I understand these concerns, and should be clear that I don't (despite my personal interest in experimenting with the idea, agreed that we don't have time for it at the moment) have any plans to introduce this sort of RPC anywhere - certainly not in Shindig itself, as any such call would be hidden behind an interface anyway.
Putting the RPC hypothetical aside, I still feel that there's value to implementing HTML parsing in terms of an interface: * Clearer separation of concerns/boundary between projects. - Corollary simplicity in testing. * Clearer API for content manipulation (that doesn't require knowledge of Caja). I could be convinced otherwise, but at this point the code involved seems of manageable size, so still worth doing. Thoughts? John On Mon, Aug 11, 2008 at 1:00 PM, Kevin Brown <[EMAIL PROTECTED]> wrote: > I agree with Louis -- that's just not practical. Every rewriting operation > must work in real time. Caja's existing html parser is adequate for our > needs, and we shouldn't go out of our way to tolerate every oddity of > random > web browsers (especially as it simply wouldn't work unless you farmed it > out > to *every* browser). Any new code needs to be grounded in practical, > current > needs, not theoretical options. We can always change code later if we find > a > real need for something like that. We have real work to do in the meantime. > > On Mon, Aug 11, 2008 at 12:06 PM, Louis Ryan <[EMAIL PROTECTED]> wrote: > > > John, > > > > From a practicality standpoint I'm a little nervous about this plan to > make > > RPCs calls out of a Java process to a native process to fetch a parse > tree > > for transformations that have to occur realtime. I don't think the > > motivating factor here is to accept all inputs that browsers can. Gadget > > developers will tailor their markup to the platform as they have done > > already. I would greatly prefer us to pick one 'good' parser and stick > with > > it for all the manageability and consumability benefits that come with > that > > decision. Perhaps Im missing something here? > > > > -Louis > > > > On Mon, Aug 11, 2008 at 11:59 AM, John Hjelmstad <[EMAIL PROTECTED]> > wrote: > > > > > On Fri, Aug 8, 2008 at 6:10 AM, Ben Laurie <[EMAIL PROTECTED]> wrote: > > > > > > > [+google-caja-discuss] > > > > > > > > On Thu, Aug 7, 2008 at 9:27 PM, John Hjelmstad <[EMAIL PROTECTED]> > > wrote: > > > > > On Thu, Aug 7, 2008 at 3:20 AM, Ben Laurie <[EMAIL PROTECTED]> > wrote: > > > > > > > > > >> On Wed, Aug 6, 2008 at 11:34 PM, John Hjelmstad <[EMAIL PROTECTED] > > > > > > wrote: > > > > >> > This proposal effectively enables the renderer to become a > > > multi-pass > > > > >> > compiler for gadget content (essentially, arbitrary web > content). > > > Such > > > > a > > > > >> > compiler can provide several benefits: static optimization of > > gadget > > > > >> content > > > > >> > (auto-proxying of images, whitespace/comment removal, > > consolidation > > > of > > > > >> CSS > > > > >> > blocks), security benefits (caja et al), new functionality > > > (annotation > > > > of > > > > >> > content for stats, document analysis, container-specific > > features), > > > > etc. > > > > >> To > > > > >> > my knowledge no such infrastructure exists today (with the > > possible > > > > >> > exception of Caja itself, which I'd like to dovetail with this > > > work). > > > > >> > > > > >> Caja clearly provides a large chunk of the code you'd need for > this. > > > > >> I'd like to hear how we'd manage to avoid duplication between the > > two > > > > >> projects. > > > > >> > > > > >> A generalised framework for manipulating content sounds like a > great > > > > >> idea, but probably should not live in either of the two projects > > (Caja > > > > >> and Shindig) but rather should be shared by both of them, I > suspect. > > > > > > > > > > > > > > > I agree on both counts. As I mentioned, the piece of this idea that > I > > > > expect > > > > > to change the most is the parse tree, and Caja's .parser.html and > > > > > .parser.css packages contain much of what I've thrown in here as a > > > base. > > > > > > > > > > My key requirements are: > > > > > * Lightweight framework. > > > > > * Parser modularity, mostly for HTML parsers (to re-use the good > work > > > > done > > > > > by WebKit or Gecko.. CSS/JS can come direct from Caja I'd bet) > > > > > * Automatic maintenance of DOM<->String conversion. > > > > > * Easy to manipulate structure. > > > > > > > > I'm not sure what the value of parser modularity is? If the resulting > > > > tree is different, then that's a problem for people processing the > > > > tree. And if it is not, then why do we care? > > > > > > > > > IMO the value of parser modularity is that the lenient parsers native > to > > > browsers can be used in place of those that might not accept all > inputs. > > > One > > > could (and I'd like to) adapt WebKit or Gecko's parsing code into a > > server > > > that runs parallel to Shindig and provides a "local RPC" service for > > > parsing > > > semi-structured HTML. The resulting tree for WebKit's parser might be > > > different than that for an XHTML parser, Gecko's parser, etc, but if > the > > > algorithm implemented atop it is rule-based rather than > strict-structure > > > based that should be fine, no? > > > > > > > > > > > > > > > > > > > > > > > > I'd love to see both projects share the same base syntax tree > > > > > representations. I considered .parser.html(.DomTree) and > .parser.css > > > for > > > > > these, but at the moment these appeared to be a little more tied to > > > > Caja's > > > > > lexer/parser implementation than I preferred (though I admit > > > > > AbstractParseTreeNode contains most of what's needed). > > > > > > > > > > To be sure, I don't see this as an end-all-be-all transformation > > system > > > > in > > > > > any way. I'd just like to put *something* reasonable in place that > we > > > can > > > > > play with, provide some benefit, and enhance into a truly > > sophisticated > > > > > vision of document rewriting. > > > > > > > > > > > > > > >> > > > > >> > > > > >> > c. Add Gadget.getParsedContent(). > > > > >> > i. Returns a mutable GadgetContentParseTree used to > manipulate > > > > Gadget > > > > >> > Contents. > > > > >> > ii. Mutable tree calls back to the Gadget object indicating > > when > > > > any > > > > >> > change is made, and emits an error if setContent() has been > called > > > in > > > > the > > > > >> > interim. > > > > >> > > > > >> In Caja we have been moving towards immutable trees... > > > > > > > > > > > > > > > Interested to hear more about this. The whole idea is for the > > gadget's > > > > tree > > > > > representation to be modifiable. Doing that with immutable trees to > > me > > > > > suggests that a rewriter would have to create a completely new tree > > and > > > > set > > > > > it as a representation of new content. That's convenient as far as > > the > > > > > Gadget's maintenance of String<->Tree representations is > concerned... > > > but > > > > > seems pretty heavyweight for many types of edits: in-situ > > modifications > > > > of > > > > > text, content reordering, etc. That's particularly so in a > > > > single-threaded > > > > > (viz rewriting) environment. > > > > > > > > Never having been entirely sold on the concept, I'll let those on the > > > > Caja team who advocate immutability explain why. > > > > > > > > > >
