Eval, literal eval, safe eval

[Mark S. Miller]

https://code.google.com/p/google-caja/source/browse/trunk/src/com/google/caja/ses/
http://research.google.com/pubs/pub40673.html
https://code.google.com/p/google-caja/wiki/SES
www-cs-students.stanford.edu/~ataly/Papers/sp11.pdf

http://wiki.ecmascript.org/doku.php?id=strawman:concurrency desperately
needs updating in light of modern promises, but see discussion of Vats and
"there".


On Sun, Nov 23, 2014 at 3:27 AM, Michał Wadas <michalwadas at gmail.com> wrote:

> Introdution:
> - eval executes piece of code
> - eval can not be safely used with external input
> - Python's ast.literal_eval would be almost useless in modern
> JavaScript (almost all data types can be easily send as JSON)
>
> literal_eval description:
> >The string or node provided may only consist of the following Python
> literal structures: strings, numbers, tuples, lists, dicts, booleans, and
> None.
>
>
>
> My proposition is "safe eval".
> Safe eval ( eval.safe(string: code, callback) ) should perform theses
> steps:
> - Create isolated realm without capabilities to perform almost any IO
> (implementation dependant - no XHR, no importScript, no require)
>

y


> - evaluate code in context of created realm
>

y


> - post result of last evaluated expression back to creator realm using
> structured-clone algorithm
>

n. Structured clone sucks.


> - call callback with returned data
>

Prefer promises to callbacks


>
> Pros:
> + sandbox offered by language
>

y. Plan is to refine Realm API for ES7 by trying to redo SES in terms of
Vats.


> + easy to run in other thread
>

y


> + quite easy to polyfill
>

Well, it wasn't as easy as I first expected, but we do have a SES polyfill.
Not yet for Vats or Dr. SES


> + servers can send computations to users
>

y


> +
> Cons:
> - Realm creation can be costly (but implementations can solve this
> problem in many ways)
>

y


> - proposal does not include support for asynchronous operations
>

Dr. SES does.


> _______________________________________________
> es-discuss mailing list
> es-discuss at mozilla.org
> https://mail.mozilla.org/listinfo/es-discuss
>



-- 
    Cheers,
    --MarkM
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.mozilla.org/pipermail/es-discuss/attachments/20141123/9d0f00b3/attachment.html>