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User Questions
The perl source directory structure
1 direct reply — Read more / Contribute
by syphilis
on Aug 16, 2022 at 08:21

    In the perl source, we find various modules in the 'cpan', 'dist' and 'ext' directories.
    What are the rules that determine which of those 3 directories houses which modules ?

    For example, why is it that POSIX is in the 'ext' directory, but threads is in the 'dist' directory ? (Why not the other way round ? Or why aren't they both in the same directory ?)

Nonrepeating characters in an RE
7 direct replies — Read more / Contribute
by BernieC
on Aug 15, 2022 at 19:32
    I have an odd problem that's hurting my head: I'm trying to construct an RE that will only match if the letter in any position does *NOT* match any other character in the string. I'm constructing this RE with a perl program and building the RE from a template. It is the *template* that says "these letters should be distinct" and then I want to run through a few thousand words to pick out the words that "match".

    For example, my "template" might look like this: "abcdefa" and I already have the code that generates (.)?????\1. I can't figure how to make the "?"s say "these guys all have to be distinct".

How to color the regex captured groups?
4 direct replies — Read more / Contribute
by ovedpo15
on Aug 12, 2022 at 12:32
    Hi Monks!
    I have a array of hashes. Each hash contains a rexes rule. Given a path, I'm trying to iterate over the rules and find the first matching rule.
    I'm trying to add a small feature which will help users to debug (since the rexes are user custom) - I want to mark the groups in the given path. For example:
    # Given path: /a/b/c/d # Given regex: ^/a/b/([^/]*)/([^\/]*) # Output: /a/b/\033[1;31mc\033[0m/\033[1;31md\033[0m
    In this case I got: /a/b/[RED]c[/RED]/[RED]d[/RED].
    The current code:
    foreach $regex_href (@rexes) { %regex = %{$regex_href}; if (@captures = ($path =~ /$regex{'regex'}/)) { # Do logic } }
    The @captures contains the group values that were captured (c and d in the example). I came a cross with the Term::ANSIColor module which can help me color the string without writing the color codes myself.
    So, what would be the best way to create a variable $output that is basically $path but colored given the captured groups? You can assume that there are always at least two groups.
How do I reference repeated capture groups?
4 direct replies — Read more / Contribute
on Aug 12, 2022 at 10:24
    Esteemed monks

    I stumbled over this 2 year old reddit-question from a user "onion" and am not too convinced about the answers given.

    Is using Regexp::Grammars really the only way to do it? Seems like overkill...

    Suppose I have this regular expression:
    my $re = qr{(\w+)(\s*\d+\s*)*}; How do I get every match matched by the second group?
    Using the regular numeric variables only gets me the last value matched, not the whole list:
    my $re = qr{(\w+)(\s*\d+\s*)*}; my $str = 'a 1 2 3 b 4 5 6'; while ($str =~ /$re/g) { say "$&: $1 $2"; } # output: # a 1 2 3 : a 3 # b 4 5 6: b 6

    How do I get every number that follows a letter in this example, and not just the last one?


    Bonus question:

    How do I do it if I have named groups? I.e. my $re = qr{(?<letter>\w+)(?<digit>\s*\d+\s*)*};

Comparing time strings from a list of HH:MM:SS times
2 direct replies — Read more / Contribute
by slugger415
on Aug 10, 2022 at 14:38

    Hello esteemed PerlMonks,

    I have a list of time strings in the HH:MM:SS format. I want to add each to a variable set with localtime and compare it to a timestamp later in the script. I'm having trouble understanding how to add that HH:MM:SS string to the localtime variable.

    #! /usr/bin/perl use Time::Piece; use strict; my(@times) = ("00:05:21","00:08:05","00:10:33"); my $startTime = localtime(); print "Start: ", $startTime, $/; foreach my $t (@times) { sleep 2; my $newTime = localtime(); my $ss = $startTime + $t; ### this is where I need advice if($ss > $newTime){ print "\$ss is greater.\n"; ### execute some functions here } print "Newtime: ", $newTime, $/; my $diff = $newTime - $startTime; print $diff, $/;

    The $diff part works but not the addition of $t, how do I add that time to it? Obviously I need to convert it to something Time::Piece understands.

    Thank you.

Rename/mkdir with File::Fetch
3 direct replies — Read more / Contribute
by justin423
on Aug 10, 2022 at 11:03
    I posted a question on here before about File:Fetch and got a bunch of great responses, so thank you all... It doesn't seem like this is possible, but can file:Fetch either rename the files to a particular filename, or alternatively create a new directory each time with a pre-determined folder name? The URL's are in format where document id is a unique number provided by the publisher. So all the files to fetch are named document.pdf. So that each successive document doesn't overwrite the previous one, I rename them to document0.pdf, document1.pdf using a loop to keep them unique. (see code below) so is there a way to either change the filename to document_id.pdf or make a new directory of data/documents/document_id/ and save the document.pdf to that new folder? I think file:fetch only takes one variable input. and won't work with SELECT DOCUMENT_ID,URL FROM LINKS
    my $query = "select url FROM LINKS"; # << minor edit my $sth = $dbh->prepare($query) or die "prepare: ".$dbh->errstr; $sth-> execute() or die "execute: ".$dbh->errstr; $i=0; while (my $ref = $sth->fetchrow_hashref()) { print "\nurl: $ref->{url}\n"; my $ff = File::Fetch->new(uri=>$ref->{url}); my $where = $ff->fetch( to => '/data/documents/'); my $error= $ff->error(); rename ("C:/data/documents/document.pdf","C:/data/documents/document$i.pdf"); ($i++); }
WWW::Mechanize and SSL
3 direct replies — Read more / Contribute
by Jonathan
on Aug 10, 2022 at 09:09

