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From Carlo Sciolla <carlo.scio...@gmail.com>
Subject Re: Chunked transfer encoding
Date Fri, 10 May 2013 10:10:53 GMT
Hi Florian,

it's not my intent to start a flame war, and we can continue offline if you
want. To the interest of the list, I'll just write here some of the reasons
behind my previous comment, and wait until I have some patch ready to prove
my points before bothering you guys again with my ramblings.

I understand your remark on the spec compliance, and that interop is at
stake when you allow the protocol details to be modified. BUT...

- There's much more to HTTP than what CMIS specifies, and Chemistry is
currently in charge of handling the transport protocol on top of which CMIS
expresses itself.

- No extensibility means that backporting of fixes might be a no-go. For
example, if I now upgrade Chemistry to the latest trunk my code doesn't
compile anymore. Subclassing would be the best way to integrate your
changes in the version I use, but that's not available to me.

- The CMIS spec is (hopefully!) not fixed and will evolve with time. OO
could help greatly e.g. to support different versions of the protocol with
a single serve instance, which is painful to implement cleanly following
the current code approach.

- Spec extensions are not evil per se. While they might indeed break
interoperability, they're also a way to open the protocol itself to
experiments and eventually drive a community based evolution of it.

- Interop is not always the top priority. CMIS and Chemistry provide a lot
of value OOTB, and I don't see why proprietary extensions should be denied
by principle. Why shouldn't I have the possibility to write a custom
extension to improve e.g. content delivery capabilities
(getContentStreamByPath, anyone?), while still retaining full protocol
compliance for B2B data exchange?

If you made it to here, a big thank you for your patience.

Hope this helps,
c.




2013/5/8 Florian Müller <fmui@apache.org>

> Hi Carlo,
>
> This code is not meant to be extensible. The CMIS standard is fixed. There
> will be no additional services or operations. Also, the semantics of the
> parameters will not change or have to be changed. Any extensions would
> bypass the specification, which would be a pain for clients and doesn't
> help interoperability.
> All methods that handle requests are stateless, isolated pieces of code.
> OO doesn't help here. And the alternative to reflections would be a 120
> lines if-statement. I can't see the advantage of that.
>
> Also, this part is considered internal code and may change at any time.
> OpenCMIS provides a lot of extensibility on the client side and keeping the
> interfaces compatible does hurt sometimes. I don't see a real use case to
> have that pain also on the server side. If there is something missing or
> wrong, we usually fix it pretty quick - as you have seen.
>
> Having said that, if you have a great idea how to refactor that code, feel
> free to provide a patch.
>
>
> - Florian
>
>
> Am Mittwoch, den 08.05.2013, 16:05 +0200 schrieb Carlo Sciolla <
> carlo.sciolla@gmail.com>:
>
>> Hi Florian,
>>
>> thanks for your quick commit, I will experiment a bit with it and let you
>> know what comes out of it. I do already have some initial comments anyway:
>>
>> - I see you only addressed the browser bindings implementation. While I
>> can
>> see the reason behind it, I think it won't hurt to also apply a similar
>> logic to the AtomPub binding
>>
>> - as I'm stuck with v0.6.0, I'm looking into ways to backport or integrate
>> your code in my app. The current logic for method dispatch in AtomPub goes
>> against extensibility (and some object oriented design principles, IMO)
>> and
>> while for the time being I can work around it, would you guys consider
>> refactoring the dispatch logic to make use of non-final classes / no
>> reflection / public constructors?
>>
>> Thanks,
>> c.
>>
>>
>> 2013/5/8 Florian Müller <fmui@apache.org>
>>
>>  Hi Carlo,
>>>
>>> I've added some new code. There are now three interfaces that let you
>>> control the server headers.
>>> The ContentStream object that is returned by getContentStream() must
>>> implement the interface(s) to trigger the behavior:
>>>
>>> ContentLengthContentStream - Sets the Content-Length header and turns
>>> chunking off.
>>>
>>> LastModifiedContentStream - Sets the Last-Modified header and respects
>>> the
>>> If-Modified-Since header.
>>>
>>> CacheHeaderContentStream - Sets the Cache-Control header, the Expires
>>> header, and the ETag header and respects the If-None-Match header.
>>>
>>>
>>> Please let me know if that works for you.
>>>
>>>
>>> - Florian
>>>
>>>
>>>  Hi there, sorry for the late reply.
>>>
>>>>
>>>> 2013/5/7 Florian Müller <fmui@apache.org>
>>>>
>>>>  That is surprising. Chunked encoding isn't really exotic.
>>>>
>>>>>
>>>>>  Definitely, but browsers are always there to remind us that world
>>>>> class
>>>>>
>>>> standards are nothing different from regional social conventions, are
>>>> they?
>>>>
>>>>
>>>>  Could you please open an Improvement issue and add a few details. I'll
>>>>
>>>>> look into it.
>>>>>
>>>>>  Thanks, here it is <https://issues.apache.org/****
>>>>> jira/browse/CMIS-655<https://issues.apache.org/**jira/browse/CMIS-655>
>>>>> <https://**issues.apache.org/jira/browse/**CMIS-655<https://issues.apache.org/jira/browse/CMIS-655>
>>>>> >
>>>>>
>>>> >.
>>>>
>>>>
>>>
>>>
>


-- 
Carlo Sciolla

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