Sandbox restriction error with html//1

Help!
1

I’m trying to use html//1 in a sandboxed call (swipl 8.2.4), but I’m getting sandbox restriction error (Could not derive which predicate may be called from html_write:html_expand(A,B,C,D)).

The simplest example is where my http server does safe_term(Goal) where Goal is:

html(p(hello),H,[]), with_output_to(string(S), print_html(H))

I tried declaring sandbox:safe_meta_predicate(html_write:html_expand/4). in the server, but that didn’t seem to change anything.

Any suggestions on how to get around this issue?

cheers,

RdR

2

Why would you do that? The HTML infrastructure is not easily compatible with sandboxing as it heavily relies on meta-calling. It can be done as you can see on this SWISH page: SWISH -- SWI-Prolog for SHaring

I don’t recall the details. I think it both relies on the devel series of SWI-Prolog and code in SWISH.

3

I’m actually trying to exclude html//1 from the safe_term/1 expansion, but safe_meta_predicate/1 seems to do something different than I expected in this regard. I thought it would “skip” over any such declared predicate, but it doesn’t seem to work that way (or I’m not doing it right, somehow).

But thanks for the pointer – I’ll have a look at the SWISH code to see how they did it there.