Unique Constraints on multiple columns?

[osseonews]

How would you create a unique constraint on multiple columns with Contember? For example, we store inventory at multiple warehouses. So we have a join table with WarehouseInventory, with foreign key back to a product_id and warehouse_id. The constraint is that a warehouse_id and product_id are unique, in that you can't have the same product stored twice at the same warehouse. Hope this makes sense.

[jonasnobile]

Hi @osseonews, thanks for your question. It's quite easy to define a unique constraint in Contember. You can use the Unique decorator to define unique constraint on multiple columns (see).

Here is simplified code how to solve your example:

import { SchemaDefinition as def } from '@contember/schema-definition'

@def.Unique('product', 'warehouse')
export class WarehouseInventory {
  product = def.manyHasOne(Product, 'inventory')
  warehouse = def.manyHasOne(Warehouse, 'inventory')
}

[osseonews]

Thanks for the quick response! Instead of opening up a new discussion, I had one other quick question. Where are the images stored in Contember cloud? When we create an Image field, it automatically creates an upload and we can upload images. But where are these images and how to access them outside of cloud? Is there an Image API of some sort? Can we export the images and host elsewhere?

[osseonews]

Thanks. So I guess, we can upload the images with Contember, then with an Action call a webhook which would then get the image and upload it to another server? Is that a possible workaround? BTW, your AI is simply incredible and a huge timesaver. I had looked at Contember around a year ago, but it was a bit too complex to set up. Now with the AI and Cloud, this is simply an incredible system. Congrats!

[matej21]

If you wish, you can entirely replace the "uploader" in your admin interface and upload it directly to your server.
Though this isn't currently documented, you can implement the FileUploader interface. For guidance, you can check the default S3 uploader and use it as a reference.
Then you just set the uploader prop of upload components.

[honzasladek]

Btw quick question @osseonews: what's your use case to upload images elsewhere? (Just curious here.)

[osseonews]

We use Cloudflare for images. It's just much better than S3 for various reasons. So we need to upload the images to cloudflare and then we get the Cloudflare Image id and can call it in our app. https://www.cloudflare.com/developer-platform/cloudflare-images/

[honzasladek]

@osseonews Thanks! We use Cloudflare Images as well but keep the images in S3 - works like a charm. Here's a very simple Cloudflare worker that will do the job (whitelists the data.eu.cntmbr.com where Contember stores the data.). It just a simple example (though works fine) for inspiration.

addEventListener('fetch', event => {
  event.respondWith(handleRequest(event.request))
})


async function handleRequest(request) {
  const whiteListOrigins = [
    'data.eu.cntmbr.com',
    'www.whatever-domain-you-want.com',
  ]
  const requestURL = new URL(request.url)
  const pathname = requestURL.pathname.split('/')

  // Check if source origin is allowed
  if(!whiteListOrigins.includes(pathname[1])) {
    return new Response("Your origin is not in allowed list.", { status: 403 })
  }

  const accept = request.headers.get('accept')
  let defaultFormat
  if (/image\/avif/.test(accept)) {
    defaultFormat = 'avif'
  } else if (/image\/webp/.test(accept)) {
    defaultFormat = 'webp'
  }

  // Get resize options from searchParams
  const width = requestURL.searchParams.get('width')
  const height = requestURL.searchParams.get('height')
  const format = requestURL.searchParams.get('format') ?? defaultFormat
  const quality = requestURL.searchParams.get('quality')
  const fit = requestURL.searchParams.get('fit')

  // Remove first /
  pathname.shift()

  return fetch('https://' + pathname.join('/'),
    {
      cf: {
        image: {
          width,
          height,
          format,
          quality,
          fit,
        }
      },
    }
  )
}