[BUGFIX][QGIS Server] GetLegendGraphic: if LAYERTITLE is false disable layer name in legend

If the layer has only one legend node, it is embedded in parent.
In QGIS Server the user can specify no layer title, so the layer title has not be displayed.

src/server/qgswmsserver.cpp

@@ -943,6 +943,14 @@ QImage* QgsWmsServer::getLegendGraphics()
           legendNode->setUserLabel( " " ); // empty string = no override, so let's use one space
         }
       }
+      else if ( !mDrawLegendLayerLabel )
+      {
+        Q_FOREACH ( QgsLayerTreeModelLegendNode* legendNode, legendModel.layerLegendNodes( nodeLayer ) )
+        {
+          if ( legendNode->isEmbeddedInParent() )
+            legendNode->setEmbeddedInParent( false );
+        }
+      }
     }
   }
 

tests/src/python/test_qgsserver.py

@@ -21,10 +21,13 @@ import urllib.error
 import email
 from io import StringIO
 from qgis.server import QgsServer
-from qgis.core import QgsMessageLog, QgsApplication
+from qgis.core import QgsMessageLog, QgsRenderChecker, QgsApplication
 from qgis.testing import unittest
+from qgis.PyQt.QtCore import QSize
 from utilities import unitTestDataPath
 import osgeo.gdal
+import tempfile
+import base64
 
 # Strip path and content length because path may vary
 RE_STRIP_UNCHECKABLE = b'MAP=[^"]+|Content-Length: \d+'
@@ -431,6 +434,81 @@ class TestQgsServer(unittest.TestCase):
         self.assertEqual(-1, h.find(b'Content-Type: text/xml; charset=utf-8'), "Header: %s\nResponse:\n%s" % (h, r))
         self.assertNotEqual(-1, h.find(b'Content-Type: image/png'), "Header: %s\nResponse:\n%s" % (h, r))
 
+    def test_getLegendGraphics_layertitle(self):
+        """Test that does not return an exception but an image"""
+        parms = {
+            'MAP': self.testdata_path + "test_project.qgs",
+            'SERVICE': 'WMS',
+            'VERSION': '1.3.0',
+            'REQUEST': 'GetLegendGraphic',
+            'FORMAT': 'image/png',
+            #'WIDTH': '20', # optional
+            #'HEIGHT': '20', # optional
+            'LAYER': u'testlayer%20èé',
+            'LAYERTITLE': 'TRUE',
+        }
+        qs = '&'.join([u"%s=%s" % (k, v) for k, v in parms.items()])
+        r, h = self._result(self.server.handleRequest(qs))
+        self._img_diff_error(r, h, "WMS_GetLegendGraphic_test", 250, QSize(10, 10))
+
+        parms = {
+            'MAP': self.testdata_path + "test_project.qgs",
+            'SERVICE': 'WMS',
+            'VERSION': '1.3.0',
+            'REQUEST': 'GetLegendGraphic',
+            'FORMAT': 'image/png',
+            #'WIDTH': '20', # optional
+            #'HEIGHT': '20', # optional
+            'LAYER': u'testlayer%20èé',
+            'LAYERTITLE': 'FALSE',
+        }
+        qs = '&'.join([u"%s=%s" % (k, v) for k, v in parms.items()])
+        r, h = self._result(self.server.handleRequest(qs))
+        self._img_diff_error(r, h, "WMS_GetLegendGraphic_test_layertitle_false", 250, QSize(10, 10))
+
+    def _result(self, data):
+        headers = {}
+        for line in data[0].decode('UTF-8').split("\n"):
+            if line != "":
+                header = line.split(":")
+                self.assertEqual(len(header), 2, line)
+                headers[str(header[0])] = str(header[1]).strip()
+
+        return data[1], headers
+
+    def _img_diff(self, image, control_image, max_diff, max_size_diff=QSize()):
+        temp_image = os.path.join(tempfile.gettempdir(), "%s_result.png" % control_image)
+
+        with open(temp_image, "wb") as f:
+            f.write(image)
+
+        control = QgsRenderChecker()
+        control.setControlPathPrefix("qgis_server")
+        control.setControlName(control_image)
+        control.setRenderedImage(temp_image)
+        if max_size_diff.isValid():
+            control.setSizeTolerance(max_size_diff.width(), max_size_diff.height())
+        return control.compareImages(control_image), control.report()
+
+    def _img_diff_error(self, response, headers, image, max_diff=10, max_size_diff=QSize()):
+        self.assertEqual(
+            headers.get("Content-Type"), "image/png",
+            "Content type is wrong: %s" % headers.get("Content-Type"))
+        test, report = self._img_diff(response, image, max_diff, max_size_diff)
+
+        with open(os.path.join(tempfile.gettempdir(), image + "_result.png"), "rb") as rendered_file:
+            encoded_rendered_file = base64.b64encode(rendered_file.read())
+            message = "Image is wrong\n%s\nImage:\necho '%s' | base64 -d >%s/%s_result.png" % (
+                report, encoded_rendered_file.strip(), tempfile.gettempdir(), image
+            )
+
+        with open(os.path.join(tempfile.gettempdir(), image + "_result_diff.png"), "rb") as diff_file:
+            encoded_diff_file = base64.b64encode(diff_file.read())
+            message += "\nDiff:\necho '%s' | base64 -d > %s/%s_result_diff.png" % (
+                encoded_diff_file.strip(), tempfile.gettempdir(), image
+            )
+
+        self.assertTrue(test, message)
 
 if __name__ == '__main__':
     unittest.main()