Padre::File - Common API for file functions

Padre documentation Contained in the Padre distribution.

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NAME

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Padre::File - Common API for file functions

DESCRIPTION

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Padre::File provides a common API for file access within Padre. It covers all the differences with non-local files by mapping every function call to the currently used transport stream.

METHODS

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RegisterProtocol

  Padre::File->RegisterProtocol($RegExp, $Module);

Class method, may not be called on an object.

A plug-in could call Padre::File->RegisterProtocol to register a new protocol to Padre::File and enable Padre to use URLs handled by this module.

Example:

  Padre::File->RegisterProtocol('^nfs\:\/\/','Padre::Plugin::NFS');

Every file/URL opened through Padre::File which starts with nfs:// is now handled through Padre::Plugin::NFS. Padre::File->new() will respect this and call Padre::Plugin::NFS->new() to handle such URLs.

Returns true on success or false on error.

Registered protocols may override the internal protocols.

DropProtocol

Drops a previously registered protocol handler. First argument must be the same regular expression (matching a protocol from an URI) that was used to register the protocol handler in the first place using RegisterProtocol. Similarly, the second argument must be the name of the class (module) that the handler was registered for. That means if you registered your protocol with

  Padre::File->RegisterProtocol(qr/^sftp:\/\//, 'Padre::File::MySFTP');

then you need to drop it with

  Padre::File->DropProtocol(qr/^sftp:\/\//, 'Padre::File::MySFTP');

Returns true if a handler was removed and the empty list if no handler was found for the given regular expression.

new

  my $file = Padre::File->new($File_or_URL);

The new constructor lets you create a new Padre::File object.

Only one parameter is accepted at the moment: The name of the file which should be used. As soon as there are HTTP, FTP, SSH and other modules, also URLs should be accepted.

If you know the protocol (which should be true every time you build the URL by source), it's better to call Padre::File::Protocol->new($URL) directly (replacing Protocol by the protocol which should be used, of course).

The module for the selected protocol should fill ->{filename} property. This should be used for all further references to the file as it will contain the file name in universal correct format (for example correct the C:\ eq C:/ problem on Windows).

Returns a new Padre::File or dies on error.

atime

  $file->atime;

Returns the last-access time of the file.

This is usually not possible for non-local files, in these cases, the empty list is returned.

basename

  $file->basename;

Returns the plain file name without path if a path/file name structure exists for this module.

blksize

  $file->blksize;

Returns the block size of the file system where the file resides.

This is usually not possible for non-local files, in these cases, the empty list is returned.

blocks

  $file->blocks;

Returns the number of blocks used by the file.

This is usually not possible for non-local files, in these cases, the empty list is returned.

browse_mtime

  $file->browse_mtime($path_and_filename);

Returns the modification time of the given file on the remote server.

Leave out the protocol and server name for remote protocols, for example

  my $file = Padre::File->new('http://perlide.org/current/foo.html');
  $file->browse_mtime('/archive/bar.html');

This returns the modification time of http://perlide.org/archive/bar.html

The default uses one Padre::File clone per request which is a reasonable fallback but very inefficient! Please add browse_… methods to the subclass module whenever possible.

browse_url_join

  $file->browse_url_join($server, $path, $basename);

Merges a server name, path name and a file name to a complete URL.

A path in this function is meant to be the local path on the server, not the Padre path (which includes the server name).

You may think of

  /tmp + padre.$$                       => /tmp/padre.$$
  C:\\temp + padre.$$                   => C:\\temp\\padre.$$

...but also remember

  http://perlide.org + about.html       => http://perlide.org/about.html

Datapoint created a file syntax...

  common + program/text                 => program/text:common

This could happen once someone adds a Padre::File::DBCFS for using a DB/C FS file server. program is the file name, text the extension and "common" is what we call a directory.

The most common seems to be a / as the directory separator character, so we'll use this as the default.

This method should care about merging double / to one if this should be done on this file system (even if the default doesn't care).

can_clone

  $file->can_clone;

Returns true if the protocol allows re-using of connections for new files (usually from the same project).

Local files don't use connections at all, HTTP uses one-request- connections, cloning has no benefit for them. FTP and SSH use connections to a remote server and we should work to get no more than one connection per server.

can_delete

  $file->can_delete;

Returns true if the protocol allows deletion of files or false if it doesn't.

can_run

  $file->can_run;

Returns true if the protocol allows execution of files or the empty list if it doesn't.

This is usually not possible for non-local files (which return true), because there is no way to reproduce a save environment for running a HTTP or FTP based file (they return false).

clone

  my $clone = $file->clone($File_or_URL);

The clone constructor lets you create a new Padre::File object reusing an existing connection.

Takes the same arguments as the new method.

If the protocol doesn't know about (server) connections/sessions, returns a brand new Padre::File object.

NOTICE: If you request a clone which is located on another server, you'll get a Padre::File object using the original connection to the original server and the original authentication data but the new path and file name!

Returns a new Padre::File or dies on error.

clone_file

  my $clone = $file->clone_file($filename_with_path);
  my $clone = $file->clone_file($path,$filename);

The clone constructor lets you create a new Padre::File object reusing an existing connection.

