diff options
Diffstat (limited to 'modules/caddyhttp/httpcache/httpcache.go')
| -rw-r--r-- | modules/caddyhttp/httpcache/httpcache.go | 242 |
1 files changed, 0 insertions, 242 deletions
diff --git a/modules/caddyhttp/httpcache/httpcache.go b/modules/caddyhttp/httpcache/httpcache.go deleted file mode 100644 index 605a183..0000000 --- a/modules/caddyhttp/httpcache/httpcache.go +++ /dev/null @@ -1,242 +0,0 @@ -// 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 httpcache - -import ( - "bytes" - "context" - "encoding/gob" - "fmt" - "io" - "log" - "net/http" - "sync" - - "github.com/caddyserver/caddy/v2" - "github.com/caddyserver/caddy/v2/modules/caddyhttp" - "github.com/golang/groupcache" -) - -func init() { - caddy.RegisterModule(Cache{}) -} - -// Cache implements a simple distributed cache. -// -// NOTE: This module is a work-in-progress. It is -// not finished and is NOT ready for production use. -// [We need your help to finish it! Please volunteer -// in this issue.](https://github.com/caddyserver/caddy/issues/2820) -// Until it is finished, this module is subject to -// breaking changes. -// -// Caches only GET and HEAD requests. Honors the Cache-Control: no-cache header. -// -// Still TODO: -// -// - Eviction policies and API -// - Use single cache per-process -// - Preserve cache through config reloads -// - More control over what gets cached -type Cache struct { - // The network address of this cache instance; required. - Self string `json:"self,omitempty"` - - // A list of network addresses of cache instances in the group. - Peers []string `json:"peers,omitempty"` - - // Maximum size of the cache, in bytes. Default is 512 MB. - MaxSize int64 `json:"max_size,omitempty"` - - group *groupcache.Group -} - -// CaddyModule returns the Caddy module information. -func (Cache) CaddyModule() caddy.ModuleInfo { - return caddy.ModuleInfo{ - ID: "http.handlers.cache", - New: func() caddy.Module { return new(Cache) }, - } -} - -// Provision provisions c. -func (c *Cache) Provision(ctx caddy.Context) error { - // TODO: use UsagePool so that cache survives config reloads - TODO: a single cache for whole process? - maxSize := c.MaxSize - if maxSize == 0 { - const maxMB = 512 - maxSize = int64(maxMB << 20) - } - poolMu.Lock() - if pool == nil { - pool = groupcache.NewHTTPPool(c.Self) - c.group = groupcache.NewGroup(groupName, maxSize, groupcache.GetterFunc(c.getter)) - } else { - c.group = groupcache.GetGroup(groupName) - } - pool.Set(append(c.Peers, c.Self)...) - poolMu.Unlock() - - return nil -} - -// Validate validates c. -func (c *Cache) Validate() error { - if c.Self == "" { - return fmt.Errorf("address of this instance (self) is required") - } - if c.MaxSize < 0 { - return fmt.Errorf("size must be greater than 0") - } - return nil -} - -func (c *Cache) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error { - // TODO: proper RFC implementation of cache control headers... - if r.Header.Get("Cache-Control") == "no-cache" || (r.Method != "GET" && r.Method != "HEAD") { - return next.ServeHTTP(w, r) - } - - getterCtx := getterContext{w, r, next} - ctx := context.WithValue(r.Context(), getterContextCtxKey, getterCtx) - - // TODO: rigorous performance testing - - // TODO: pretty much everything else to handle the nuances of HTTP caching... - - // TODO: groupcache has no explicit cache eviction, so we need to embed - // all information related to expiring cache entries into the key; right - // now we just use the request URI as a proof-of-concept - key := r.RequestURI - - var cachedBytes []byte - err := c.group.Get(ctx, key, groupcache.AllocatingByteSliceSink(&cachedBytes)) - if err == errUncacheable { - return nil - } - if err != nil { - return err - } - - // the cached bytes consists of two parts: first a - // gob encoding of the status and header, immediately - // followed by the raw bytes of the response body - rdr := bytes.NewReader(cachedBytes) - - // read the header and status first - var hs headerAndStatus - err = gob.NewDecoder(rdr).Decode(&hs) - if err != nil { - return err - } - - // set and write the cached headers - for k, v := range hs.Header { - w.Header()[k] = v - } - w.WriteHeader(hs.Status) - - // write the cached response body - io.Copy(w, rdr) - - return nil -} - -func (c *Cache) getter(ctx context.Context, key string, dest groupcache.Sink) error { - combo := ctx.Value(getterContextCtxKey).(getterContext) - - // the buffer will store the gob-encoded header, then the body - buf := bufPool.Get().(*bytes.Buffer) - buf.Reset() - defer bufPool.Put(buf) - - // we need to record the response if we are to cache it; only cache if - // request is successful (TODO: there's probably much more nuance needed here) - rr := caddyhttp.NewResponseRecorder(combo.rw, buf, func(status int, header http.Header) bool { - shouldBuf := status < 300 - - if shouldBuf { - // store the header before the body, so we can efficiently - // and conveniently use a single buffer for both; gob - // decoder will only read up to end of gob message, and - // the rest will be the body, which will be written - // implicitly for us by the recorder - err := gob.NewEncoder(buf).Encode(headerAndStatus{ - Header: header, - Status: status, - }) - if err != nil { - log.Printf("[ERROR] Encoding headers for cache entry: %v; not caching this request", err) - return false - } - } - - return shouldBuf - }) - - // execute next handlers in chain - err := combo.next.ServeHTTP(rr, combo.req) - if err != nil { - return err - } - - // if response body was not buffered, response was - // already written and we are unable to cache - if !rr.Buffered() { - return errUncacheable - } - - // add to cache - dest.SetBytes(buf.Bytes()) - - return nil -} - -type headerAndStatus struct { - Header http.Header - Status int -} - -type getterContext struct { - rw http.ResponseWriter - req *http.Request - next caddyhttp.Handler -} - -var bufPool = sync.Pool{ - New: func() interface{} { - return new(bytes.Buffer) - }, -} - -var ( - pool *groupcache.HTTPPool - poolMu sync.Mutex -) - -var errUncacheable = fmt.Errorf("uncacheable") - -const groupName = "http_requests" - -type ctxKey string - -const getterContextCtxKey ctxKey = "getter_context" - -// Interface guards -var ( - _ caddy.Provisioner = (*Cache)(nil) - _ caddy.Validator = (*Cache)(nil) - _ caddyhttp.MiddlewareHandler = (*Cache)(nil) -) |