Initial commit: JSON Loader (Dynamic) ComfyUI node

Auto-discovers JSON keys and exposes them as typed output slots.
Includes JS frontend for refresh, connection-safe updates, and
workflow persistence of keys and types.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
2026-02-23 19:32:57 +01:00
commit 79157f4289
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<p align="center">
<svg xmlns="http://www.w3.org/2000/svg" width="460" height="90" viewBox="0 0 460 90">
<defs>
<linearGradient id="bg" x1="0%" y1="0%" x2="100%" y2="100%">
<stop offset="0%" style="stop-color:#1a1a2e" />
<stop offset="100%" style="stop-color:#16213e" />
</linearGradient>
<linearGradient id="accent" x1="0%" y1="0%" x2="100%" y2="0%">
<stop offset="0%" style="stop-color:#2b9348" />
<stop offset="100%" style="stop-color:#0f3460" />
</linearGradient>
</defs>
<rect width="460" height="90" rx="14" fill="url(#bg)" />
<rect x="20" y="65" width="420" height="3" rx="1.5" fill="url(#accent)" opacity="0.6" />
<text x="230" y="32" text-anchor="middle" fill="#2b9348" font-family="monospace" font-size="12" font-weight="bold">{ Dynamic }</text>
<text x="230" y="54" text-anchor="middle" fill="#eee" font-family="sans-serif" font-size="20" font-weight="bold">ComfyUI JSON Dynamic Loader</text>
<text x="230" y="82" text-anchor="middle" fill="#888" font-family="sans-serif" font-size="10">Auto-discover JSON keys as typed output slots</text>
</svg>
</p>
<p align="center">
<img src="https://img.shields.io/badge/License-Apache_2.0-blue.svg" alt="License" />
<img src="https://img.shields.io/badge/ComfyUI-Custom%20Node-purple" alt="ComfyUI" />
</p>
A single ComfyUI node that reads any JSON file and **automatically creates output slots** for every key it finds. No hardcoded outputs &mdash; when your JSON structure changes, just click Refresh.
## Features
- **Auto-discovery** &mdash; reads JSON keys and exposes them as named outputs
- **Type detection** &mdash; `INT`, `FLOAT`, `STRING` types with colored connectors
- **Batch support** &mdash; `sequence_number` input for `batch_data` arrays
- **Connection-safe refresh** &mdash; adding new keys preserves existing links
- **Workflow persistence** &mdash; keys, types, and connections survive save/reload
## Installation
```bash
cd ComfyUI/custom_nodes/
git clone <this-repo> ComfyUI-JSON-Dynamic
# Restart ComfyUI
```
## Usage
1. Add **JSON Loader (Dynamic)** node to your workflow
2. Enter a `json_path` and `sequence_number`
3. Click **Refresh Outputs**
4. Outputs appear named after your JSON keys with correct types
5. Connect to downstream nodes
<p align="center">
<svg xmlns="http://www.w3.org/2000/svg" width="500" height="240" viewBox="0 0 500 240">
<defs>
<linearGradient id="dynBg" x1="0%" y1="0%" x2="0%" y2="100%">
<stop offset="0%" style="stop-color:#353545" />
<stop offset="100%" style="stop-color:#252535" />
</linearGradient>
</defs>
<rect x="20" y="10" width="240" height="220" rx="10" fill="url(#dynBg)" stroke="#2b9348" stroke-width="2" />
<rect x="20" y="10" width="240" height="28" rx="10" fill="#2b9348" />
<rect x="20" y="28" width="240" height="10" fill="#2b9348" />