Takes one or two arguments:

either the complete path + file name of an URL
or the path and file name as separate arguments

If the protocol doesn't know about (server) connections/sessions, returns a brand new Padre::File object.

Returns a new Padre::File or dies on error.

ctime

  $file->ctime;

Returns the last-change time of the inode (not the file!).

This is usually not possible for non-local files, in these cases, the empty list is returned.

delete

  $file->delete;

Removes the current object's file from disk (or whereever it's stored).

Should clear any caches.

dev

  $file->dev;

Returns the device number of the file system where the file resides.

This is usually not possible for non-local files, in these cases, the empty list is returned.

dirname

  $file->dirname;

Returns the plain path without file name if a path/file name structure exists for this module.

Returns the empty list on failure or undefined behaviour for the given protocol.

error

  $file->error;

Returns the last error message (like $! for system calls).

exists

  $file->exists;

Returns true if the file exists. Returns false if the file doesn't exist. Returns the empty list if unsure (network problem, not implemented).

filename

  $file->filename;

Returns the the file name including path handled by this object.

Please remember that Padre::File is able to open many URL types. This file name may also be a URL. Please use the basename and dirname methods to split it (assuming that a path exists in the current protocol).

gid

  $file->gid;

Returns the real group ID of the file group.

This is usually not possible for non-local files, in these cases, the empty list is returned.

inode

  $file->inode;

Returns the inode number of the file.

This is usually not possible for non-local files, in these cases, the empty list is returned.

mime

  $file->mime;
  $file->mime('text/plain');

Returns or sets the MIME type of the file.

mode

  $file->mode;

Returns the file mode (type and rights). See also: stat in perlfunc. To get the POSIX file permissions as the usual octal number (as opposed to a string) use:

  use Fcntl ':mode';
  my $perms_octal = S_IMODE($file->mode);

This is usually not possible for non-local files, in these cases, the empty list is returned.

mtime

  $file->mtime;

Returns the last-modification (change) time of the file.

  $file->nlink;

Returns the number of hard links to the file.

This is usually not possible for non-local files, in these cases, the empty list is returned.

rdev

  $file->rdev;

Returns the device identifier.

This is usually not possible for non-local files, in these cases, the empty list is returned.

read

  $file->read;

Reads the file contents and returns them.

Returns the empty list on error. The error message can be retrieved using the error method.

servername

  $file->servername;

Returns the server name for this module - if the protocol knows about a server, local files don't.

WARNING: The Padre path includes the server name in a protocol dependent syntax!

size

  $file->size;

Returns the file size in bytes or the empty list if the method was not implemented by the Padre::File subclass.

stat

  $file->stat;

This emulates a stat call and returns the same values:



  0 dev      device number of file system
  1 ino      inode number
  2 mode     file mode  (type and permissions)
  3 nlink    number of (hard) links to the file
  4 uid      numeric user ID of file's owner
  5 gid      numeric group ID of file's owner
  6 rdev     the device identifier (special files only)
  7 size     total size of file, in bytes
  8 atime    last access time in seconds since the epoch
  9 mtime    last modify time in seconds since the epoch
 10 ctime    inode change time in seconds since the epoch (*)
 11 blksize  preferred block size for file system I/O
 12 blocks   actual number of blocks allocated

A module should fill as many items as possible, but if you're thinking about using this method, always remember

1.

Usually, you need only one or two of the items, request them directly.

2.

Besides from local files, most of the values will not be accessible (resulting in empty lists/false returned).

3.

On most protocols these values must be requested one-by-one, which is very expensive.

Please always consider using the function for the value you really need instead of using stat!

uid

  $file->uid;

Returns the real user ID of the file owner.

This is usually not possible for non-local files, in these cases, the empty list is returned.

write

  $file->write($Content);
  $file->write($Content,$Coding);

Writes the given $Content to the file, if a encoding is given and the protocol allows encoding, it is respected.

Returns 1 on success. Returns 0 on failure. Returns the empty list if the function is not available on the protocol.

INTERNAL METHODS

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_info

  $file->_info($message);

Shows $message to the user as an information. The output is guaranteed to be non-blocking and messages shown this way must be safe to be ignored by the user.

Doesn't return anything.

Padre documentation Contained in the Padre distribution. 
package Padre::File;

use 5.008;
use strict;
use warnings;

our $VERSION = '0.86';

# a list of registered protocol handlers. Structure:
# regexp => [handler1, handler2, ...]
# Note that ONLY THE FIRST handler is used! This is meant to allow
# for plugins to enable and disable handlers with falling back to
# the previously instantiated handlers.
our %RegisteredModules;


sub RegisterProtocol {
	shift if defined $_[0] and $_[0] eq __PACKAGE__;
	my $regexp = shift;
	my $module = shift;

	return () if not defined $regexp or $regexp eq '';
	return () if not defined $module or $module eq '';
	$regexp = "$regexp";

