[issue13167] Add get_metadata to packaging

[Barry A. Warsaw]

Barry A. Warsaw <barry at python.org> added the comment:

On Oct 13, 2011, at 04:01 PM, Éric Araujo wrote:

>The PEP 376 implementation in packaging.database has been called ugly and
>opaque.  When discussing PEP 396 for example (that’s why I’m adding Barry and
>Antoine to nosy, for their feedback),
>get_distribution(name).metadata['Version'] did not seem to agree with
>everyone.  (Note that there are shortcuts for two metadata fields: name and
>version also exist as get_distribution(name).name / .version.)

I don't entirely remember my objections to the API, but I wonder if you
couldn't provide attribute access via properties on .metadata?  Or are there
keys that can't be mapped to identifiers (modulo typical dash-to-underscore
mappings)?

>I’m not sure how we can make it less opaque, unless we force people to read
>documentation: PEP 376 proposes a database of installed distributions;
>packaging.database offers get_distribution, which returns an object with some
>attributes.  I can’t have an outside view on this, so maybe you can explain
>what’s opaque and ugly so that we can try to improve it.
>
>I’ve found in distutils-sig archives from two or three years ago that people
>intended to offer a get_metadata function that would take a distribution name
>(i.e. pyOpenSSL, Babel, flufl.enum) and return a mapping object with the
>metadata read from the installed dist-info/METADATA file.  Does that look
>better to you?

So, that would mean instead of

get_distribution(name).metadata['Version']

you'd use

get_metadata(name)['Version']

?

I'm not sure that's really buys you much.

Maybe we just need to live with the current API for a while before we try to
improve it.

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