MSI install of dll on request from FireFox

With the new firefox we are shipping more and more libraries as the XPom interfaces we interact with are changing. We are at 10 dlls and increasing, each with a size of almost 2M.

This size is a concern for some users.

While we look at restructuring the library to seperate the parts we can make common between them, we are thinking about how we might reduce space on the disk while supporting version upgrades.

For instance, user has FireFox 3.6 and 4.0 installed and when our product is installed we install a dll for each version. When Firefox is 4.0 upgraded (say to 6.0) how might we now install from the msi the missing dll for 6.0 support.

Any ideas on how we could achieve this?开发者_开发技巧 Are we worrying for no reason?

My first thought was we 'AllowAdvertise' and when FF tries to load the dll as directed by chrome it will cause the install, it doesn't seem to work.

My first reaction is to suggest that you move away from XPCOM and towards js-ctypes. After all, this is the direction that Mozilla is pushing extension developers (see Wladimir Palant's comments for example). If there isn't anything in your binary code that absolutely positively requires use of XPCOM, you'll be much happier to ship a DLL that interfaces with JS when needed via js-ctypes.

I guess that your extension is Windows-only so supporting multiple platforms is not an issue. A possible short-term solution:

• Have a separate extension package for each Firefox version, mark it as compatible with this Firefox version only (e.g. minVersion 4.0 and maxVersion 4.*).
• When your extension is installed, install the version that is compatible with user's installed Firefox version.
• Make sure that your extensions have an updateURL entry that is pointing to your server. It is important to have %APP_VERSION% in the URL.
• Make sure to test Firefox betas and prepare a new extension version in time for the next Firefox release (releases are scheduled on Tuesdays every 6 weeks, next release being on September 27th).
• Configure your server to indicate different packages as updates depending on the Firefox version used. So an update check with %APP_VERSION% 4.0.1 would be sent to extension-ff4.xpi while %APP_VERSION% 6.0 would get extension-ff6.xpi.

Firefox will always check for extension updates when the application is updated. If you can give it a compatible update it will install it. But preparing new packages every six weeks requires tons of effort and I guess that you want to refactor your code/move to js-ctypes ASAP. Oh, and I think that you need to ignore the unlikely scenario that some user has more than one Firefox version installed.