DemonGatanjieu-Anomalous_Model_Browser/docs/architecture/backend.md

Backend Architecture

Read this document for changes to api/, scraper.py, model files and sidecars, recipe persistence, or filesystem-facing routes.

Runtime and route boundary

__init__.py exposes the frontend directory and imports the modular route package. api/__init__.py registers aiohttp routes, all prefixed with /anomalous/. Changes to Python modules require a full ComfyUI restart; a frontend reload alone does not replace registered handlers or module state. Route registration uses explicit module references. tests/test_route_manifest.py locks the HTTP method/path pairs so internal ownership changes cannot silently drop, duplicate, or rename an endpoint.

The backend owns filesystem authority. A browser-supplied path, filename, category, output reference, recipe asset, or archive member is untrusted until validated. Use the shared helpers in api/path_utils.py (also re-exported by the small api/utils.py compatibility facade):

• resolve_folder_subdir() for configured model-folder boundaries;
• resolve_within() for containment below an owned root;
• require_filename() for single-file identifiers.

Never rely only on .. rejection. Absolute Windows paths, UNC paths, alternate separators, device paths, and symlinks can bypass naïve string checks. Media routes also enforce an explicit extension allowlist.

Configured model scope belongs to api.folder_types. Category mode uses get_active_folder_types(); folder-manager-facing library enumeration uses get_active_model_roots() so physical mode can retain the exact registered type, path_idx, and real root for every enabled directory. Real roots are deduplicated without merging same-named files from different roots. Do not hardcode a walk across checkpoints, loras, or another category. A directory disabled in config.json must cause no walk or metadata I/O.

/anomalous/all_scan_models follows that current folder-manager mode and keeps its paginated response plus limit=0 full-list behavior. Its local source-link inventory recognizes GGUF and PTH case-insensitively in addition to the existing list formats. This route-level inventory does not expand global model-format, scanner, metadata-parser, recovery, or cloud-identification support.

Storage ownership

Runtime UI settings and newly stored API keys live in api/config.json. scraper.py reads it first and may fall back to the legacy root config.json. Secrets are never persisted to browser localStorage.

Workflow Recipes live below the active ComfyUI user directory in workflows/anomalous_recipes; Parameter Notebooks live in workflows/anomalous_parameters. They are user data, not repository assets. Writes validate their bounded schema and use atomic replacement.

Backend modules follow route/domain/storage ownership. Model discovery, identity recovery, metadata mutation, and cover media live in model_catalog.py, model_resolution.py, model_metadata.py, and model_media.py. Recipe graph rules, recipe shaping, image processing, and persistence/history live in workflow_schema.py, recipe_schema.py, recipe_images.py, and recipe_store.py; recipes.py is the HTTP facade. Material shaping, private assets, and the single persistence lock/summary cache live in material_schema.py, material_assets.py, and material_store.py; materials.py owns request/response mapping and compatibility entry points.

The former mixed utility routes are separated: media_routes.py owns card thumbnails and model/output media lookups, gallery_routes.py owns the bounded output snapshot and deletion (searched through image_search.py, which reads PNG text chunks only and caches per-image records by mtime), translation_routes.py owns provider fallback, and folder_types.py owns configured visibility and scan scope.

Offline inference sidecars use non-positive Civitai IDs as sentinels. Metadata normalization must not expose those values as release-page URLs or resolved model/version identities; only positive IDs may form a Civitai source link.

Prompt Notes use workflows/anomalous_notebooks. First access copies legacy api/notebooks records without deleting originals or overwriting current notes. Conflicts receive a deterministic recovered filename. A completion marker makes the copy retryable after write failure and prevents deleted notes reappearing. Invalid legacy records remain untouched and are listed in the migration marker. Notebook I/O runs in a worker under its persistence lock; the UI queues snapshots and reports failed saves instead of showing success. api.path_utils.atomic_write_json owns bounded, flushed temporary writes followed by atomic file replacement.

The recipe card endpoint returns lightweight metadata. Full graphs and history are fetched only for detail, edit, compare, restore, export, or another operation that needs them. Successful save, update, and restore responses include a compact integrity receipt containing graph counts and the persisted workflow fingerprint.

Package import is inspect-then-commit. recipe_packages.py accepts only bounded ZIP packages with a manifest, recipe JSON, declared contained WebP assets, and optional bounded history. It rejects traversal, symlinks, undeclared members, archive bombs, and checksum failures; stages all content before the final rename; and restores the previous recipe set if replacement commit fails. Packages never install code or dependencies.

