urlencode query in subscription payloads

Author: fbattello

README.md

@@ -251,6 +251,33 @@ client.count("ParkingSpot", q='refParkingSite=="urn:ngsi-ld:OffStreetParking:por
 client.close()
 ```
 
+### Let's go further
+
+1. Develop a NGSI-LD Agent
+
+    - Collect incoming data from parking IoT *(ground sensors, cameras)* and the parking system API
+    - Clean data, process data and convert to NGSI-LD entities
+    - Create or update entities into the NGSI-LD broker
+
+2. Subscribe to events
+
+    - Create a subscription to be informed when parking occupation exceeds 90%
+    - The software that listens to these highly-occupied parking entities can also be a NGSI-LD Agent
+
+    <br>Example : programatically subscribe to events
+
+    ```python
+    from ngsildclient import SubscriptionBuilder
+
+    subscr = SubscriptionBuilder("https://parkingsystem.example.com:8000/subscription/high-occupancy")
+        .description("Notify me of high occupancy on parking porto-23889")
+        .select_type("OffStreetParking")
+        .watch(["occupancy"])
+        .query('occupancy>0.9;controlledAsset=="urn:ngsi-ld:OffStreetParking:porto-ParkingLot-23889"')
+        .build()
+    client.subscriptions.create(subscr)
+    ```
+
 ## Where to get it
 
 The source code is currently hosted on GitHub at :

src/ngsildclient/api/helper/subscription.py

@@ -10,7 +10,9 @@
 # Author: Fabien BATTELLO <fabien.battello@orange.com> et al.
 
 from dataclasses import dataclass
-from ...model.constants import CORE_CONTEXT
+
+import ngsildclient.utils.url as url
+from ngsildclient.model.constants import CORE_CONTEXT
 
 
 @dataclass
@@ -126,7 +128,7 @@ def watch(self, value: list[str]):
     def query(self, value: str):
         if not isinstance(value, str):
             raise ValueError("query shall be a string")
-        self._subscr.query = value
+        self._subscr.query = url.escape(value)
         return self
 
     def notif(self, value: list[str]):

tests/test_helper_subscription.py

@@ -20,7 +20,7 @@ def test_build_subscription():
         .description("Notify me of low feedstock on Farm:001")
         .select_type("FillingLevelSensor")
         .watch(["filling"])
-        .query("filling>0.4;filling<0.6;controlledAsset==urn:ngsi-ld:Building:farm001")
+        .query('filling>0.4;filling<0.6;controlledAsset=="urn:ngsi-ld:Building:farm001"')
         .notif(["filling", "controlledAsset"])
     )
     subscription = builder.build()
@@ -29,7 +29,7 @@ def test_build_subscription():
         "description": "Notify me of low feedstock on Farm:001",
         "entities": [{"type": "FillingLevelSensor"}],
         "watchedAttributes": ["filling"],
-        "q": "filling>0.4;filling<0.6;controlledAsset==urn:ngsi-ld:Building:farm001",
+        "q": "filling%3E0.4%3Bfilling%3C0.6%3BcontrolledAsset%3D%3D%22urn%3Angsi-ld%3ABuilding%3Afarm001%22",
         "isActive": True,
         "notification": {
             "attributes": ["filling", "controlledAsset"],