Quasi-nested collections can be created but not accessed or deleted

[greenlaw]

FIrst of all, thank you for this project.

I'm just getting started with it (using pgstac backend), and was hoping to be able to set up a hierarchical collection structure according to some of the best practices I've seen, but it appears that stac-fastapi currently only supports a flat structure (i.e., does not support collections-within-collections). Is this correct or am I just approaching it in the wrong way?

I attempted this with a POST to /collections and providing IDs like parentcollection and parentcollection/childcollection, which successfully created both collections, but seemingly at root catalog level and with no relationship to each other.

Additionally, while both are returned when listing all collections (GET /collections), the child collection is inaccessible from the collections/{collection_id} endpoint, so cannot be retrieved/updated/deleted. I also tried with url encoding (GET /collections/parentcollection%2Fchildcollection), but that also doesn't seem to work.

If nested structures or certain characters (like /) are unsupported in identifiers, I would have expected the validation to fail during the initial POST. If nested structures are intended to be supported, then it seems there is a problem with the FastAPI route configuration.

Example:

$ curl -X 'GET' \   
  'http://localhost:10000/collections' \           
  -H 'accept: application/json' | jq  
{
  "collections": [
    {
      "id": "parentcollection",
      "type": "Collection",
      "links": [
        {
          "rel": "items",
          "type": "application/geo+json",
          "href": "http://localhost:10000/collections/parentcollection/items"
        },
        {
          "rel": "parent",
          "type": "application/json",
          "href": "http://localhost:10000/"
        },
        {
          "rel": "root",
          "type": "application/json",
          "href": "http://localhost:10000/"
        },
        {
          "rel": "self",
          "type": "application/json",
          "href": "http://localhost:10000/collections/parentcollection"
        }
      ],
      "title": "parentcollection",
      "assets": null,
      "extent": {
        "spatial": {
          "bbox": [
            [
              0,
              -90,
              360,
              90
            ]
          ]
        },
        "temporal": {
          "interval": [
            [
              null,
              null
            ]
          ]
        }
      },
      "license": "proprietary",
      "keywords": null,
      "providers": [
        {
          "url": "https://www.example.com",
          "name": "Test",
          "roles": [
            "host",
            "producer",
            "processor",
            "licensor"
          ],
          "description": null
        }
      ],
      "summaries": {},
      "description": "description",
      "stac_version": "1.0.0",
      "stac_extensions": null
    },
    {
      "id": "parentcollection/childcollection",
      "type": "Collection",
      "links": [
        {
          "rel": "items",
          "type": "application/geo+json",
          "href": "http://localhost:10000/collections/parentcollection/childcollection/items"
        },
        {
          "rel": "parent",
          "type": "application/json",
          "href": "http://localhost:10000/"
        },
        {
          "rel": "root",
          "type": "application/json",
          "href": "http://localhost:10000/"
        },
        {
          "rel": "self",
          "type": "application/json",
          "href": "http://localhost:10000/collections/parentcollection/childcollection"
        }
      ],
      "title": "parentcollection/childcollection",
      "assets": null,
      "extent": {
        "spatial": {
          "bbox": [
            [
              0.013488,
              -89.72341099999998,
              359.986566,
              89.72348699999999
            ]
          ]
        },
        "temporal": {
          "interval": [
            [
              "2022-01-08T00:00:00",
              null
            ]
          ]
        }
      },
      "license": "proprietary",
      "keywords": null,
      "providers": [
        {
          "url": "https://www.example.com",
          "name": "Test",
          "roles": [
            "host",
            "producer",
            "processor",
            "licensor"
          ],
          "description": null
        }
      ],
      "summaries": {},
      "description": "Child description",
      "stac_version": "1.0.0",
      "stac_extensions": null
    }
  ],
  "links": [
    {
      "rel": "root",
      "type": "application/json",
      "href": "http://localhost:10000/"
    },
    {
      "rel": "parent",
      "type": "application/json",
      "href": "http://localhost:10000/"
    },
    {
      "rel": "self",
      "type": "application/json",
      "href": "http://localhost:10000/collections"
    }
  ]
}

$ curl -X 'GET' \
  'http://localhost:10000/collections/parentcollection/childcollection' \
  -H 'accept: application/json'
{"detail":"Not Found"}

$ curl -X 'DELETE' \
  'http://localhost:10000/collections/parentcollection/childcollection' \
  -H 'accept: application/json'
{"detail":"Not Found"}

