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Stable Cascade | ComfyUI API 工作流格式优化

news 来源：原创 2024/9/21 12:21:30

前言

目前，ComfyUI 是运行 Stable Cascade 模型的首选。ComfyUI 可直接保存生图工作流为 API 格式，但该 API 格式文本行数较多且节点顺序与逻辑执行顺序不一致，不利于编写或修改 API 的调用代码。本文主要介绍 ComfyUI 工作流（API 格式）的结构与格式优化。

2024-4-21 发布工作流自动优化代码：[Stable Diffusion | ComfyUI API 工作流自动优化]

ComfyUI API 工作流的保存

在 ComfyUI 浏览器界面中点击右上角红框内按钮打开设置界面。

勾选 Enable Dev mode Options 后即出现 API 工作流保存按钮（右侧红框）。

以下为通过 ComfyUI 保存的 Stable Cascade 模型文生图 API 工作流，共163行。

{"3": {"inputs": {"seed": 314307448448003,"steps": 20,"cfg": 4,"sampler_name": "euler_ancestral","scheduler": "simple","denoise": 1,"model": ["41",0],"positive": ["6",0],"negative": ["7",0],"latent_image": ["34",0]},"class_type": "KSampler","_meta": {"title": "KSampler"}},"6": {"inputs": {"text": "evening sunset scenery blue sky nature, glass bottle with a fizzy ice cold freezing rainbow liquid in it","clip": ["41",1]},"class_type": "CLIPTextEncode","_meta": {"title": "CLIP Text Encode (Positive Prompt)"}},"7": {"inputs": {"text": "text, watermark","clip": ["41",1]},"class_type": "CLIPTextEncode","_meta": {"title": "CLIP Text Encode (Negative Prompt)"}},"8": {"inputs": {"samples": ["33",0],"vae": ["42",2]},"class_type": "VAEDecode","_meta": {"title": "VAE Decode"}},"9": {"inputs": {"filename_prefix": "ComfyUI","images": ["8",0]},"class_type": "SaveImage","_meta": {"title": "Save Image"}},"33": {"inputs": {"seed": 183495397600639,"steps": 10,"cfg": 1.1,"sampler_name": "euler_ancestral","scheduler": "simple","denoise": 1,"model": ["42",0],"positive": ["36",0],"negative": ["7",0],"latent_image": ["34",1]},"class_type": "KSampler","_meta": {"title": "KSampler"}},"34": {"inputs": {"width": 1024,"height": 1024,"compression": 42,"batch_size": 1},"class_type": "StableCascade_EmptyLatentImage","_meta": {"title": "StableCascade_EmptyLatentImage"}},"36": {"inputs": {"conditioning": ["6",0],"stage_c": ["3",0]},"class_type": "StableCascade_StageB_Conditioning","_meta": {"title": "StableCascade_StageB_Conditioning"}},"41": {"inputs": {"ckpt_name": "stable_cascade_stage_c.safetensors"},"class_type": "CheckpointLoaderSimple","_meta": {"title": "Load Checkpoint"}},"42": {"inputs": {"ckpt_name": "stable_cascade_stage_b.safetensors"},"class_type": "CheckpointLoaderSimple","_meta": {"title": "Load Checkpoint"}}
}

2. ComfyUI API 工作流结构简介

ComfyUI API 工作流为 json 格式，包含各节点的输入输出信息。

以节点3（KSampler）和节点36（StableCascade_StageB_Conditioning）为例

其中，红框内为从其他节点输入的变量，蓝框内为节点内部输入的变量，绿色框内为节点输出变量，对应关系见上下两图。此外，“class_type”:“…” 为节点类型，“_meta”:{“title”:“…”} 为节点名称。

