Before, Caddy couldn't support graceful (zero-downtime) restarts when the reloaded Caddyfile had a host in it that was elligible for a LE certificate because the port was already in use. This commit makes it possible to do zero-downtime reloads and issue certificates for new hosts that need it. Supports only http-01 challenge at this time.

OCSP stapling is improved in that it updates before the expiration time when the validity window has shifted forward. See 30c94908. Before it only used to update when the status changed.

This commit also sets the user agent for Let's Encrypt requests with a string containing "Caddy".

By separating scheme and port at the parser, we are able to set the port appropriately and also keep the semantics of the scheme being specified by the user later on. The parser also stores an address' original input. Also, the config refactor makes it possible to partially load a config - valuable for determining which ones will need Let's Encrypt integration turned on during a restart.

wrap lines to 80 characters

more copy edits

also linked to bug reporting article.

add links to inspired by projects and updated language with golang.

copy edit to wrap around 80 chars

not all lines wrap at 80 characters but now most do.

rewrite: Use middleware.Replacer for simple rule

proxy: Two small websocket fixes

browse: allow consecutive spaces in the header

Add a few super minor lint fixes

Other lint warnings left behind are ones due to external package and
due to maintainer's preferences.

Made a faulty assumption that virualhosts could share acme proxy handlers; turns out they can't without fumbling up the middleware configuration (middleware chains overlap and cross over into other virtualhosts)!

Hosts which are eligible for automatic HTTPS have default port "https" but other hosts (wildcards, loopback, etc.) have the default port 2015. The default host of empty string should be more IPv6-compatible.

proxy: make http header block scoped

proxy: make tests workable when offline

Instead of accessing the google website, we setup a local server
for test, then tests will work fine even we are offline.

Fix issue #346
Signed-off-by: Tw <tw19881113@gmail.com>

Each proxy block should could specify its own http header
instead of sharing a global one.

Fix issue #341
Signed-off-by: Tw <tw19881113@gmail.com>

proxy: 'except' property to ignore subpaths

parser: Allow use of environment variables in tokens