refac: code interpreter

src/lib/workers/pyodide.worker.ts

@@ -77,6 +77,35 @@ self.onmessage = async (event) => {
 	await loadPyodideAndPackages(self.packages);
 
 	try {
+		// check if matplotlib is imported in the code
+		if (code.includes('matplotlib')) {
+			// Override plt.show() to return base64 image
+			await self.pyodide.runPythonAsync(`import base64
+import os
+from io import BytesIO
+
+# before importing matplotlib
+# to avoid the wasm backend (which needs js.document', not available in worker)
+os.environ["MPLBACKEND"] = "AGG"
+
+import matplotlib.pyplot
+
+_old_show = matplotlib.pyplot.show
+assert _old_show, "matplotlib.pyplot.show"
+
+def show(*, block=None):
+	buf = BytesIO()
+	matplotlib.pyplot.savefig(buf, format="png")
+	buf.seek(0)
+	# encode to a base64 str
+	img_str = base64.b64encode(buf.read()).decode('utf-8')
+	matplotlib.pyplot.clf()
+	buf.close()
+	print(f"data:image/png;base64,{img_str}")
+
+matplotlib.pyplot.show = show`);
+		}
+
 		self.result = await self.pyodide.runPythonAsync(code);
 
 		// Safely process and recursively serialize the result