The %HTML.Forms directive enables Forms module regardless of the %HTML.Trusted
value. This adds support for form elements without enabling other unsafe
modules, such as Scripts, Iframe or Object.
To achieve the same effect without this directive one has to explicitly list
all enabled modules in %HTML.AllowedModules, and any not listed will be
removed. This however is not very convenient, as the allowed modules may vary
between doctypes.
Resolves#213.
This mega-patch rips out the FixNesting implementation and the related
ChildDef components. The primary algorithmic change is to convert from
use of tokens to tree nodes, which are far more amenable to the style
of processing that FixNesting uses. Additionally, FixNesting has been
changed to go bottom-up rather than top-down, in order to avoid needing
to implement backtracking.
This patch simplifies a good deal of the relevant logic, since we no
longer need to continually recalculate the nesting structure when
processing things. However, the conversion to the alternate format
incurs some overhead, so for small inputs these changes are not a win.
One possibility to greatly reduce the constant factors here is to switch
to entirely using libxml's representation, and never serializing tokens;
this would require one to rewrite injectors, however.
The iterative post-order traversal in FixNesting is a bit subtle, but
we have essentially reified the stack and continuations.
We've removed support for %Core.EscapeInvalidChildren.
Signed-off-by: Edward Z. Yang <ezyang@mit.edu>
The purpose of this addition is twofold. In trusted mode, iframes are
now unconditionally allowed.
However, many online video providers (YouTube, Vimeo) and other web
applications (Google Maps, Google Calendar, etc) provide embed code in
iframe format, which is useful functionality in untrusted mode.
You can specify iframes as trusted elements with %HTML.SafeIframe;
however, you need to additionally specify a whitelist mechanism such as
%URI.SafeIframeRegexp to say what iframe embeds are OK (by default
everything is rejected).
Note: As iframes are invalid in strict doctypes, you will not be able to
use them there.
We also added an always_load parameter to URIFilters in order to support
the strange nature of the SafeIframe URIFilter (it always needs to be
loaded, due to the inability of accessing the %HTML.SafeIframe directive
to see if it's needed!) We expect this URIFilter can expand in the future
to offer more complex validation mechanisms.
Signed-off-by: Bradley M. Froehle <brad.froehle@gmail.com>
Signed-off-by: Edward Z. Yang <ezyang@mit.edu>
