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From Gavin Cornwell <gavin.cornw...@alfresco.com>
Subject Re: Browser binding implementation
Date Thu, 17 Apr 2014 21:08:33 GMT
Hi Peter,

I have applied the patch you attached to CMIS-787. 

I also applied the patch from Mike attached to CMIS-784. The default test server for the browser
binding branch is now an Alfresco 4.2 Enterprise server. I’ve left the other servers configured
but disabled.

I now see what you mean about the retrieving type definitions from CMISBrowserUtil. To be
honest I saw this class as being a simple helper class with simple JSON to CMIS object parsing
methods, it’s already going beyond that.

I think we should consider adding the common parsing code to CMISBrowserBaseService (but defined
as a Protected category like in the AtomPub binding) as there’s a good chance it’s going
to be required by the other services as we implement them. The typeDefinition retrieval method
could also be added to the base class if that’s required to parse succinct properties. 

If we need to do type definition caching (it sounds like a good idea) we should store that
in the bindingSession.

What do you think?

I’m still looking through your other changes, I’ll send a separate email with my thoughts
soon.

Regards,

Gavin



On 17 Apr 2014, at 19:38, Sutter, Peter <peter.sutter@sap.com> wrote:

> Hi Mike, Hi Gavin,
> 
> I went for the category approach. Will also attach the diff of my changes
> to jira in a few seconds.
> 
> 
> The AtomPub binding does not need fetch the type definitions as they come
> along with the response..
> 
> Best regards,
> Peter
> 
> 
> On 4/17/14, 5:35 PM, "Gavin Cornwell" <gavin.cornwell@alfresco.com> wrote:
> 
>> Hi Peter,
>> 
>> Yes, NSNull is one of those annoyances of parsing JSON in ObjectiveC!
>> What approach did you decide to go with?
>> 
>> I haven¹t taken a look at your first set of changes yet (I will try to
>> tonight) but passing CMISSession around the binding implementation
>> doesn¹t sound like something we want to do to be honest. The CMISSession
>> classes are supposed to sit on top of the binding implementation so doing
>> this could introduce some interesting cyclic dependencies.
>> 
>> I¹m not sure what the answer is to be honest at the moment. If we need
>> access to the type cache maybe that¹s an indication the one we have is in
>> the wrong place. The AtomPub binding must have faced a similar issue how
>> has it dealt with the issue you¹re seeing?
>> 
>> I will try and take a look tonight and come back with something a little
>> more concrete.
>> 
>> Regards,
>> 
>> Gavin
>> 
>> 
>> 
>> On 17 Apr 2014, at 13:48, Mike Hatfield <mike.hatfield@alfresco.com>
>> wrote:
>> 
>>> Hi Peter
>>> 
>>> This JSON behaviour presumably stems from the limitation on
>>> NSDictionary and NSArray that they cannot contain nil objects, so NSNull
>>> is used instead.
>>> 
>>> There seem to be two popular workarounds if the client code requires
>>> nil instead of NSNull:
>>> 1 - A category on NSDictionary, e.g. -
>>> (id)cmis_objectForKeyNotNull:(id)key { Š }
>>> 2 - A macro, e.g. NilOrObjectForKey(json, key) which would do the same
>>> thing.
>>> 
>>> Neither of those solutions would add too much overhead, although
>>> clearly we would no longer benefit from modern Objective-C syntax in
>>> those instances.
>>> 
>>> I'm not currently up-to-speed with the browser binding branch, so can't
>>> comment on your second issue.
>>> 
>>> Regards,
>>> Mike
>>> 
>>> On 17 Apr 2014, at 13:17, Sutter, Peter <peter.sutter@sap.com> wrote:
>>> 
>>>> Hi there,
>>>> 
>>>> I¹m facing currently an issue with [NSJSONSerialization
>>>> JSONObjectWithData:options:error:] and would like to hear your opinion.
>>>> The method returns for keys that do not have a value the NSNull object.
>>>> 
>>>> E.g. when reading the repository info and the description is null on
>>>> the server,
>>>> 
>>>> repoInfo.desc = repo[kCMISBrowserJSONRepositoryDescription];
>>>> 
>>>> 
>>>> repoInfo.desc has the NSNull object instead of nil. Is there a better
>>>> way than to wrap this "dictionary[<key>]² with a helper method?
>>>> 
>>>> Something like
>>>> 
>>>> + (id)valueOrNil:(id)value
>>>> 
>>>> {
>>>> 
>>>>  return value == [NSNull null] ? nil : value;
>>>> 
>>>> }
>>>> 
>>>> But then we have to wrap all calls when accessing the value of the
>>>> dictionary with such a method and this would blow up the code.. or do I
>>>> miss something here?
>>>> 
>>>> 
>>>> The other thing is I need to access the CMISSession within the
>>>> CMISBrowserUtil so that I can retrieve the type definitions (and also
>>>> make use of the type cache) when converting the succinctProperties.
>>>> 
>>>> I could add the CMISSession as property to the CMISBrowserBaseService.
>>>> From there I could pass the session to the CMISBrowserUtil. Any
>>>> objections or even a better approach as this seems to me like a dirty
>>>> workaround?
>>>> 
>>>> 
>>>> Best regards,
>>>> 
>>>> Peter
>>> 
>> 
> 


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