Class: QgsProcessingRegistry

Registry for various processing components, including providers, algorithms and various parameters and outputs.

QgsProcessingRegistry is not usually directly created, but rather accessed through QgsApplication.processingRegistry().

Class Hierarchy

Base classes

QObject

class qgis.core.QgsProcessingRegistry

Bases: QObject

__init__(parent: QObject | None = None)

Constructor for QgsProcessingRegistry.

Parameters:

parent (Optional[QObject] = None)

addAlgorithmAlias(self, aliasId: str | None, actualId: str | None)

Adds a new alias to an existing algorithm.

This allows algorithms to be referred to by a different provider ID and algorithm name to their actual underlying provider and algorithm name. It provides a mechanism to allow algorithms to be moved between providers without breaking existing scripts or plugins.

The aliasId argument specifies the “fake” algorithm id (eg “fake_provider:fake_alg”) by which the algorithm can be referred to, and the actualId argument specifies the real algorithm ID for the algorithm.

Added in version 3.10.

Parameters:

• aliasId (Optional[str])

• actualId (Optional[str])

addParameterType(self, type: QgsProcessingParameterType | None) → bool

Register a new parameter type for processing. Ownership is transferred to the registry. Will emit parameterTypeAdded.

See also

removeParameterType()

Added in version 3.2.

Parameters:

type (Optional[QgsProcessingParameterType])

Return type:

bool

addProvider(self, provider: QgsProcessingProvider | None) → bool

Add a processing provider to the registry. Ownership of the provider is transferred to the registry, and the provider’s parent will be set to the registry. Returns False if the provider could not be added (eg if a provider with a duplicate ID already exists in the registry). Adding a provider to the registry automatically triggers the providers QgsProcessingProvider.load() method to populate the provider with algorithms.

See also

removeProvider()

Parameters:

provider (Optional[QgsProcessingProvider])

Return type:

bool

algorithmById(self, id: str | None) → QgsProcessingAlgorithm | None

Finds an algorithm by its ID. If no matching algorithm is found, None is returned.

See also

algorithms()

See also

createAlgorithmById()

Parameters:

id (Optional[str])

Return type:

Optional[QgsProcessingAlgorithm]

algorithmInformation(self, id: str | None) → QgsProcessingAlgorithmInformation

Returns basic algorithm information for the algorithm with matching ID.

This method uses an internal cache to ensure that information is quickly returned and is suitable for calling many times.

Added in version 3.32.

Parameters:

id (Optional[str])

Return type:

QgsProcessingAlgorithmInformation

algorithms(self) → List[QgsProcessingAlgorithm]

Returns a list of all available algorithms from registered providers.

See also

algorithmById()

Return type:

List[QgsProcessingAlgorithm]

createAlgorithmById(self, id: str | None, configuration: Dict[str, Any] = {}) → QgsProcessingAlgorithm | None

Creates a new instance of an algorithm by its ID. If no matching algorithm is found, None is returned. Callers take responsibility for deleting the returned object.

The configuration argument allows passing of a map of configuration settings to the algorithm, allowing it to dynamically adjust its initialized parameters and outputs according to this configuration. This is generally used only for algorithms in a model, allowing them to adjust their behavior at run time according to some user configuration.

See also

algorithms()

See also

algorithmById()

Parameters:

• id (Optional[str])

• configuration (Dict[str, Any] = {})

Return type:

Optional[QgsProcessingAlgorithm]

parameterType(self, id: str | None) → QgsProcessingParameterType | None

Returns the parameter type registered for id.

Added in version 3.2.

Parameters:

id (Optional[str])

Return type:

Optional[QgsProcessingParameterType]

signal parameterTypeAdded

pyqtSignal(*types, name: str = …, revision: int = …, arguments: Sequence = …) -> PYQT_SIGNAL

types is normally a sequence of individual types. Each type is either a type object or a string that is the name of a C++ type. Alternatively each type could itself be a sequence of types each describing a different overloaded signal. name is the optional C++ name of the signal. If it is not specified then the name of the class attribute that is bound to the signal is used. revision is the optional revision of the signal that is exported to QML. If it is not specified then 0 is used. arguments is the optional sequence of the names of the signal’s arguments.

signal parameterTypeRemoved

pyqtSignal(*types, name: str = …, revision: int = …, arguments: Sequence = …) -> PYQT_SIGNAL

types is normally a sequence of individual types. Each type is either a type object or a string that is the name of a C++ type. Alternatively each type could itself be a sequence of types each describing a different overloaded signal. name is the optional C++ name of the signal. If it is not specified then the name of the class attribute that is bound to the signal is used. revision is the optional revision of the signal that is exported to QML. If it is not specified then 0 is used. arguments is the optional sequence of the names of the signal’s arguments.

parameterTypes(self) → List[QgsProcessingParameterType]

Returns a list with all known parameter types.

Added in version 3.2.

Return type:

List[QgsProcessingParameterType]

signal providerAdded

pyqtSignal(*types, name: str = …, revision: int = …, arguments: Sequence = …) -> PYQT_SIGNAL

types is normally a sequence of individual types. Each type is either a type object or a string that is the name of a C++ type. Alternatively each type could itself be a sequence of types each describing a different overloaded signal. name is the optional C++ name of the signal. If it is not specified then the name of the class attribute that is bound to the signal is used. revision is the optional revision of the signal that is exported to QML. If it is not specified then 0 is used. arguments is the optional sequence of the names of the signal’s arguments.

providerById(self, id: str | None) → QgsProcessingProvider | None

Returns a matching provider by provider ID.

Parameters:

id (Optional[str])

Return type:

Optional[QgsProcessingProvider]

signal providerRemoved

pyqtSignal(*types, name: str = …, revision: int = …, arguments: Sequence = …) -> PYQT_SIGNAL

types is normally a sequence of individual types. Each type is either a type object or a string that is the name of a C++ type. Alternatively each type could itself be a sequence of types each describing a different overloaded signal. name is the optional C++ name of the signal. If it is not specified then the name of the class attribute that is bound to the signal is used. revision is the optional revision of the signal that is exported to QML. If it is not specified then 0 is used. arguments is the optional sequence of the names of the signal’s arguments.

providers(self) → List[QgsProcessingProvider]

Gets list of available providers.

Return type:

List[QgsProcessingProvider]

removeParameterType(self, type: QgsProcessingParameterType | None)

Unregister a custom parameter type from processing. The type will be deleted. Will emit parameterTypeRemoved.

See also

addParameterType()

Added in version 3.2.

Parameters:

type (Optional[QgsProcessingParameterType])

removeProvider(self, provider: QgsProcessingProvider | None) → bool

Removes a provider implementation from the registry (the provider object is deleted). Returns False if the provider could not be removed (eg provider does not exist in the registry).

See also

addProvider()

removeProvider(self, providerId: Optional[str]) -> bool Removes a provider implementation from the registry (the provider object is deleted). Returns False if the provider could not be removed (eg provider does not exist in the registry).

See also

addProvider()

Parameters:

provider (Optional[QgsProcessingProvider])

Return type:

bool