Fair warning at the start -- you will need progress during the full duration of the assignment and will greatly benefit from working at a steady pace.  Like all assignments in this class, this is certainly not easy.  It's expected that you will run into things that you're not immediately sure how to implement.  But with some thought, you'll be able to come up with good solutions and learn valuable programming skills!  This assignment will give you experience with several new things, such as daemons, network programming, coding to a protocol, and caching (i.e. you'll find this very rewarding at the end if you give yourself time to do a good job).

Find your new partner for HW2 as soon as possible, and go ahead and get started sketching out a plan & high-level design. Please feel free to reach out to instructor(s) for “automatic” partner pairing.  Note also that (as we discussed for daemons) you will be dealing with multi-threaded code.  Debugging can be difficult so you'll want to leave time for working through issues.

Important Notes

• Use of good object-oriented C++ abstractions and RAII (something we'll discuss in class soon, related to exceptions) is highly encouraged as it will make your coding go much smoother.
• Your code should be developed only by you and your partner. Using libraries (e.g. Boost), consulting resources about how sockets work, consulting resources about the HTTP protocol is good. But what would not be acceptable would be to use other's code or search and use things from a resource like "here is code for a proxy server" or "So you have an assignment to write a web proxy? Heres what you do..." If you're not sure whether a library is reasonable to use, please ask.
• You can use libraries to help with http parsing (i.e. help you get the various fields, etc. into data structures). But you should not use libraries that do any proxy functions for you. It is a good opportunity to dive deep into HTTP request and HTTP response.
• The grade will be composed of three parts: functionality/performance, code quality/style (i.e. use of RAII), and danger log

Important Reference Resources

This assignment will require reading RFC specs (i.e. related to HTTP) -- this is the "coding to a spec" part of the assignment.  Here are a few pointers to get started:

• The document that lays out everything about HTTP is https://tools.ietf.org/html/rfc7231. It is ... long. But you don't need most of it. Sections 4,5,6,7 are the most useful.
• https://tools.ietf.org/html/rfc7234 describes the rules of expiration time and cacheability requirements.
• https://tools.ietf.org/html/rfc7230 describes the HTTP format (e.g. section 2 to know where an HTTP request starts / ends)
• Socket programming: consult 650 material and/or this is a great reference: http://beej.us/guide/bgnet/html/multi/index.html
• UNIX daemons: consult our lecture slides