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arnab@perl (arnab@perl)

arnab@perl: user since 2006-10-28 04:31:59

Non-blocking connect() and gethostbyname()? (Anonymous Monk)

I'm using IO::Socket right now to do some non-blocking network IO for a graphical application. IO::Socket has a blocking() method that purports to toggle blocking mode. It seems to work for reading and writing, but its connect() method--which gets called when you do IO::Socket::INET->new()--does not. First it calls gethostbyname(), which blocks, then it blocks using IO::Select to timeout the connect call. I don't want to rewrite the whole thing to use POE. Is there any way to do a non-blocking connect and gethostbyname() using IO::Socket? If not, what would be the least obtrusive alternatives?

[OT] When coders don't see eye to eye (Anonymous Monk)

Dear monks,

I'm currently involved in a web project with a friend.

It's the first time I'm jointly coding a website with another person. We sometimes have quite different approaches to the same problem, and we fail to see eye to eye.

Here's is one and I hope to seek your advice and opinions.

We are divided over the how to treat the "removal" of a post from a forum. The questionable post will still be somewhere in database, but we need a way to indicate that action was taken against it.

To make things concrete, we've two MySQL tables (simplified) as follows:

posts_tbl
post_id author_id message deleted_flag

removed_tbl
post_id message deleted_by_id date

Let's say we have too approaches A and B.

When a message that is deemed inappropriate is removed via a button click, Approach A goes likes this:

In posts_tbl, the "message" field is updated with the replacement text "Removed by USERNAME" and the "deleted_flag" column with a value of 1 (the default is 0) (Note: the username is available at the point of update, so it's updated into the message filed as part of the replacement text).

In removed_tbl, the original message is inserted into the message field, together with the post_id, the date, the member id of the person carrying out the deletion.

Approach A's points are:

a) When displaying posts in a web page, all posts can be directly retrieved from posts_tbl, including messages that contain "Removed by USERNAME".
b) Saving of processing time because there's no need for additional code to check whether a message was removed.
c) Greater flexibility because different pieces of data are stored in two different tables.
d) Greater expandability. When a different reason for removing the post is needed, a new column can be added to removed_tbl to store that reason.

The sql to retrieve messages from posts_tbl will be straightforward without having to link to removed_tbl to retrieve the username of the person who deleted the post (assuming the other information in removed_tbl is not needed for display). The code will be simpler too.

Approach B is:

removed_tbl should be changed to:
post_id deleted_by_id date

When a removal is carried out:

In posts_tbl, the "message" field remains unchanged while the "deleted_flag" column is updated with a value of 1.

In removed_tbl, the necessary information is inserted (post_id, member id of the person deleting the message, date)

Approach's B points are:

a) The original message should not be touched in posts_tbl.
b) There's duplication of data if the message field of posts_tbl is updated with the string "Removed by ...".
c) There's also duplication of data because "Removed by ..." and "deleted_flag" both indicate the particular post has been removed.
d) The string "Removed by ..." should be added in the code for outputting to a webpage, so that it doesn't get stored anywhere. When a different wording is needed e.g. changing "Removed by ..." to "Deleted by ...", only that the hard-coded string needs to be changed.
e) posts_tbl stores all original posts, so it's easier for retrieval.

Cons of Approach B:

a) The sql to retrieve messages will require an additional condition to link posts_tbl to removed_tbl to retrieve the username of whoever deleted the post.
b) The code will need to check for whether a post has been removed so it can output the string "Removed by ...".

There are other ways for sure. But between the two outlined above, which is a better solution?

It's a bit longish but I need to paint as accurate a picture as possible.

Would appreciate your enlightment :)

Thank you and I look foward to hearing from you :)

foreach in HoHoA problems (mdunnbass)

Hi Monks,

I am trying to have a look at the elements of arrays in a dynamically created HoHoA. When I try something like this:

 my ($span, %matches) = @_; my ($site, $fastaseq, $fasta, $sitekey) = ''; my ($setscounter,$lowerlimit,$upperlimit,$i,$set,$yes,$low,$hit) = 0; my %sets = (); FASTA: for $fastaseq (keys %matches) {       $sitekey = '';       SITEKEY: for $sitekey (sort {$a <=> $b } keys %{$matches{$fastaseq}}) {         if (@{$matches{$fastaseq}{$sitekey}}) {          SET: foreach $hit (@{$matches{$fastaseq}{$sitekey}}) {            print "\$matches{$fastaseq}{$sitekey} is: $matches{$fastaseq}{$sitekey}\n";            print "\$hit is: ",$hit,"\n";            print "\$hit is: ",$matches{$fastaseq}{$sitekey}[$hit],"\n";            if ($hit >= $lowerlimit && $hit <= $upperlimit) { #some code}}}}}

I get the following output:

$matches{>LG_XIV}{0} is: ARRAY(0x182bb14)Use of uninitialized value in print at MyScript line 386.$hit is: $hit is: 6906413Use of uninitialized value in numeric ge (>=) at MyScript line 388.

