Using {{$runIndex}} to save base64 shows me an undefined file

Roee_Aizman · September 23, 2025, 2:50pm

I downloaded 2 files

And I am runnign a loop to save them in different names “generated_image_{{$runIndex}}” using a loop

It does save them as generated_image_0 and generated_image_1, however when I am trying to use the second one (generated_image_1 it shows it as a null or undefined.

What can it be?

Roee_Aizman · September 23, 2025, 2:52pm

Share the output returned by the last node

“output”: “undeffined”

Expected output

“output”: “the model image base64

Information on your n8n setup

n8n version: 1.107.3
Database (default: SQLite): default
n8n EXECUTIONS_PROCESS setting (default: own, main): sorry have no idea
Running n8n via (Docker, npm, n8n cloud, desktop app): n8n cloud
Operating system:

Wouter_Nigrini · September 23, 2025, 3:03pm

Please can you share your workflow in a code block so we can try and see what the issue is?

Roee_Aizman · September 23, 2025, 4:29pm

Of course.

How can I share it without the credentials?

Roee_Aizman · September 23, 2025, 5:00pm

Here is the lfow:

</>

{
“nodes”: [
{
“parameters”: {
“httpMethod”: “POST”,
“path”: “148270d8-f42b-41ef-8334-688d4d9da647”,
“options”: {}
},
“type”: “n8n-nodes-base.webhook”,
“typeVersion”: 2.1,
“position”: [
-96,
-80
],
“id”: “13fd0db3-eef1-4d38-a9a0-b159ef8f9c3c”,
“name”: “Webhook”,
“webhookId”: “148270d8-f42b-41ef-8334-688d4d9da647”
},
{
“parameters”: {
“operation”: “toBinary”,
“sourceProperty”: “candidates[0].content.parts[0].inlineData.data”,
“binaryPropertyName”: “=generated_image”,
“options”: {
“fileName”: “generated_image2”
}
},
“type”: “n8n-nodes-base.convertToFile”,
“typeVersion”: 1.1,
“position”: [
1472,
-272
],
“id”: “8b060caf-e2cf-4abd-9ac9-8270b77f1e5c”,
“name”: “Save final results”
},
{
“parameters”: {
“url”: “={{ $json.url }}”,
“options”: {
“response”: {
“response”: {
“responseFormat”: “file”
}
}
}
},
“type”: “n8n-nodes-base.httpRequest”,
“typeVersion”: 4.2,
“position”: [
496,
-112
],
“id”: “39f26c04-6365-4b9a-94f3-ee371ed5de57”,
“name”: “HTTP Request”
},
{
“parameters”: {
“operation”: “binaryToPropery”,
“destinationKey”: “=generated_image_{{$runIndex}}”,
“options”: {}
},
“type”: “n8n-nodes-base.extractFromFile”,
“typeVersion”: 1,
“position”: [
1200,
32
],
“id”: “3aecd95e-2bcc-4ec6-8cf4-2fa4b70e8dd6”,
“name”: “Extract from File”
},
{
“parameters”: {
“assignments”: {
“assignments”: [
{
“id”: “e8249f97-507c-4162-9c2a-58ffe6dfff25”,
“name”: “change”,
“value”: “Create a professional e-commerce fashion photo. Take the cloth from the first image and let the model from the second image wear it. Generate a realistic, full-body shot of the model wearing the cloth, with the lighting and shadows adjusted to match the same environment of the model, the result should be the same model in the same environment wearnig the cloth”,
“type”: “string”
}
]
},
“options”: {}
},
“type”: “n8n-nodes-base.set”,
“typeVersion”: 3.4,
“position”: [
96,
-112
],
“id”: “f5f35748-61a5-47fa-b663-96cfc2a5bbfe”,
“name”: “Edit Fields8”
},
{
“parameters”: {
“jsCode”: “const images = $(‘Webhook’).first().json.body.images;\n\nreturn images.map(img => {\n return {\n json: {\n url: img.url,\n type: img.type\n }\n };\n});\n”
},
“type”: “n8n-nodes-base.code”,
“typeVersion”: 2,
“position”: [
288,
-80
],
“id”: “2698c469-3315-4385-a393-bea4921ff61e”,
“name”: “Code”
},
{
“parameters”: {
“options”: {}
},
“type”: “n8n-nodes-base.splitInBatches”,
“typeVersion”: 3,
“position”: [
736,
-96
],
