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From Philip Martin <philip.mar...@wandisco.com>
Subject Re: Subversion C API
Date Mon, 09 Nov 2015 16:08:14 GMT
The svnlook client uses the FS API to read details of revisions and
transactions.  Look at the code that implements 'svnlook tree'.

"Ren Wang" <renwang101@gmail.com> writes:

> Hi Philip,
>
> Yes, we are looking for the local access and FS API.
>
> The following are the use cases that we need as the starting point:
>
> 1) create file and folder
> 2) open a directory/root and get its latest files and folders
> 3) modify a file, folder
> 4) delete file and folder
>
> Not sure if there is a programming guide. From the test source code
> (test_fs), I can figure out use case (1), (3) and (4). But not sure how to
> do for use case (2) open a directory/root and get its latest files and
> folders.
>
>
>
>
> -----Original Message-----
> From: Philip Martin [mailto:philip.martin@wandisco.com] 
> Sent: Monday, November 9, 2015 9:43 AM
> To: Ren Wang <renwang101@gmail.com>
> Cc: 'Bert Huijben' <bert@qqmail.nl>; users@subversion.apache.org
> Subject: Re: Subversion C API
>
> The FS API, svn_fs_ and svn_repos_, provides access to a repository on the
> local filesystem.  It provides a transactional API to commits:
> create a txn, populate the txn, commit or delete the txn.  The servers
> svnserve and mod_dav_svn use this API.
>
> The RA API, svn_ra_, provides access to a repository via an URL such as
> http://, svn://, file:// etc.  Usually this repository will be on a remote
> server running svnserve or mod_dav_svn.  It also provides a transactional
> API to commits but is more restricted: the FS API provides random access to
> the txn while the RA API requires an ordered pass over the txn.  The client
> svnmucc uses this API.
>
> The client API, svn_client_, provides access to a repository via a working
> copy or via an URL.  It provides a higher level API that does not expose
> transactions, but instead provides functions to make a commit, do an import,
> etc.  The client svn uses this API.
>
> If you want network access, or you want to use Subversion's
> authentication/authorization, then use the RA or client APIs.  If you want
> local access, and more freedom with transaction handling, then use the FS
> API.
>
> "Ren Wang" <renwang101@gmail.com> writes:
>
>> Hi Bert,
>>
>>  
>>
>> Thank you very much for the detail explanations.
>>
>>  
>>
>> We have been thinking about the option to develop our own repository 
>> layer vs subversion API file:/// <file:///\\>  repository API 
>> (libsvn_fs). This is why we are looking for programming guide and 
>> sample code for supporting our use cases. So far, we only have the 
>> test code from subversion, such as test_fs project which is not enough for
> us.
>>
>>  
>>
>> I will take a look of the svnmucc code.
>>
>>  
>>
>> Regards,
>>
>>  
>>
>> Ren
>>
>>  
>>
>> From: Bert Huijben [mailto:bert@qqmail.nl]
>> Sent: Sunday, November 8, 2015 12:28 PM
>> To: 'Ren Wang' <renwang101@gmail.com>; users@subversion.apache.org
>> Subject: RE: Subversion C API
>>
>>  
>>
>> Mod_dav mostly uses the repository layer api. In a few specific cases 
>> it goes into the fs layer directly. sometimes because something isn't 
>> mapped, but in other cases because mod_dav was developed very early in 
>> the development process and the repository layer wasn't as complete as 
>> it is today.
>>
>>  
>>
>> But is the client layer really that expensive for you that you can't use
> it?
>> Did you measure it?
>>
>>  
>>
>> I can't imagine usecases where the performance is that critical that 
>> you really can't afford the thin layer that the file:/// <file:///\\> 
>> repository api has, but don't want a specialized datastore 100% 
>> optimized for your usecase.
>>
>>  
>>
>> I can think of a few cases where you might want to avoid the overhead 
>> of having a working copy, but even there the costs aren't usually that 
>> high that it makes sense to spend a lot of time to develop something else.
>>
>> (And in many cases the still private API behind svnmucc can already 
>> help you
>> there)
>>
>>  
>>
>>                 Bert
>>
>>  
>>
>> From: Ren Wang [mailto:renwang101@gmail.com]
>> Sent: vrijdag 6 november 2015 19:44
>> To: users@subversion.apache.org <mailto:users@subversion.apache.org>
>> Subject: Subversion C API
>>
>>  
>>
>> I have posted the same question to the stackoverflow, here it is. 
>> Looking forward to hear from you:
>>
>>  
>>
>> We are considering to use Subversion as the file system layer to store 
>> version enabled documents. Since the security function will be handled 
>> by other code, I am considering to directly use the Subversion FS C API
> layer.
>> I wonder if there any good sample code for using Subversion FS APIs?
>>
>>  
>>
>> Someone answered back:
>>
>> Subversion's FSFS store is meant to be used by the subversion server. 
>> While it might be useable in other scenarios, whatever sits on top of 
>> it will likely have to act much like a subversion server when interacting
> with it.
>> Subversion differentiates between client workspaces and the server 
>> storage space. If you are going to leverage subversion components, 
>> your application needs to realize that these two spaces are not the 
>> same within a subversion architecture, and therefore should not be the 
>> same within your solution that uses their components.
>>
>> Why not just embed a subversion client into the place you desire and 
>> then go from there? The user workspace will still be "the subversion user
> workspace"
>> and the server side will be the server side. In fact, check out 
>> tortise SVN (or other desktop integrations of subversion). You might 
>> not even need to write anything.
>>
>> I asked again with more context for the project:
>>
>> SVN Client API will have performance penalty since it will go through 
>> other layers such as user authentications, authorizations, transport 
>> etc. which are not needed for us. Subversion server side API will 
>> bypass those calls. I wonder which API mod_dav_svn used.
>>
>> Regards,
>>
>> Ren
>>
>>  
>>
>
> --
> Philip Martin
> WANdisco
>

-- 
Philip Martin
WANdisco

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