BTW - line 386 is the first print $hit line, and so on. I'm using use strict and use warnings, and I am scratching my head like mad to try to figure out what's wrong. I've been staring at this so long, I am losing my train of thought anymore.

If I replace the straight $hit calls in the greater than comparison with $matches{$fastaseq}{$sitekey}[$hit], I get no change.

Basically, I just want to know what each of the values in the array $matches{$fastaseq}{$sitekey} array is, and then throw it into the comparison on that if (>= && <=) line. But, no dice.

Does anyone have any ideas, or can point out what I'm doing wrong?

Thanks, Matt



Howto include Module with Specific Methods with PAR's pp utility (monkfan)
Hi,
Suppose I have a code (mycode.pl) that has include the following modules#!/usr/bin/perl -wuse strict;use Algorithm::Loops 'NestedLoops';use List::Compare;use List::Util qw (min max);use somelib;  # (somelib.pm)# rest of the code
Now I want to 'compile' into an 'executable' of this code using PAR's [http://search.cpan.org/~smueller/PAR-0.957/script/pp|pp] utility. I tried the following command:#!/usr/bin/bashpp -M Algorithm::Loops qw(NestedLoops) -M List::Compare -M List::Util qw(min max)  -a somelib.pm mycode.out
But it gives:-bash: syntax error near unexpected token `('
What's the way to overcome this?
Regards,
Edward


Form letters: eval a string to substutite perl variables (brycen)
Updated: Here's what I want to do. Given a file:"Dear $row->{name}; thanks for giving us money."
I want to slurp it in:undef($/);$block = ;
Then substitue in a loop:$sql = "select email,name from database";while( $row=getrow($sql) ) {   print "Working on $row->{name}\n";   eval{$block);   send_email($row->{email},$block);  }The idea is to use perl syntax and the perl parser for the substitution, rather than a made up syntax (e.g. %NAME% and s/%NAME%/$name/). Is this crazy?


dbi:csv how to (zli034)
I have many csv file to orgnize. I try to use dbi:csv but not a clue. 
 use DBI;    $dbh = DBI->connect("DBI:CSV:f_dir=/base/")        or die "Cannot connect: " . $DBI::errstr;    $sth = $dbh->prepare("CREATE TABLE a (id INTEGER, name CHAR(10))")        or die "Cannot prepare: " . $dbh->errstr();    $sth->execute() or die "Cannot execute: " . $sth->errstr();    $sth->finish();    $dbh->disconnect();
When I use this code, where is the data base locates? Is that a file or something else? Can I use a existing csv file as a data base? I totally dont know how to ge the codes from cpan work for me.
 Code tags added by [GrandFather]


wjw's scratchpad (wjw)
Will have to put something here.. perhaps when I have an itch...


Renaming CPAN modules (b10m)
Brethren,
I've been mainting a CPAN module called Business::TPGPost, which will calculate the shipping cost based on TPG Post (Dutch postal service) rates for some time. Recently, the company changed it's name from TPG Post to TNT Post.
Since the rates will most likely be updated per January 1st, I'll be updating it, like a good CPAN user is supposed ;-) But, should I rename my module to Business::TNTPost, or even Business::TNT::NL, or keep the old name? How do other CPAN authors handle namechanges like this?
I can see where a namechange would be preferred for new users, but would "older users" (if they exist at all) be aware of this name change?
-- 
b10m

All code is usually tested, but rarely trusted.


amitJha (amitJha)
amitJha: user since 2006-10-27 16:40:59


Mystery of missing functions (throop)
Perl monks,I, a pilgrim, seek deeper insight to things Perl.There are certain operations on arrays for which most programming languages have functions, but for which Perl does not.  There are instructions on how to do these things in the perldoc, but they aren't core functions:Getting the maximum or minumum element in an array of numbers;  
 Getting the union, intersection or difference of two arrays.
I expect that this is not an oversight, but is rather part of the Perl philosophy.  But I cannot divine why.  Will a brother monk instruct me?throop


stolkin (stolkin)
stolkin: user since 2006-10-27 15:28:54


HTML::CalendarMonth or HTML::Calendar::Simple (Anonymous Monk)
Hi everyone.  Looking for a perl module to handle my calendar html to keep track of users posts on my site.  I stumbled between these two and both look like they can get the job done for me.  Not sure how to judge which one is better.  HTML::CalendarMonth is newer.  What I need is a large printed calendar that takes up the whole screen. Can anyone tell me which one I should be using?  Thanks.


help find this script (Tbob)
I saw this simple email form; I would like to put it on my site. It contains 5 spaces: 2 radial buttons and a check  box. I want to us it to send a link to my webpage to friends and relatives or either the full page. Out of the five spaces, there is a space for the persons email address, a space for my name, a space for my email and a text area for my comments. The email form starts with a script