“id”: “1b7f6c5b-78d1-4580-8e66-b0375c9cf5fa”,
“name”: “Loop Over Items”
},
{
“parameters”: {
“assignments”: {
“assignments”: [
{
“id”: “c84c58c3-3a8a-4e82-8414-ca602730eb97”,
“name”: “product”,
“value”: “={{ $json.generated_image_0 }}”,
“type”: “string”
},
{
“id”: “15448af7-97aa-40f5-a36b-3202cbac23ea”,
“name”: “model”,
“value”: “={{ $json.generated_image_1 }}”,
“type”: “string”
}
]
},
“options”: {}
},
“type”: “n8n-nodes-base.set”,
“typeVersion”: 3.4,
“position”: [
1024,
-192
],
“id”: “edc27be1-646c-4c1d-9edc-4964bbbafdcf”,
“name”: “Edit Fields”
},
{
“parameters”: {
“method”: “POST”,
“url”: “https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash-image-preview:generateContent”,
“sendHeaders”: true,
“headerParameters”: {
“parameters”: [
{
“name”: “x-goog-api-key”,
“value”: “yBa”
}
]
},
“sendBody”: true,
“specifyBody”: “json”,
“jsonBody”: "={\n “contents”: [\n {\n “parts”: [\n {\n “inline_data”: {\n “mime_type”: “image/png”,\n “data”: “{{ $json.product }}”\n }\n },\n {\n “inline_data”: {\n “mime_type”: “image/jpeg”,\n “data”: “{{ $json.model }}”\n }\n },\n {\n “text”: “{{ $(‘Edit Fields8’).item.json.change }}”\n }\n ]\n }\n ]\n} ",
“options”: {}
},
“type”: “n8n-nodes-base.httpRequest”,
“typeVersion”: 4.2,
“position”: [
1264,
-240
],
“id”: “68521d8d-60eb-41f0-a33e-48195acc7d5f”,
“name”: “Model wears the cloth”
}
],
“connections”: {
“Webhook”: {
“main”: [
[
{
“node”: “Edit Fields8”,
“type”: “main”,
“index”: 0
}
]
]
},
“HTTP Request”: {
“main”: [
[
{
“node”: “Loop Over Items”,
“type”: “main”,
“index”: 0
}
]
]
},
“Extract from File”: {
“main”: [
[
{
“node”: “Loop Over Items”,
“type”: “main”,
“index”: 0
}
]
]
},
“Edit Fields8”: {
“main”: [
[
{
“node”: “Code”,
“type”: “main”,
“index”: 0
}
]
]
},
“Code”: {
“main”: [
[
{
“node”: “HTTP Request”,
“type”: “main”,
“index”: 0
}
]
]
},
“Loop Over Items”: {
“main”: [
[
{
“node”: “Edit Fields”,
“type”: “main”,
“index”: 0
}
],
[
{
“node”: “Extract from File”,
“type”: “main”,
“index”: 0
}
]
]
},
“Edit Fields”: {
“main”: [
[
{
“node”: “Model wears the cloth”,
“type”: “main”,
“index”: 0
}
]
]
},
“Model wears the cloth”: {
“main”: [
[
{
“node”: “Save final results”,
“type”: “main”,
“index”: 0
}
]
]
}
},
“pinData”: {
“Webhook”: [
{
“headers”: {
“host”: “n8n.roeeaizman.com”,
“user-agent”: “Deno/2.3.1”,
“content-length”: “637”,
“accept”: “/”,
“accept-encoding”: “gzip,br”,
“accept-language”: “*”,
“cdn-loop”: “deno;s=deno;d=f67vaeed9zzc”,
“content-type”: “application/json”,
“via”: “2.0 Caddy”,
“x-forwarded-for”: “35.236.74.252”,
“x-forwarded-host”: “n8n.roeeaizman.com”,
“x-forwarded-proto”: “https”
},
“params”: {},
“query”: {},
“body”: {
“project_id”: “68d2970ebce4185676a1a08e”,
“images”: [
{
“image_number”: 1,
“type”: “product”,
“url”: “https://base44.app/api/apps/68d25b21170607c38292d2b2/files/public/68d25b21170607c38292d2b2/3c5d46d2b_f59e29cbc_15e33569-dd21-4395-93d3-3331a17ab627.png”,
“order”: 1
},
{
“image_number”: 2,
“type”: “model”,
“url”: “https://base44.app/api/apps/68d25b21170607c38292d2b2/files/public/68d25b21170607c38292d2b2/efdbc4c77_model.jpg”
}
],
“total_product_images”: 1,
“total_images”: 2,
“timeout”: 300,
“callback_instructions”: “Generate high-quality fashion visualizations showing the model wearing the products from multiple angles including front, side, and back views.”
},
“webhookUrl”: “https://n8n.roeeaizman.com/webhook-test/13dbf528-a666-4d82-bf3e-5998da0f8b1e”,
“executionMode”: “test”
}
]
},
“meta”: {
“instanceId”: “3efbe569e558a18a54352d7073a74807fb3f352c1b3f6b3fdfb719b0cd89fe51”
}
}

