Configuration file access
use Config::Record;
# Create an empty record & then load from file
my $config = Config::Record->new();
$config->load("/etc/myapp.cfg");
# Create & load, then save to filename
my $config = Config::Record->new(file => "/etc/myapp.cfg");
$config->save("/etc/myapp.cfg");
# Load / save from filehandle
my $fh = IO::File->new("/etc/myapp.cfg");
my $config = Config::Record->new(file => $fh);
$config->save($fh);
# Get a config value, throw error if not found
my $value = $config->get("foo");
# Get a config value, return 'eek' if not found
my $value = $config->get("foo", "eek");
# Set a value
$config->set("foobar", "wizz");
# Get a deep config value (ie nested hash)
my $value = $config->get("foo/bar", "eek");
# Get first element of an array param
my $value = $config->get("people/[0]/forename");
# Get the raw hash reference forming the record
my $record = $config->record();
# Get a new config object rooted at a sub-hash
my $config = $config->view("foo");
This module provides an \s-1API\s0 for loading and saving of simple configuration file records. Entries in the configuration file are essentially key,value pairs, with the key and values separated by a single equals symbol. The \*(C`key\*(C' consists only of alphanumeric characters. There are three types of values, scalar values can contain anything except newlines. Trailing whitespace will be trimmed unless the value is surrounded in double quotes. eg
foo = Wizz foo = "Wizz.... "
Long lines can be split with a backslash character, without introducing newlines. Without double quotes, whitespace at beginning and end of lines will be trimmed eg
foo = This is a long \ line of text foo = "This is a long " \ "line of text"
Multi-line strings can be provided as '\s-1HERE\s0' documents, eg
foo = <<EOF This is a multiple paragraph block of text with newlines preserved EOF
Array values consist of a single right round bracket, following by one \*(C`value\*(C' per line, terminated by a single left round bracket. eg
foo = ( Wizz "Wizz... " )
Hash values consist of a single right curly bracket, followed by one key,value pair per line, terminated by a single left curly bracket. eg
foo = { one = Wizz two = "Wizz.... " }
Arrays and hashes can be nested to arbitrary depth.
name = Foo title = "Wizz bang wallop" eek = ( OOhh Aahhh Wizz ) people = ( { forename = John surnamne = Doe } { forename = Some surname = One } ) wizz = { foo = "Elk" ooh = "fds" }
The syntax described thus far is classed as the base feature set. By passing the \*(C`features\*(C' parameter when creating an instance of the \*(C`Config::Record\*(C' class, it is possible to turn on certain extra features
The keys for configuration parameters are normally restricted to only contain the characters 'a-Z', '0-9', '_', '-' and '.'. Sometimes it is desirable to allow arbitrary characters for keys. If this capability is required then the \*(C`quotedkeys\*(C' parameter can be set.
\s-1EXAMPLE\s0
name = Foo title = "Wizz bang wallop" " some parameter " = ( foo bar } "an embeded \" quote" = bar "an embeded \\ backslash" = wizz
With large configuration files it can be desirable to split them into a number of smaller files. If this capability is required, then the \*(C`includes\*(C' feature can be requested. Each included file must follow the syntax rules already described.
\s-1EXAMPLE\s0
In the main file
name = Foo title = "Wizz bang wallop" foo = @include(somefile.cfg)
And in somefile.cfg
firstname = Joe lastname = Blogs
Is equivalent to
name = Foo title = "Wizz bang wallop" foo = { firstname = Joe lastname = Blogs }
Creates a new config object, loading parameters from the file specified by the \*(C`file\*(C' parameter. The \*(C`file\*(C' parameter can either be a string representing a fully qualified filename, or a IO::Handle object. If the \*(C`file\*(C' parameter is a string, this filename will be saved and future calls to \*(C`load\*(C' or \*(C`save\*(C' are permitted to omit the filename. If the \*(C`file\*(C' parameter is not supplied then an empty configuration record is created. The \*(C`features\*(C' parameter allows extra parser features to be enabled. The two valid keys for the associated hash as \*(C`includes\*(C' and \*(C`quotedkeys\*(C' as described earlier in this document. Loads and parses a configuration record. The \*(C`file\*(C' parameter can either be a string representing a fully qualified filename, or an IO::Handle object. The $file parameter may be omitted, if a filename was specified in the constructor, or in previous calls to \*(C`load\*(C' or \*(C`save\*(C'. Prior to loading the record, the current contents of this configuration are cleared. Saves the configuration record to a file. The \*(C`file\*(C' parameter can either be a string representing a fully qualified filename, or an IO::Handle object opened for writing. The $file parameter may be omitted, if a filename was specified in the constructor, or in previous calls to \*(C`load\*(C' or \*(C`save\*(C'. Gets the value of a configuration parameter corresponding to the name \*(C`key\*(C'. If there is no value in the record, then the optional \*(C`default\*(C' is returned. Sets the value of a configuration parameter corresponding to the name \*(C`key\*(C'. Return a new Config::Record object, rooted at the specified key. If the key doesn't resolve to a hash reference an error will be raised. Retrieves a hash reference for the entire configuration record. Currently this is the actual internal storage record, so changes will modify the configuration. In the next release this will be changed to be a deep clone of the internal storage record.
Config::Record has the following limitations
If you load and then save a configuration file all comments are removed & whitespace normalized.
Ordering of elements in hash ref are not preserved across load and save sequence
These limitations may be fixed in a future release if there is demand from users...
Daniel Berrange <[email protected]>
Copyright (C) 2000-2007 Daniel P. Berrange <[email protected]>
perl(1)