Add new qgisapp Python context manager for creating QGIS apps

qgis · May 20, 2014 · 19e727e · 19e727e
1 parent 938f288
commit 19e727e
Showing 1 changed file with 41 additions and 0 deletions.
diff --git a/python/core/contextmanagers.py b/python/core/contextmanagers.py
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+import sys
+from contextlib import contextmanager
+from qgis.core import QgsApplication
+
+
+@contextmanager
+def qgisapp(args=None, guienabled=True, configpath=None, sysexit=True):
+    """
+    Create a new QGIS Qt application.  
+    
+    You should use this before creating any Qt widgets or QGIS objects for
+    your custom QGIS based application.
+       
+    usage:
+        from qgis.core.contextmanagers import qgisapp
+
+        def main(app):
+            # Run your main code block
+
+	    with qgisapp(sys.argv) as app:
+		    main(app)
+
+
+    args - args passed to the underlying QApplication.
+    guienabled - True by default will create a QApplication with a GUI. Pass
+                 False if you wish to create no GUI based app, e.g a server app.
+    configpath - Custom config path QGIS will use to load settings.
+    sysexit - Call sys.exit on app exit. True by default.
+    """
+    if not args:
+        args = []
+    app = QgsApplication(args, guienabled, configpath)
+    QgsApplication.initQgis()
+    yield app
+    if guienabled:
+        exitcode = app.exec_()
+    else:
+        exitcode = 0
+    QgsApplication.exitQgis()
+    if sysexit:
+        sys.exit(exitcode)