以节点36 “stage_c” 输入为例（下图右侧红框内），“3” 表示从节点3输入，0 表示节点3的第一个输出变量（此处排序从0开始，自上至下递增）。

ComfyUI API 工作流格式优化

3.1 工作流文本简化

json 格式对首行缩进、空格、换行并不敏感，因此可以删除不必要的空格和换行以简化工作流。以下为简化后的工作流，共12行：

{
"3":{"inputs":{"seed":314307448448003,"steps":20,"cfg":4,"sampler_name":"euler_ancestral","scheduler":"simple","denoise":1,"model":["41",0],"positive":["6",0],"negative":["7",0],"latent_image":["34",0]},"class_type":"KSampler","_meta":{"title":"KSampler"}},
"6":{"inputs":{"text":"evening sunset scenery blue sky nature,glass bottle with a fizzy ice cold freezing rainbow liquid in it","clip":["41",1]},"class_type":"CLIPTextEncode","_meta":{"title":"CLIPTextEncode(PositivePrompt)"}},
"7":{"inputs":{"text":"text,watermark","clip":["41",1]},"class_type":"CLIPTextEncode","_meta":{"title":"CLIPTextEncode(NegativePrompt)"}},
"8":{"inputs":{"samples":["33",0],"vae":["42",2]},"class_type":"VAEDecode","_meta":{"title":"VAEDecode"}},
"9":{"inputs":{"filename_prefix":"ComfyUI","images":["8",0]},"class_type":"SaveImage","_meta":{"title":"SaveImage"}},
"33":{"inputs":{"seed":183495397600639,"steps":10,"cfg":1.1,"sampler_name":"euler_ancestral","scheduler":"simple","denoise":1,"model":["42",0],"positive":["36",0],"negative":["7",0],"latent_image":["34",1]},"class_type":"KSampler","_meta":{"title":"KSampler"}},
"34":{"inputs":{"width":1024,"height":1024,"compression":42,"batch_size":1},"class_type":"StableCascade_EmptyLatentImage","_meta":{"title":"StableCascade_EmptyLatentImage"}},
"36":{"inputs":{"conditioning":["6",0],"stage_c":["3",0]},"class_type":"StableCascade_StageB_Conditioning","_meta":{"title":"StableCascade_StageB_Conditioning"}},
"41":{"inputs":{"ckpt_name":"stable_cascade_stage_c.safetensors"},"class_type":"CheckpointLoaderSimple","_meta":{"title":"LoadCheckpoint"}},
"42":{"inputs":{"ckpt_name":"stable_cascade_stage_b.safetensors"},"class_type":"CheckpointLoaderSimple","_meta":{"title":"LoadCheckpoint"}}
}

实践表明，“_meta”:{“title”:“…”} 节点名称在 API 调用过程中无实际意义，也可以删除，再次简化后的工作流：

{
"3":{"inputs":{"seed":314307448448003,"steps":20,"cfg":4,"sampler_name":"euler_ancestral","scheduler":"simple","denoise":1,"model":["41",0],"positive":["6",0],"negative":["7",0],"latent_image":["34",0]},"class_type":"KSampler"},
"6":{"inputs":{"text":"evening sunset scenery blue sky nature,glass bottle with a fizzy ice cold freezing rainbow liquid in it","clip":["41",1]},"class_type":"CLIPTextEncode"},
"7":{"inputs":{"text":"text,watermark","clip":["41",1]},"class_type":"CLIPTextEncode","_meta":{"title":"CLIPTextEncode(NegativePrompt)"}},
"8":{"inputs":{"samples":["33",0],"vae":["42",2]},"class_type":"VAEDecode"},
"9":{"inputs":{"filename_prefix":"ComfyUI","images":["8",0]},"class_type":"SaveImage"},
"33":{"inputs":{"seed":183495397600639,"steps":10,"cfg":1.1,"sampler_name":"euler_ancestral","scheduler":"simple","denoise":1,"model":["42",0],"positive":["36",0],"negative":["7",0],"latent_image":["34",1]},"class_type":"KSampler"},
"34":{"inputs":{"width":1024,"height":1024,"compression":42,"batch_size":1},"class_type":"StableCascade_EmptyLatentImage"},
"36":{"inputs":{"conditioning":["6",0],"stage_c":["3",0]},"class_type":"StableCascade_StageB_Conditioning"},
"41":{"inputs":{"ckpt_name":"stable_cascade_stage_c.safetensors"},"class_type":"CheckpointLoaderSimple"},
"42":{"inputs":{"ckpt_name":"stable_cascade_stage_b.safetensors"},"class_type":"CheckpointLoaderSimple"}
}