<text x="140" y="31" text-anchor="middle" fill="#fff" font-family="sans-serif" font-size="13" font-weight="bold">JSON Loader (Dynamic)</text>
<text x="35" y="60" fill="#ccc" font-family="monospace" font-size="10">json_path: /data/prompt.json</text>
<text x="35" y="78" fill="#ccc" font-family="monospace" font-size="10">sequence_number: 1</text>
<rect x="45" y="88" width="190" height="24" rx="5" fill="#2b9348" opacity="0.3" stroke="#2b9348" stroke-width="1"/>
<text x="140" y="104" text-anchor="middle" fill="#2b9348" font-family="sans-serif" font-size="11" font-weight="bold">Refresh Outputs</text>
<circle cx="260" cy="130" r="5" fill="#6bcb77"/>
<text x="245" y="134" text-anchor="end" fill="#ccc" font-family="monospace" font-size="10">general_prompt</text>
<circle cx="260" cy="150" r="5" fill="#6bcb77"/>
<text x="245" y="154" text-anchor="end" fill="#ccc" font-family="monospace" font-size="10">negative</text>
<circle cx="260" cy="170" r="5" fill="#4d96ff"/>
<text x="245" y="174" text-anchor="end" fill="#ccc" font-family="monospace" font-size="10">seed</text>
<circle cx="260" cy="190" r="5" fill="#ff6b6b"/>
<text x="245" y="194" text-anchor="end" fill="#ccc" font-family="monospace" font-size="10">flf</text>
<circle cx="260" cy="210" r="5" fill="#6bcb77"/>
<text x="245" y="214" text-anchor="end" fill="#ccc" font-family="monospace" font-size="10">camera</text>
<line x1="265" y1="130" x2="340" y2="130" stroke="#6bcb77" stroke-width="1.5"/>
<line x1="265" y1="170" x2="340" y2="165" stroke="#4d96ff" stroke-width="1.5"/>
<rect x="340" y="115" width="140" height="65" rx="8" fill="url(#dynBg)" stroke="#555" stroke-width="1.5" />
<text x="410" y="137" text-anchor="middle" fill="#aaa" font-family="sans-serif" font-size="11">KSampler</text>
<circle cx="340" cy="130" r="4" fill="#6bcb77"/>
<text x="350" y="150" fill="#777" font-family="monospace" font-size="9">positive</text>
<circle cx="340" cy="165" r="4" fill="#4d96ff"/>
<text x="350" y="170" fill="#777" font-family="monospace" font-size="9">seed</text>
</svg>
</p>
## Type Handling
| JSON type | Output type | Connector |
|:---|:---|:---|
| `42` (integer) | `INT` | Blue |
| `3.14` (float) | `FLOAT` | Teal |
| `"hello"` (string) | `STRING` | Pink |
| `true` / `false` | `STRING` (`"true"` / `"false"`) | Pink |
## JSON Format
Works with flat JSON or `batch_data` arrays:
```json
{
"batch_data": [
{
"sequence_number": 1,
"general_prompt": "A cinematic scene...",
"seed": 42,
"flf": 0.5,
"camera": "pan_left",
"my_custom_key": "any value"
}
]
}
```
Without `batch_data`, reads keys directly from the root object.
## License
[Apache 2.0](LICENSE)

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from .json_loader_dynamic import NODE_CLASS_MAPPINGS, NODE_DISPLAY_NAME_MAPPINGS
WEB_DIRECTORY = "./web"
__all__ = ['NODE_CLASS_MAPPINGS', 'NODE_DISPLAY_NAME_MAPPINGS', 'WEB_DIRECTORY']

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import json
import os
import logging
from typing import Any
logger = logging.getLogger(__name__)
KEY_BATCH_DATA = "batch_data"
MAX_DYNAMIC_OUTPUTS = 32
class AnyType(str):
"""Universal connector type that matches any ComfyUI type."""
