Add limit & order for requests

lizmap_server/expression_service.py

@@ -782,6 +782,9 @@ def virtualFields(params: Dict[str, str], response: QgsServerResponse, project:
             FILTER=An expression to filter layer
             FIELDS=list of requested field separated by comma
             WITH_GEOMETRY=False
+            LIMIT=number of features to return or nothing to return all
+            SORTING_ORDER=asc or desc, default = asc
+            SORTING_FIELD=field name to sort by
         """
         logger = Logger()
         layer_name = params.get('LAYER', '')
@@ -865,6 +868,30 @@ def virtualFields(params: Dict[str, str], response: QgsServerResponse, project:
 
         req = QgsFeatureRequest()
 
+        # set limit
+        req_limit = params.get('LIMIT', '-1')
+        try:
+            req.setLimit(int(req_limit))
+        except ValueError:
+            raise ExpressionServiceError(
+                "Bad request error",
+                f"Invalid LIMIT for 'VirtualFields': \"{req_limit}\"",
+                400)
+
+        # set orderby
+        req_sorting_order_param = params.get('SORTING_ORDER', '')
+
+        if req_sorting_order_param in ('asc', 'desc'):
+            # QGIS expects a boolean to know how to sort
+            req_sorting_field = params.get('SORTING_FIELD', '')
+            order_by_clause = QgsFeatureRequest.OrderByClause(req_sorting_field, req_sorting_order_param == 'asc')
+            req.setOrderBy(QgsFeatureRequest.OrderBy([order_by_clause]))
+        elif req_sorting_order_param != '' :
+            raise ExpressionServiceError(
+                "Bad request error",
+                f"Invalid SORTING_ORDER for 'VirtualFields': \"{req_sorting_order_param}\"",
+                400)
+
         # get filter
         req_filter = params.get('FILTER', '')
         if req_filter:

test/test_expression_service_virtualfields.py

@@ -1,6 +1,7 @@
 import json
 
 from urllib.parse import quote
+from test.utils import _build_query_string, _check_request
 
 __copyright__ = 'Copyright 2019, 3Liz'
 __license__ = 'GPL version 3'
@@ -204,3 +205,88 @@ def test_request_with_filter_fields_geometry(client):
     assert b['features'][0]['properties']['a'] == 1
     assert 'b' in b['features'][0]['properties']
     assert b['features'][0]['properties']['b'] == 2
+
+def test_request_limit(client):
+    """  Test Expression VirtualFields request
+    """
+    projectfile = "france_parts.qgs"
+
+    # Make a request
+    qs = {
+        "SERVICE": "EXPRESSION",
+        "REQUEST": "VirtualFields",
+        "MAP": "france_parts.qgs",
+        "LAYER": "france_parts",
+        "VIRTUALS": "{\"a\":\"%s\", \"b\":\"%s\"}" % (
+        quote('1', safe=''), quote('1 + 1', safe='')),
+        "LIMIT": "2",
+    }
+
+    rv = client.get(_build_query_string(qs), projectfile)
+    b = _check_request(rv, http_code=200)
+
+    assert 'type' in b
+    assert b['type'] == 'FeatureCollection'
+
+    assert 'features' in b
+    assert len(b['features']) == 2
+
+    assert 'type' in b['features'][0]
+    assert b['features'][0]['type'] == 'Feature'
+
+    assert 'geometry' in b['features'][0]
+    assert b['features'][0]['geometry'] is None
+
+    assert 'properties' in b['features'][0]
+    assert 'NAME_1' in b['features'][0]['properties']
+    assert 'Region' in b['features'][0]['properties']
+
+    assert 'a' in b['features'][0]['properties']
+    assert b['features'][0]['properties']['a'] == 1
+    assert 'b' in b['features'][0]['properties']
+    assert b['features'][0]['properties']['b'] == 2
+
+
+def test_request_order(client):
+    """  Test Expression VirtualFields request
+    """
+    projectfile = "france_parts.qgs"
+
+    # Make a request
+    qs = {
+        "SERVICE": "EXPRESSION",
+        "REQUEST": "VirtualFields",
+        "MAP": "france_parts.qgs",
+        "LAYER": "france_parts",
+        "VIRTUALS": "{\"a\":\"%s\", \"b\":\"%s\"}" % (
+        quote('1', safe=''), quote('1 + 1', safe='')),
+        "SORTING_ORDER": "desc",
+        "SORTING_FIELD": "NAME_1",
+    }
+
+    rv = client.get(_build_query_string(qs), projectfile)
+    b = _check_request(rv, http_code=200)
+
+    assert 'type' in b
+    assert b['type'] == 'FeatureCollection'
+
+    assert 'features' in b
+    assert len(b['features']) == 4
+
+    assert 'type' in b['features'][0]
+    assert b['features'][0]['type'] == 'Feature'
+
+    assert 'geometry' in b['features'][0]
+    assert b['features'][0]['geometry'] is None
+
+    assert 'properties' in b['features'][0]
+    assert 'NAME_1' in b['features'][0]['properties']
+    assert 'Region' in b['features'][0]['properties']
+
+    assert 'a' in b['features'][0]['properties']
+    assert b['features'][0]['properties']['a'] == 1
+    assert 'b' in b['features'][0]['properties']
+    assert b['features'][0]['properties']['b'] == 2
+
+    assert b['features'][0]['id'] == 'france_parts.2'
+    assert b['features'][3]['id'] == 'france_parts.0'