def layer_is_empty(self, layer):
"""
Check if a vector layer is empty (not data)
:param layer: qdjango Layer model instance
:return: True or False
:rtype: boolean
"""
qgis_layer = get_qgis_layer(layer)
if qgis_layer.type() == QgsMapLayer.VectorLayer:
return not bool(count_qgis_features(qgis_layer))
else:
return False
def response_data_mode(self, request, export_features=False):
"""
Query layer and return data
:param request: DjangoREST API request object
:param formatter: Boolean, default False, True for to use QgsJsonExport.exportFeatures method
:return: response dict data
"""
# Create the QGIS feature request, it will be passed through filters
# and to the final QGIS API get features call.
qgis_feature_request = QgsFeatureRequest()
# Prepare arguments for the get feature call
kwargs = {}
# Apply filter backends, store original subset string
original_subset_string = self.metadata_layer.qgis_layer.subsetString()
if hasattr(self, 'filter_backends'):
for backend in self.filter_backends:
backend().apply_filter(request, self.metadata_layer.qgis_layer, qgis_feature_request, self)
# Paging cannot be a backend filter
if 'page' in request.query_params:
kwargs['page'] = request.query_params.get('page')
kwargs['page_size'] = request.query_params.get('page_size', 10)
self.features = get_qgis_features(
self.metadata_layer.qgis_layer, qgis_feature_request, **kwargs)
ex = QgsJsonExporter(self.metadata_layer.qgis_layer)
# If 'unique' request params is set,
# api return a list of unique
# field name sent with 'unique' param.
# --------------------------------------
# IDEA: for big data it'll be iterate over features to get unique
# c++ iteration is fast. Instead memory layer fith to much features can be a problem.
if 'unique' in request.query_params:
vl = QgsVectorLayer(QgsWkbTypes.displayString(self.metadata_layer.qgis_layer.wkbType()),
"temporary_vector", "memory")
pr = vl.dataProvider()
# add fields
pr.addAttributes(self.metadata_layer.qgis_layer.fields())
vl.updateFields() # tell the vector layer to fetch changes from the provider
res = pr.addFeatures(self.features)
uniques = vl.uniqueValues(
self.metadata_layer.qgis_layer.fields().indexOf(request.query_params.get('unique'))
)
values = []
for u in uniques:
try:
if u:
values.append(json.loads(QgsJsonUtils.encodeValue(u)))
except Exception as e:
logger.error(f'Response vector widget unique: {e}')
continue
self.results.update({
'data': values,
'count': len(values)
})
del(vl)
else:
# patch for return GeoJson feature with CRS different from WGS84
# TODO: use .setTransformGeometries( false ) with QGIS >= 3.12
ex.setSourceCrs(QgsCoordinateReferenceSystem('EPSG:4326'))
# check for formatter query url param and check if != 0
if 'formatter' in request.query_params:
formatter = request.query_params.get('formatter')
if formatter.isnumeric() and int(formatter) == 0:
export_features = False
else:
export_features = True
if export_features:
feature_collection = json.loads(ex.exportFeatures(self.features))
else:
# to exclude QgsFormater used into QgsJsonjExporter is necessary build by hand single json feature
ex.setIncludeAttributes(False)
feature_collection = {
'type': 'FeatureCollection',
'features': []
}
for feature in self.features:
fnames = [f.name() for f in feature.fields()]
feature_collection['features'].append(
json.loads(ex.exportFeature(feature, dict(zip(fnames, feature.attributes()))))
)
# FIXME: QGIS api reprojecting?
# Reproject if necessary
# if self.reproject:
# self.reproject_featurecollection(feature_collection)
# Change media
self.change_media(feature_collection)
self.results.update(APIVectorLayerStructure(**{
'data': feature_collection,
'count': count_qgis_features(self.metadata_layer.qgis_layer, qgis_feature_request, **kwargs),
'geometryType': self.metadata_layer.geometry_type,
}).as_dict())
# FIXME: add extra fields data by signals and receivers
# FIXME: featurecollection = post_serialize_maplayer.send(layer_serializer, layer=self.layer_name)
# FIXME: Not sure how to map this to the new QGIS API
# Restore the original subset string
self.metadata_layer.qgis_layer.setSubsetString(original_subset_string)
def response_data_mode(self, request, export_features=False):
"""
Query layer and return data
:param request: DjangoREST API request object
:param formatter: Boolean, default False, True for to use QgsJsonExport.exportFeatures method
:return: response dict data
"""