</>

Roee_Aizman · September 23, 2025, 5:01pm

<{
“nodes”: [
{
“parameters”: {
“httpMethod”: “POST”,
“path”: “148270d8-f42b-41ef-8334-688d4d9da647”,
“options”: {}
},
“type”: “n8n-nodes-base.webhook”,
“typeVersion”: 2.1,
“position”: [
-96,
-80
],
“id”: “13fd0db3-eef1-4d38-a9a0-b159ef8f9c3c”,
“name”: “Webhook”,
“webhookId”: “148270d8-f42b-41ef-8334-688d4d9da647”
},
{
“parameters”: {
“operation”: “toBinary”,
“sourceProperty”: “candidates[0].content.parts[0].inlineData.data”,
“binaryPropertyName”: “=generated_image”,
“options”: {
“fileName”: “generated_image2”
}
},
“type”: “n8n-nodes-base.convertToFile”,
“typeVersion”: 1.1,
“position”: [
1472,
-272
],
“id”: “8b060caf-e2cf-4abd-9ac9-8270b77f1e5c”,
“name”: “Save final results”
},
{
“parameters”: {
“url”: “={{ $json.url }}”,
“options”: {
“response”: {
“response”: {
“responseFormat”: “file”
}
}
}
},
“type”: “n8n-nodes-base.httpRequest”,
“typeVersion”: 4.2,
“position”: [
496,
-112
],
“id”: “39f26c04-6365-4b9a-94f3-ee371ed5de57”,
“name”: “HTTP Request”
},
{
“parameters”: {
“operation”: “binaryToPropery”,
“destinationKey”: “=generated_image_{{$runIndex}}”,
“options”: {}
},
“type”: “n8n-nodes-base.extractFromFile”,
“typeVersion”: 1,
“position”: [
1200,
32
],
“id”: “3aecd95e-2bcc-4ec6-8cf4-2fa4b70e8dd6”,
“name”: “Extract from File”
},
{
“parameters”: {
“assignments”: {
“assignments”: [
{
“id”: “e8249f97-507c-4162-9c2a-58ffe6dfff25”,
“name”: “change”,
“value”: “Create a professional e-commerce fashion photo. Take the cloth from the first image and let the model from the second image wear it. Generate a realistic, full-body shot of the model wearing the cloth, with the lighting and shadows adjusted to match the same environment of the model, the result should be the same model in the same environment wearnig the cloth”,
“type”: “string”
}
]
},
“options”: {}
},
“type”: “n8n-nodes-base.set”,
“typeVersion”: 3.4,
“position”: [
96,
-112
],
“id”: “f5f35748-61a5-47fa-b663-96cfc2a5bbfe”,
“name”: “Edit Fields8”
},
{
“parameters”: {
“jsCode”: “const images = $(‘Webhook’).first().json.body.images;\n\nreturn images.map(img => {\n return {\n json: {\n url: img.url,\n type: img.type\n }\n };\n});\n”
},
“type”: “n8n-nodes-base.code”,
“typeVersion”: 2,
“position”: [
288,
-80
],
“id”: “2698c469-3315-4385-a393-bea4921ff61e”,
“name”: “Code”
},
{
“parameters”: {
“options”: {}
},
“type”: “n8n-nodes-base.splitInBatches”,
“typeVersion”: 3,
“position”: [
736,
-96
],
“id”: “1b7f6c5b-78d1-4580-8e66-b0375c9cf5fa”,
“name”: “Loop Over Items”
},
{
“parameters”: {
“assignments”: {
“assignments”: [
{
“id”: “c84c58c3-3a8a-4e82-8414-ca602730eb97”,
“name”: “product”,
“value”: “={{ $json.generated_image_0 }}”,
“type”: “string”
},
{
“id”: “15448af7-97aa-40f5-a36b-3202cbac23ea”,
“name”: “model”,
“value”: “={{ $json.generated_image_1 }}”,
“type”: “string”
}
]
},
“options”: {}
},
“type”: “n8n-nodes-base.set”,
“typeVersion”: 3.4,
“position”: [
1024,
-192
],
“id”: “edc27be1-646c-4c1d-9edc-4964bbbafdcf”,
“name”: “Edit Fields”
