NAME
Data::Validate::Struct - Validate recursive Hash Structures
SYNOPSIS
use Data::Validate::Struct;
my $validator = new Data::Validate::Struct($reference);
if ( $validator->validate($config_hash_reference) ) {
print "valid\n";
}
else {
print "invalid " . $validator->errstr() . "\n";
}
DESCRIPTION
This module validates a config hash reference against a given hash
structure in contrast to Data::Validate in which you have to check each
value separately using certain methods.
This hash could be the result of a config parser or just any hash
structure. Eg. the hash returned by XML::Simple could be validated using
this module. You may also use it to validate CGI input, just fetch the
input data from CGI, map it to a hash and validate it.
Data::Validate::Struct uses some of the methods exported by
Data::Validate, so you need to install it too.
PREDEFINED BUILTIN DATA TYPES
int Match a simple integer number.
range(a-b)
Match a simple integer number in a range between a and b. Eg:
{ loginport => 'range(22-23)' }
hex Match a hex value.
oct Match an octagonal value.
number
Match a decimal number, it may contain , or . and may be signed.
word
Match a single word, _ and - are tolerated.
line
Match a line of text - no newlines are allowed.
text
Match a whole text(blob) including newlines. This expression is very
loosy, consider it as an alias to any.
regex
Match a perl regex using the operator qr(). Valid examples include:
qr/[0-9]+/
qr([^%]*)
qr{\w+(\d+?)}
Please note, that this doesn't mean you can provide here a regex
against config options must match.
Instead this means that the config options contains a regex.
eg:
$cfg = {
grp = qr/root|wheel/
};
regex would match the content of the variable 'grp' in this example.
To add your own rules for validation, use the type() method, see
below.
uri Match an internet URI.
ipv4
Match an IPv4 address.
cidrv4
The same as above including cidr netmask (/24), IPv4 only, eg:
10.2.123.0/23
Note: shortcuts are not supported for the moment, eg:
10.10/16
will fail while it is still a valid IPv4 cidr notation for a network
address (short for 10.10.0.0/16). Must be fixed in Regex::Common.
ipv6
Match an IPv6 address. Some examples:
3ffe:1900:4545:3:200:f8ff:fe21:67cf
fe80:0:0:0:200:f8ff:fe21:67cf
fe80::200:f8ff:fe21:67cf
ff02:0:0:0:0:0:0:1
ff02::1
cidrv6
The same as above including cidr netmask (/64), IPv6 only, eg:
2001:db8:dead:beef::1/64
2001:db8::/32
quoted
Match a text quoted with single quotes, eg:
'barbara is sexy'
hostname
Match a valid hostname, it must qualify to the definitions in RFC
2396.
resolvablehost
Match a hostname resolvable via dns lookup. Will fail if no dns is
available at runtime.
path
Match a valid absolute path, it won't do a stat() system call. This
will work on any operating system at runtime. So this one:
C:\Temp
will return TRUE if running on WIN32, but FALSE on FreeBSD!
fileexists
Look if value is a file which exists. Does a stat() system call.
user
Looks if the given value is an existent user. Does a getpwnam()
system call.
group
Looks if the given value is an existent group. Does a getgrnam()
system call.
port
Match a valid tcp/udp port. Must be a digit between 0 and 65535.
vars
Matches a string of text containing variables (perl style variables
though) eg:
$user is $attribute
I am $(years) old
Missing ${points} points to succeed
MIXED TYPES
If there is an element which could match more than one type, this can be
matched by using the pipe sign "|" to separate the types.
{ name => 'int | number' }
There is no limit on the number of types that can be checked for, and
the check is done in the sequence written (first the type 'int', and
then 'number' in the example above).
OPTIONAL ITEMS
If there is an element which is optional in the hash, you can use the
type 'optional' in the type. The 'optional' type can also be mixed with
ordinary types, like:
{ name => 'text | optional' }
The type 'optional' can be placed anywhere in the type string.
NEGATIVE MATCHING
In some rare situations you might require a negative match. So a test
shall return TRUE if a particular value does NOT match the given type.
This might be usefull to prevent certain things.
To achieve this, you just have to prepend one of the below mentioned
types with the keyword no.
Example:
$ref = { path => 'novars' }
This returns TRUE if the value of the given config hash does NOT contain
ANY variables.
VALIDATOR STRUCTURE
The expected structure must be a standard perl hash reference. This hash
may look like the config you are validating but instead of real-live
values it contains types that define of what type a given value has to
be.
In addition the hash may be deeply nested. In this case the validated
config must be nested the same way as the reference hash.
Example:
$reference = { user => 'word', uid => 'int' };
The following config would be validated successful:
$config = { user => 'HansDampf', uid => 92 };
this one not:
$config = { user => 'Hans Dampf', uid => 'nine' };
^ ^^^^
| |
| +----- is not a number
+---------------------- space not allowed
For easier writing of references you yould use a configuration file
parser like Config::General or Config::Any, just write the definition
using the syntax of such a module, get the hash of it and use this hash
as validation reference.
NESTED HASH STRUCTURES
You can also match against nested structures. Data::Validate::Struct
iterates into the given config hash the same way as the reference hash
looks like.
If the config hash doesn't match the reference structure, perl will
throw an error, which Data::Validate::Struct catches and returns FALSE.
Given the following reference hash:
$ref = {
'b1' => {
'b2' => {
'b3' => {
'item' => 'int'
}
}
}
}
Now if you validate it against the following config hash it will return
TRUE:
$cfg = {
'b1' => {
'b2' => {
'b3' => {
'item' => '100'
}
}
}
}
If you validate it for example against this hash, it will return FALSE:
$cfg = {
'b1' => {
'b2' => {
'item' => '100'
}
}
}
SUBROUTINES/METHODS
validate($config)
$config must be a hash reference you'd like to validate.
