refactor(*): 代码质量 - 优化前后端实现并完善协议与画布验证

web/src/lib/json-event-stream.ts

@@ -0,0 +1,29 @@
+type EventBuffer = { buffer: string };
+
+/** Feed complete JSON data frames to a protocol adapter; retain a partial tail. */
+export function consumeJsonEvents(state: EventBuffer, chunk: string, receive: (payload: unknown) => void, flush = false) {
+    state.buffer += chunk;
+    const input = state.buffer;
+    let offset = 0;
+    const boundaries = input.matchAll(/\r?\n\r?\n/g);
+    for (const boundary of boundaries) {
+        deliver(input.slice(offset, boundary.index), receive);
+        offset = boundary.index + boundary[0].length;
+        // Advance only after parsing succeeds, so an invalid frame isn't silently lost.
+        state.buffer = input.slice(offset);
+    }
+    if (flush) {
+        deliver(input.slice(offset), receive);
+        state.buffer = "";
+    }
+}
+
+function deliver(frame: string, receive: (payload: unknown) => void) {
+    const values: string[] = [];
+    for (const line of frame.split(/\r?\n/)) {
+        if (line.slice(0, 5) !== "data:") continue;
+        values.push(line.charAt(5) === " " ? line.slice(6) : line.slice(5));
+    }
+    const data = values.join("\n").trim();
+    if (data.length && data !== "[DONE]") receive(JSON.parse(data));
+}