RE: Subversion C API

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_at_wandisco.com]
Sent: Monday, November 9, 2015 9:43 AM
To: Ren Wang <renwang101_at_gmail.com>
Cc: 'Bert Huijben' <bert_at_qqmail.nl>; users_at_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_at_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_at_qqmail.nl]
> Sent: Sunday, November 8, 2015 12:28 PM
> To: 'Ren Wang' <renwang101_at_gmail.com>; users_at_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_at_gmail.com]
> Sent: vrijdag 6 november 2015 19:44
> To: users_at_subversion.apache.org <mailto:users_at_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