1 files changed, 70 insertions, 0 deletions
diff --git a/frontend/src/lib/api.ts b/frontend/src/lib/api.ts
new file mode 100644
index 0000000..923a6e8
--- /dev/null
+++ b/frontend/src/lib/api.ts
@@ -0,0 +1,70 @@
+export interface ApiErrorShape {
+  code: string;
+  message: string;
+  details?: unknown;
+}
+
+export interface ApiErrorBody {
+  error: ApiErrorShape;
+}
+
+export class ApiError extends Error {
+  status: number;
+  code: string;
+  details?: unknown;
+
+  constructor(status: number, code: string, message: string, details?: unknown) {
+    super(message);
+    this.name = 'ApiError';
+    this.status = status;
+    this.code = code;
+    this.details = details;
+  }
+}
+
+interface Options {
+  method?: string;
+  body?: unknown;
+  signal?: AbortSignal;
+}
+
+export async function apiFetch<T = unknown, R = T>(url: string, options: Options = {}): Promise<R> {
+  const headers: Record<string, string> = { accept: 'application/json' };
+  let bodyStr: string | undefined;
+  if (options.body !== undefined) {
+    headers['content-type'] = 'application/json';
+    bodyStr = JSON.stringify(options.body);
+  }
+  let res: Response;
+  try {
+    res = await fetch(url, {
+      method: options.method ?? 'GET',
+      headers,
+      body: bodyStr,
+      credentials: 'same-origin',
+      signal: options.signal
+    });
+  } catch (e) {
+    if (e instanceof DOMException && e.name === 'AbortError') throw e;
+    throw new ApiError(0, 'network', '网络请求失败，请确认服务已启动后重试');
+  }
+  if (res.status === 204) {
+    return undefined as R;
+  }
+  const contentType = res.headers.get('content-type') ?? '';
+  if (!contentType.includes('application/json')) {
+    if (!res.ok) {
+      throw new ApiError(res.status, 'server_error', `服务返回错误（HTTP ${res.status}）`);
+    }
+    throw new ApiError(res.status, 'bad_response', '服务返回了非预期的非 JSON 响应（接口约定为 JSON）');
+  }
+  const parsed: unknown = await res.json().catch(() => null);
+  if (!res.ok) {
+    const errBody = parsed as ApiErrorBody | null;
+    if (errBody?.error) {
+      throw new ApiError(res.status, errBody.error.code, errBody.error.message, errBody.error.details);
+    }
+    throw new ApiError(res.status, 'server_error', `服务返回错误（HTTP ${res.status}）`);
+  }
+  return parsed as R;
+}