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// Copyright 2015 Matthew Holt and The Caddy Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package caddyhttp
import (
"encoding/json"
"fmt"
"net/http"
"github.com/caddyserver/caddy/v2"
)
// ServerRoute represents a set of matching rules,
// middlewares, and a responder for handling HTTP
// requests.
type ServerRoute struct {
Group string `json:"group,omitempty"`
MatcherSets []map[string]json.RawMessage `json:"match,omitempty"`
Handle []json.RawMessage `json:"handle,omitempty"`
Terminal bool `json:"terminal,omitempty"`
// decoded values
matcherSets []MatcherSet
handlers []MiddlewareHandler
}
// Empty returns true if the route has all zero/default values.
func (sr ServerRoute) Empty() bool {
return len(sr.MatcherSets) == 0 &&
len(sr.Handle) == 0 &&
len(sr.handlers) == 0 &&
!sr.Terminal &&
sr.Group == ""
}
func (sr ServerRoute) anyMatcherSetMatches(r *http.Request) bool {
for _, ms := range sr.matcherSets {
if ms.Match(r) {
return true
}
}
// if no matchers, always match
return len(sr.matcherSets) == 0
}
// MatcherSet is a set of matchers which
// must all match in order for the request
// to be matched successfully.
type MatcherSet []RequestMatcher
// Match returns true if the request matches all
// matchers in mset.
func (mset MatcherSet) Match(r *http.Request) bool {
for _, m := range mset {
if !m.Match(r) {
return false
}
}
return true
}
// RouteList is a list of server routes that can
// create a middleware chain.
type RouteList []ServerRoute
// Provision sets up all the routes by loading the modules.
func (routes RouteList) Provision(ctx caddy.Context) error {
for i, route := range routes {
// matchers
for _, matcherSet := range route.MatcherSets {
var matchers MatcherSet
for modName, rawMsg := range matcherSet {
val, err := ctx.LoadModule("http.matchers."+modName, rawMsg)
if err != nil {
return fmt.Errorf("loading matcher module '%s': %v", modName, err)
}
matchers = append(matchers, val.(RequestMatcher))
}
routes[i].matcherSets = append(routes[i].matcherSets, matchers)
}
routes[i].MatcherSets = nil // allow GC to deallocate - TODO: Does this help?
// handlers
for j, rawMsg := range route.Handle {
mh, err := ctx.LoadModuleInline("handler", "http.handlers", rawMsg)
if err != nil {
return fmt.Errorf("loading handler module in position %d: %v", j, err)
}
routes[i].handlers = append(routes[i].handlers, mh.(MiddlewareHandler))
}
routes[i].Handle = nil // allow GC to deallocate - TODO: Does this help?
}
return nil
}
// BuildCompositeRoute creates a chain of handlers by
// applying all of the matching routes.
func (routes RouteList) BuildCompositeRoute(rw http.ResponseWriter, req *http.Request) Handler {
if len(routes) == 0 {
return emptyHandler
}
var mid []Middleware
groups := make(map[string]struct{})
for _, route := range routes {
// route must match at least one of the matcher sets
if !route.anyMatcherSetMatches(req) {
continue
}
// if route is part of a group, ensure only the
// first matching route in the group is applied
if route.Group != "" {
_, ok := groups[route.Group]
if ok {
// this group has already been satisfied
// by a matching route
continue
}
// this matching route satisfies the group
groups[route.Group] = struct{}{}
}
// apply the rest of the route
for _, mh := range route.handlers {
// we have to be sure to wrap mh outside
// of our current stack frame so that the
// reference to this mh isn't overwritten
// on the next iteration, leaving the last
// middleware in the chain as the ONLY
// middleware in the chain!
mid = append(mid, wrapMiddleware(mh))
}
// if this route is supposed to be last, don't
// compile any more into the chain
if route.Terminal {
break
}
}
// build the middleware chain, with the responder at the end
stack := emptyHandler
for i := len(mid) - 1; i >= 0; i-- {
stack = mid[i](stack)
}
return stack
}
// wrapMiddleware wraps m such that it can be correctly
// appended to a list of middleware. We can't do this
// directly in a loop because it relies on a reference
// to mh not changing until the execution of its handler,
// which is deferred by multiple func closures. In other
// words, we need to pull this particular MiddlewareHandler
// pointer into its own stack frame to preserve it so it
// won't be overwritten in future loop iterations.
func wrapMiddleware(mh MiddlewareHandler) Middleware {
return func(next HandlerFunc) HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) error {
// TODO: This is where request tracing could be implemented; also
// see below to trace the responder as well
// TODO: Trace a diff of the request, would be cool too! see what changed since the last middleware (host, headers, URI...)
// TODO: see what the std lib gives us in terms of stack tracing too
return mh.ServeHTTP(w, r, next)
}
}
}
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