	# no double insertion
	return ()
		if exists $RegisteredModules{$regexp}
			and grep { $_ eq $module } @{ $RegisteredModules{$regexp} };

	unshift @{ $RegisteredModules{$regexp} }, $module;

	return 1;
}



sub DropProtocol {
	shift if defined $_[0] and $_[0] eq __PACKAGE__;
	my $regexp = shift;
	my $module = shift;

	return () if not defined $regexp or $regexp eq '';
	return () if not defined $module or $module eq '';
	$regexp = "$regexp";

	return () if not exists $RegisteredModules{$regexp};

	my $modules  = $RegisteredModules{$regexp};
	my $n_before = @$modules;
	@$modules = grep { $_ ne $module } @$modules; # drop this module only

	delete $RegisteredModules{$regexp} if @$modules == 0;

	return $n_before != @$modules;
}



sub new {
	my $class = shift;
	my $URL   = shift;
	my %args  = @_;

	return if not defined($URL) or $URL eq '';

	my $self;

	for ( keys(%RegisteredModules) ) {
		next if $URL !~ /$_/;
		my $module = $RegisteredModules{$_}->[0];
		if ( eval "require $module; 1;" ) {
			$self = $module->new($URL);
			return $self;
		}
	}

	if ( $URL =~ /^file\:(.+)$/i ) {
		require Padre::File::Local;
		$self = Padre::File::Local->new( $1, @_ );

	} elsif ( $URL =~ /^https?\:\/\//i ) {
		require Padre::File::HTTP;
		$self = Padre::File::HTTP->new( $URL, @_ );
	} elsif ( $URL =~ /^ftp?\:/i ) {
		require Padre::File::FTP;
		$self = Padre::File::FTP->new( $URL, @_ );
	} else {
		require Padre::File::Local;
		$self = Padre::File::Local->new( $URL, @_ );
	}

	$self->{Filename} = $self->{filename}; # Temporary hack

	# Copy the info message handler to self
	$self->{info_handler} = $args{info_handler} if defined( $args{info_handler} );

	return $self;

}


sub atime { }


# Fallback if the module has no such function:
# It turned out that returning everything is much better
# than returning undef for this function:
sub basename {
	my $self = shift;
	return $self->{filename};
}


sub blksize { }


sub blocks { }


sub browse_mtime {
	my $self     = shift;
	my $filename = shift;

	my $file = $self->clone_file($filename);
	return $file->mtime;
}


# Note: Don't use File::Spec->catfile here as it may mix up http or
#       other pathnames. This is a default and should be overriden
#       by each Padre::File::* - module!
sub browse_url_join {
	my $self     = shift;
	my $server   = shift;
	my $path     = shift;
	my $basename = shift;

	return $self->{protocol} . '://' . $server . '/' . $path . '/' . $basename if defined($basename);
	return $self->{protocol} . '://' . $server . '/' . $path;
}


sub can_clone {

	# Cloning needs to be supported by the protocol, the safer
	# option is false here.
	return 0;
}


sub can_delete {

	# If the module does not state that it could remove files,
	# we return a safe default of false.
	return 0;
}


sub can_run {

	# If the module does not state that it could do "run",
	# we return a safe default of false.
	return 0;
}


sub clone {
	my $self = shift;

	my $class = ref($self);

	return $class->new(@_);
}


sub clone_file {
	my $self     = shift;
	my $path     = shift;
	my $filename = shift;

	return $self->clone( $self->browse_url_join( $self->servername, $path, $filename ) );
}


sub ctime { }


sub delete { }


sub dev { }


sub dirname { }


sub error {
	my $self = shift;
	return $self->{error};
}


# Fallback if the module has no such function:
sub exists {

	my $self = shift;

	# A size indicates that the file exists:
	return 1 if $self->size;

	return;
}


# Fallback if the module has no such function:
sub filename {
	my $self = shift;
	return $self->{filename};
}


sub gid { }


sub inode { }


sub mime {
	my $self     = shift;
	my $new_mime = shift;
	defined($new_mime) and $self->{MIME} = $new_mime;
	return $self->{MIME};
}


sub mode { }


sub mtime { }


sub nlink { }


sub rdev { }


sub servername {
	my $self = shift;
	return '';
}



sub size { }


sub stat {
	my $self = shift;

	# If the module has a own stat function, we won't ever reach this point!

	return (
		$self->dev,
		$self->inode,
		$self->nlink,
		$self->uid,
		$self->gid,
		$self->rdev,
		$self->size,
		$self->atime,
		$self->mtime,
		$self->ctime,
		$self->blksize,
		$self->blocks
	);

}


sub uid { }


sub write { }


sub _info {
	my $self    = shift;
	my $message = shift;

	# Return silently if no handler for info message is defined
	return unless defined( $self->{info_handler} ) and ( ref( $self->{info_handler} ) eq 'CODE' );

	# Handle the info message but don't fail on DIEs:
	eval { &{ $self->{info_handler} }( $self, $message ); };
}

1;

# Copyright 2008-2011 The Padre development team as listed in Padre.pm.
# LICENSE
# This program is free software; you can redistribute it and/or
# modify it under the same terms as Perl 5 itself.