extract pattern from large blob of text

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

I would like to extract the value for 'var nonce' from the following text blob (string)

"...

var realm = "heaven";
var nonce = "186248:541534:a67930c5cffeb25a5485e6b4f32570e2";
var qop = "auth";
var uri = "/earth.lp";

...."
[download]

Currently my code looks a like:

my $req = HTTP::Request->new(GET => $server_endpoint);
my $resp = $ua->request($req);
    my $message = $resp->decoded_content;

$message =~ m/nonce/i;
 print " starts: @- \n ends:  @+ \n";
[download]

To get the begin and end of the nonce keyword (and next I will need to extract the value (186248:541534:a67930c5cffeb25a5485e6b4f32570e2) ).

Problem is I do not get the start or end position back on this string? what am I missing here?

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Re: extract pattern from large blob of text by Corion (Patriarch) on Mar 06, 2015 at 14:40 UTC
`@-` and `@+` are arrays, as documented in perlvar. Maybe you wanted to actually capture things? My approach would be to also capture the nonce value in the same regular expression match: `if( $message =~ /nonce\s+=\s+"([^"]+)"/ ){ my $nonce= $1; print "Found nonce: $nonce\n"; } else { die "No nonce found in message:" . $message; };` [download]	[reply] [d/l] [select]
Re^2: extract pattern from large blob of text by littleperl (Initiate) on Mar 06, 2015 at 14:51 UTC
very usable example, thx Seems the formatting of $message is not correct to me, I have added how I get to the content of $message to the original post.	[reply]
Re^3: extract pattern from large blob of text by Corion (Patriarch) on Mar 06, 2015 at 14:56 UTC
If you think the formatting of `$message` is not what you want it to be, what steps have you taken to confirm this? Maybe printing `$message` might show you the content?	[reply] [d/l] [select]
Re^4: extract pattern from large blob of text by littleperl (Initiate) on Mar 06, 2015 at 15:14 UTC
Re: extract pattern from large blob of text by hdb (Monsignor) on Mar 06, 2015 at 14:52 UTC
...and why are you not directly extracting the string, like `/var nonce = "(.*?)";/`? (untested) `$1` will contain what you look for.	[reply] [d/l] [select]
Re^2: extract pattern from large blob of text by littleperl (Initiate) on Mar 06, 2015 at 15:17 UTC
thank you very much for the great assistance, case solved.	[reply]