Merge branch 'doh-any-origin' into 'master'

http DoH: make answers include access-control-allow-origin: *

See merge request !823

NEWS

 Knot Resolver 4.x.y (2019-0m-dd)
 ================================
 
+Improvements
+------------
+- DNS-over-HTTPS: answers include `access-control-allow-origin: *` (!823)
+
 Bugfixes
 --------
 - TCP to upstream: don't send wrong message length (unlikely, !816)

modules/http/http.lua.in

@@ -165,11 +165,12 @@ local function serve(endpoints, h, stream)
 		entry = endpoints[path:match '^/[^/?]*']
 	end
 	-- Unpack MIME and data
-	local data, mime, ttl, err
+	local data, mime, ttl, any_origin, err
 	if entry then
 		mime = entry[1]
 		data = entry[2]
 		ttl = entry[4]
+		any_origin = entry[5]
 	end
 	-- Get string data out of service endpoint
 	if type(data) == 'function' then
@@ -196,6 +197,9 @@ local function serve(endpoints, h, stream)
 		if ttl then
 			hsend:append('cache-control', string.format('max-age=%d', ttl))
 		end
+		if any_origin then
+			hsend:append('access-control-allow-origin', '*')
+		end
 		assert(stream:write_headers(hsend, false))
 		assert(stream:write_chunk(data, true))
 	end

modules/http/http_doh.lua

@@ -112,6 +112,6 @@ end
 -- Export endpoints
 return {
 	endpoints = {
-		['/doh']   = {'text/plain', serve_doh},
+		['/doh']   = {'text/plain', serve_doh, nil, nil, true},
 	}
 }