},
{
“parameters”: {
“method”: “POST”,
“url”: “https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash-image-preview:generateContent”,
“sendHeaders”: true,
“headerParameters”: {
“parameters”: [
{
“name”: “x-goog-api-key”,
“value”: “yBa”
}
]
},
“sendBody”: true,
“specifyBody”: “json”,
“jsonBody”: "={\n “contents”: [\n {\n “parts”: [\n {\n “inline_data”: {\n “mime_type”: “image/png”,\n “data”: “{{ $json.product }}”\n }\n },\n {\n “inline_data”: {\n “mime_type”: “image/jpeg”,\n “data”: “{{ $json.model }}”\n }\n },\n {\n “text”: “{{ $(‘Edit Fields8’).item.json.change }}”\n }\n ]\n }\n ]\n} ",
“options”: {}
},
“type”: “n8n-nodes-base.httpRequest”,
“typeVersion”: 4.2,
“position”: [
1264,
-240
],
“id”: “68521d8d-60eb-41f0-a33e-48195acc7d5f”,
“name”: “Model wears the cloth”
}
],
“connections”: {
“Webhook”: {
“main”: [
[
{
“node”: “Edit Fields8”,
“type”: “main”,
“index”: 0
}
]
]
},
“HTTP Request”: {
“main”: [
[
{
“node”: “Loop Over Items”,
“type”: “main”,
“index”: 0
}
]
]
},
“Extract from File”: {
“main”: [
[
{
“node”: “Loop Over Items”,
“type”: “main”,
“index”: 0
}
]
]
},
“Edit Fields8”: {
“main”: [
[
{
“node”: “Code”,
“type”: “main”,
“index”: 0
}
]
]
},
“Code”: {
“main”: [
[
{
“node”: “HTTP Request”,
“type”: “main”,
“index”: 0
}
]
]
},
“Loop Over Items”: {
“main”: [
[
{
“node”: “Edit Fields”,
“type”: “main”,
“index”: 0
}
],
[
{
“node”: “Extract from File”,
“type”: “main”,
“index”: 0
}
]
]
},
“Edit Fields”: {
“main”: [
[
{
“node”: “Model wears the cloth”,
“type”: “main”,
“index”: 0
}
]
]
},
“Model wears the cloth”: {
“main”: [
[
{
“node”: “Save final results”,
“type”: “main”,
“index”: 0
}
]
]
}
},
“pinData”: {
“Webhook”: [
{
“headers”: {
“host”: “n8n.roeeaizman.com”,
“user-agent”: “Deno/2.3.1”,
“content-length”: “637”,
“accept”: “/”,
“accept-encoding”: “gzip,br”,
“accept-language”: “*”,
“cdn-loop”: “deno;s=deno;d=f67vaeed9zzc”,
“content-type”: “application/json”,
“via”: “2.0 Caddy”,
“x-forwarded-for”: “35.236.74.252”,
“x-forwarded-host”: “n8n.roeeaizman.com”,
“x-forwarded-proto”: “https”
},
“params”: {},
“query”: {},
“body”: {
“project_id”: “68d2970ebce4185676a1a08e”,
“images”: [
{
“image_number”: 1,
“type”: “product”,
“url”: “https://base44.app/api/apps/68d25b21170607c38292d2b2/files/public/68d25b21170607c38292d2b2/3c5d46d2b_f59e29cbc_15e33569-dd21-4395-93d3-3331a17ab627.png”,
“order”: 1
},
{
“image_number”: 2,
“type”: “model”,
“url”: “https://base44.app/api/apps/68d25b21170607c38292d2b2/files/public/68d25b21170607c38292d2b2/efdbc4c77_model.jpg”
}
],
“total_product_images”: 1,
“total_images”: 2,
“timeout”: 300,
“callback_instructions”: “Generate high-quality fashion visualizations showing the model wearing the products from multiple angles including front, side, and back views.”
},
“webhookUrl”: “https://n8n.roeeaizman.com/webhook-test/13dbf528-a666-4d82-bf3e-5998da0f8b1e”,
“executionMode”: “test”
}
]
},
“meta”: {
“instanceId”: “3efbe569e558a18a54352d7073a74807fb3f352c1b3f6b3fdfb719b0cd89fe51”
}
}/>

