Writing text to textarea from a text file in perl

问题:

I am trying to populate a textarea with text. The text will be comments a user has made. It will be loaded from a file called comments.txt

The file template is:

 username1
 commentscomments
 commentscomments
 username2
 commentscommentscome
 comchefhjshfhhfjdjdj
 dfhfhjdijedhdjdjdjdj
 username3
 februgusyfvretgtyef

I also have a file called accounts.txt which stores the usernames.

My current code just writes the entire comments.txt file to the textarea

  my $username=(param('username')); 
  open my $FHIN, '<', "comments.txt" || die "$!";
  my @fhin = <$FHIN>;
  print textarea(-name=>"CommentArea",-default=>"@fhin",-rows=>10,-columns=>60);

I was thinking should I have a sub that returns an array of strings that are the comments of the user? And how should I structure it should I have a loop of the comment file that checks if each line eq the username and if it does it prints each line until it comes to another line that matches a line on the accounts.txt

Basically the textarea should only show:

 commentscommentscome
 comchefhjshfhhfjdjdj
 dfhfhjdijedhdjdjdjdj

if username2 is the user thats logged on.

Any help is appreciated!

回答1:

Assuming you have a list of all the user accounts and you put that into a hash, you could do it as follows.

sub get_comments {
  my ($username, $filename, $all_users) = @_; # $all_users is a hashref

  open my $FHIN, '<', $filename or die "Cannot open $filename for reading: $!";

  my @comments;
  my $found; # starts out as undef
  while (my $line = <$FHIN>) {
    chomp $line;

    if (exists $all_users->{$line}) {
      last if $found; # stop once we find another user
      if ($line eq $username) {
        $found++;
        next;
      }
    }

    push @comments, $line if $found;
  }
  return \@comments;
}

my $comments = get_comments(param('username'), 'comments.txt', $all_users);
print textarea(
  -name    => "CommentArea",
  -default => join("\n", @{ $comments }),
  -rows    => 10,
  -columns => 60,
);

It opens your file and checks for usernames. If it finds our username, it will start saving the lines after that until it finds a different username and stops. The file name is an argument so you do not have to rely on a single file and can get that from config (or use a test file for unit testing).

There is no need to close the file handle as it will go out of scope and implicitly close at the end of the sub.

It prints:

<textarea name="CommentArea"  rows="10" cols="60">commentscommentscome
comchefhjshfhhfjdjdj
dfhfhjdijedhdjdjdjdj</textarea>