This week I've spent some time trying to fix bugs preventing Umbraco from running unmodified on Mono. Unfortunately, some modifications to Umbraco source code (diff here) were necessary due to the inherent Windows-centric coding in parts of the CMS. The diff above takes care of just one part of the cross-platform issues in Umbraco, namely it replaces hard-coded use of the \ directory separator character with the, correct, Path.DirectorySeparatorChar. For some reason MONO_IOMAP mechanism didn't take care of the problem, hence the workaround (I'm going to fix the IOMAP issue after I'm back from vacation mid-August). The other cross-platform issue is (very common in Windows .NET applications) inconsistent use of file naming case which MONO_IOMAP is dealing with nicely.

Making Umbraco run on Mono required some fixes to our ASP.NET parser (revisions 138474, 138520, 138521 and 138592 in trunk, for those interested. Backported to both 2.4 and 2.4.2 branches) as well as making AppDomain not reload when Umbraco writes to the Web.config file. All of the fixes willbe part of the upcoming 2.4.2.3 release. There are however some issues not fixed yet, but with workarounds:

Web.config modifications during setup

Generally it works fine - application isn't restarted, data is written to the config file, but for some reason Umbraco installer caches data from before database access credentials change. So if, for instance, you were presented with MS-SQL setup box and switched to MySQL, the connection and/or database creation will fail trying to use MS-SQL code. This is a bug in Mono which I'm going to investigate in August. Workaround for this issue is to stop the app after selecting the new database provider and credentials and just restart the installation process - everything will work fine from that moment on.

VistaDB not working

VistaDB comes without source, so I wasn't able to investigate what the issue was. The symptom is that when trying to connect to or populate VistaDB database you will get either a ThreadAbortException, a TypeInitializationException or a JIT error about invalid IL in the VistaDB assembly. This is likely a runtime issue - to be investigated. You can use either SQL Server or MySQL providers instead (I used MySQL for testing).

Intermittent exceptions

Sometimes visiting certain pages in the admin interface causes an exception to be thrown (usually NullReferenceException) but I never succeeded in reproducing the exception(s) by repeating the actions. To be investigated.

TinyDLL.dll is a native library

Since it is native, our compiler cannot figure out what to do with it and throws an exception. Simply remove the dll from there - it shouldn't be there anyway.

So, this is the current status of Umbraco on Mono - please play with it and report any bugs you might find, giving exact directions how to reproduce the issue. I will take a look at them once I'm back from vacations.

Since not everybody might want to or know how to compile and set up Umbraco from sources, I have precompiled the package with the diff applied and repackaged the 4.0.2.1 distribution with the bin/ assemblies replaced by their "Mono versions" (note that the ONLY difference in the assemblies is that the patched ones are cross-platform). Here are the download locations:

• Full 4.0.2.1 distribution. Identical to upstream 4.0.2.1 except for the patched assemblies. Original assemblies retained in the bin.original folder.
• Just the patched and compiled assemblies for 4.0.2.1 - move the original bin/ folder out of the way and replace it with what's in the archive.