Event-loop and scan-state rules

Potentially large disk work does not run on the aiohttp event loop. Recursive walks, bulk metadata parsing, full-file hashing, and similar operations use asyncio.to_thread() or the established worker process/thread path. Reading a small bounded safetensors header is acceptable; reading a whole multi-gigabyte model to discover metadata is not.

Background work claims state before launching. Folder scans use .scan_in_progress; global quick scans use .global_scan_in_progress; deep missing-model scans use GLOBAL_SCAN_STATE and the corresponding status route. Marker files are versioned JSON records containing backend session, owner PID, worker PID, and job ID. Status checks validate ownership and process liveness; file existence alone is not proof that a scan is active.

A marker owned by a dead process, or a legacy plain-text marker, represents an interrupted job. Its marker, progress file, and pending selection may be removed so a restart does not permanently lock scanning. A still-running orphan worker remains locked until that recorded process exits.

scraper.py --progress-file atomically publishes enumeration state, selected file count, current index, and filename. Status responses merge worker progress with parent-owned folder progress. The frontend can reconstruct this state by polling after its UI has been reopened.

Metadata and cache behavior

The output gallery keeps one ordered directory snapshot for at most ten seconds and 50,000 images. Page requests reuse it; explicit refresh and image deletion invalidate it immediately. Larger inventories are returned normally but not cached.

Metadata and embedded safetensors-header hashes may be cached only in a bounded cache. The key includes the model's real path and the physical size, mtime_ns, and ctime_ns signatures of the model and relevant sidecars. Return independent copies; never expose cached mutable dictionaries or lists.

Folder listing inventories a directory once with os.scandir() and preserves preview priority: .preview.* before bare same-stem media. Avoid an exists() sequence for every candidate when the directory inventory already has the answer.

Preview URLs use the selected preview file's stable nanosecond modification time as the cache version. Do not append Date.now() or random request tokens during ordinary listing. A changed file must change its URL; an unchanged file should remain browser-cacheable.

Preview lookup tries a contained exact relative path first and recursively walks the library only for unresolved basename fallbacks. This locates presentation for a model value already supplied by ComfyUI; it is not Model Doctor discovery.

Balanced grid thumbnails are derived, longest-edge 512 px WebP files in ComfyUI's temporary area. Their cache is keyed by source real path and physical signature and capped at 256 MiB with oldest-accessed eviction. The original mode serves source covers, and detail views always use originals. Derived media never modifies or sits beside a user's cover; unsupported, animated, or failed inputs fall back to the original.

Model sidecar and cover lifecycle

Sidecar handling is non-negotiable because it can destroy user metadata or media.

• .civitai_bak.* is a persistent restore source created from a real Civitai download. Setting a custom cover changes only .preview.*.
• Cover reset first restores .civitai_bak.* to .preview.*. Otherwise it may remove .preview.* only when a bare original cover can take over. If the preview is the only image, preserve it and return a visible warning. Reset never silently downloads from the network.
• Physical rename moves every recognized sidecar to the new model stem. Model deletion may clean sidecars only after the main model is successfully deleted.
• Foundation components—vae, vae_approx, clip, text_encoders, and clip_vision—are never physical-rename targets. UI and all backend entry points enforce the same denial.
• Main model extensions (.safetensors, .ckpt, .pt, .bin) are never sidecar suffixes. Cleanup must not delete a same-stem model with another extension. If such a sibling remains, ambiguous stem-keyed sidecars remain.
• Rename/delete/reset uses centralized immutable suffix tuples and a constant number of exact-path checks. Do not walk, glob, index, hash, or call the network for these operations.

Keep product wording precise: deletion cleans sidecars; rename migrates them.

Backend implementation rules

• Prefer standard-library and existing ComfyUI facilities; missing optional dependencies must fail as a localized capability, not break plugin import.
• Use os.path, pathlib, os.sep, or normalization helpers for paths. Avoid hand-written backslash replacement.
• Update an existing .civitai.info dictionary rather than overwriting it with a one-field object.
• Large input collections use a JSON POST body. Do not place them in a query string or pass them as command-line arguments on Windows.
• The private local tests/ directory is ignored and is not imported by runtime code or shipped in the installable plugin.