migration: establish exact preserved app baseline

app/static/shared/api.js

@@ -0,0 +1,102 @@
+(function exposeApiClient(global) {
+  "use strict";
+
+  let csrfTokenSupplier = () => "";
+  let unauthorizedHandler = () => {};
+
+  class ApiError extends Error {
+    constructor(message, status = 0, payload = null) {
+      super(message);
+      this.name = "ApiError";
+      this.status = status;
+      this.payload = payload;
+    }
+  }
+
+  function configure(options = {}) {
+    if (typeof options.csrfToken === "function") csrfTokenSupplier = options.csrfToken;
+    if (typeof options.onUnauthorized === "function") unauthorizedHandler = options.onUnauthorized;
+  }
+
+  function requestOptions(method, body, signal) {
+    const normalizedMethod = String(method || "GET").toUpperCase();
+    const options = { method: normalizedMethod, headers: {}, signal };
+    const csrfToken = csrfTokenSupplier();
+    if (!["GET", "HEAD", "OPTIONS"].includes(normalizedMethod) && csrfToken) {
+      options.headers["X-CSRF-Token"] = csrfToken;
+    }
+    if (body !== null && body !== undefined) {
+      options.headers["Content-Type"] = "application/json";
+      options.body = JSON.stringify(body);
+    }
+    return options;
+  }
+
+  async function parseJson(response) {
+    try {
+      return await response.json();
+    } catch (_error) {
+      return {};
+    }
+  }
+
+  function handleUnauthorized(response, url) {
+    if (response.status === 401 && !String(url).startsWith("/api/auth/")) {
+      unauthorizedHandler({ response, url });
+    }
+  }
+
+  async function request(url, method = "GET", body = null, options = {}) {
+    const response = await fetch(url, requestOptions(method, body, options.signal));
+    const payload = await parseJson(response);
+    handleUnauthorized(response, url);
+    if (!response.ok || payload.error) {
+      throw new ApiError(payload.error || "请求失败", response.status, payload);
+    }
+    return payload;
+  }
+
+  async function streamNdjson(url, options = {}) {
+    const response = await fetch(
+      url,
+      requestOptions(options.method || "POST", options.body, options.signal),
+    );
+    if (!response.ok) {
+      const payload = await parseJson(response);
+      handleUnauthorized(response, url);
+      throw new ApiError(
+        payload.error || options.errorMessage || "流式请求暂不可用",
+        response.status,
+        payload,
+      );
+    }
+    if (!response.body) throw new ApiError("当前浏览器不支持流式回答", response.status);
+    const reader = response.body.getReader();
+    const decoder = new TextDecoder();
+    let buffer = "";
+    const consume = (line) => {
+      if (!line.trim()) return;
+      let event;
+      try {
+        event = JSON.parse(line);
+      } catch (_error) {
+        throw new ApiError("流式响应格式错误", response.status);
+      }
+      if (event.type === "error") {
+        throw new ApiError(event.error || options.errorMessage || "流式请求失败", response.status, event);
+      }
+      options.onEvent?.(event);
+    };
+    while (true) {
+      const { value, done } = await reader.read();
+      buffer += decoder.decode(value || new Uint8Array(), { stream: !done });
+      const lines = buffer.split("\n");
+      buffer = lines.pop() || "";
+      lines.forEach(consume);
+      if (done) break;
+    }
+    if (buffer.trim()) consume(buffer);
+  }
+
+  global.XiaobaiAPI = Object.freeze({ ApiError, configure, request, streamNdjson });
+})(window);