    Firstly, apologies as this is more a SSL issue than just Perl. I have an HTTPS url that I want to pull some data from (the url is another server on our local network). The url works fine with Chrome, MS Edge etc but I'm getting a certificate error running my test script from a dev server (Ubuntu). Also wget also fails with certificate errors.

    #!/usr/bin/perl use strict; use warnings; use WWW::Mechanize; use Net::SSLeay; my $m = WWW::Mechanize->new( autocheck => 1 ); print "LWP: $LWP::UserAgent::VERSION\n"; print "Mech: $WWW::Mechanize::VERSION\n"; print "Net::SSLeay $Net::SSLeay::VERSION\n"; my $url = $ARGV[0]; $m->get($url); print $m->content();
    Which outputs;
    $ ./ LWP: 6.43 Mech: 1.96 Net::SSLeay 1.88 Error GETing https://xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx: Can't conn +ect to xxxxxxxxxxx:443 (certificate verify failed) at ./ lin +e 15. $
    I suspect there is something available on the companies servers that satisfies browsers but isn't available elsewhere. Anyone seen this before and have any idea what I need to do? Thanks
How to use the right timezone in a DBIx::Class ResultSet call?
1 direct reply — Read more / Contribute
by LittleJack
on Aug 08, 2022 at 21:38

    I have a working DBIx::Class resultset which looks roughly like this:

    my $tasks_to_do = $self->search( { -and => [ scheduled_run_time => { '<= +', 'NOW()'}, status => 'pending' ] } );

    But I need that "NOW()" to be in Sydney, Australia time, not the server time which is UTC.

    In the script which calls this ResultSet method I've got both

    BEGIN { $ENV{TZ} = 'Australia/Sydney'; }


    $schema->storage->dbh_do(sub {"SET TIMEZONE='Australia/Sydney'"} );

    But it still returns no records.

    Due diligence: I know there are records because if I go in to the db manually and do this:

    sessions=> SET TIMEZONE='UTC'; SET sessions=> select * from mytable where scheduled_run_time <= NOW() and + status = 'pending';

    I get "no rows", but if I do this:

    sessions=> SET TIMEZONE='Australia/Sydney'; SET sessions=> select * from mytable where scheduled_run_time <= NOW() and + status = 'pending';

    I get the expected number of records.

    TIA. I have had my coffee by the way.

cURL and HTTP::Request
2 direct replies — Read more / Contribute
by jeanbaptiste93
on Aug 08, 2022 at 18:10

    Hi, all!

    I am trying to call a particular API endpoint and am being unsuccessful. I have been able to make calls to dozens of endpoints to the same API, so I was unsure as to what the issue was. I tried a cURL with the relevant params and it worked successfully. But I am being unable to replicate it to HTTP::Request.

    Here's the cURL:

    curl --request PUT --url 'https://[URL]/[ENDPOINT]/item?key=[KEY]&token=[TOKEN]' --header 'Content-Type: application/json' --data '{"value": {"text": "38"}}'

    I have tried:

    my $browser = LWP::UserAgent::JSON->new(); my $response = $browser->put( $url, Content => to_json($data) );


    my $request = HTTP::Request::JSON->new( 'PUT', $url, [ Accept => 'application/json', 'Content-Type' => 'application/json', ], to_json($data) ); my $browser = LWP::UserAgent::JSON->new(); my $response = $browser->request($request);

    and similar solutions to no avail. I appreciate any help!

Allowing regex entries in web form to search database: Risks or gotchas?
4 direct replies — Read more / Contribute
by Polyglot
on Aug 08, 2022 at 13:10

    I have a research-oriented database, online, accessible via my own web interface and open to public use. The application is set up to allow read-only access to the database, the CGI script is hosted on a linux server, and the script is definitely not set as setuid. I am not allowing any use of nested executable code inside the regex, via the following sort of rules during the parsing of the query:

    return "ERROR: For security and bandwidth reasons, query may not conta +in pure wildcards." if $SR_query =~ m/^[( ]*\.\s*(?:(?:\{\s*\d+\s*,?\ +s*\d*\s*})?|[*+?]*)[) ]*$/; return "ERROR: Regex containing code disallowed." if $SR_query =~ m[\( +\?\??\{];

    Beyond these fundamental/basic protections against potential malicious actors, is there anything I might be blindly walking into by unleashing this capability in my website?

    I have had to run a rather complicated subroutine on the query itself to prevent taint from objecting to it--even though the code is never "executed" other than being inserted into a m// to run against text drawn from the database prior to formatting the results for return to the browser. But this is a small price to pay for the very useful functionality of having regex-capable searches on the database.



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