# Create the QGIS feature request, it will be passed through filters
# and to the final QGIS API get features call.
qgis_feature_request = QgsFeatureRequest()
# Prepare arguments for the get feature call
kwargs = {}
# Apply filter backends, store original subset string
original_subset_string = self.metadata_layer.qgis_layer.subsetString()
if hasattr(self, 'filter_backends'):
try:
for backend in self.filter_backends:
backend().apply_filter(request, self.metadata_layer,
qgis_feature_request, self)
except Exception as e:
raise APIException(e)
# Paging cannot be a backend filter
if 'page' in request.query_params:
kwargs['page'] = request.query_params.get('page')
kwargs['page_size'] = request.query_params.get('page_size', 10)
# Make sure we have all attrs we need to build the server FID
provider = self.metadata_layer.qgis_layer.dataProvider()
if qgis_feature_request.flags() & QgsFeatureRequest.SubsetOfAttributes:
attrs = qgis_feature_request.subsetOfAttributes()
for attr_idx in provider.pkAttributeIndexes():
if attr_idx not in attrs:
attrs.append(attr_idx)
qgis_feature_request.setSubsetOfAttributes(attrs)
self.features = get_qgis_features(self.metadata_layer.qgis_layer,
qgis_feature_request, **kwargs)
# Reproject feature if layer CRS != Project CRS
if self.reproject:
for f in self.features:
self.reproject_feature(f)
ex = QgsJsonExporter(self.metadata_layer.qgis_layer)
# If 'unique' request params is set,
# api return a list of unique
# field name sent with 'unique' param.
# --------------------------------------
# IDEA: for big data it'll be iterate over features to get unique
# c++ iteration is fast. Instead memory layer with too many features can be a problem.
if 'unique' in request.query_params:
vl = QgsVectorLayer(
QgsWkbTypes.displayString(
self.metadata_layer.qgis_layer.wkbType()),
"temporary_vector", "memory")
pr = vl.dataProvider()
# add fields
pr.addAttributes(self.metadata_layer.qgis_layer.fields())
vl.updateFields(
) # tell the vector layer to fetch changes from the provider
res = pr.addFeatures(self.features)
uniques = vl.uniqueValues(
self.metadata_layer.qgis_layer.fields().indexOf(
request.query_params.get('unique')))
values = []
for u in uniques:
try:
if u:
values.append(json.loads(QgsJsonUtils.encodeValue(u)))
except Exception as e:
logger.error(f'Response vector widget unique: {e}')
continue
# sort values
values.sort()
self.results.update({'data': values, 'count': len(values)})
del (vl)
else:
ex.setTransformGeometries(False)
# check for formatter query url param and check if != 0
if 'formatter' in request.query_params:
formatter = request.query_params.get('formatter')
if formatter.isnumeric() and int(formatter) == 0:
export_features = False
else:
export_features = True
if export_features:
feature_collection = json.loads(
ex.exportFeatures(self.features))
else:
# to exclude QgsFormater used into QgsJsonExporter is necessary build by hand single json feature
ex.setIncludeAttributes(False)
feature_collection = {
'type': 'FeatureCollection',
'features': []
}
for feature in self.features:
fnames = []
date_fields = []
for f in feature.fields():
fnames.append(f.name())
if f.typeName() in ('date', 'datetime', 'time'):
date_fields.append(f)
jsonfeature = json.loads(
ex.exportFeature(
feature, dict(zip(fnames, feature.attributes()))))
# Update date and datetime fields value if widget is active
if len(date_fields) > 0:
for f in date_fields:
field_idx = self.metadata_layer.qgis_layer.fields(
).indexFromName(f.name())
options = self.metadata_layer.qgis_layer.editorWidgetSetup(
field_idx).config()
if 'field_iso_format' in options and not options[
'field_iso_format']:
try:
jsonfeature['properties'][f.name()] = feature.attribute(f.name())\
.toString(options['field_format'])
except:
pass
feature_collection['features'].append(jsonfeature)
# Change media
self.change_media(feature_collection)
# Patch feature IDs with server featureIDs
fids_map = {}
for f in self.features:
fids_map[f.id()] = server_fid(f, provider)
for i in range(len(feature_collection['features'])):
f = feature_collection['features'][i]
f['id'] = fids_map[f['id']]
self.results.update(
APIVectorLayerStructure(
**{
'data':
feature_collection,
'count':
count_qgis_features(self.metadata_layer.qgis_layer,
qgis_feature_request, **kwargs),
'geometryType':
self.metadata_layer.geometry_type,
}).as_dict())
# FIXME: add extra fields data by signals and receivers
# FIXME: featurecollection = post_serialize_maplayer.send(layer_serializer, layer=self.layer_name)
# FIXME: Not sure how to map this to the new QGIS API
# Restore the original subset string
self.metadata_layer.qgis_layer.setSubsetString(original_subset_string)