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Packaging Libraries before deploying my Scripts.
1 direct reply — Read more / Contribute
by ArunMKumar
on Oct 25, 2016 at 07:02
    Namaste Monks.. I have written a set of scripts, on a local system (my laptop) The work fine here.
    Now My scripts are required to be deployed in remote system(s) and the thing I am worried about is the availability and the installation of the Libraries that I have used.
    The 2 Libraries that are currently in use are "XML::LibXML" and "Spreadsheet::ParseExcel".
    I have this idea where I will put them in a "lib" directory in the same project Directory, and the scripts will refer from them. My questions are as follows.
    I have installed them in a directory, using the commands as follows from the extracted tar files.

    perl Makefile.Pl
    make test
    make install PREFIX=<path_to_lib> LIB=<path_to_lib>

    I also see the .pm files being populated in various tree structures in that lib directory.
    My question now is , How do i force my scripts to reference this lib directory when It wants to look for the modules?
    I am new to perl, from what I searched online I think it has to do with modifying @INC variable, while some solutions say about explicitly including these versions of the library (which I have no clue, as those post included their own perl modules).
    so.. How do i force my scripts to use these libraries exclusively, and not throw an error when i deploy them to different systems (all Linux systems with perl 5 or above for sure).
heredoc and carriers return
2 direct replies — Read more / Contribute
by gabrielsousa
on Oct 25, 2016 at 05:18

    heredoc read the LF ( \n ) , but dont parse / stores the carriers return ( \r )

    how can i force heredoc to read and store carriers return ( \r ) ?
Detecting stale pid file under *nix
3 direct replies — Read more / Contribute
by Dallaylaen
on Oct 24, 2016 at 17:36

    This is more of a Unix question rather than a Perl one, but still...

    I'm looking for a way to stop my daemon, but I don't want to terminate an innocent bystander process. I came up with idea that PID file is created after the process has been spawned. Therefore, it's not older then the process, so the following code was written which seems to work correctly on my Ubuntu:

    open (my $fd, "<", $conf->{pidfile}) or die "Failed to read pidfile $conf->{pidfile}: $!"; my $pid = <$fd>; chomp $pid; die "Broken pid file $conf->{pidfile}" unless $pid =~ /^\d+$/; # detect stale pid if ([stat $fd]->[9] >= ([stat "/proc/$pid"]->[9] || 9**9**9)) { print "Killing pid $pid...\n"; kill INT => $pid; };

    Of course, it can still be tricked by touching the pid file, but then it's also possible to write rubbish into the pid file anyway.

    Now I would like to ask what is the proper way of avoiding sending signal to a wrong process? CPAN has a multitude of modules for PID file handling, I was unable to choose one.

    Thank you!

Default import function
4 direct replies — Read more / Contribute
by Athanasius
on Oct 24, 2016 at 02:17

    According to the documentation for import:

    There is no builtin import function. It is just an ordinary method (subroutine) defined (or inherited) by modules that wish to export names to another module. The use function calls the import method for the package used.

    However, when I create an empty module (file “”):

    package MyMod; 1;

    and print out its symbol table (file “”):

    use strict; use warnings; use Data::Dump; use MyMod; dd \%MyMod::;

    the output shows that an import function is already present:

    16:10 >perl { import => *MyMod::import } 16:10 >

    Where does it come from? Is the documentation incorrect, or am I simply misreading it?


    Athanasius <°(((><contra mundum Iustus alius egestas vitae, eros Piratica,

XML::LibXML drives me to drinking
3 direct replies — Read more / Contribute
by tunafish
on Oct 22, 2016 at 19:37

    I'm trying to figure out XML::LibXML. It's rough going. I need to be able to access the text content of a node by name. Here is my code:

    #!/usr/bin/perl use strict; use XML::LibXML; my $string = qq~<?xml version="1.0"?> <ItemLookupResponse xmlns=" +ervice/2013-08-01"> <Items> <Item> <ASIN>B01KI4JSQY</ASIN> </Item> </Items> </ItemLookupResponse> ~; my $parser = XML::LibXML->new->load_xml(string => $string, {no_blanks +=> 1}); my $xml = XML::LibXML::XPathContext->new($parser); $xml->registerNs('x', ' +ce/2013-08-01'); # Parse items foreach my $item ($xml->findnodes('/x:ItemLookupResponse/x:Items/x:Ite +m', $parser)){ print $item->firstChild->nodeName, "\n"; print $item->firstChild->toString, "\n"; print $item->findvalue('ASIN'), "\n"; print $item->findvalue('./ASIN'), "\n"; print $item->findvalue('./ASIN', $item), "\n"; }

    Expected result:


    Actual result:


    Probably I'm just misunderstanding something in the docs. But I don't know what it is. I tried $item->findvalue('x:ASIN'), but that threw an error. Please help. I have a family. If I become an alcoholic, they will suffer.

