NAME
Validator::Declarative - Declarative parameters validation
VERSION
version 1.20130722.2105
SYNOPSIS
sub MakeSomethingCool {
my $serialized_parameters;
my ( $ace_id, $upm_id, $year, $week, $timestamp_ms ) = Validator::Declarative->validate(
\@_ => [
ace_id => 'id',
upm_id => 'id',
year => 'year',
week => 'week',
timestamp_ms => [ 'to_msec', 'mdy', 'timestamp' ],
],
);
# here all parameters are validated
# .......
}
DESCRIPTION
Almost every function checks the input parameters, in one or other
manner. But often checking of some parameters are not made at all or are
made not properly.
In most cases, checking is done by means of one or more conditional
statements for each parameter individually. This reduces the readability
of the code and makes it difficult to maintain.
Often checking is done using "unless" with several conditions, which
make things even worse.
Also, lot of conditional statements increases the cyclomatic complexity
of the function, which makes it impossible to use automated tests to
check the quality and complexity of the code.
To solve these problems, we can use declarative description of function
parameters.
IMPLEMENTATION
In general, code for declarative validation definition looks like this:
my ($param1_name, $param2_name) = Validator::Declarative->validate( \@_ => [
param1_name => [ validation_definition1 ],
param2_name => [ validation_definitions2 ],
....
]);
This is usual key=>value pairs, but it should be written as array, not
as hash, because order does matter: one pair represents one parameter,
and order of pairs should be same as order of parameters in @_.
Each validation definition is an array ref. For simple cases, when
validation definition is represented by only one rule, we can type less
and skip surrounding brackets:
my ($param1_name, $param2_name, $param3_name, $param4_name) = Validator::Declarative->validate( \@_ => [
param1_name => 'name_of_rule1',
param2_name => { 'name_of_rule2' => param_for_rule2 },
param3_name => { 'name_of_rule3' => [ params_for_rule3 ] },
param4_name => { 'name_of_rule4' => { hash_of_params_for_rule4 } },
....
]);
These are shortcuts for:
my ($param1_name, $param2_name, $param3_name, $param4_name) = Validator::Declarative->validate( \@_ => [
param1_name => [ 'name_of_rule1' ],
param2_name => [ { 'name_of_rule2' => param_for_rule2 } ],
param3_name => [ { 'name_of_rule3' => [ params_for_rule3 ] } ],
param4_name => [ { 'name_of_rule4' => { hash_of_params_for_rule4 } } ],
....
]);
Grammars
Grammars for validation rules are:
simple
validation_rule ::= 'rule_name'
parameterized
validation_rule ::= { 'rule_name' => 'parameter' }
validation_rule ::= { 'rule_name' => [ 'parameter' ] }
validation_rule ::= { 'rule_name' => [ 'param1', 'param2', ... ] }
validation_rule ::= { 'rule_name' => { 'param1' => 'param2', ... } }
set of rules
validation_rule ::= validation_rule, validation_rule, ....
Rules
Possible kinds of rules are: types (simple and parametrized),
converters, constraints.
Simple and parametrized rules works only on defined values, for undef
all of them return OK (this is needed to support declarations of
optional parameters).
Simple types
any
always true, aliases: string
bool
qr/^(1|true|yes|0|false|no|)$/i, empty string accepted as false,
arbitrary data is not allowed
float
qr/^[+-]?\d+(:?\.\d*)?$/
int
qr/^[+-]?\d+$/, aliases: integer
positive
>0
negative
<0
id
int && positive
email
result of Email::Valid->address($_)
Simple types (date-like)
year
int && [1970 .. 3000]
week
int && [1 .. 53]
month
int && [1 .. 12]
day
int && [1 .. 31]
ymd
like YYYY-MM-DD
mdy
like M/D/Y (M and D can be 1 or 2 digits, Y can be 2 or 4 digits)
time
like HH:MM:SS, 00:00:00 ... 23:59:59
hhmm
like HH:MM, 00:00 ... 23:59
timestamp
almost same as float (because of Time::HiRes), but can't have sign
msec
timestamp in milliseconds (ts/1000), alias to timestamp
Parametrized types
min => value
minimal accepted value for parameter
max => value
maximal accepted value for parameter
ref => ref_type | [ref_types]
ref($_) && ref($_) eq (any of @ref_types)
class => class_name | [class_names]
blessed($_) && $_->isa(any of @class_names)
can => method_name | [method_names]
blessed($_) && $_->can(all of @method_names), aliases: ducktype
can_any => method_name | [method_names]
blessed($_) && $_->can(any of @method_names)
any_of => [values]
anything from values provided in array ref, aliases: enum
list_of => validation_rule
list of "values with specific validation check", recursive
hash_of => { simple_type => validation_rule }
hash of "keys with specific simple type" to "values with specific
validation check", recursive
hash_of => [ validation_rule => validation_rule ]
hash of "keys with specific validation check" to "values with specific
validation check", recursive
hash => { key => validation_rule, .... }
hash with specified key names (not required to exists) and "values with
specific validation check", recursive
date => format | [formats]
date/time in specific format
Types ref and class can be used as simple (without parameter), in this
case they check whether ref($_) and blessed($_) returns true.
