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File::Content - Regular expression interface to content of a file. |
File::Content - Regular expression interface to content of a file.
Wraps all the accessing of a file into a convenient set of calls for reading and writing data, including a simple regex interface.
use File::Content;
my $o_fil = File::Content->new('/etc/passwd');
my @orig = $o_fil->read;
$o_fil->append("appended:entry:4:A second name::etc::sh\n");
$o_fil->replace('^(?:[^:]:){3}([^:]+):', 'replaced:entry:4:another name::etc::sh\n');
$o_fil->prepend("prepended:entry:4:A first name::etc::sh\n");
print 'new names: ' = $o_fil->search('(name.+):');
See the METHODS manpage and the EXAMPLES manpage.
The idea is to standardise accessing of files for repetitive and straight forward tasks, and remove the repeated and therefore error prone file access I have seen in many sites, where varying, (with equivalently varying success), methods are used to achieve essentially the same result - a simple search and replace and/or a regex match.
Approaches to opening and working with files vary so much, where one person may wish to know if a file exists, another wishes to know whether the target is a file, or if it is readable, or writable and so on. Sometimes, in production code even (horror), file's are opened without any checks of whether the open was succesful. Then there's a loop through each line to find the first or many patterns to read and/or replace. With a failure, normally the only message is 'permission denied', is that read or write access, does the file even exist? etc.
This module attempts to provide a plain/generic interface to accessing a file's contents. This will not suit every situation, but I have included some examples which will hopefully demonstrate that it may be used in situations where people would normally go through the same procedure for the umpteenth time to get at the same data.
One last thing - I'm sure this could be made much more efficient, and I'll be very interested to try and incorporate any suggestions to that effect. Note though that the intention has been to create a simple moderately consistent interface, rather than a complicated one. Sometimes it's better to roll your own, and sometimes you don't have to reinvent the wheel - TMTOWTDI.
my $o_rw = File::Content->new($filename); # read-write
my $o_ro = File::Content->new($filename, 'ro'); # read-only
Theoretically you can mix and match your read and writes so long as you don't open read-only.
my $o_fil = File::Content->new($file);
my @partial = $o_fil->search($pattern);
my $i_cnt = $o_fil->replace($search, $replace);
Note that if you open a file read-only and then attempt to write to it, that will be regarded as an error, even if you change the permissions in the meantime.
my $o_fil = $o_fil->do('insert', @insertargs)->do('append', @appendargs)->do('read');
my @data = $o_fil->read;
my @written = $o_fil->write;
my @prepended = $o_fil->prepend(\@lines);
my @inserted = $o_fil->insert($i_lineno, \@lines);
my @appended = $o_fil->append(\@lines);
Note - you must use capturing parentheses for this to work!
my @addrs = $o_fil->search('/^(.*\@.*)$/');
my @names = $o_fil->search('/^(?:[^:]:){4}([^:]+):/');
my @data = $o_fil->replace($search, $replace);
my @data = $o_fil->replace(
q|\<a href=(['"])([^$1]+)?$1| => q|'my.sales.com'|,
);
This is simple, in that you can do almost anything in the search side, but the replace side is a bit more restricted, as we can't effect the replacement modifiers on the fly.
If you really need this, perhaps (?{}) can help?
Returns File::stat object for the file.
print 'File size: '.$o_fil->stat->size;
| sub xfstat { | |
| my $self = shift; | |
| my $file = shift || '_'; |
# print "file($file) stat: ".Dumper(stat($file));
# return stat($file);
}
my @res = $o_fil->dummy(@args);
Various variables may be set affecting the behaviour of the module.
$File::Content::DEBUG = 1;
Default = 0 (don't die - just warn);
$File::Content::FATAL = 1; # die
Default is 0, ie; methods normally returns a list.
Hopefully future versions of perl may return a reference if you request one, but as this is not supported generically yet, nor do we, so we require the variable to be set. There may be an argument to make this a reference by default, feedback will decide.
$File::Content::REFERENCE = 1;
my $a_ref = $o_fil->search('.*');
print "The log: \n".@{ $a_ref };
Unset if you don't want this behaviour.
$File::Content::STRING = 0; # per line
Read-only permissions may be explicitly set using one of the following keys:
$File::Content::PERMISSIONS = 'ro'; # or readonly or <
Or, equivalently, for read-write (default):
rw readwrite +<
The default is 0 ie; start at the start of the file...
$File::Content::REVERSE = 1; # tac
Private methods not expected to be called outside this class, and completely unsupported.
Expected to metamorphose regularly - do not call these directly - you have been warned!
my $get = $o_fil->_var($key); # get
my $set = $o_fil->_var($key, $val); # set
$o_fil->_debug($msg) if $File::Content::DEBUG;
print $o_fil->_vars;
my $c_sub = $o_fil->_err('insert'); # or default
See the EXAMPLES manpage for info on how to pass your own error handlers in.
my $file = $o_fil->_mapfile($filename);
my $perms = $o_fil->_mapperms('+<');
my $h_errs = $o_fil->_maperrs(\%error_handlers);
my $entered = $o_fil->enter('search');
my $left = $o_fil->_leave('search');
Returns undef otherwise.
my $FH = $o_fil->_fh($FH);
The following utility methods return integer values
1 = success
0 = failure
my $i_ok = $o_file->_init($file, $perm, $h_errs);
my $i_isok = $o_fil->_check_access($filename, $permissions);
my $i_ok = $o_fil->_open;
my $i_ok = $o_fil->_lock;
my $i_ok = $o_fil->unlock;
my $i_ok = $o_fil->_close;
$o_fil->truncate;
Typical construction examples:
my $o_rw = File::Content->new($filename, 'rw');
my $o_ro = File::Content->new($filename, 'ro');
Failure is indicated by an error routine being called, this will print out any error to STDERR, unless warnings are declared fatal, in which case we croak. You can register your own error handlers for any method mentioned in the the METHOD manpage section of this document, in addition is a special init call for initial file opening and general setting up.
Create a read-write object with a callback for all errors:
my $o_rw = File::Content->new($filename, 'ro', {
'error' => \&myerror,
});
Create a read-only object with a separate object handler for each error type:
my $o_rw = File::Content->new($filename, 'rw', {
'error' => $o_generic->error_handler,
'insert' => $o_handler->insert_error,
'open' => $o_open_handler,
'read' => \&carp,
'write' => \&write_error,
});
From the command line:
perl -MFile::Content -e ``File-Content->new('./test.txt')->insert('123', '456')>'';
If you still have problems, mail me the output of
make test TEST_VERBOSE=1
Richard Foley <C> richard.foley@rfi.net 2001
For those that are interested, the docs and tests were (mostly) written before the code.
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File::Content - Regular expression interface to content of a file. |