Class: QgsProjectBadLayerHandler

Interface for classes that handle missing layer files when reading project files.

Class Hierarchy

Subclasses

QgsStoreBadLayerInfo

Stores layer IDs for bad (broken) layers.

Methods

dataSource	Returns the data source for the given layer
dataType	Returns data type associated with the given QgsProject file Dom node
providerType	Returns the physical storage type associated with the given layer
setDataSource	Set the datasource element to the new value

Virtual Methods

In PyQGIS, only methods marked as virtual can be safely overridden in a Python subclass of QgsProjectBadLayerHandler. See the FAQ for more details.

handleBadLayers

This method will be called whenever the project tries to load layers which cannot be accessed.

Attributes

IS_BOGUS
IS_DATABASE
IS_FILE
IS_RASTER
IS_URL
IS_Unknown
IS_VECTOR

class qgis.core.QgsProjectBadLayerHandler

Bases: object

class DataType

Bases: int

IS_BOGUS = 2

IS_DATABASE = 1

IS_FILE = 0

IS_RASTER = 1

IS_URL = 2

IS_Unknown = 3

IS_VECTOR = 0

class ProviderType

Bases: int

dataSource(self, layerNode: QDomNode) → str

Returns the data source for the given layer

The QDomNode is a QgsProject Dom node corresponding to a map layer state.

Essentially dumps datasource tag.

Parameters:

layerNode (QDomNode)

Return type:

str

dataType(self, layerNode: QDomNode) → QgsProjectBadLayerHandler.DataType

Returns data type associated with the given QgsProject file Dom node

The Dom node should represent the state associated with a specific layer.

Parameters:

layerNode (QDomNode)

Return type:

QgsProjectBadLayerHandler.DataType

virtual handleBadLayers(self, layers: Iterable[QDomNode])

This method will be called whenever the project tries to load layers which cannot be accessed. It should inform the user about this and if possible offer to fix the unavailable layers by setting a valid datasource, e.g. by showing a file dialog.

The default implementation will dismiss all bad layers and write information to the log.

Parameters:

layers (Iterable[QDomNode])

providerType(self, layerNode: QDomNode) → QgsProjectBadLayerHandler.ProviderType

Returns the physical storage type associated with the given layer

The QDomNode is a QgsProject Dom node corresponding to a map layer state.

If the provider tag is “ogr”, then it’s a file type.

However, if the layer is a raster, then there won’t be a provider tag. It will always have an associated file.

If the layer doesn’t fall into either of the previous two categories, then it’s either a database or URL. If the datasource tag has “url=”, then it’s URL based and if it has “dbname=”>, then the layer data is in a database.

Parameters:

layerNode (QDomNode)

Return type:

QgsProjectBadLayerHandler.ProviderType

setDataSource(self, layerNode: QDomNode, dataSource: str | None)

Set the datasource element to the new value

Parameters:

• layerNode (QDomNode)

• dataSource (Optional[str])