It returns a true value if the given structure looks valid.
If the return value is false (0), then the error message will be
written to the variable $!.
type(%types)
You can enhance the validator by adding your own rules. Just add one
or more new types using a simple hash using the type() method.
Values in this hash can be regexes or anonymous subs.
"type" does accept either a hash (%hash), a hash ref (%$hash) or a
list of key/values ("key => value") as input.
For details see "CUSTOM VALIDATORS".
debug()
Enables debug output which gets printed to STDERR.
errors
Returns an array ref with the errors found when validating the hash.
Each error is on the format '<value> doesn't match <types> at
<ref>', where <ref> is a comma separated tree view depicting where
in the the error occured.
errstr()
Returns the last error, which is useful to notify the user about
what happened. The format is like in "errors".
EXPORTED FUNCTIONS
add_validators
This is a class function which adds types not per object but globally
for each instance of Data::Validate::Struct.
use Data::Validate::Struct qw(add_validators);
add_validators( name => .. );
my $v = Data::Validate::Struct->new(..);
Parameters to add_validators are the same as of the type method.
For details see "CUSTOM VALIDATORS".
CUSTOM VALIDATORS
You can add your own validators, which maybe regular expressions or
anonymous subs. Validators can be added using the type() method or
globally using the add_validators() function.
CUSTOM REGEX VALIDATORS
If you add a validator which is just a regular expressions, it will
evaluated as is. This is the most simplest way to customize validation.
Sample:
use Data::Validate::Struct qw(add_validators);
add_validators(address => qr(^\w+\s\s*\d+$));
my $v = Data::Validate::Struct->new({place => 'address'});
$v->validate({place => 'Livermore 19'});
Regexes will be executed exactly as given. No flags or ^ or $ will be
used by the module. Eg. if you want to match the whole value from
beginning to the end, add ^ and $, like you can see in our 'address'
example above.
CUSTOM VALIDATOR FUNCTIONS
If the validator is a coderef, it will be executed as a sub.
Example:
use Data::Validate::Struct qw(add_validators);
add_validators(
list => sub {
my $list = shift;
my @list = split /\s*,\s*/, $list;
return scalar @list > 1;
},
);
In this example we add a new type 'list', which is really simple. 'list'
is a subroutine which gets called during evaluation for each option
which you define as type 'list'.
Such a subroutine must return a true value in order to produce a match.
It receives the following arguments:
* value to be evaluated
* unparsed arguments, if defined in the reference
* array of parsed arguments, tokenized by , and -
That way you may define a type which accepts an arbitrary number of
arguments, which makes the type customizable. Sample:
# new validator
$v4 = Data::Validate::Struct->new({ list => nwords(4) });
# define type 'nwords' with support for 1 argument
$v4->type(
nwords => sub {
my($val, $ignore, $count) = @_;
return (scalar(split /\s+/, $val) == $count) ? 1 : 0;
},
);
# validate
$v4->validate({ list => 'these are four words' });
CUSTOM VALIDATORS USING A GRAMMAR
Sometimes you want to be more flexible, in such cases you may use a
parser generator to validate input. This is no feature of
Data::Validate::Struct, you will just write a custom code ref validator,
which then uses the grammar.
Here's a complete example using Parse::RecDescent:
use Parse::RecDescent;
use Data::Validate::Struct qw(add_validators);
my $grammar = q{
line: expr(s)
expr: number operator number
number: int | float
int: /\d+/
float: /\d*\\.\d+/
operator: '+' | '-' | '*' | '/'
};
my $parse = Parse::RecDescent->new($grammar);
add_validators(calc => sub { defined $parse->line($_[0]) ? 1 : 0; });
my $val = Data::Validate::Struct->new({line => 'calc'});
if ($val->validate({line => "@ARGV"})) {
my $r;
eval "\$r = @ARGV";
print "$r\n";
}
else {
print "syntax error\n";
}
Now you can use it as follows:
./mycalc 54 + 100 - .1
153.9
./mycalc 8^2
syntax error
NEGATED VALIDATOR
A negative/reverse match is automatically added as well, see "NEGATIVE
MATCHING".
EXAMPLES
Take a look to t/run.t for lots of examples.
CONFIGURATION AND ENVIRONMENT
No environment variables will be used.
SEE ALSO
I recommend you to read the following documentations, which are supplied
with perl:
perlreftut Perl references short introduction.
perlref Perl references, the rest of the story.
perldsc Perl data structures intro.
perllol Perl data structures: arrays of arrays.
Data::Validate common data validation methods.
Data::Validate::IP common data validation methods for IP-addresses.
LICENSE AND COPYRIGHT
Copyright (c) 2007-2015 T. v.Dein
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
BUGS AND LIMITATIONS
Some implementation details as well as the API may change in the future.
This will no more happen if entering a stable release (starting with
1.00).
To submit use <http://rt.cpan.org>.
INCOMPATIBILITIES
None known.
DIAGNOSTICS
To debug Data::Validate::Struct use debug() or the perl debugger, see
perldebug.
For example to debug the regex matching during processing try this:
perl -Mre=debug yourscript.pl
DEPENDENCIES
Data::Validate::Struct depends on the module Data::Validate,
Data::Validate:IP, Regexp::Common, File::Spec and File::stat.
AUTHORS
T. v.Dein <tlinden |AT| cpan.org>
Per Carlson <pelle |AT| cpan.org>
Thanks to David Cantrell for his helpful hints.
VERSION
0.10