Joseph CostaandClaude Opus 4.8
2f95e6be96
OpenAI-compatible image endpoint that proxies to a ComfyUI server: fills a
workflow template with per-request params (prompt/size/n/seed/steps/checkpoint),
submits to ComfyUI, polls history, fetches images, returns OpenAI image shape.
- router.py: _handle_image + fill_workflow + route; env ROUTER_COMFYUI /
ROUTER_COMFY_CHECKPOINT / ROUTER_COMFY_WORKFLOW
- comfyui-workflow.json: default SD/SDXL text2img template with {{SENTINELS}}
- docs/IMAGES.md + README: config, usage, custom workflows
- verified: templating + clean error when ComfyUI is down; end-to-end pending
a live ComfyUI
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2.7 KiB
Image generation (ComfyUI)
The router exposes an OpenAI-compatible POST /v1/images/generations endpoint
backed by a ComfyUI server. It submits
a workflow to ComfyUI, polls until it finishes, fetches the images, and returns them
in OpenAI's image-response shape — so any OpenAI image client works.
Configure
| Env var | Default | Purpose |
|---|---|---|
ROUTER_COMFYUI |
http://127.0.0.1:8188 |
ComfyUI server URL |
ROUTER_COMFY_CHECKPOINT |
(unset) | your checkpoint filename, e.g. sd_xl_base_1.0.safetensors |
ROUTER_COMFY_WORKFLOW |
comfyui-workflow.json |
the workflow template (see below) |
At minimum, set ROUTER_COMFY_CHECKPOINT to a model that exists in your
ComfyUI (ComfyUI/models/checkpoints/), or hardcode it into the template's
ckpt_name. Then restart the router.
Use
curl http://<host>:8080/v1/images/generations -H 'content-type: application/json' -d '{
"prompt": "a red fox in a snowy forest, cinematic lighting",
"n": 1, "size": "1024x1024"
}'
# -> {"created": ..., "data": [{"b64_json": "<png>"}]}
response_format:b64_json(default) orurl(returns adata:URL).- Extra (non-OpenAI) knobs the router honors:
negative_prompt,steps. - Works with the OpenAI SDK:
images.generate(prompt=..., size=..., n=...).
The workflow template
comfyui-workflow.json is a ComfyUI API-format workflow with string sentinels
the router substitutes per request:
| Sentinel | Filled with |
|---|---|
{{PROMPT}} |
the request prompt |
{{NEGATIVE}} |
negative_prompt |
{{WIDTH}} / {{HEIGHT}} |
parsed from size |
{{BATCH}} |
n |
{{SEED}} |
a fresh seed |
{{STEPS}} |
steps (default 25) |
{{CHECKPOINT}} |
ROUTER_COMFY_CHECKPOINT |
The default is a standard SD/SDXL text-to-image graph. To use your own (Flux,
a fancier pipeline, LoRAs, upscalers, etc.): build it in ComfyUI, export via
Save (API Format), then replace the values you want driven by requests with the
sentinels above. Point ROUTER_COMFY_WORKFLOW at your file. Anything without a
sentinel stays fixed.
Notes
- Not yet verified end-to-end — it was written before ComfyUI was installed.
Once your ComfyUI is up (
ROUTER_COMFYUIreachable, checkpoint set), test with the curl above; if a node name/shape differs, adjust the template. - Generation can take a while; the router polls up to ~10 min per request.
- Video: ComfyUI video workflows (AnimateDiff, SVD, etc.) also export to API format and return frames/files — the same endpoint can drive them, but the response mapping for multi-frame/video output may need a tweak. Ask when you get there.