- From: Mark Nottingham <mnot@mnot.net>
- Date: Tue, 31 Oct 2017 09:47:26 +1100
- To: Alex Rousskov <rousskov@measurement-factory.com>
- Cc: HTTP Working Group <ietf-http-wg@w3.org>, Poul-Henning Kamp <phk@phk.freebsd.dk>
> On 31 Oct 2017, at 9:24 am, Alex Rousskov <rousskov@measurement-factory.com> wrote: > > On 10/29/2017 06:57 PM, Mark Nottingham wrote: >> https://mnot.github.io/I-D/structured-headers/ > >> * Is the parsing too strict, not strict enough, or just right? > > AFAICT, the top-level parsing algorithm in Section 3 is missing a > catch-all rule for trailing garbage. For example, right now, the > following malformed Item header field will pass all checks and return a > "valid" String to the caller. It should throw a "trailing garbage" error > instead. > > Foo: "valid" garbage! > > When fixing that, tolerating trailing BWS may be a good idea. Good point, thanks. >> Note that input_string may incorporate multiple header lines combined >> into one comma-separated field-value > > I understand the desire to limit this specification to parsing a single > header field or equivalent, leaving the Pandora box of combining > same-name fields closed. However, this honorable approach complicates > placing interoperability limits on the number of list members: An > application that parses individual fields (and possibly never combines > the results!) may not hit the limit that an application combining raw > value strings before parsing would hit. > > IMHO, we should explicitly say something (conservative) about this > problem so that header generators know how the limits may be applied. If the document progresses this seems worth addressing. >> However, field definitions are encouraged to clearly state additional >> constraints upon the syntax, as well as the consequences when those >> constraints are violated. > > I would rephrase that phrase to avoid a misunderstanding: That phrase is > talking about additional _semantic_ restrictions (on top of the frozen > syntax rules), not additional syntax constraints. Ack. > Not sure whether this is in your "interesting things to discuss" scope, > but please allow empty quoted strings :-). Good point :) > Thank you, > > Alex. > P.S. I am not reporting individual BNF and algorithm problems because > they seem to be outside the "interesting things to discuss" scope. Thanks for your forbearance; we'll get there :) -- Mark Nottingham https://www.mnot.net/
Received on Monday, 30 October 2017 22:47:57 UTC