$ curl -X 'GET' \   
  'http://localhost:10000/collections/parentcollection%2Fchildcollection' \
  -H 'accept: application/json'    
{"detail":"Not Found"}

[greenlaw]

It looks like this affects not only collections, but also any items with a slash in their identifier. The API is happy to create these records, but there doesn't seem to be a way to access them afterwards.

curl -X 'POST' \
  'http://localhost:10000/collections/testcollection/items' \                                                                       
  -H 'accept: application/json' \  
  -H 'Content-Type: application/json' \
  -d '{"type": "Feature", "geometry": {"type": "Polygon", "coordinates": [[[-4.244302848573078e-06, -89.72341099999998], [-4.244302848573078e-06, 89.72348699999999], [359.986566, 89.72348699999999], [359.986566, -89.72341099999998], [-4.244302848573078e-06, -89.72341099999998]]]}, "properties": {"datetime": "2023-04-20T12:00:00+00:00"}, "id": "item/with/slashes", "bbox": [-4.244302848573078e-06, 89.73697924796991, 360.0000582443028, -89.7369032479699], "stac_version": "1.0.0", "assets": {}, "links": [], "stac_extensions": [], "collection": "testcollection"}'            
{"type":"Feature","stac_version":"1.0.0","stac_extensions":[],"id":"item/with/slashes","geometry":{"type":"Polygon","coordinates":[[[-4.244302848573078e-06,-89.72341099999998],[-4.244302848573078e-06,89.72348699999999],[359.986566,89.72348699999999],[359.986566,-89.72341099999998],[-4.244302848573078e-06,-89.72341099999998]]]},"bbox":[-4.244302848573078e-06,89.73697924796991,360.0000582443028,-89.7369032479699],"properties":{"datetime":"2023-04-20T12:00:00+00:00"},"links":[{"rel":"collection","type":"application/json","href":"http://localhost:10000/collections/testcollection"},{"rel":"parent","type":"application/json","href":"http://localhost:10000/collections/testcollection"},{"rel":"root","type":"application/json","href":"http://localhost:10000/"},{"rel":"self","type":"application/geo+json","href":"http://localhost:10000/collections/testcollection/items/item/with/slashes"}],"assets":{},"collection":"testcollection"}

$ curl -X 'GET' \
  'http://localhost:10000/collections/testcollection/items' \       
  -H 'accept: application/geo+json'
{"type":"FeatureCollection","context":{"limit":10,"returned":1},"features":[{"id":"item/with/slashes","bbox":[-4.244302848573078e-6,89.73697924796991,360.0000582443028,-89.7369032479699],"type":"Feature","links":[{"rel":"collection","type":"application/json","href":"http://localhost:10000/collections/testcollection"},{"rel":"parent","type":"application/json","href":"http://localhost:10000/collections/testcollection"},{"rel":"root","type":"application/json","href":"http://localhost:10000/"},{"rel":"self","type":"application/geo+json","href":"http://localhost:10000/collections/testcollection/items/item/with/slashes"}],"assets":{},"geometry":{"type":"Polygon","coordinates":[[[-4.24430284857308e-6,-89.72341099999998],[-4.24430284857308e-6,89.72348699999999],[359.986566,89.72348699999999],[359.986566,-89.72341099999998],[-4.24430284857308e-6,-89.72341099999998]]]},"collection":"testcollection","properties":{"datetime":"2023-04-20T12:00:00+00:00"},"stac_version":"1.0.0","stac_extensions":[]}],"links":[{"rel":"collection","type":"application/json","href":"http://localhost:10000/collections/testcollection"},{"rel":"parent","type":"application/json","href":"http://localhost:10000/collections/testcollection"},{"rel":"root","type":"application/json","href":"http://localhost:10000/"},{"rel":"self","type":"application/geo+json","href":"http://localhost:10000/collections/testcollection/items"}]}

$ curl -X 'GET' \ 
  'http://localhost:10000/collections/testcollection/items/item/with/slashes' \
  -H 'accept: application/geo+json'  
{"detail":"Not Found"}

$ curl -X 'GET' \
  'http://localhost:10000/collections/testcollection/items/item%2Fwith%2Fslashes' \
  -H 'accept: application/geo+json'
{"detail":"Not Found"}

[gadomski]

If nested structures or certain characters (like /) are unsupported in identifiers, I would have expected the validation to fail during the initial POST.

I think that's a fair assumption. I'm going to move this issue to stac-fastapi-pgstac, and create a copy of it in stac-fastapi-sqlalchemy, as those checks need to be added at the backend level.