reactjs.net clearscriptv8 compiler error

error
Here’s another one for the error message Googlers. Recently I ran into a nasty build error on TeamCity after adding ReactJS.NET Nuget packages to an ASP.NET MVC solution.
Locally everything built just find, but on TeamCity the build failed with the following error message when trying to compile the MVC views:

[AspNetCompiler] ASPNETCOMPILER error ASPCONFIG: Could not load file or assembly 'ClearScriptV8-32.DLL' or one of its dependencies. The specified module could not be found.

Normally you get this type of errors when an assembly can’t be found or isn’t copied to the bin folder for some reason.
In this case it turns out to be more or less the opposite case. The DLL is in the bin folder, but .NET should be ignoring it. Apparently ASP.NET tries to load all DLL files in the bin folder, which it should not do for the v8 ones, making it crash and burn.
The clue came from this StackOverflow post and this blog post. The fix in the blog post is a bit hacky but pointed me in the right direction. The SO answer to change the web.config is spot on.

So the trick is to exclude the offending binaries by listing them in the web.config compilation section:

<configuration>
    <system.diagnostics>
        <trace autoflush="true" />
    </system.diagnostics>
    <system.web>
        <compilation>
            <assemblies>
                <remove assembly="ClearScriptV8-64" />
                <remove assembly="ClearScriptV8-32" />
                <remove assembly="v8-ia32.dll" />
                <remove assembly="v8-x64.dll" />
                       ....
            </assemblies>
        </compilation>

This way the DLL’s are no longer automatically scanned, and your build can nicely go on compiling those MVC views without any trouble.

Photo by strange little woman on stream, cc-licensed.

class not registered error in PowerShell on commandlet

I ran into this weird COM component error trying to run a commandlet from an IIS administration module.

Retrieving the COM class factory for component with CLSID {688EEEE5-6A7E-422F-B2E1-6AF00DC944A6}
 failed due to the following error: 80040154 Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_
 CLASSNOTREG)).

The module imported fine and I could list the available commandlets and get help on them. So everything seemed to be installed properly. It just turned out that I was running the command on the wrong platform.

Or to be more exact, I ran the command in a 32-bit mode Powershell instance while I should have been in a 64 bit version. The COM component that was called is a 64 bit one, and that didn’t sit well with the 32-bit Powershell instance.

So how do you see what version of Powershell you’re in? Find out by running this statement , which returns true or false:

[Environment]::Is64BitProcess

Now that you know what mode you’re in, try the other one. You should have both in your Start Menu, where the 32-bit one has (x86) appended to the name. In my case that did the trick.

Windows search results for Powershell shows all versions available of the PS shell.

 

erase free space on an SSD drive

DeleteAs you probably know (because you’re reading this post) Windows doesn’t really destroy a file when it is deleted. It merely removes the references in the file table so you don’t see it in on the file system anymore. But the file is still intact sitting there on your hard drive until some other file is written over it.
If you want to truly erase those files on a HDD drive you can use a number of tools to erase the free space on the drive. What these tools do is simply overwrite all free space with random data and thus effectively overwriting and destroying those deleted files still sitting intact in your free disk space.
Free tools that can do this are the command line Secure Delete tool from System Internals and the handy CCleaner (see the tools menu).

For an SSD drive however overwriting the free space with random data is bad for your drive. SSD’s have a limited number of times you can write data to their blocks. Using a random data overwrite tool, which can even end up do this multiple times, is just a bad idea.

Luckily everything is built into your SSD drive to do this automatically. It’s called the TRIM function and from Windows 7 on this is activated by default so normally you don’t have to do a thing to take advantage of this secure-delete feature.

However if you are like me then you want to be sure if this feature is activated.
On Windows, you can do this by opening a command prompt and entering the following command:

fsutil behavior query disabledeletenotify

If you get the following, your TRIM command is already active on Windows:

NTFS DisableDeleteNotify = 0

If this would return a value of 1, you can activate the TRIM function with this command:

fsutil behavior set DisableDeleteNotify 0

You can find more detailed instructions and information about activating the TRIM function here:
How to check if TRIM is enabled on your SSD and how to enable it
Why SSD TRIM support is so important and how to enable it

And then there’s always Google of course.

Photo by Delete, cc-licensed.