Shortening paths for display
1 direct reply — Read more / Contribute
by morelenmir
on Oct 22, 2016 at 17:08

    There used to be an undocumented win32 function called 'PathSetDlgItemPath'. This allowed you to set the text of a windows control to a file or folder path, automatically editing what was displayed to fit inside the available client area. It did this where necessary by shortening the path using '...' ellipsis characters.

    I wondered if there was anything similar for perl? I guess, rather than the size of a windows control it would need to be told the maximum number of characters you wanted to display.

    "Aure Entuluva!" - Hurin Thalion at the Nirnaeth Arnoediad.
Adding a database table using DBIx::Class
1 direct reply — Read more / Contribute
by davies
on Oct 22, 2016 at 08:01

    tl;dr: Are there any docs that actually show a simple example of creating a table with DBIC, whether from SQL (which I know I know how to write) or a DBIC class module (which I think I know how to write)? If not, would any kind monk please give me such an example?

    TIA & Regards,

    John Davies

How to concatenate utf8 safely?
2 direct replies — Read more / Contribute
by gregor42
on Oct 21, 2016 at 10:22

    I am humbled and seeking help.

    This concerns data containing names so getting it Right is important.

    It is likely that I am fundamentally missing something when it comes to safely concatenating strings.

    A hand-rolled point solution sometimes works as intended and others times results in the dreaded:

    Wide character in syswrite

    I assume that the problem is my code and not the data coming in since one can usually depend on people to get their own names right.. But then i18n characters are tricksy, like Hobbits...

    sub jibe { my($s,$t) = @_; my $r = join('', (is_utf8($s)?$s:decode('utf8',$s)), (is_utf8($t)?$t +:decode('utf8',$t))); return $r; }

    To give it context, let's say that we are creating common name from given name plus surname: (Anglo-centric, I know...)

    my $cn = jibe(jibe($givenname," "),$sn);

    Thank you in advance for any nudges in the right direction that anyone might provide.

    Wait! This isn't a Parachute, this is a Backpack!
Get latest file created or modified & matching part of file name :
1 direct reply — Read more / Contribute
by rahulme81
on Oct 21, 2016 at 09:49

    Hello Monks

    I have a directory with a bunch of files. I'm trying to find the latest file created or modified by time in a directory and using the following pattern

    opendir(my $DIRH, $DIR) or die "Error opening $DIR: $!"; my @files = map { [ stat "$DIR/$_", $_ ] } grep( ! /^\.\.?$/, readdir( $DIRH ) ); #This find me +all files not have dot in directory #How this grep can be accommodate for my regular expre +ssion ????? closedir($DIRH); sub latestFile { $b->[0]->ctime <=> $a->[0]->ctime } my @latest_files = sort latestFile @files; my @latest = @{$latest_files[0]}; my $name = pop(@latest); print "Latest file created fro $name\n";

    This is giving the latest file in the directory, but not the file which i need as per my regular expression.

    I need to parse the file and do something, which eventually I am able to achieve

    Facing difficulty with file name pattern match and get the latest file

Module for form validation and resubmission
1 direct reply — Read more / Contribute
by Dallaylaen
on Oct 21, 2016 at 07:33

    Hello, dear esteemed monks!

    tl;dr: I'm thinking of a module that (1) compiles a set of validation rules once and (2) for each hashref given to it later, returns another object containing valid data, errors, AND initial input for processing and/or resubmission.

    Is there such a module already? If not, should I roll my own? If yes, does the API described below seem sensible?

    Now the whole story. Some time ago there was a discussion here at Perlmonks pointing out that it would be nice to make create button act as preview if post content was edited. Can't find proofs now, but the idea impressed me much.

    Recently I started looking for a form validator. My initial idea was to build a permanent validator object once and keep throwing inputs at it later. And I found a module with almost the interface I imagined - Validator::LIVR.