3.2 工作流节点重新排序

从上面简化后的工作流不难看出节点顺序和编号都是混乱的，以下介绍如何重新排序工作流内的节点信息。

Stable Cascade 文生图工作流逻辑执行顺序：

加载 stable_cascade_stage_c.safetensors （节点41）；
正向提示词 CLIPTextEncode（节点6）；
负向提示词 CLIPTextEncode（节点7）；
StableCascade_EmptyLatentImage （节点34）；
Stage_C 阶段采样 KSampler （节点3）；
StableCascade_StageB_Conditioning （节点36）；
加载 stable_cascade_stage_b.safetensors （节点42）；
Stage_B 阶段采样 KSampler （节点33）；
VAEDecode （节点8）；
SaveImage （节点9）；

按逻辑执行顺序重新排序的工作流：

{
"41":{"inputs":{"ckpt_name":"stable_cascade_stage_c.safetensors"},"class_type":"CheckpointLoaderSimple"},
"6":{"inputs":{"text":"evening sunset scenery blue sky nature,glass bottle with a fizzy ice cold freezing rainbow liquid in it","clip":["41",1]},"class_type":"CLIPTextEncode"},
"7":{"inputs":{"text":"text,watermark","clip":["41",1]},"class_type":"CLIPTextEncode","_meta":{"title":"CLIPTextEncode(NegativePrompt)"}},
"34":{"inputs":{"width":1024,"height":1024,"compression":42,"batch_size":1},"class_type":"StableCascade_EmptyLatentImage"},
"3":{"inputs":{"seed":314307448448003,"steps":20,"cfg":4,"sampler_name":"euler_ancestral","scheduler":"simple","denoise":1,"model":["41",0],"positive":["6",0],"negative":["7",0],"latent_image":["34",0]},"class_type":"KSampler"},
"36":{"inputs":{"conditioning":["6",0],"stage_c":["3",0]},"class_type":"StableCascade_StageB_Conditioning"},
"42":{"inputs":{"ckpt_name":"stable_cascade_stage_b.safetensors"},"class_type":"CheckpointLoaderSimple"},
"33":{"inputs":{"seed":183495397600639,"steps":10,"cfg":1.1,"sampler_name":"euler_ancestral","scheduler":"simple","denoise":1,"model":["42",0],"positive":["36",0],"negative":["7",0],"latent_image":["34",1]},"class_type":"KSampler"},
"8":{"inputs":{"samples":["33",0],"vae":["42",2]},"class_type":"VAEDecode"},
"9":{"inputs":{"filename_prefix":"ComfyUI","images":["8",0]},"class_type":"SaveImage"}
}

