feature/IO-3052-Skia-Canvas-Handler: Fix missing checks

Signed-off-by: Dave Richer <dave@imexsystems.ca>

server/render/canvas-handler.js

@@ -77,21 +77,36 @@ const processCanvasRequest = async (req, res, isSkia = false) => {
 
   const configuration = getChartConfiguration(keys, values, override);
 
+  // Placeholders to allow fine control over GAC
+  let canvas = null;
+  let ctx = null;
+  let chart = null;
+  let chartImage = null;
+
   try {
-    const canvas = isSkia ? new Canvas(width, height) : createCanvas(width, height);
+    // Create the canvas
-    const ctx = canvas.getContext("2d");
+    canvas = isSkia ? new Canvas(width, height) : createCanvas(width, height);
+    ctx = canvas.getContext("2d");
 
     // Render the chart
-    const chart = new Chart(ctx, configuration);
+    chart = new Chart(ctx, configuration);
 
     // Generate and send the image
-    const chartImage = isSkia ? (await canvas.toBuffer("image/png")).toString("base64") : canvas.toDataURL();
+    chartImage = isSkia ? (await canvas.toBuffer("image/png")).toString("base64") : canvas.toDataURL();
 
-    chart.destroy();
     res.status(200).send(isSkia ? `data:image/png;base64,${chartImage}` : chartImage);
   } catch (error) {
+    // Log the error and send the response
     logger.log("canvas-error", "error", "jsr", null, { error: error.message });
     res.status(500).send("Failed to generate canvas.");
+  } finally {
+    // Cleanup resources
+    if (chart) {
+      chart.destroy();
+    }
+    ctx = null; // Explicitly nullify for garbage collection
+    canvas = null; // Explicitly nullify for garbage collection
+    chartImage = null;
   }
 };