Version Control with Subversion, 2nd Edition

Network Model

At some point, you’re going to need to understand how your Subversion client communicates with its server. Subversion’s networking layer is abstracted, meaning that Subversion clients exhibit the same general behaviors no matter what sort of server they are operating against. Whether speaking the HTTP protocol (http://) with the Apache HTTP Server or speaking the custom Subversion protocol (svn://) with svnserve, the basic network model is the same. In this section, we’ll explain the basics of that network model, including how Subversion manages authentication and authorization matters.

Requests and Responses

The Subversion client spends most of its time managing working copies. When it needs information from a remote repository, however, it makes a network request, and the server responds with an appropriate answer. The details of the network protocol are hidden from the user—the client attempts to access a URL, and depending on the URL scheme, a particular protocol is used to contact the server (see the sidebar Repository URLs).

Tip

Run svn --version to see which URL schemes and protocols the client knows how to use.

When the server process receives a client request, it often demands that the client identify itself. It issues an authentication challenge to the client, and the client responds by providing credentials back to the server. Once authentication is complete, the server responds with the original information that the client asked for. Notice that this system ...