Re: encode/decode support for base64url

On Wed, Sep 17, 2025 at 12:56 AM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>
wrote:

> On Wed, Aug 6, 2025 at 12:43 PM Florents Tselai
> <florents(dot)tselai(at)gmail(dot)com> wrote:
> >
> >
> >
> > On Wed, Aug 6, 2025 at 4:34 PM Florents Tselai <
> florents(dot)tselai(at)gmail(dot)com> wrote:
> >>
> >> Attaching v6 again because it wasn't picked up the last time.
> >> Trying from Gmail's web page this time.
> >>
> >>
> >>
> >> On Tue, Aug 5, 2025 at 12:40 PM Florents Tselai <
> florents(dot)tselai(at)gmail(dot)com> wrote:
> >>>
> >>>
> >>>
> >>> On 1 Aug 2025, at 1:13 PM, Florents Tselai <florents(dot)tselai(at)gmail(dot)com>
> wrote:
> >>>
> >>>
> >>> On Tue, Jul 29, 2025 at 3:25 PM Daniel Gustafsson <daniel(at)yesql(dot)se>
> wrote:
> >>>>
> >>>> > On 12 Jul 2025, at 21:40, David E. Wheeler <david(at)justatheory(dot)com>
> wrote:
> >>>>
> >>>> > Thank you! This looks great. The attached revision makes a a couple
> of minor changes:
> >>>>
> >>>> I also had a look at this today and agree that it looks pretty close
> to being
> >>>> done, and a feature we IMHO would like to have.
> >>>
> >>>
> >>> Thanks for having a look Daniel!
> >>>
> >>>>
> >>>>
> >>>>
> >>>> The attached version also adds a commit message, tweaks the
> documentation along
> >>>> with a few small changes to error message handling etc.
> >>>
> >>>
> >>> In the doc snippet
> >>>
> >>> > The base64url alphabet use '-' instead of '+' and '_' instead of '/'
> and also omits the '=' padding character.
> >>>
> >>> Should be
> >>>
> >>> > The base64url alphabet uses '-' instead of '+' and '_' instead of
> '/', and also omits the '=' padding character.
> >>>
> >>> I'd also add a comma before "and also"
> >>>
> >>>>
> >>>> The base64 code this extends is the RFC 2045 variant while base64url
> is based
> >>>> on base64 from RFC 3548 (obsoleted by RFC 4648). AFAICT this is not
> a problem
> >>>> here but has anyone else verified this?
> >>>
> >>>
> >>> I don't see how this can be a problem in practice.
> >>> The conversions are straightforward,
> >>> and the codepath used with url=true is a new one and doesn't change
> past behavior.
> >>>
> >>>
> >>> Here’s a v6; necessary because func.sgml was split .
> >>> No other changes compared to v5.
> >
> >
> > v6 introduced some whitespace errors in the regression files.
> >
> > Here's a v7 that fixes that
>
> While the patch looks good to me I have one question:
>
> - errmsg("invalid symbol \"%.*s\" found while
> decoding base64 sequence",
> - pg_mblen(s - 1), s - 1)));
> + errmsg("invalid symbol \"%.*s\" found while
> decoding %s sequence",
> + pg_mblen(s - 1), s - 1,
> + url ? "base64url" : "base64")));
>
> The above change makes the error message mention the encoding name
> properly. On the other hand, in pg_base64_decode_internal() there are
> two places where we report invalid data and always mention 'based64'
> in the error message:
>
> ereport(ERROR,
> (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
> errmsg("unexpected \"=\" while decoding base64 sequence")));
>
> and
>
> ereport(ERROR,
> (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
> errmsg("invalid base64 end sequence"),
> errhint("Input data is missing padding, is truncated, or is
> otherwise corrupted.")));
>
> Do we need to have a similar change for these messages?
>

Good catch, Masahiko-san. They shouldn't be hardcoded either.

I've updated that and also the wording in the regression tests, too.