def __ne__(self, __value: object) -> bool:
return False
any_type = AnyType("*")
try:
from server import PromptServer
from aiohttp import web
except ImportError:
PromptServer = None
def read_json_data(json_path: str) -> dict[str, Any]:
if not os.path.exists(json_path):
logger.warning(f"File not found at {json_path}")
return {}
try:
with open(json_path, 'r') as f:
data = json.load(f)
except (json.JSONDecodeError, IOError) as e:
logger.warning(f"Error reading {json_path}: {e}")
return {}
if not isinstance(data, dict):
logger.warning(f"Expected dict from {json_path}, got {type(data).__name__}")
return {}
return data
def get_batch_item(data: dict[str, Any], sequence_number: int) -> dict[str, Any]:
"""Resolve batch item by sequence_number field, falling back to array index."""
if KEY_BATCH_DATA in data and isinstance(data[KEY_BATCH_DATA], list) and len(data[KEY_BATCH_DATA]) > 0:
for item in data[KEY_BATCH_DATA]:
if int(item.get("sequence_number", 0)) == sequence_number:
return item
idx = max(0, min(sequence_number - 1, len(data[KEY_BATCH_DATA]) - 1))
logger.warning(f"No item with sequence_number={sequence_number}, falling back to index {idx}")
return data[KEY_BATCH_DATA][idx]
return data
# --- API Route ---
if PromptServer is not None:
@PromptServer.instance.routes.get("/json_dynamic/get_keys")
async def get_keys_route(request):
json_path = request.query.get("path", "")
try:
seq = int(request.query.get("sequence_number", "1"))
except (ValueError, TypeError):
seq = 1
data = read_json_data(json_path)
target = get_batch_item(data, seq)
keys = []
types = []
if isinstance(target, dict):
for k, v in target.items():
keys.append(k)
if isinstance(v, bool):
types.append("STRING")
elif isinstance(v, int):
types.append("INT")
elif isinstance(v, float):
types.append("FLOAT")
else:
types.append("STRING")
return web.json_response({"keys": keys, "types": types})
class JSONLoaderDynamic:
@classmethod
def INPUT_TYPES(s):
return {
"required": {
"json_path": ("STRING", {"default": "", "multiline": False}),
"sequence_number": ("INT", {"default": 1, "min": 1, "max": 9999}),
},
"optional": {
"output_keys": ("STRING", {"default": ""}),
"output_types": ("STRING", {"default": ""}),
},
}
RETURN_TYPES = tuple(any_type for _ in range(MAX_DYNAMIC_OUTPUTS))
RETURN_NAMES = tuple(f"output_{i}" for i in range(MAX_DYNAMIC_OUTPUTS))
FUNCTION = "load_dynamic"
CATEGORY = "utils/json"
OUTPUT_NODE = False
def load_dynamic(self, json_path, sequence_number, output_keys="", output_types=""):
data = read_json_data(json_path)
target = get_batch_item(data, sequence_number)
keys = [k.strip() for k in output_keys.split(",") if k.strip()] if output_keys else []
results = []
for key in keys:
val = target.get(key, "")
if isinstance(val, bool):
results.append(str(val).lower())
elif isinstance(val, int):
results.append(val)
elif isinstance(val, float):
results.append(val)
else:
results.append(str(val))
while len(results) < MAX_DYNAMIC_OUTPUTS:
results.append("")
return tuple(results)
NODE_CLASS_MAPPINGS = {
"JSONLoaderDynamic": JSONLoaderDynamic,
}
NODE_DISPLAY_NAME_MAPPINGS = {
"JSONLoaderDynamic": "JSON Loader (Dynamic)",
}

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import { app } from "../../scripts/app.js";
import { api } from "../../scripts/api.js";
app.registerExtension({
name: "json.dynamic.loader",
async beforeRegisterNodeDef(nodeType, nodeData, app) {
if (nodeData.name !== "JSONLoaderDynamic") return;
const origOnNodeCreated = nodeType.prototype.onNodeCreated;
nodeType.prototype.onNodeCreated = function () {
origOnNodeCreated?.apply(this, arguments);
// Hide internal widgets (managed by JS)