Type date can be used as simple (without parameter), in this case it
accept all same formats that accepted by any_to_mdy():
/^20\d\d\d\d\d\d$/
/^[+-]?\d{1,10}$/
/^[+-]?\d{11,13}$/
/^\d\d\d\d-?\d\d-?\d\d(?:t\d\d:?\d\d:?\d\d(?:z|\+00)?)?$/i
/\d+\D+\d+\D+\d+/
When parameter to date is not skipped, it should be name of any of
date-like simple type ('year', 'week', 'mdy' etc) or formatting string
for DateTime::Format::Strptime::parse_datetime (example:
'%e/%b/%Y:%H:%M:%S %z', see DateTime::Format::Strptime for details).
There is no strict requirement for installed DateTime::Format::Strptime
- if module can't be loaded, checking with the appropriate format will
always lead to a positive result.
Converters
default => value
substitute $_ with provided value (only when actual parameter is undef)
assume_true
substitute $_ with 0 if it looks like false value (see bool, except for
empty string), and 1 otherwise
assume_false
substitute $_ with 1 if it looks like true value (see bool, except for
empty string), and 0 otherwise
Constraints
required
result of defined($_), applied by default
optional
OK if !defined($_)
not_empty
for list_of/hash_of/hash: has at least one element
for any/string: length($_) > 0
Order of execution
Order of rules in validation definition doesn't matters.
All specified rules will be executed in this order:
1. Actual parameter is checked to satisfy all constraints.
It's error to specify both required and optional at the same time.
If none of required and optional were specified, then required is
implied.
2. Actual parameter is passed thru converter (if any).
It's error to specify more than one converter, except for default. If
present, default will be executed at first place.
It's error to specify default if there is no optional constraint.
3. Parameter (actual or modified by converter, if any) is checked to satisfy any type (simple or parametrized).
If no one type were specified, then any is implied.
Order of types in checking is not defined and doesn't matter.
First successful check will finish entire validation for this parameter.
Errors and logging
For any calls all parameters will be checked, and in case of any errors
exception should be thrown.
Description of all errors will be included into exception text message.
METHODS
validate(\@params => \@rules)
register_type( $name => $code, ...)
register_converter( $name => $code, ...)
register_constraint( $name => $code, ...)
EXAMPLES
# Parameter is optional, and can be any type
field_name => [ 'any', 'optional' ]
# Parameter is optional, and it's id in database
field_name => [ 'id', 'optional' ]
# Parameter is optional, and it's id in database, with default value
field_name => [ 'id', 'optional', {default => undef} ]
# Parameter is optional, and it's id or list of ids in database
field_name => [ 'id', 'optional', {list_of => 'id'} ]
# Parameter is mandatory, and can be any type
field_name => 'any' # full form: [ 'required', 'any' ]
# Parameter is mandatory, and it's id in database
field_name => 'id' # full form: [ 'required', 'id' ]
# Parameter is mandatory, and it's id or list of ids in database
field_name => [ 'id', {list_of => 'id'} ]
# full form: [ 'required', 'id', {list_of => 'id'} ]
# Parameter is bool and optional
field_name => [ 'bool', 'optional' ]
# Parameter is bool and optional, and default is true
field_name => [ 'bool', 'optional', {default => 1} ]
# Parameter args is mandatory, and it's hash with keys:
# - suspensions: not required, hash with keys:
# - cssnote_ref: not required, id
# - review_deadline: not required, timestamp
# - reasons: required, can be id or list of ids
# - resumptions: not required, hash with keys:
# - cssnote_ref: not required, id
# - reasons: required, can be id, list of ids or hash "id to id"
# At least one key (suspensions or resumptions) should exists in args.
args => [ 'not_empty', { hash => {
suspensions => { hash => {
cssnote_ref => [ 'optional', 'id' ],
review_deadline => [ 'optional', 'timestamp' ],
reasons => [ 'id', {list_of => 'id'} ],
}},
resumptions => { hash => {
cssnote_ref => [ 'optional', 'id' ],
reasons => [ 'id', {list_of => 'id'}, {hash_of => {'id' => 'id'}} ],
}},
}}]
SEE ALSO
Inspired by Validator::LIVR -
<https://github.com/koorchik/Validator-LIVR>
AUTHOR
Oleg Kostyuk, "<cub at cpan.org>"
TODO
Implement types list_of, hash_of, hash and date.
Implement additional converters, like to_ts, to_mdy and several others.
BUGS
Please report any bugs or feature requests to Github
<https://github.com/cub-uanic/Validator-Declarative>
AUTHOR
Oleg Kostyuk <cub@cpan.org>
COPYRIGHT AND LICENSE
This software is Copyright (c) 2013 by Oleg Kostyuk.
This is free software, licensed under:
The (three-clause) BSD License