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133 lines
4.4 KiB
Python
133 lines
4.4 KiB
Python
"""
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***************************************************************************
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user.py
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---------------------
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Date : January 2015
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Copyright : (C) 2015 by Nathan Woodrow
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Email : woodrow dot nathan at gmail dot com
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***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************
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"""
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__author__ = "Nathan Woodrow"
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__date__ = "January 2015"
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__copyright__ = "(C) 2015, Nathan Woodrow"
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import os
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import sys
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import glob
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import traceback
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from qgis.PyQt.QtCore import QCoreApplication, qDebug
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from qgis.core import Qgis, QgsApplication, QgsMessageLog
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def load_user_expressions(path):
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"""
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Load all user expressions from the given paths
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"""
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# Loop all py files and import them
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modules = glob.glob(path + "/*.py")
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names = [os.path.basename(f)[:-3] for f in modules]
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for name in names:
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if name == "__init__":
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continue
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# As user expression functions should be registered with qgsfunction
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# just importing the file is enough to get it to load the functions into QGIS
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try:
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__import__(f"expressions.{name}", locals(), globals())
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except:
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error = traceback.format_exc()
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msgtitle = QCoreApplication.translate("UserExpressions", "User expressions")
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msg = QCoreApplication.translate(
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"UserExpressions", "The user expression {0} is not valid"
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).format(name)
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QgsMessageLog.logMessage(
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msg + "\n" + error, msgtitle, Qgis.MessageLevel.Warning
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)
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def reload_user_expressions(path):
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"""
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Reload all user expressions from the given path
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"""
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# First unload expression modules, looping all
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# py files and remove them from sys.modules
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modules = glob.glob(path + "/*.py")
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names = [os.path.basename(f)[:-3] for f in modules]
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for name in names:
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if name == "__init__":
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continue
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mod = f"expressions.{name}"
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if mod not in sys.modules:
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continue
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# try removing path
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if hasattr(sys.modules[mod], "__path__"):
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for path in sys.modules[mod].__path__:
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try:
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sys.path.remove(path)
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except ValueError:
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# Discard if path is not there
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pass
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# try to remove the module from python
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try:
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del sys.modules[mod]
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except:
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qDebug("Error when removing module:\n%s" % traceback.format_exc())
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# Finally, load again the users expressions from the given path
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load_user_expressions(path)
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userpythonhome = os.path.join(QgsApplication.qgisSettingsDirPath(), "python")
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expressionspath = os.path.join(userpythonhome, "expressions")
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sys.path.append(userpythonhome)
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if not os.path.exists(expressionspath):
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os.makedirs(expressionspath)
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initfile = os.path.join(expressionspath, "__init__.py")
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if not os.path.exists(initfile):
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open(initfile, "w").close()
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template = """from qgis.core import *
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from qgis.gui import *
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@qgsfunction(group='Custom', referenced_columns=[])
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def my_sum(value1, value2):
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\"\"\"
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Calculates the sum of the two parameters value1 and value2.
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<h2>Example usage:</h2>
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<ul>
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<li>my_sum(5, 8) -> 13</li>
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<li>my_sum(\"field1\", \"field2\") -> 42</li>
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</ul>
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\"\"\"
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return value1 + value2
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"""
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default_expression_template = template
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try:
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import expressions
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expressions.load = load_user_expressions
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expressions.load(expressionspath)
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expressions.template = template
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expressions.reload = reload_user_expressions
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except ImportError:
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# We get a import error and crash for some reason even if we make the expressions package
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# TODO Fix the crash on first load with no expressions folder
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# But for now it's not the end of the world if it doesn't load the first time
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pass
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