I want to create a piece of software that intercepts the explorer’s access to the thumbnail cache. The software shall accept the explorer’s requests and return possitive or negative results depending on a certain condition (e.g. is a drive mounted and for what file is the thumbnail requested). Furthermore the mounted drive contains a key to decrypt the custom thumbnails. If the drive or key file isn’t available, the tool shall just tell the explorer that no thumbnail exists.
My problems:
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Which language is capable of intercepting such request? Is there some standard way of doing this? Can I just fake an entire file? E.g. all access to the file are routed to my application?
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Is the file format of thumbnailcache.db documented? Does explorer pull the entire file into memory? What is the smartest way to intercept the communication?
I am thankful for any hints, even if they are only a partial solution.
Regarding intercepting access – you need to create/use filesystem filter driver. You can write your own or use our CallbackFilter product.
With filter driver you can deny requests, modify them, serve fake file contents etc.