krisn0x · September 23, 2025, 5:11pm

Please try sharing it once more like so

Roee_Aizman · September 23, 2025, 5:13pm

I cant share it as the canvas, I don’t know how to do it so I dont want to share again.
Only if I understand how to do it right

krisn0x · September 23, 2025, 5:16pm

You can either follow my gif example, or you can export it as JSON and upload it to G Drive. None of these methods will export your credentials so don’t worry.

Edit: here it is again, my bad

Roee_Aizman · September 23, 2025, 5:18pm

Hey.

This is my workflow:

Roee_Aizman · September 23, 2025, 5:24pm

Roee_Aizman · September 23, 2025, 5:25pm

Done @krisn0x and @Wouter_Nigrini

krisn0x · September 23, 2025, 5:34pm

Here you go! Feel free to mark this as Solution if it helped

Roee_Aizman · September 23, 2025, 6:03pm

Wow!!!

So Why it happened to me as it was undefined?

Just an aggregate

Thanks a lot @krisn0x

krisn0x · September 23, 2025, 6:08pm

The data is there, but it’s arriving in separate items. While in your Set Fields node you try to get all items at the same time. There is a difference in n8n whenever data is split into items vs all items into 1 object. You can manipulate this with the Split out and Aggregate nodes

Anytime! Like if it helped Mark as Solution if I solved it

Roee_Aizman · September 23, 2025, 6:44pm

I tried to split before.Anyway Thanks a lot, however I still cannot send the binary to the respond of the webhook.Any case you understand why?

krisn0x · September 23, 2025, 7:29pm

what’s the issue there? can you grab a screenshot of the problematic node with its input and output?

Roee_Aizman · September 24, 2025, 3:34am

Hey @krisn0x thanks for being with me

I am getting a webhook and wait for the last respond to webhook to send the generated image from nano banana

the problem is that the client (base44 or postman) does not wait for the response of the respond to webhook.:

Roee_Aizman · September 24, 2025, 3:51am

should be with some more cotent inside

Wouter_Nigrini · September 24, 2025, 8:53am

The credentials should be stripped unless you had them hardcoded in headers etc, then you must just delete it first