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ParamProcessor is a parameter processing library that provides a way to declaratively define a set of parameters and how they should be processed. It can take such declarations together with a list of raw parameters and provide the processed values. For example, if one defines a parameter to be an integer, in the range [0, 100], then ParamProcessor will verify the input is an integer, in the specified range, and return it as an actual integer variable.

Also see ParserHooks, a library that builds on top of ParamProcessor and provides MediaWiki integration.

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On Packagist: Latest Stable Version Download count


The recommended way to use this library is via Composer.


To add this package as a local, per-project dependency to your project, simply add a dependency on param-processor/param-processor to your project's composer.json file. Here is a minimal example of a composer.json file that just defines a dependency on version 1.x of this package:

    "require": {
        "param-processor/param-processor": "~1.0"


Get the code of this package, either via git, or some other means. Also get all dependencies. You can find a list of the dependencies in the "require" section of the composer.json file. Then take care of autoloading the classes defined in the src directory.


The goal of the ParamProcessor library is to make parameter handling simple and consistent.

In order to achieve this, a declarative API for defining parameters is provided. Passing in such parameter definitions together with a list of raw input into the processor leads to a processed list of parameters. Processing consists out of name and alias resolving, parsing, validation, formatting and defaulting.

If ones defines an "awesomeness" parameter of type "integer", one can be sure that at the end of the processing, there will be an integer value for the awesomeness parameter. If the user did not provide a value, or provided something that is invalid, while the parameter it is required, processing will abort with a fatal error. If on the other hand there is a default, the default will be set. If the value was invalid, a warning will be kept track of. In case the user provides a valid value, for instance "42" (string), it will be turned in the appropriate 42 (int).

Implementation structure

Parameters are defined using the ParamProcessor\ParamDefinition class. Users can also use the array format to define parameters and not be bound to this class. At present, it is preferred to use this array format as the class itself is not stable yet.

Processing is done via ParamProcessor\Processor.

Defining parameters

Array definition schema

These fields are supported:

Name Type Default Description
name string required
type string (enum) string
default mixed null If this value is null, the parameter has no default and is required
aliases array of string empty array Aliases for the name
trim boolean inherited from processor options If the value should be trimmed
islist boolean false
delimiter string , The delimiter between values if it is a list
manipulatedefault boolean true If the default value should also be manipulated
values array Allowed values
message string required
post-format callback none Takes the value as only parameter and returns the new value

The requires fields currently are: name and message

Core parameter types

Name PHP return type Description
string string Default type
Supported options:
  • length: int or false (overrides minlength and maxlength)
  • minlength: int or false
  • maxlength: int or false
  • regex: string
boolean boolean Accepts "yes", "no", "on", "off", "true" and "false"
float float Supported options:
  • lowerbound: int, float or false
  • upperbound: int, float or false
  • range: [lowerbound, upperbound]
  • withinrange: [float $point, float $deviation]
integer integer Supported options: same as for float
dimension string Value for a width or height attribute in HTML
Supported options:
  • allowauto: bool
  • maxpercentage: int
  • minpercentage: int
  • units: array of string
  • defaultunit: string
  • lowerbound: int, float or false
  • upperbound: int, float or false

Defining parameter types

  • string-parser Name of a class that implements the ValueParsers\ValueParser interface
  • validation-callback Callback that gets the raw value as only parameter and returns a boolean
  • validator Name of a class that implements the ValueValidators\ValueValidator interface

As an example, the Maps MediaWiki extension defines a coordinate parameter type that turns the input into a DataValues\LatLongValue value object.

Usage example

Defining parameters

$parameterDefinitions = [
    'username' => [
        'minlength' => 1,
        'maxlength' => 20
    'job' => [
        'default' => 'unknown',
        'values' => [ 'Developer', 'Designer', 'Peasant' ]
    'favourite-numbers' => [
        'type' => 'int',
        'islist' => true,
        'default' => []

Processing input using defined parameters

$processor = ParamProcessor\Processor::newDefault();

        'username' => 'Jeroen',
        'favourite-numbers' => '42, 1337, not a number',

foreach ($processor->processParameters()->getParameters() $parameter) {
    echo $parameter->getName();

// username: string(6) "Jeroen"
// job: string(7) "unknown"
// favourite-numbers: array(2) {[0]=>int(42), [1]=>int(1337)}

Alternative way to input parameters:

        'username = Jeroen',
        'favourite-numbers=42, 1337, not a number',



ParamProcessor has been written by Jeroen De Dauw to support the Maps and Semantic MediaWiki projects.

