Bug: Filter passes query validation, but the filter is not applied

[bart-degreed]

Description

Consider the request:

/documents/1?include=collaborators&filter[collaborators.first-name]=like:john

This request passes query validation, but the filter is not applied. It returns all collaborators. This is likely caused by EF Core not supporting filtered includes. In contrast, the next request:

/documents/1/collaborators?filter[first-name]=like:john

returns the next error message:

Query parameter filter is currently not supported on nested resource endpoints (i.e. of the form '/article/1/author?filter=...'

which is helpful. I think the fix would be to return the same error message in this case, instead of silently ignoring the filter.

Environment

v4.0.0-alpha4

[bart-degreed]

I was looking into fixing this, but unfortunately the error is raised from within the query string parsing logic. Since I'm actually using the nested filtering construct for Elasticsearch-based resources (non-Entity Framework Core), I'll leave the bug in for now.

[maurei]

This should be a fairly easy issue to pick up for anyone out there looking to make a first contribution. Indeed, it looks like a validation issue in the corresponding IQueryParameterService implementation.

[bart-degreed]

For my use case, it is unfortunate that the query validation logic is implemented apart from the resource-specific service that can or cannot provide nested includes. To overcome that, the IResourceService would need to have some mechanism to expose its capabilities.

I haven't tried, but maybe we can add a capabilities property to IFilterService or its base, and then have IResourceService assign that from its constructor.

[bart-degreed]

This works correctly for 1-to-1 relationships, but crashes on 1-to-many.

filtered: /articles?include=author&filter[author.firstName]=John
crash: /blogs?include=articles&filter[articles.title]=like:art

In addition to this, the filtering pass does not execute when getting by ID.

discarded: /articles/1?include=author&filter[author.firstName]=John
discarded: /blogs/1?include=articles&filter[articles.title]=like:art