Facebook Pages: How to post multiple photos to a single post from a Data Store array?

How To
1

Hi guys

I’m building a two-scenario approval system and I’m stuck on the final step: posting multiple photos to a single Facebook post.

Here is my workflow:

  1. Scenario 1: A LIFF form sends data (including an array of public Supabase URLs called imageUrls) to a webhook. This data is then saved to a Data Store record. This part works perfectly.

  2. Scenario 2: This scenario triggers when I approve the post via a LINE postback. It successfully gets the record from the Data Store. I can see the complete array of imageUrls in the output.

The Problem: I am now trying to send this array of URLs to the Facebook Pages > Create a Post module.

Based on community advice, I have tried the following in the Attachments > Media field:

  • I enabled the Map toggle.

  • I used the formula: {{map(3.imageUrls; "url")}}

However, this is not working. I have encountered two different errors depending on small changes:

  • BundleValidationError: Array of objects expected in parameter 'photos'.

  • BundleValidationError: Missing value of required parameter 'photos'.

It feels like my imageUrls array from the Data Store isn’t being transformed correctly by the map() function for the Facebook module. If I try to post just a single image {{3.imageUrls[0]}} (without the map function), it works, but that’s not what I need.

Could anyone please advise on the correct way to map an array of text URLs from a Data Store to the Media attachment field for creating a single post with multiple photos?

Thank you so much for your help!

Best regards.

3

Hey there,

the map() function creates a primitive array, which most likely doesn’t work here. Check the documentation for the exact structure you are looking for and transform the array to match that.