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https://github.com/claytono/config-validate

Config::Validate perl module
https://github.com/claytono/config-validate

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Config::Validate perl module

Host: GitHub
URL: https://github.com/claytono/config-validate
Owner: claytono
Created: 2009-06-29T16:35:49.000Z (over 15 years ago)
Default Branch: master
Last Pushed: 2009-06-29T16:39:02.000Z (over 15 years ago)
Last Synced: 2023-04-13T04:58:03.776Z (over 1 year ago)
Language: Perl
Homepage: http://search.cpan.org/~cmo/Config-Validate-0.2.6/
Size: 188 KB
Stars: 1
Watchers: 2
Forks: 0
Open Issues: 0
Metadata Files:
- Readme: README
- Changelog: Changes

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README

NAME
Config::Validate - Validate data structures generated from configuration
files. (Or anywhere else)

VERSION
Version 0.2.6

DESCRIPTION
This module is for validating configuration data that has been read in
already and is in a Perl data structure. It does not handle reading or
parsing configuration files since there are a plethora of available
modules on CPAN to do that task. Instead it concentrates on verifying
that the data read is correct, and providing defaults where appropriate.
It also allows you to specify that a given configuration key may be
available under several aliases, and have those renamed to the canonical
name automatically.

The basic model used is that the caller provides a schema as a perl data
structure that describes the constraints to verify against. The caller
can then use the "Config::Validate" object to validate any number of
data structures against the configured schema. If the data structure
conforms to the schema given, then a new data structure will be
returned, otherwise an exception is thrown.

Probably the easiest way to explain the intent is that
"Config::Validate" is trying to be like "Params::Validate" for
configuration files and other data structures.

This module has the following features:

* Data structure depth is only limited by stack depth
* Can provide defaults for missing items at any level of the data
structure.
* Can require that items exist, or items can be optional.
* Can validate items in the data structure against a number of built in
data types, and users can easily add more data types.
* Configuration keys can be known by several names, and will be
normalized to the canonical name in the data structure returned by the
validation.

SCHEMA DEFINITION
The most complex part of using "Config::Validate" is defining the schema
to validate against. The schema takes the form of set of nested hashes.

Here is an example schema you might use if you were writing something
that needs to validate a database connection configuration file.

my $schema = { db => {
type => 'nested',
alias => 'dbinfo',
child => {
hostname => {
type => 'hostname'
alias => [ qw(host server) ],
default => 'localhost,
},
port => {
type => 'integer',
max => 64*1024 - 1,
min => 1,
default => '3306',
},
username => {
type => 'string'
optional => 1,
alias => 'user',
},
password => {
type => 'string',
optional => 1,
alias => [ qw(pass passwd) ],
},
database => {
type => 'string',
alias => 'dbname',
},
column_types => {
type => 'hash',
keytype => 'string',
child => {
id => {
type => 'string',
default => 'INT',
},
},
},
allowed_users => {
type => 'array',
subtype => 'string',
},
};

This is a somewhat long example of what a schema can look like. This
uses most of the features available. The basic format is that a schema
consists of a hash of hashes. Each of it's children describe a single
field in the data structure to be validated. The only required key in
the field definition is "type", which defines how that element in the
data/config hash should be validated.

VALIDATION TYPES
Below is a list of the built in validation types, and the options they
take. There are several global options that any of these can take that
are documented below.

nested
The "nested" type provides a way to validate nested hash references.
Valid options are:

* child Hash reference that defines all the valid keys and values in the
nested section. Required.

integer
The "integer" type expects a whole number that can be positive or
negative. Valid options are:

* min Smallest valid value

* max Largest valid value

float
The "float" type verifies that the value meets the "looks_like_number"
test from Scalar::Util. Valid options are:

* min Smallest valid value

* max Largest valid value

string
The "string" type does no validation if no addition restrictions are
specified. Valid options are:

* min Minimum length

* max Maximum length

* regex String must match the regex provided.

boolean
The "boolean" type looks for a number of specific values, and converts
them to 0 or 1. The values considered to be true are: 1, "y", "yes",
"t", "true" and "on". The values considered to be false are 0, "n",
"no", "f", "false", "off". These values are not case sensitive. The
"boolean" type takes no options.

directory
The "directory" type verifies that the value is a directory that exists.
The "directory" type takes no options.

file
The "file" type verifies that the value is a file, or a symlink that
points at a file that exists. The "file" type takes no options.

domain
The "domain" type uses the Data::Validate::Domain "is_domain" function
to verify that the value is a validate domain name. This does not look
the value up in DNS and verify that it exists. The "domain" type takes
no options.

hostname
The "hostname" type uses the Data::Validate::Domain "is_hostname"
function to verify that the value is a validate hostname name. This does
not look the value up in DNS and verify that it exists. The "hostname"
type takes no options.

array
The "array" type verifies that the value is an array reference. If the
"array_allows_scalar" option is turned on (it is by default), then if a
scalar value is found, then it will automatically be converted to an
array reference with a single element.

