Mac vs. PC line breaks

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

I am trying to get an upload of a CSV file from an upload field on a webpage. Currently the webpage is used by Mac, Windows, and Linux users. When a Mac user uploads, $/ is not set correctly so the CSV appears as a single line and gets thrown out by the system. How can I accurately figure out whether I need to update $/ to use the correct line breaks so that my CSV file gets parsed correctly.

   
my $file = $q->upload('event_upload'); 
my $start_row = $q->param('row_start');

## Toss out lines until we hit the specified start row
if ($start_row) {
  for (1..$start_row) {
       my $garbage = <$file>;
  }
}
while (my $line = <$file>) {
### Do file stuff
}
[download]

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Comment on Mac vs. PC line breaks Download Code

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Re: Mac vs. PC line breaks by Joost (Canon) on Aug 05, 2005 at 16:06 UTC
`# guess to set $/ to correct linebreaks # untested code. local $/ = \1000; # read first 1000 bytes local $_ = <$file>; my $newline; for my $test ("\015\012","\015","\012") { # match various newline char +s, default to unix $newline = $test; last if /$test/; } local $/ = $newline; seek $file,0,0; # rewind to start of file` [download] You should probably also use Text::xSV or Text::CSV_XS instead of trying to parse it yourself. update: qw() doesn't interpolate \015, so I fixed that update2: ikegami pointed out a typo. I fixed it. "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply] [d/l]
Re^2: Mac vs. PC line breaks by ikegami (Patriarch) on Aug 05, 2005 at 17:24 UTC
Typo: `"\015\12"` should be `"\015\012"` But why not replace `my $newline; for my $test ("\015\012","\015","\012") { # Default to unix. $newline = $test; last if /$test/; }` [download] with `# Default to unix. my ($newline) = /(\015\012\|\015\|\012)/ ? $1 : "\012";` [download] which simplies to `# Default to unix. my ($newline) = /(\015\012?)/ ? $1 : "\012";` [download]	[reply] [d/l] [select]
Re^3: Mac vs. PC line breaks by Joost (Canon) on Aug 05, 2005 at 18:19 UTC
I like that. Maybe a bit less obvious to the casual reader (especially the last simplification), but I would prefer it to my code :-) "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply]
Re: Mac vs. PC line breaks by jhourcle (Prior) on Aug 05, 2005 at 16:07 UTC
The logic to handle this was just recently in the question alter $/ - but why? Of course, you'd probably want to localize the changes to $/, especially if the program persists through more than one file upload	[reply]