for (const name of ["output_keys", "output_types"]) {
const w = this.widgets?.find(w => w.name === name);
if (w) { w.type = "hidden"; w.computeSize = () => [0, -4]; }
}
// Remove all 32 default outputs from Python RETURN_TYPES
while (this.outputs.length > 0) {
this.removeOutput(0);
}
// Add Refresh button
this.addWidget("button", "Refresh Outputs", null, () => {
this.refreshDynamicOutputs();
});
this.setSize(this.computeSize());
};
nodeType.prototype.refreshDynamicOutputs = async function () {
const pathWidget = this.widgets?.find(w => w.name === "json_path");
const seqWidget = this.widgets?.find(w => w.name === "sequence_number");
if (!pathWidget?.value) return;
try {
const resp = await api.fetchApi(
`/json_dynamic/get_keys?path=${encodeURIComponent(pathWidget.value)}&sequence_number=${seqWidget?.value || 1}`
);
const { keys, types } = await resp.json();
// Store keys and types in hidden widgets for persistence
const okWidget = this.widgets?.find(w => w.name === "output_keys");
if (okWidget) okWidget.value = keys.join(",");
const otWidget = this.widgets?.find(w => w.name === "output_types");
if (otWidget) otWidget.value = types.join(",");
// Build a map of current output names to slot indices
const oldSlots = {};
for (let i = 0; i < this.outputs.length; i++) {
oldSlots[this.outputs[i].name] = i;
}
// Build new outputs, reusing existing slots to preserve links
const newOutputs = [];
for (let k = 0; k < keys.length; k++) {
const key = keys[k];
const type = types[k] || "*";
if (key in oldSlots) {
// Reuse existing slot object (keeps links intact)
const slot = this.outputs[oldSlots[key]];
slot.type = type;
newOutputs.push(slot);
delete oldSlots[key];
} else {
// New key — create a fresh slot
newOutputs.push({ name: key, type: type, links: null });
}
}
// Disconnect links on slots that are being removed
for (const name in oldSlots) {
const idx = oldSlots[name];
if (this.outputs[idx]?.links?.length) {
for (const linkId of [...this.outputs[idx].links]) {
this.graph?.removeLink(linkId);
}
}
}
// Reassign the outputs array and fix link slot indices
this.outputs = newOutputs;
if (this.graph) {
for (let i = 0; i < this.outputs.length; i++) {
const links = this.outputs[i].links;
if (!links) continue;
for (const linkId of links) {
const link = this.graph.links[linkId];
if (link) link.origin_slot = i;
}
}
}
this.setSize(this.computeSize());
app.graph.setDirtyCanvas(true, true);
} catch (e) {
console.error("[JSONLoaderDynamic] Refresh failed:", e);
}
};
// Restore state on workflow load
const origOnConfigure = nodeType.prototype.onConfigure;
nodeType.prototype.onConfigure = function (info) {
origOnConfigure?.apply(this, arguments);
// Hide internal widgets
for (const name of ["output_keys", "output_types"]) {
const w = this.widgets?.find(w => w.name === name);
if (w) { w.type = "hidden"; w.computeSize = () => [0, -4]; }
}
const okWidget = this.widgets?.find(w => w.name === "output_keys");
const otWidget = this.widgets?.find(w => w.name === "output_types");
const keys = okWidget?.value
? okWidget.value.split(",").filter(k => k.trim())
: [];
const types = otWidget?.value
? otWidget.value.split(",")
: [];
// On load, LiteGraph already restored serialized outputs with links.
// Rename and set types to match stored state (preserves links).
for (let i = 0; i < this.outputs.length && i < keys.length; i++) {
this.outputs[i].name = keys[i].trim();
if (types[i]) this.outputs[i].type = types[i];
}
// Remove any extra outputs beyond the key count
while (this.outputs.length > keys.length) {
this.removeOutput(this.outputs.length - 1);
}
this.setSize(this.computeSize());
};
},
});