A little about the project 

Oops! is a proxy server, the main development goals of which are: stability of work, speed of service, support for basic network protocols, modularity, ease of use.
Why did you need another such server if you already have Squid? Personally, I was not satisfied with Squid in several ways, so I wanted to get rid of it. And that was done.

The main differences from Squid:

Each request is served by a separate thread, which makes it possible to use all available processors on a multiprocessor machine.
Cached documents are stored in one or more large files. This allows you to remove the burden of working with directories from the operating system and speed up access to documents, as well as use raw-devices as a storage location for cached objects.
The modular structure of the program allows you to extend its functions without changing the kernel code.
Particular attention is paid to ensuring reliable, long-term, uninterrupted operation, convenience and ease of configuration / reconfiguration. So, for example, reconfiguration on the fly does not lead to the break of already established connections.