WIP: Provide OCSP verification endpoint and persist certs to disk

[jameshartig]

Depends on cloudflare/cfssl#309

[mediocregopher]

Instead of checking if the file exists, you might as well just do a Create and Chmod on it either way and save some code.

[jameshartig]

@mediocregopher thanks! I just updated and fixed your comments. I also added /list and /revoke.

[mediocregopher]

you can initialize channels in the global scope like this:

+var (
    listCh  = make(chan listReq)
    saveCh = make(chan saveReq)
    timeFmt = "2006-01-02T15:04:05"
    fileFmt = "%s | %s | %s | %s"
)

[mediocregopher]

In main.go you have a lot of repeated code in the handlers. I think quite a bit of it could be generalized into some middleware, specifically the readAndVerifyBody and verifyTimestamp stuff.

It's a bit tricky because multiple things need to use the raw body data, I would suggest first passing all requests through a middleware which reads the body into a buffer (using an http.MaxBytesReader) and replaces the Body field on the request with that buffer, so future middleware and handlers can all use it.

[jameshartig]

Okay so I fixed all the code comments you already made and I'll work on the middleware next week at some point.