Release notes

1.12.0 (2021-05-04)

  • Allowed installation with PHP 8.x

1.11.0 (2021-03-18)

  • Allowed installation with new DataValue library versions

1.10.0 (2019-08-03)

  • Removed DimensionParam
  • Fixed bug in parsing of parameters of type dimension

1.9.0 (2019-08-03)

  • Added ParamDefinitionFactory::newDefinitionsFromArrays

1.8.0 (2019-08-03)

  • Removed ParamDefinitionFactory::getComponentForType
  • Added ParamDefinitionFactory constructor
  • Added ParameterTypes constructor
  • Added ParameterTypes::addType
  • Added ParameterTypes::newCoreTypes
  • Added ProcessingResult::getParameterArray

1.7.0 (2019-08-02)

  • Added ParameterTypes public constants: BOOLEAN, FLOAT, INTEGER, STRING, DIMENSION
  • Deprecated ParamDefinition::getCleanDefinitions in favour of ParamDefinitionFactory
  • Deprecated ParamDefinition::setDefault in favour of constructor parameter
  • Deprecated Processor::getParameterValues in favour of processParameters and ProcessingResult
  • Deprecated Processor::getErrors in favour of processParameters and ProcessingResult
  • Deprecated Processor::getErrorMessages in favour of processParameters and ProcessingResult
  • Deprecated Processor::hasErrors in favour of processParameters and ProcessingResult
  • Deprecated Processor::hasFatalError in favour of processParameters and ProcessingResult
  • Deprecated parameter dependencies
    • Deprecated ParamDefinition::hasDependency
    • Deprecated ParamDefinition::addDependencies
    • Deprecated ParamDefinition::getDependencies
    • Deprecated dependencies key in ParamDefinition::setArrayValues parameter
    • Deprecated TopologicalSort
    • Deprecated TSNode
  • Deprecated extending ParamDefinition
  • Deprecated StringParam
  • Deprecated DimensionParam
  • Deprecated ParamDefinition::setArrayValues
  • Deprecated ParamDefinition::$acceptOverriding
  • Deprecated ParamDefinition::$accumulateParameterErrors
  • Deprecated Param::$accumulateParameterErrors
  • Deprecated Settings
  • Deprecated Options::setRawStringInputs
  • Deprecated Options::isStringlyTyped

1.6.1 (2019-07-28)

  • Fixed message defaulting bug in ParamDefinition

1.6.0 (2019-07-28)

  • Added Processor::setParameterDefinitions
  • Deprecated second parameter of Processor::setParameters in favour of setParameterDefinitions
  • Deprecated second parameter of Processor::setFunctionParams in favour of setParameterDefinitions
  • Deprecated second parameter of ParamDefinitionFactory::newDefinitionFromArray
  • Deprecated return value of ParamDefinitionFactory::registerType
  • Deprecated ParamDefinitionFactory::registerGlobals
  • Deprecated typed-parser key in parameter type definitions

1.5.0 (2019-07-28)

  • Improved code comments and added extra type checks

1.4.2 (2018-11-26)

  • Fixed defaulting behaviour of list parameters

1.4.1 (2018-11-26)

  • List parameters are no longer set to their default when a single value is invalid

1.4.0 (2018-11-25)

  • Dropped support for PHP older than 7.1
  • Added ParameterTypes to allow gradual migration away from the now deprecated $wgParamDefinitions
  • Deprecated $wgParamDefinitions
  • Deprecated $egValidatorSettings

1.3.4 (2018-05-05)

  • Fixed deprecation notice occurring with PHP 7.2+

1.3.3 (2017-09-28)

  • Installation together with DataValues 2.x is now allowed
  • Installation together with DataValues Common 0.4.x is now allowed

1.3.2 (2017-03-26)

  • Fixed clearing of processing errors when making multiple processing calls to one Processor instance

1.3.1 (2016-09-21)

  • Fixed ParamDefinitionFactory emitting a warning when initialized without the global wgParamDefinitions being set

1.3.0 (2016-07-15)

  • Dropped support for PHP 5.3 and PHP 5.4.
  • Fixed bug in ParamDefinition::format

1.2.5 (2016-05-23)

  • Fixed bug in Processor::newProcessingResult

1.2.4 (2016-05-15)

  • Fixed bug in ParamDefinition::getAllowedValues

1.2.3 (2016-04-04)

  • Installation together with DataValues Interfaces 0.2.x is now allowed
  • Installation together with DataValues Common 0.3.x is now allowed
  • The component is now also tested against PHP 7

1.2.2 (2014-10-24)

  • Installation together with DataValues 1.x is now allowed.

1.2.0 (2014-09-12)

  • Dropped dependency on DataValues Geo.

1.1.0 (2014-05-07)

  • Dropped dependency on DataValues Time.
  • Use PSR-4 based loading rather than PSR-0 based loading.
  • Fixed Windows compatibility in PHPUnit bootstrap

1.0.2 (2013-12-16)

  • Removed dependency on data-values/number
  • Updated required version of data-values/common from ~0.1 to ~0.2.

1.0.1 (2013-11-29)

  • Implemented ProcessingResult::hasFatal
  • Added ProcessingResultTest

1.0.0 (2013-11-21)

First release as standalone PHP library.