fix(mhz19): gestion d'erreurs JSON pour le capteur CO2

Le script get_data.py retourne maintenant toujours du JSON, meme en cas
d'erreur (port serie, absence de donnees). Cote web, les erreurs sont
affichees proprement dans la carte capteur.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

MH-Z19/get_data.py

@@ -12,47 +12,42 @@ import time
 parameter = sys.argv[1:]
 port = '/dev/' + parameter[0]
 
-ser = serial.Serial(
+
+def read_co2():
+    try:
+        ser = serial.Serial(
             port=port,
             baudrate=9600,
             parity=serial.PARITY_NONE,
             stopbits=serial.STOPBITS_ONE,
             bytesize=serial.EIGHTBITS,
             timeout=1
-)
+        )
+    except serial.SerialException as e:
+        print(json.dumps({"error": f"Serial port error: {e}"}))
+        return
 
-READ_CO2_COMMAND = b'\xFF\x01\x86\x00\x00\x00\x00\x00\x79'
+    READ_CO2_COMMAND = b'\xFF\x01\x86\x00\x00\x00\x00\x00\x79'
 
-
-def read_co2():
+    try:
         ser.write(READ_CO2_COMMAND)
         time.sleep(2)
         response = ser.read(9)
+
         if len(response) < 9:
-        print("Error: No data or incomplete data received.")
-        return None
+            print(json.dumps({"error": "No data or incomplete data received from sensor"}))
+            return
+
         if response[0] == 0xFF:
             co2_concentration = response[2] * 256 + response[3]
-        return co2_concentration
+            print(json.dumps({"CO2": co2_concentration}))
         else:
-        print("Error reading data from sensor.")
-        return None
-
-
-def main():
-    try:
-        co2 = read_co2()
-        if co2 is not None:
-            data = {"CO2": co2}
-            json_data = json.dumps(data)
-            print(json_data)
-        else:
-            print("Failed to get CO2 data.")
-    except KeyboardInterrupt:
-        print("Program terminated.")
+            print(json.dumps({"error": "Invalid response from sensor"}))
+    except Exception as e:
+        print(json.dumps({"error": str(e)}))
     finally:
         ser.close()
 
 
 if __name__ == '__main__':
-    main()
+    read_co2()

html/sensors.html

@@ -299,7 +299,15 @@ function getMHZ19_values(){
                         tableBody.innerHTML = "";
                         $("#loading_mhz19").hide();
 
-                        if (response.CO2 !== undefined) {
+                        if (response.error) {
+                            $("#data-table-body_mhz19").append(`
+                                <tr>
+                                    <td colspan="2" class="text-danger">
+                                        ⚠ ${response.error}
+                                    </td>
+                                </tr>
+                            `);
+                        } else if (response.CO2 !== undefined) {
                             $("#data-table-body_mhz19").append(`
                                 <tr>
                                     <td>CO2</td>
@@ -311,6 +319,14 @@ function getMHZ19_values(){
                     error: function(xhr, status, error) {
                         console.error('AJAX request failed:', status, error);
                         $("#loading_mhz19").hide();
+                        const tableBody = document.getElementById("data-table-body_mhz19");
+                        tableBody.innerHTML = `
+                            <tr>
+                                <td colspan="2" class="text-danger">
+                                    ⚠ Erreur de communication avec le capteur
+                                </td>
+                            </tr>
+                        `;
                     }
             });
         }