Implement conditional requests: If-Match, If-Modified-Since, If-None-Match, If-Range, If-Unmodified-Since and Last-Modified

This feature is dependent on the implementation of the ETag see #40

Implement capabilities required for conditional requests:

• If-Match,
• If-Modified-Since,
• If-None-Match,
• If-Range,
• If-Unmodified-Since and
• Last-Modified (Not exactly a conditional request but utilizes the same mechanisms)

Because these requests require knowledge of the actual response and to prevent us having to re-compose the response for every question this will benefit considerably from a server side cache solution as suggested in #60

Did I miss anything?

What are your thoughts, suggestions, special requirements? Do you know of any current implementations we might benefit from referencing? Warnings? Concerns? Are you able to help?

Get involved and you can also be part of making Respect/Rest even more awesome than it is, there is more than enough ways for you to help, feel free to contact any of the Respect developers if you need help getting involved!

Also a big thank you to our current supporters you guys rock! Keep up the good work!

Start by reviewing the dependent ETag implementation in issue #40 and the server-side cache proposal in issue #60, then consult the linked RFC sections for each conditional-request header. Done means the REST implementation supports If-Match, If-Modified-Since, If-None-Match, If-Range, If-Unmodified-Since, and Last-Modified using the relevant response information.