* subkey
Required option that specifies the type of the elements of the
array.

hash
The "hash" type validates a hash reference of key/value pairs.

* keytype
Required option that specifies the type of validation to do on
hash keys

* child If the "hash" type finds a "child" option, then it will validate
any keys in the hash against the fields in the "child"
definition. Note that it is NOT an error if elements are found
in the hash that are not in child. If you want that behavior,
you should use the "nested" type instead.

COMMON OPTIONS
There are a set of options that can be added to any field definition,
that provide a common set of functionality to all.

* alias The "alias" option allows you to specify other names that a
particular field might be known by. For example, you may have a
field named "password", but also want to accept "pass", "passwd"
and "pw". If any of the aliases are found, then they will be
renamed in the data structure that is returned by "validate".
This option can point to a scalar, or an array reference.

* callback
The "callback" option allows you to specify a callback that will
be called after any other validation has been done for a
specific field in the data structure. The callback sub is called
with a reference to the "Config::Validate" object (one is
created automatically if you're using the functional interface),
the value to be verified, the definition of the field, and an
array reference containing the path into the data structure. You
can use the "mkpath" method to convert the path to a more
readable form for error messages and such.

* default
The "default" option allows you to specify a default for the
field. This implicitly means the field is not required to exist
in the data structure being validated. As many levels as
necessary will be created in the resulting data structure to
insure the default is created.

* optional
If the "optional" option is true, then the field is not
required. If "optional" is false, or not defined, then the field
is required.

SUBROUTINES/METHODS
new
The new method constructs a "Config::Validate" object, and returns it.
It accepts the following arguments:

* schema
A validation schema as described in the "SCHEMA DEFINITION"
section above.

* data_path
If this is set to true, and the "Data::Path" module is
available, then the "validate" method/function will encapsulate
the results returned in a "Data::Path" instance. Defaults to
false;

* data_path_options
If the "data_path" option is true, then this should be a hash
reference to be passed in as the second argument to the
"Data:Path" constructor.

* array_allows_scalar
If this is true, then scalars will be autopromoted to a single
element array reference when validating "array" types.

* debug Enables debugging output.

* on_debug
Allows you to define a callback for debugging output. A default
callback will be provided if this isn't set. The default
callback simply prints the debug output to STDOUT. If you set
the callback, then will be called with the object as the first
parameter, and the additional parameters should be joined to
form the entire message.

In addition, any of these can read or changed after the object is
created, via an accessor with the same name as the parameter.

validate
The validate sub can be called as either a function, or as a instance
method.

If it is called as an instance method, then it expects a single "config"
parameter which should be the data structure/config to be validated.

my $result = $obj->validate(config => $config)

If it is called as a function, then it accepts two parameters. The
"config" parameter should be the data structure/config to be validated,
and the "schema" parameter should be the schema.

my $result = validate(config => $config, schema => $schema)

The "config" parameter above can be a hash reference, or it can be a
"Config::General" object. If it is a "Config::General" object, then the
validate sub will automatically call the "getall" method on the object.

If any errors are encountered, then the validate sub will call die to
throw an exception. In that case the value of $@ contain an error
message describing the problem.

There was formerly a one and two argument variant of this sub. It is
still supported, but deprecated.

add_type
The "add_type" method allows you to register a validation type on just a
single instance of "Config::Validate". The parameters are as follows:

* name This is the name to be specified in the schema to use this
validation type. This is a mandatory parameter.

* validate
The value of "validate" should be a callback that will be run
when it is necessary to validate a field of this type. The
callback will be passed the "Config::Validate" object, the name
of the field being validated, the schema definition of that
field, and an array reference containing the path into the data
structure. You can use the "mkpath" method to convert the path
to a more readable form for error messages and such.

* init The value of "init" should be a callback that will be run before
any validation is done. The callback will be passed the
"Config::Validate" object, the schema, and the configuration
being validated.

* finish
The value of "finish" should be a callback that will be run
after any validation is done. The callback will be passed the
"Config::Validate" object, the schema, and the configuration
being validated.

add_default_type
The "add_default_type" method allows you to register a validation type
for all new "Config::Validate" instances. It can be called as a
function, class method, or instance method. If it is called as an
instance method, then the new type will also be added to that instance.
The parameters are the same as "add_type".

reset_default_types
The "reset_default_types" method removes all user defined types from the
base class. Any instances that are alread created will retain their
existing type configuration.

mkpath
This is a convenience function for people writing callbacks and user
defined type validation. It takes either an array or array reference and
returns a string that represents the path to a specific item in the
configuration. This might be useful if you're interested in having your
error messages be consistent with the rest of "Config::Validate". This
is available for export, but not exported by default. Note: this is a
function, not a method.

AUTHOR
Clayton O'Neill

Eval for e-mail address: "join('@', join('.', qw(cv 20 coneill)),
'xoxy.net')"

This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself, either Perl version 5.8.5 or, at
your option, any later version of Perl 5 you may have available.