. The link related to windows specifically so I wasn't able to use it.	[reply]


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