libravatar-fans team mailing list archive

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On Tue, 27 Nov 2018 at 11:45, Tristan Le Guern <tleguern@xxxxxxxxxxx> wrote:

> Thanks for your inputs.
>
> Le 23/11/2018 à 20:58, Francois Marier a écrit :
> > In general, I think we should always return an image. That's what the
> > clients are expecting.
> While it makes sense I think it is also brittle as the API is not future
> proof. I am not sure it is an important property though.
>
> >> * What to do if the size option is supplied but has no value ?
> >> * What to do if the size option is supplied but the value is not an
> integer?
> >> * What to do if the size option is supplied but the value is 0 ?
> >>
> >>    + ivatar and libravatar both return an avatar of the default size ;
> >>    + libravatar.cgi returns the HTTP status code 400.
> >
> > I think it makes sense to do the best we can here and return something to
> > clients that don't do proper error-checking on their end (e.g. a piece of
> > software that includes Libravatar support and lets admins configure the
> > avatar size to any value).
>
> So ignoring the size parameter entirely if it is invalid or empty seems
> to be favoured. This is also partially what Gravatar does (it has its
> own quirks like returning a 1 pixel sized image if the value is negative
> or gibberish but the regular size if the value is 0).
>
> >> * What to do if the size option is supplied but the value is negative ?
> >>
> >>    + ivatar crashes (issue #21) ;
> >>    + libravatar returns an avatar of the default size ;
> >>    + libravatar.cgi returns the HTTP status code 400.
> >
> > I imagine ivatar will fix the crash and match the libravatar behaviour
> here.
>
> Yes, it should be fixed in the git repository but the running instance
> is still crashing.
>
> >> * What to do if the size option is supplied but the value is too big ?
> >>
> >>    + ivatar returns an avatar of the maximum allowed size (512) ;
> >>    + libravatar returns an avatar of the requested size ;
> >>    + libravatar.cgi returns the HTTP status code 400.
> >
> > ivatar's behaviour seems ideal here.
>
> Oliver rightly corrected me here. Ivatar returns directly an avatar of
> the maximum allowed size while Libravatar /redirects/ to an avatar of
> the maximum allowed size. This second behaviour is also what Gravatar is
> doing, albeit with a different maximum (2048).
>
> >> * What to do if the default option is supplied but has no value ?
> >> * What to do if the default option is supplied but has an unhandled
> value
> >> (such as d=unicorn) ?
> >>
> >>    + ivatar and libravatar both return the user's avatar ;
> >>    + libravatar.cgi returns the HTTP status code 400.
> >
> > Again, I think it makes sense to do the best we can when the API is
> > accidentally misused by a client.
> Gravatar has a specific quirks here: if the default parameter has an
> invalid value such as "unicorn" but the hash matches a user then it is
> ignored, otherwise it returns a HTTP status code 400. I really think
> this is the worst behaviour as the result is not consistent.
>
> >> * What to do if the default option is supplied but has an unhandled
> value
> >> (such as d=unicorn) and the forcedefault option is set to true ?
> >>
> >>    + ivatar returns an HTML document, the home page ;
> >>    + libravatar doesn't implement forcedefault ;
> >>    + libravatar.cgi returns the HTTP status code 400.
> >
> > Following the principle of being tolerant of bad configurations, I guess
> we
> > should ignore the invalid value and just use the "default" page we would
> use
> > if the "d" option wasn't specified.
> If we have a mechanism to retrieve valid values for the default
> parameter then it is okay for me to ignore invalid ones.
>
> So to summarise:
>
> * empty parameters must be ignored ;
> * values for the size parameter must be integer ;
> * values smaller than the allowed minimum for the size parameter must be
> ignored ;
> * values greater than the allowed maximum for the size parameter must be
> replaced with this maximum ;
> * unknown values for the default parameter must be ignored.
>
> Does everyone agree ?
>

Hello, sorry for the very late resposne.

I probably agree if "must be ignored" means "replace with a reasonable
default".

Michal


>
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