Differentiate no results from invalid/unsupported filters

[merkys]

When searching for spacegroup="P1" on https://optimade.science, all providers but MPDS result in "No results". However, filter spacegroup="P1" is not defined in the OPTIMADE standard, thus it is nonstandard. Therefore, replies "No results" from other providers give false impressions that these databases do not contain P1 structures, which some of them do. Therefore I propose catching HTTP 4xx and 5xx from providers and reporting them as such.

[blokhin]

Accepted. I couldn't believe no other providers can handle such queries!

[blokhin]

Do you know how exactly the spacegroups can be queried?

[merkys]

Do you know how exactly the spacegroups can be queried?

Currently, however, the specification does not have means to query spacegroups.

I can think of two methods to detect and report invalid/unsupported queries:

1. Send the user-typed query to each provider and then inspect the HTTP return status. This method will allow individual providers to support nonstandard queries, just like MPDS supports spacegroup.
2. Parse the query to immediately report invalid/unsupported (as per the specification) queries. This should be more difficult to implement, but would reduce the load on the providers.

[blokhin]

Alright. I better remove the example with the spacegroup then. I expected this is fully valid example.

[merkys]

Alright. I better remove the example with the spacegroup then. I expected this is fully valid example.

It is not valid, indeed. Moreover, according to the specification, / symbols in filter strings must be percent-encoded. This is the reason why spacegroup= queries originating from https://optimade.science caught my eye in the first place. Probably percent-encoding issue should be better posted as a separate GitHub issue.

[blokhin]

Closed by the 2.0.2 release of https://github.com/tilde-lab/optimade-client

[blokhin]

Re-opening wrt Materials-Consortia/OPTIMADE#405