Tomer Gabel's annoying spot on the 'net RSS 2.0
# Thursday, 26 March 2009

It seems nothing to do with maintaining this website is as easy or as simple as it should be. Whenever I switch hosts it’s an uphill struggle to get the site up and running again; whenever I upgrade dasBlog to a newer version I have to learn a lot about how it works, how ASP.NET works, how IIS is configured etc. It’s enough to make me seriously consider hosting my blog elsewhere and/or moving to another blogging platform, but the truth is I love dasBlog so much I simply forget how complex and volatile it can be and have to go through the same frustrating process whenever something changes.

The way I update my site is usually this:

  1. Ensure I have an up-to-date local mirror of the website. dasBlog keeps all of its data in XML files, so backing up the website is simply a question of wget –-passive-ftp –m; I have a daily scheduled task to take care of this.
  2. Copy the latest mirrored version to a working directory; set the directory up as an IIS website/virtual directory.
  3. Test the new working copy to make sure it works.
  4. Perform whatever modifications are required.
  5. Test again to make sure that the website works with multiple browsers (this time I tested with Chrome, Firefox 3.1 Beta 3 and IE 8)
  6. Upload the website over FTP using the FileZilla client. I always verify that the relevant configuration files and binaries are overwritten and nothing else.

This process generally allows me to test upgrades before uploading them to the “production” website, as well as provides an easy rollback path if something goes wrong. Thing is, something always goes wrong. In this case, although nothing’s changed in the site configuration I started getting SecurityExceptions just after the upgrade:

Request for the permission of type 'System.Security.Permissions.SecurityPermission, mscorlib, Version=, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.

This is one of the least informative error messages I have ever seen. All it tells me is that a request for some permission is denied; it doesn’t say what permission was requested, nor by whom (the stack trace seemed to indicate the permission was asserted from within System.Diagnostics.Trace, which doesn’t make much sense). A quick web search brought me to this page, which deals specifically with installing dasBlog on a GoDaddy-hosted website. Because GoDaddy runs ASP.NET applications under a modified medium trust that allows file-system access only to the virtual directory hierarchy, the site recommends adding a virtual directory for each of dasBlog’s writable directories (content, siteconfig, logs); I tried this out and the problem was not resolved.

At this point I was getting desperate, and was willing to try just about anything to get the site up and running again. Eventually I ran a diff between the site backup and the newly modified version, and found a new openidConsumerTrace.txt file in the site root. I’ve never seen that one before; where'd it come from? A quick search showed the following section in the web.config file:

    <assert assertuienabled="false"/>
        <add name="OpenID" value="4"/>

    <trace autoflush="true" indentsize="4">
            <add name="fileLogger" type="System.Diagnostics.TextWriterTraceListener"
                 initializeData="openidConsumerTrace.txt" traceOutputOptions="None"/>

A-ha! So the OpenID activity trace log is written to the virtual root, which is not writable (I set the ACLs to only allow writes to the above three directories). I tried changing the trace file path to ~/logs/openidConsumerTrace.txt (which is a virtual directory and has the appropriate write ACL), but this did not resolve the problem. At this point I was ready to roll back to the previous version and work on switching to another (perhaps hosted) blogging platform, and in my despair I simply commented out the whole system.diagnostics section; oddly enough, this resolved the problem…

Now I know dasBlog is free and there’s little or no point complaining, so I hope this post helps someone handle the problem. And if anyone from the dasBlog team is reading this… please be a little more careful with undocumented dependencies?

Thursday, 26 March 2009 15:32:08 (Jerusalem Standard Time, UTC+02:00)  #    -
Development | Software
Send mail to the author(s) Be afraid.
<2017 February>
All Content © 2017, Tomer Gabel
Based on the Business theme for dasBlog created by Christoph De Baene (delarou)