DBD::SQLite::VirtualTable::FileContent (3)

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NAME

DBD::SQLite::VirtualTable::FileContent -- virtual table for viewing file contents

SYNOPSIS

Within Perl :

  $dbh->sqlite_create_module(fcontent => "DBD::SQLite::VirtualTable::FileContent");

Then, within

  CREATE VIRTUAL TABLE tbl USING fcontent(
     source      = src_table,
     content_col = content,
     path_col    = path,
     expose      = "path, col1, col2, col3", -- or "*"
     root        = "/foo/bar"
     get_content = Foo::Bar::read_from_file
    );

  SELECT col1, path, content FROM tbl WHERE ...;

DESCRIPTION

A ``FileContent'' virtual table is bound to some underlying source table, which has a column containing paths to files. The virtual table behaves like a database view on the source table, with an added column which exposes the content from those files.

This is especially useful as an ``external content'' to some fulltext table (see DBD::SQLite::Fulltext_search) : the index table stores some metadata about files, and then the fulltext engine can index both the metadata and the file contents.

PARAMETERS

Parameters for creating a "FileContent" virtual table are specified within the "CREATE VIRTUAL TABLE" statement, just like regular column declarations, but with an '=' sign. Authorized parameters are :

source

The name of the source table. This parameter is mandatory. All other parameters are optional.

content_col

The name of the virtual column exposing file contents. The default is "content".

path_col

The name of the column in "source" that contains paths to files. The default is "path".

expose

A comma-separated list (within double quotes) of source column names to be exposed by the virtual table. The default is "*", which means all source columns.

root

An optional root directory that will be prepended to the path column when opening files.

get_content

Fully qualified name of a Perl function for reading file contents. The default implementation just slurps the entire file into a string; but this hook can point to more sophisticated implementations, like for example a function that would remove html tags. The hooked function is called like this :

  $file_content = $get_content->($path, $root);

AUTHOR

Laurent Dami <dami@cpan.org>

COPYRIGHT AND LICENSE

Copyright Laurent Dami, 2014.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.