issue_comments

@simonw:

The problem there is that ?_size=x isn't actually doing the same thing as the SQL limit keyword.

Interesting! Although I don't think it matters too much what the underlying implementation is - I more meant that limit is familiar to developers conceptually as "up to and including this number, if they exist", whereas "size" is potentially more ambiguous. However, it's probably no big deal either way.

I think it’s a good idea if the top level item of the response JSON is always an object, rather than an array, at least as the default.

I agree it is more predictable if the top level item is an object with a rows or data object that contains an array of data, which then allows for other top-level meta data.

I can see the argument for removing this and just using an array for convenience - but I think that's OK as an option (as you have now).

Rather than have lots of top-level keys you could have a "meta" object to contain non-data stuff. You could use something like "links" for API endpoint URLs (or use a standard like HAL). Which would then leave the top level a bit cleaner - if that's what you what.

Have you had much feedback from users who use the Datasette API a lot?

Minor suggestion: rename size query param to limit, to better reflect that it’s a maximum number of rows returned rather than a guarantee of getting that number, and also for consistency with the SQL keyword?

I like the idea of specifying a limit of 0 if you don’t want any rows data - and returning an empty array under the rows key seems fine.

Have you given any thought as to whether to pretty print (format with spaces) the output or not? Can be useful for debugging/exploring in a browser or other basic tools which don’t parse the JSON. Could be default (can’t be much bigger with gzip?) or opt-in.

I think it’s a good idea if the top level item of the response JSON is always an object, rather than an array, at least as the default. Mainly because it allows you to add extra keys in a backwards-compatible way. Also just seems more expected somehow.

The API design guidance for the UK government also recommends this: https://www.gov.uk/guidance/gds-api-technical-and-data-standards#use-json

I also strongly dislike having versioned APIs (eg with a /v1/ path prefix, as it invariably means that old versions stop working at some point, even though the bit of the API you’re using might not have changed at all.

I vote against headers. It has a lot of strikes against it: poor discoverability, new developers often don’t know how to use them, makes CORS harder, makes it hard to use eg with JQ, needs ad hoc specification for each bit of metadata, etc.

The only advantage of headers is that you don’t need to do .rows, but that’s actually good as a data validation step anyway—if .rows is missing assume there’s an error and do your error handling path instead of parsing the rest.