| 296 | ) |
| 297 | @action(detail=False, methods=["get"], url_path="regex-preview") |
| 298 | def regex_preview(self, request, *args, **kwargs): |
| 299 | # `regex` (third-party) supports a per-call timeout that bounds |
| 300 | # catastrophic backtracking; paired with PATTERN_MAX_LEN to keep |
| 301 | # the endpoint safe under adversarial input. |
| 302 | import regex as re |
| 303 | |
| 304 | SCAN_CAP = 5000 |
| 305 | PATTERN_MAX_LEN = 512 |
| 306 | REGEX_TIMEOUT = 0.1 |
| 307 | |
| 308 | group_name = request.query_params.get("channel_group") |
| 309 | if not group_name: |
| 310 | return Response( |
| 311 | {"detail": "channel_group is required"}, |
| 312 | status=status.HTTP_400_BAD_REQUEST, |
| 313 | ) |
| 314 | |
| 315 | # Group names are not unique across M3U accounts (two providers |
| 316 | # can both publish a "Sports" group). Scope to the calling |
| 317 | # account so the sample reflects only the user's edits. |
| 318 | m3u_account_id = request.query_params.get("m3u_account_id") |
| 319 | if m3u_account_id is not None: |
| 320 | try: |
| 321 | m3u_account_id = int(m3u_account_id) |
| 322 | except (TypeError, ValueError): |
| 323 | return Response( |
| 324 | {"detail": "m3u_account_id must be an integer"}, |
| 325 | status=status.HTTP_400_BAD_REQUEST, |
| 326 | ) |
| 327 | |
| 328 | find_pat = request.query_params.get("find") or None |
| 329 | replace_pat = request.query_params.get("replace") or "" |
| 330 | match_pat = request.query_params.get("match") or None |
| 331 | exclude_pat = request.query_params.get("exclude") or None |
| 332 | for label, value in ( |
| 333 | ("find", find_pat), |
| 334 | ("replace", replace_pat), |
| 335 | ("match", match_pat), |
| 336 | ("exclude", exclude_pat), |
| 337 | ): |
| 338 | if value is not None and len(value) > PATTERN_MAX_LEN: |
| 339 | return Response( |
| 340 | {"detail": f"{label} exceeds {PATTERN_MAX_LEN} characters"}, |
| 341 | status=status.HTTP_400_BAD_REQUEST, |
| 342 | ) |
| 343 | try: |
| 344 | limit = int(request.query_params.get("limit", 10)) |
| 345 | except (TypeError, ValueError): |
| 346 | limit = 10 |
| 347 | limit = max(1, min(limit, 50)) |
| 348 | |
| 349 | find_re = None |
| 350 | match_re = None |
| 351 | exclude_re = None |
| 352 | find_error = None |
| 353 | match_error = None |
| 354 | exclude_error = None |
| 355 | if find_pat: |