Subversion - Can I set auto-props on the server side?

It's not possible. There is a long standing feature request for broadcasting configs to client. It's not presently due until 2.0, or later.

The closest you can come is to use hooks. Either with a pre-commit to prevent incorrectly configured clients from submitting the wrong data. Or a post-commit to retro-fix wrong data.

Neither is great and I believe the latter is even advised against.

Apache Subversion 1.8 introduced the Repository Dictated Configuration feature which requires SVN 1.8 client. (1.8 server is not required, in other words).

With Subversion 1.8, you can configure auto-props patterns within a repository using the new Subversion svn:auto-props inherited property.

For example, setting svn:auto-props value to *.bmp = svn:mime-type=image/bmp property on the root of your repository (or repository path that represents a root of a project) will result into each newly added bitmap file to have the MIME type applied automatically.

You can store multi-line values in Subversion properties, so you can add the following (quite standard) svn:needs-lock and MIME pattern to svn:auto-props:

*.bmp = svn:mime-type=image/bmp;svn:needs-lock=*
*.gif = svn:mime-type=image/gif;svn:needs-lock=*
*.ico = svn:mime-type=image/x-icon;svn:needs-lock=*
*.jpeg = svn:mime-type=image/jpeg;svn:needs-lock=*
*.jpg = svn:mime-type=image/jpeg;svn:needs-lock=*
*.png = svn:mime-type=image/png;svn:needs-lock=*
*.tif = svn:mime-type=image/tiff;svn:needs-lock=*
*.tiff = svn:mime-type=image/tiff;svn:needs-lock=*    
*.doc = svn:mime-type=application/msword;svn:needs-lock=*
*.jar = svn:mime-type=application/octet-stream;svn:needs-lock=*
*.odc = svn:mime-type=application/vnd.oasis.opendocument.chart;svn:needs-lock=*
*.odf = svn:mime-type=application/vnd.oasis.opendocument.formula;svn:needs-lock=*
*.odg = svn:mime-type=application/vnd.oasis.opendocument.graphics;svn:needs-lock=*
*.odi = svn:mime-type=application/vnd.oasis.opendocument.image;svn:needs-lock=*
*.odp = svn:mime-type=application/vnd.oasis.opendocument.presentation;svn:needs-lock=*
*.ods = svn:mime-type=application/vnd.oasis.opendocument.spreadsheet;svn:needs-lock=*
*.odt = svn:mime-type=application/vnd.oasis.opendocument.text;svn:needs-lock=*
*.pdf = svn:mime-type=application/pdf;svn:needs-lock=*
*.ppt = svn:mime-type=application/vnd.ms-powerpoint;svn:needs-lock=*
*.ser = svn:mime-type=application/octet-stream;svn:needs-lock=*
*.swf = svn:mime-type=application/x-shockwave-flash;svn:needs-lock=*
*.vsd = svn:mime-type=application/x-visio;svn:needs-lock=*
*.xls = svn:mime-type=application/vnd.ms-excel;svn:needs-lock=*
*.zip = svn:mime-type=application/zip;svn:needs-lock=*

While there is no great answer to this, you can use svn_apply_autoprops.py which I wrote to apply your standard auto-props to a working copy to bring all the files there into compliance.