Python expressions support

qgis_resource_sharing/resource_handler/__init__.py

@@ -5,6 +5,7 @@
 from .expression_handler import ExpressionHandler  # noqa: F401
 from .model_handler import ModelHandler  # noqa: F401
 from .processing_handler import ProcessingScriptHandler  # noqa: F401
+from .python_expressions_handler import PythonExpressionsHandler  # noqa: F401
 from .r_handler import RScriptHandler  # noqa: F401
 from .style_handler import StyleResourceHandler  # noqa: F401
 from .svg_handler import SVGResourceHandler  # noqa: F401

qgis_resource_sharing/resource_handler/python_expressions_handler.py

@@ -0,0 +1,93 @@
+import logging
+import shutil
+from pathlib import Path
+
+from processing.tools.system import mkdir, userFolder
+
+from qgis_resource_sharing.resource_handler.base import BaseResourceHandler
+
+PYTHON_EXPRESSIONS_FOLDER = "python/expressions"
+PYTHON_EXPRESSIONS = (
+    "python_expressions"  # Resource Sharing collection subdirectory name
+)
+LOGGER = logging.getLogger("QGIS Resource Sharing")
+
+
+class PythonExpressionsHandler(BaseResourceHandler):
+    """Handler for python expressions."""
+
+    IS_DISABLED = False
+
+    def __init__(self, collection_id):
+        """Constructor of the base class."""
+        BaseResourceHandler.__init__(self, collection_id)
+        LOGGER.info("Python Expressions")
+
+    @classmethod
+    def dir_name(cls):
+        LOGGER.info(f"Expressions folder")
+        return PYTHON_EXPRESSIONS
+
+    def install(self):
+        """Install the models from the collection.
+
+        Copy the python expressions (*.py) in the directory of the
+        Resource Sharing collection to the user's python expressions directory.
+        """
+        # Return silently if the directory does not exist
+        if not Path(self.resource_dir).exists():
+            return
+
+        # Handle the python expressions files located in self.resource_dir
+        python_expression_files = []
+        for item in Path(self.resource_dir).glob("*.py"):
+            file_path = Path(self.resource_dir, item)
+            python_expression_files.append(file_path)
+        valid = 0
+        for python_expression_file in python_expression_files:
+            LOGGER.info(
+                f"Processing installing files {python_expression_file.as_posix()}"
+            )
+            # Install the python expression file silently
+            try:
+                shutil.copy(python_expression_file, self.python_expressions_folder())
+                valid += 1
+            except OSError as e:
+                LOGGER.error(
+                    "Could not copy python expression '"
+                    + str(python_expression_file)
+                    + "':\n"
+                    + str(e)
+                )
+        if valid > 0:
+            self.refresh_python_expressions_provider()
+        self.collection[PYTHON_EXPRESSIONS] = valid
+
+    def uninstall(self):
+        """Uninstall the collection's models from the processing toolbox."""
+        if not Path(self.resource_dir).exists():
+            return
+        # Remove the model files that are present in this collection
+        for item in Path(self.resource_dir).glob("*.py"):
+            python_expression_path = Path(self.python_expressions_folder(), item.name)
+            if python_expression_path.exists():
+                python_expression_path.unlink()
+        self.refresh_python_expressions_provider()
+
+    def refresh_python_expressions_provider(self):
+        # for item in Path(self.resource_dir).glob("*.py"):
+        #     python_expression_path = Path(self.python_expressions_folder(), item.name)
+        #     with open(python_expression_path) as file:
+        #         eval(file.read())
+        pass
+
+    def default_python_expressions_folder(self):
+        """Return the default location of the processing models folder."""
+        folder = Path(userFolder(), "..", PYTHON_EXPRESSIONS_FOLDER)
+        mkdir(str(folder))
+        return str(folder)
+
+    def python_expressions_folder(self):
+        """Return the folder where processing expects to find models."""
+        # Use the default location
+        return self.default_python_expressions_folder()

qgis_resource_sharing/utilities.py

@@ -21,6 +21,7 @@
     "models": "Processing model",
     "rscripts": "R script",
     "checklists": "Dataset QA Workbench checklist",
+    "python_expressions": "Python Expressions",
 }