    However, after trying to actually implement form validation & resubmission, I found myself juggling 3 hashrefs (valid data, errors, raw user input for reentry). This was not very convenient, so I decided to pack them into one object, adding is_valid() method on top. And I found a module on CPAN with almost the interface I imagined (but without the "compile once" part) - Data::CGIForm.

    So I crossed these two and got roughly the following API:

    # initialization # the hash describes regexps, requiredness, and other checks # per input key my $validator = My::Class->new ( { ... } ); # later when processing request my $form = $validator->validate( { get => "params" } ); if ($form->is_valid) { do_something( $form->data ); redirect( "/somewhere" ); } else { show_form_again( display_errors => $form->error, input_defaults => + $form->raw ); };

    Also error content (and thus is_valid return value) can be modified, just like in Data::CGIForm:

    if (!load_user($form->data->{user})) { $form->error( user => "No such user in database" ); };

    Unfortunately, the Data::CGIForm has a fatal flaw: error() without arguments acts like my is_valid(), while separate errors() method returns all errors as hash. Error/errors is prone to typoes in my opinion, but maybe I should shut up my ego and stay compatible to an existing API instead?

    Thank you

How relevant is the order of 'use's ?
2 direct replies — Read more / Contribute
by Krambambuli
on Oct 20, 2016 at 07:47
    Dear Monks,

    I have two simple modules:
    package Demo1; use base qw/Exporter/; $SUCCESS = 1; BEGIN { use Exporter(); @ISA = qw(Exporter); @EXPORT = qw( $SUCCESS ) } 1;
    package Demo2; sub import { ${[caller]->[0].'::'}{$_} = ${__PACKAGE__."::"}{$_} foreach grep { not /^(ISA|isa|BEGIN|import|Dumper)$/ } keys %{__PACKAGE__."::"}; } use constant { SUCCESS => 0, }; 1;
    and a minimalistic test program, that is
    #!/usr/bin/perl use strict; use warnings; use Demo1; use Demo2; print "SUCCESS: ", SUCCESS, "\n"; print "\$SUCCESS: $SUCCESS\n"; exit;
    If I run the program as shown, I see an compile time error, like
    Bareword "SUCCESS" not allowed while "strict subs" in use at ./ + line 9. Execution of ./ aborted due to compilation errors.
    but if I simply change the order of the use instructions, i.e. I run
    #!/usr/bin/perl use strict; use warnings; use Demo2; use Demo1; print "SUCCESS: ", SUCCESS, "\n"; print "\$SUCCESS: $SUCCESS\n"; exit;
    then the displayed result is the expected one,
    I'd love to understand what's happening here - and would bve grateful to learn if there is a way to not have to use the two modules in a strict order in order to have the code working nevertheless.

    Many thanks in advance.
How to pass a Format Heading from a variable?
3 direct replies — Read more / Contribute
by ankit.tayal560
on Oct 20, 2016 at 01:01
    SCRIPT TO GENERATE REPORT : use warnings; format DATA2= ------------------------------------------------------------ @<<<<<<<<<<<<< @<<<<<<<<< @######### @######## $name $format $matches $runs ------------------------------------------------------------ . format DATA2_TOP= Records/Data of the trio ============================================================ Name Format of match matches played runs scored ============================================================ . open(DATA,"<C:/Perl/perl_tests/sports.txt"); @array=<DATA>; close(DATA); open(DATA2,">>c:/perl/perl_tests/blank.txt"); foreach(@array) { chop; ($name,$format,$matches,$runs)=(split(/!/)); write(DATA2); }

    My sports.txt file is as follows:

    sports.txt file : sachin tendulkar!ODI!434!12000 sachin tendulkar!Test!246!10900 sachin tendulkar!T20!189!5000 sourav ganguly!ODI!334!8000 sourav ganguly!Test!235!5000 sourav ganguly!T20!124!1800 rahul dravid!ODI!387!9000 rahul dravid!Test!212!5980 rahul dravid!T20!43!1345

    The formatted report which I am getting in blank.txt is the final report I want but here in this script the heading of the report i.e. "records/data of the trio" is directly given. how can I pass a variable in place of that title.?Any Help is appreciated!

New Meditations
Testing Dancer applications with a custom database
No replies — Read more | Post response
by Corion
on Oct 24, 2016 at 13:10

    While developing a plugin for Dancer as a wrapper around one of my modules, I wanted to unit test my code using a mock database instead of the database I do interactive tests with. Surprisingly, I didn't find documentation on how to supply Dancer::Plugin::Database with your own test database.

