Going through the SDK docs, why was a scheme like 'http://localhost:8000::people' chosen instead of the plain old 'http://localhost:8000/people'? Are there any benefits? If yes, curious to know what they are.
In this case, we need to be able to address either a database and a dataset. The presence of a :: makes it unambiguous.
In our sample data (see https://github.com/attic-labs/noms/blob/master/doc/cli-tour.... for example) we actually have this exact path, and the database is "http://demo.noms.io/cli-tour" and the dataset is "sf-fire-inspections/raw". We need the "::".
Allowing "/" in a dataset name is very convenient (it's common in git branches). Allowing "/" in database names is essential for URLs.
- I remember the Rails community trying to use `;` which broke Mongrel 1. Mongrel's parser was generated from the RFC. There was a huge flame war about that back in the day. The Rails core team at the time thought that Mongrel should make an exception to a reserved character. (And after all was said and done, it got changed back to `/` for that particular use-case).
- When working on IPv6 support about 3 years ago, one of the things I added to an open source Ruby project was IPv6 literals into the URL. This was a case of using `:`. Even though this was defined in the RFC specifying the literal, I found out at that time the Ruby standard library was written in a way that assumes you would never have `:` in the URL other than to delimit the port. I ended up having to do some workarounds for that.
That's with Ruby. I wouldn't be surprised if many other extant libraries parsing URLs that might break -- at least not without escaping those characters.
See: https://perishablepress.com/stop-using-unsafe-characters-in-...
You don't NEED ":". You NEED some sort of delimiter that can clearly distinguish between database and dataset; you happen to pick ':' to satisfy that. There might be a different delimiter that works better.
The other option is to not pretend that is a URL and call that something else.
Post-script: I think this project is a great idea. I'm looking forward to see how it turns out.
So:
http://localhost:8000::dataset
may break code that tries to discern the host name. However:
http://localhost:8000/::dataset
Might not. Further, you could also reserve `_` in your scheme to refer to the default database:
http://localhost:8000/_::dataset
But as I mentioned in my previous reply, there may be unintended consequences. If this is something you guys want to do (and have HTTP/HTTPS URL compatibility) to check it out on different language/platform and see if your scheme breaks things. (And definitely see if Windows library assumes this; Windows file paths uses `:` as a reserved character)
groovy -e "new URL('http://localhost:8000::people')" Caught: java.net.MalformedURLException
Python breaks:
>>> urlparse('http://localhost:8000::people') ParseResult(scheme='http', netloc='localhost:8000::people', path='', params='', query='', fragment='')
You could easily say everything before either ? or ; always refers to a database, and use a query parameter or a semicolon to delineate a dataset. Or you resource paths:
Address a dataset:
http://demo.noms.io/?dataset=cli-tour/sf-fire-inspections/raw
http://demo.noms.io/;cli-tour/sf-fire-inspections/raw
http://demo.noms.io/dataset/cli-tour/sf-fire-inspections/raw
http://demo.noms.io/database/cli-tour/sf-fire-inspections
http://demo.noms.io/catalog/cli-tour/sf-fire-inspections
http://demo.noms.io/database/cli-tour/sf-fire-inspections;raw
http://demo.noms.io/database/cli-tour/sf-fire-inspections?dataset=raw http://demo.noms.io/cli-tour#sf-fire-inspections/raw
To clarify, we don't think of these specs as URLs. The part before the final double-colon is a URL. To parse one, you get the final double colon, and take everything to the left as a URL.
There's some info on the syntax here:
https://github.com/attic-labs/noms/blob/master/doc/spelling....
Though it's not presented as a formal grammar in that doc, our most important criteria for the syntax was:
- unambiguousness
- interacts well with the shell, since we frequently use these as part of command linesThat makes it a lot clearer. :). Looking forward to take noms for a spin soon.
But everyone else will because you are including the protocol, and at the end of the day, they are a uniform way of identifying a resource, so they are functionally URIs.
Otherwise, you should probably either conform to the HTTP(S) protocol spec or makeup your own, e.g. noms+http://dbinstance.noms.foo::database/dataset
SQLAlchemy and most DB URIs are good examples on how to do this. For example, you can connect to a MySQL database instance and give it a default namespace/schema/database.
Part of the issue here is the ambiguity between a database, a database instance/server/host, a dataset/table, a catalog/namespace/schema, and what all those words and concepts mean. There's little consensus across fields, because even if computer scientists say "Okay, this is what a dataset actually is", somebody, whether it's a biologist or a physicist, will throw up their arms in protest.
...but yeah, I am also curious.
Not sure what :: would be.