processing extended

_static/scripts/processing_buffer.py

@@ -1,9 +1,13 @@
 from qgis import processing
 
+output = '/tmp/pozarni_stanice_10km.shp'
 processing.run("native:buffer", {
     'INPUT': '/home/martin/geodata/gismentors/qgis-data/shp/osm/pozarni_stanice.shp',
     'DISTANCE': 10000,
     'SEGMENTS': 10,
     'DISSOLVE': True,
-    'OUTPUT': '/tmp/pozarni_stanice_10km.shp'
+    'OUTPUT': output
 })
+
+layer = QgsVectorLayer(output, os.path.basename(output), 'ogr')
+QgsProject.instance().addMapLayer(layer)

_static/scripts/processing_search.py

@@ -1,6 +1,9 @@
 from qgis import processing
 
 for alg in QgsApplication.processingRegistry().algorithms():
-    name = alg.displayName()
-    if 'buffer' in name:
-        print(alg.id(), "->", name)
+    if 'buffer' in alg.id():
+        print(alg.id(), "->", alg.displayName())
+
+    if alg.id() == 'native:buffer':
+        for p in alg.parameterDefinitions():
+            print(p.name(), p.description())

python/processing.rst

@@ -8,19 +8,36 @@ for details.
 
 QGIS processing is available in Python through ``processing``
 module. On line :lcode:`3` we will loop over all available
-algorithms. By a simple condition on line :lcode:`5` only tools
+algorithms. By a simple condition on line :lcode:`4` only tools
 containing a word "buffer" in the name will be printed out.
 
 .. literalinclude:: ../_static/scripts/processing_search.py
    :language: python
    :linenos:
-   :emphasize-lines: 1, 3, 5
+   :lines: 1-5
+   :emphasize-lines: 1, 3, 4
 
+List parameters for selected algorithm:
+
+.. literalinclude:: ../_static/scripts/processing_search.py
+   :language: python
+   :linenos:
+   :lines: 7-9
+   :emphasize-lines: 2
+
 Let's select `native:buffer
 <https://docs.qgis.org/3.28/en/docs/user_manual/processing_algs/qgis/vectorgeometry.html#qgisbuffer>`__
 tool and execute it by Python code.
 
 .. literalinclude:: ../_static/scripts/processing_buffer.py
    :language: python
+   :lines: 1-10
    :linenos:
-   :emphasize-lines: 3
+   :emphasize-lines: 4
+
+Newly created layer can be added into layer tree (see next section for :doc:`pyqgis_intro`):
+
+.. literalinclude:: ../_static/scripts/processing_buffer.py
+   :language: python
+   :lines: 12-13
+   :linenos: