Can I have the IO::PgLoFile namespace?
Here is the pod:
NAME
IO::PgLoFile - Emulate IO::File interface for PostgreSQL Large
Objects
SYNOPSIS
use IO::PgLoFile;
use DBI;
$dbh = DBI->connect("dbi:Pg:dbname=mah", "", "",
{RaiseError=>1,
AutoCommit=>0}) # <- Absolutely necessary!
$io = IO::PgLoFile->new($dbi);
$io = IO::PgLoFile->new($var);
tie *IO, 'IO::PgLoFile';
# read data
<$io>;
$io->getline;
read($io, $buf, 100);
# write data
print $io "string\n";
$io->print(@data);
syswrite($io, $buf, 100);
select $io;
printf "Some text %s\n", $str;
# seek
$pos = $io->getpos;
$io->setpos(0); # rewind
$io->seek(-30, -1);
**** WARNING ****
To use this module, you *must* feed your DBI connection
`AutoCommit => 0'. See the PostgreSQL documentation for more
details.
DESCRIPTION
The `IO::PgLoFile' module provide the `IO::File' interface for
Large Objects (aka BLOBs) in a PostgreSQL database. An
`IO::PgLoFile' object can be attached to a Large Object ID, and
will make it possible to use the normal file operations for
reading or writing data, as well as seeking to various locations
of the object.
This provides a tremendous amount of convenience since you can
treat the object just like a regular file and operate on it as
you would normally in Perl instead of doing all sorts of funky
stuff like:
$dbh->func($lobjfd, $buff, $len, "lo_read");
you get:
<$lobjfd>
I based this code on Gisle Aas' IO::String, so the interface is
similar.
The `IO::PgLoFile' module provide an interface compatible with
`IO::File' as distributed with IO-1.20, but the following
methods are not available; new_from_fd, fdopen, format_write,
format_page_number, format_lines_per_page, format_lines_left,
format_name, format_top_name.
The following methods are specific for the `IO::PgLoFile' class:
$io = IO::PgLoFile->new( $dbh[, $objid] )
The constructor returns a newly created `IO::PgLoFile'
object. You must supply it with a database handle. It takes
an optional argument which is oid of the large objectto read
from or write into. If no $objid argument is given, then a
new large object is created.
The `IO::PgLoFile' object returned will be tied to itself.
This means that you can use most perl IO builtins on it too;
readline, <>, getc, print, printf, syswrite, sysread, close.
$io->open( $dbh[, $objid] )
Attach an existing IO::PgLoFile object to some other $objid,
or create a new large object if no $objid is given. The
position is reset back to 0.
$io->oid
This method will return the oid of the large object. This is
useful for when you create a large object and what to put a
reference to it in another table.
$io->pad( [$char] )
The pad() method makes it possible to specify the padding to
use if the object is extended by either the seek() or
truncate() methods. It is a single character and defaults to
"\0".
Currently, extending the large object via seek() or
truncate() is not possible.
$io->pos( [$newpos] )
Yet another interface for reading and setting the current
read/write position within the object (the normal
getpos/setpos/tell/seek methods are also available). The
pos() method will always return the old position, and if you
pass it an argument it will set the new position.
One more difference compared to IO::Handle, is that the write()
and syswrite() methods allow the length argument to be left out.
BUGS
The perl TIEHANDLE interface is still not complete. There are
quite a few file operations that will not yet invoke any method
on the tied object. See the perltie manpage for details.
SEE ALSO
the IO::File manpage, the IO::String manpage
COPYRIGHT
Copyright 2000 Mark A. Hershberger, <[EMAIL PROTECTED]>.
This library is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
