Re: [OAUTH-WG] application/x-www-form-urlencoded vs JSON (Proposal)

Pid <pid@pidster.com> Wed, 05 May 2010 22:35 UTC

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Subject: Re: [OAUTH-WG] application/x-www-form-urlencoded vs JSON (Proposal)
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On 05/05/2010 19:49, DeWitt Clinton wrote:
> Having written more than one compliant JSON parser myself, it is most
> certainly not "trivial", and not something that can be safely done with
> a regular expression or other hacks.
> 
> That said, it's not /hard/, and that alone is no reason not to mandate
> JSON, but I do want people to be clear about what mandating JSON means.
>  Clients will need a fully compliant parser.  Period.  If the OAuth spec
> requires JSON, then it should require it by reference to RFC 4627, not
> just by giving some examples that demonstrate the curly braces.
> 
> -DeWitt

I know it's late, but can I add my 2 cents - as a developer who'll be
implementing this?


In the original post, Dick suggested that developers were having trouble
with the URL encoding format - but I respectfully suggest that JSON is
going to be more problematic.

There's no guarantee that an external JSON parser will be available for
a given platform/language/business, (perhaps because of licensing, if
not other more technical reasons).  So that means writing one.

Writing a JSON parser just to cover the simple usage proposed won't be
too tricky, but if the JSON response is so simple why bother adding this
dependency at all?  I'm slightly baffled...


URL encoding is required for at least one flow, so IMHO it might as well
stay for the rest.  Simplicity is important.


Can someone from the pro-JSON side offer a clearer explanation as to the
benefits, so I can stop scratching my head about it all, please?



Respectfully,

Pid


> On Wed, May 5, 2010 at 11:38 AM, Torsten Lodderstedt
> <torsten@lodderstedt.net <mailto:torsten@lodderstedt.net>> wrote:
> 
>     Am 05.05.2010 20:01, schrieb Evan Gilbert:
>>
>>
>>     On Wed, May 5, 2010 at 10:59 AM, Evan Gilbert <uidude@google.com
>>     <mailto:uidude@google.com>> wrote:
>>
>>
>>
>>         On Wed, May 5, 2010 at 10:47 AM, Torsten Lodderstedt
>>         <torsten@lodderstedt.net <mailto:torsten@lodderstedt.net>> wrote:
>>
>>             Even if not supported directly by the platform there are
>>             many JSON libraries available these days.
>>
>>
>>         It's not hard to add JSON support, but it's a factor in the
>>         choice.
>>          
>>
>>
>>             http://www.json.org/ lists 3 libraries for Objective-C alone.
>>
>>             Moreover, the JSON documents we are discussing now are
>>             simple, something like
>>
>>
>>             { "access_token": "SlAV32hkKG", "expires_in": "3600",
>>             "refresh_token": "8xLOxBtZp8" }
>>
>>             Parsing such a document is not a challenge even without
>>             library support.
>>
>>
>>         Per notes above - the client needs to do understand form
>>         encoding anyway. The client needs to parse the redirect_uri
>>         and also needs to generate form encoded requests.
>>
>>
>>     Also, for the User-Agent flow, parsing potentially untrusted JSON
>>     in JavaScript is difficult. The normal path of using eval() is
>>     unsafe and leads to XSS holes - you need to run regex matcher to
>>     verify that the JSON content has no executable code.
> 
>     You are right, using eval to parse JSON is dangerous and thus as far
>     as I understand, the recommended way is to use a JSON parser (aka
>     native JSON support)?
> 
>     regards,
>     Torsten.
> 
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