curl --request POST \
  --url https://api.thehaystack.ai/v2/haystack/items/{itemId}/resources/create \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "title": "<string>",
  "contentType": "file",
  "subTitle": "<string>",
  "description": "<string>",
  "resourceTypeId": 123,
  "fileMimeType": "application/pdf",
  "fileSizeBytes": 1048576,
  "originalFilename": "<string>",
  "linkTarget": "<string>",
  "externalPlatform": "youtube",
  "externalPlatformId": "dQw4w9WgXcQ"
}
'

{
  "resource": {
    "id": 123,
    "itemId": 123,
    "title": "<string>",
    "subTitle": "<string>",
    "description": "<string>",
    "resourceTypeId": 123,
    "displayOrder": 123,
    "contentType": "file",
    "fileMimeType": "<string>",
    "fileSizeBytes": 123,
    "externalPlatform": "youtube",
    "externalPlatformId": "<string>",
    "thumbnailImgUrl": "<string>",
    "url": "<string>",
    "resourceType": {
      "id": 123,
      "name": "<string>"
    },
    "linkTarget": "<string>"
  },
  "uploadUrl": "https://s3.amazonaws.com/bucket/key?signature=..."
}