    After some reading through the test suite of Dancer::Plugin::Database, it seems that the magic is in overwriting the configuration at the right time. To give this approach a broader exposure and to maybe invite some comments or better suggestions, let's look through the code:

    In the prelude, we load Dancer, Dancer::Test and the application I'm writing, tentatively named mychat. We plan for three tests:

    #!perl -w use strict; use warnings; use Test::More import => ['!pass']; use Data::Dumper; use Dancer ':syntax'; use DBIx::RunSQL; use Dancer::Plugin::Database; # the order is important use mychat; use Dancer::Test; plan tests => 3;

    Then, we set up our own in-memory database and create all tables and triggers from the SQL file stored in sql/create.sql. This gives us a pristine database that contains only initial data.

    # set up our own database instead of whatever is in the config my $conf = { Database => { dsn => 'dbi:SQLite:dbname=:memory:', connection_check_threshold => 0.1, sqlite_unicode => 1, dbi_params => { RaiseError => 0, PrintError => 0, PrintWarn => 0, }, }, }; set plugins => $conf; # Set up a fresh instance my $dbh = database; $dbh = DBIx::RunSQL->create( dbh => $dbh, sql => 'sql/create.sql', );

    Since what I really want to test is whether image upload and retrieval works, let's fake a PNG image and "upload" it into the application:

    my $payload = join '', "\x89", 'PNG', "\x0d\x0a", "\x1a", "\x0a", (map { chr($_) x (1024 * 256) } 1..3) ; # Insert image into database my $upload = Dancer::Request::Upload->new( filename => 'test.png', tempname => 'test2.png', size => length($payload), headers => { 'Content-Type' => 'image/png', }, ); # Insert into DB my $content = mychat::UserContent->store( config->{image_store}, $dbh, $upload, { extension => 'png', content_type => 'image/png', }, $payload );

    After all this setup, we can now run three tests as if we had a standard Dancer application and can check that URLs exist where we expect them and that we get the appropriate content from each URL:

    ok $content, "We successfully saved the user content"; route_exists(['GET', '/image_store/'], "We find /image_store/fo"); # Check that we can access it through /image_store/sha1.jpg my $name = $content->{digest} . ".png"; response_status_is ['GET',"/image_store/$name"], 200, "GET '/image_sto +re/$name' succeeds" or diag Dumper read_logs();
RFC: MVC::Neaf aka Not Even A Framework, part 2
No replies — Read more | Post response
by Dallaylaen
on Oct 18, 2016 at 16:10

    Hello dear fellow monks,

    After weeks of hesitation, I finally decided to share a piece of work called MVC::Neaf. Neaf [ni:f] stands for Not Even A Framework.

    It aims to keep things simple and straightforward, while maintaining some degree of separation between logic and presentation.

    Not to repeat myself, here's the original post.

    I know there's a lot to do, so I would appreciate any feedback. If you dare to try it out, please send bug reports and feature requests to github.


New Cool Uses for Perl
extracting strings from non-text files
1 direct reply — Read more / Contribute
by RonW
on Oct 20, 2016 at 21:09

    A coworker (on MS Windows) was cursing he couldn't see what symbol names might be hidden in a non-text configuration file for a proprietary, 3rd party tool he has to use. Since I didn't want to risk being constantly asked to "dump symbols" using my Lunix system, I took a few minutes to write the following program in Perl. Made him happy (for now, at least).

    Note: The tool being used only supports ASCII characters, so I didn't bother with encodings. Probably didn't need to specify ":bytes" in the open statement, but no harm in doing so.

    Maybe others will find this useful.

    #!perl use 5.010_000; use warnings; use strict; if ((@ARGV < 1)) { $0 =~ m#([^\\/]+$)#; my $name = $1 // $0; print STDERR "$name file ...\n" . <<'_DESCRIPTION_'; Extract ASCII strings from files listed. Multiple files allowed. _DESCRIPTION_ exit 1; } for my $file (@ARGV) { open my $fh, '<:bytes', $file or die "Error: Can't open '$file': $ +!\n"; my $buf; while (read $fh, $buf, 1024) { my @strings = split /\P{PosixGraph}/, $buf; for (@strings) { next if /^\s*$/; print "$_\n"; } } }
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