可以看到节点编号很乱，重新给节点编号并更新节点间的关联关系，重新编号后的工作流：

{
"1":{"inputs":{"ckpt_name":"stable_cascade_stage_c.safetensors"},"class_type":"CheckpointLoaderSimple"},
"2":{"inputs":{"text":"evening sunset scenery blue sky nature,glass bottle with a fizzy ice cold freezing rainbow liquid in it","clip":["1",1]},"class_type":"CLIPTextEncode"},
"3":{"inputs":{"text":"text,watermark","clip":["1",1]},"class_type":"CLIPTextEncode"},
"4":{"inputs":{"width":1024,"height":1024,"compression":42,"batch_size":1},"class_type":"StableCascade_EmptyLatentImage"},
"5":{"inputs":{"seed":314307448448003,"steps":20,"cfg":4,"sampler_name":"euler_ancestral","scheduler":"simple","denoise":1,"model":["1",0],"positive":["2",0],"negative":["3",0],"latent_image":["4",0]},"class_type":"KSampler"},
"6":{"inputs":{"conditioning":["2",0],"stage_c":["5",0]},"class_type":"StableCascade_StageB_Conditioning"},
"7":{"inputs":{"ckpt_name":"stable_cascade_stage_b.safetensors"},"class_type":"CheckpointLoaderSimple"},
"8":{"inputs":{"seed":183495397600639,"steps":10,"cfg":1.1,"sampler_name":"euler_ancestral","scheduler":"simple","denoise":1,"model":["7",0],"positive":["6",0],"negative":["3",0],"latent_image":["4",1]},"class_type":"KSampler"},
"9":{"inputs":{"samples":["8",0],"vae":["7",2]},"class_type":"VAEDecode"},
"10":{"inputs":{"filename_prefix":"ComfyUI","images":["9",0]},"class_type":"SaveImage"}
}

至此，工作流格式优化结束，优化后的工作流逻辑清晰，行数由原始的163行减至12行。

3.3 检验格式优化后的工作流

将优化后的工作流文件拖入 ComfyUI 浏览器界面，可以看到工作流连接正确。

此时再次通过 ComfyUI 保存 API 格式的工作流文件，内容如下。可以发现再次保存的 API 工作流节点顺序与手工优化的工作流节点顺序一致，说明原始工作流中节点顺序混乱与工作流制作过程有关，与 ComfyUI 程序无关。在 ComfyUI 中设计工作流的时候，添加、删除、修改节点可能会导致节点编号和顺序发生变化。

{"1": {"inputs": {"ckpt_name": "stable_cascade_stage_c.safetensors"},"class_type": "CheckpointLoaderSimple","_meta": {"title": "Load Checkpoint"}},"2": {"inputs": {"text": "evening sunset scenery blue sky nature,glass bottle with a fizzy ice cold freezing rainbow liquid in it","clip": ["1",1]},"class_type": "CLIPTextEncode","_meta": {"title": "CLIP Text Encode (Prompt)"}},"3": {"inputs": {"text": "text,watermark","clip": ["1",1]},"class_type": "CLIPTextEncode","_meta": {"title": "CLIP Text Encode (Prompt)"}},"4": {"inputs": {"width": 1024,"height": 1024,"compression": 42,"batch_size": 1},"class_type": "StableCascade_EmptyLatentImage","_meta": {"title": "StableCascade_EmptyLatentImage"}},"5": {"inputs": {"seed": 314307448448003,"steps": 20,"cfg": 4,"sampler_name": "euler_ancestral","scheduler": "simple","denoise": 1,"model": ["1",0],"positive": ["2",0],"negative": ["3",0],"latent_image": ["4",0]},"class_type": "KSampler","_meta": {"title": "KSampler"}},"6": {"inputs": {"conditioning": ["2",0],"stage_c": ["5",0]},"class_type": "StableCascade_StageB_Conditioning","_meta": {"title": "StableCascade_StageB_Conditioning"}},"7": {"inputs": {"ckpt_name": "stable_cascade_stage_b.safetensors"},"class_type": "CheckpointLoaderSimple","_meta": {"title": "Load Checkpoint"}},"8": {"inputs": {"seed": 183495397600639,"steps": 10,"cfg": 1.1,"sampler_name": "euler_ancestral","scheduler": "simple","denoise": 1,"model": ["7",0],"positive": ["6",0],"negative": ["3",0],"latent_image": ["4",1]},"class_type": "KSampler","_meta": {"title": "KSampler"}},"9": {"inputs": {"samples": ["8",0],"vae": ["7",2]},"class_type": "VAEDecode","_meta": {"title": "VAE Decode"}},"10": {"inputs": {"filename_prefix": "ComfyUI","images": ["9",0]},"class_type": "SaveImage","_meta": {"title": "Save Image"}}
}

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