Beefy Boxes and Bandwidth Generously Provided by pair Networks
P is for Practical
 
PerlMonks  

comment on

( [id://3333]=superdoc: print w/replies, xml ) Need Help??
You can't or its very hard to debug cgi w/o access to the webserver's error log, so when you say "it didn't work" you should be sure (and say) there's nothing in there. Sprinkling a bunch of 'print STDERR' lines in the code (in my favorite format, my $debug = 30;):
for ($loop=1; $loop <= $form{'files'}; $loop++){ if ($form{"img$loop"}){ print STDERR "in if: form var img${loop} is $form{img${loop}}\n" if $debug > 15; ... print STDERR "done mussing: form1 img$loop is $form1{img${loop}}\n" if $debug > 10; print STDERR "opening: form filename is $form{filename}\n" if $debug > 20; open(FILE, ">$form{'filename'}/$form1{\"img$loop\"}") or die "can't open ", "$form{filename}/$form1{img${loop}}", ": $!"; while ($bytesread=read($file,$buffer,1024)) { print STDERR "while: read $bytesread\n" if $debug > 20;
You also seem to be unsure of the hash syntax; you don't need single quotes for constants: e.g.
$hash{'this'} eq $hash{this};
and, if you're mixing a var in a string ("img$loop") a good idea is to use the curly brackets to be sure it gets handled (and to make it apparent to the humans; "img${loop}" So:
$hash{"img$loop"} eq $hash{"img${loop}"}
but clearer/safer/cleaner is:
my $this_loop = "img${loop}"; $hash{$this_loop} = ...
Doesn't cost you anything, code is more readable and its easier to use/debug, just print $this_loop or:
my $img_file = "$form{filename}/$form1{$this_loop}"; open(FILE, ">$img_file") or die "can't open $img_file: $!";
Do this, look through the error log and then you can confidently say 'its not working' ... probably, though, you'll see something useful in there. Oh, if its a busy server, prefix all the print STDERR msgs w/ "my_cgi: ..." so they'll stand out in the log. And when it works, my $debug = 0 makes them all go away.

Update:Are you using (and if no, why not!? ;-) cgi.pm? It does the upload for you (search on cgi upload sysread) if you're using the upload stuff, so sysread won't find anything to ... well read. 'course, that means all that debugging would be for naught, but still its good practice. Sort of that "set a monk on fire" idea (hmm, bad connotations there, sorry).

a


In reply to Re: Re: Cgi UpDATE by a
in thread Cgi Upload by pokemonk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or How to display code and escape characters are good places to start.
Log In?
Username:
Password:

What's my password?
Create A New User
Domain Nodelet?
Chatterbox?
and the web crawler heard nothing...

How do I use this?Last hourOther CB clients
Other Users?
Others meditating upon the Monastery: (7)
As of 2024-04-25 08:29 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found