3 // Copyright 2013 Ernest Micklei. All rights reserved.
4 // Use of this source code is governed by a license
5 // that can be found in the LICENSE file.
7 // FilterChain is a request scoped object to process one or more filters before calling the target RouteFunction.
8 type FilterChain struct {
9 Filters []FilterFunction // ordered list of FilterFunction
10 Index int // index into filters that is currently in progress
11 Target RouteFunction // function to call after passing all filters
14 // ProcessFilter passes the request,response pair through the next of Filters.
15 // Each filter can decide to proceed to the next Filter or handle the Response itself.
16 func (f *FilterChain) ProcessFilter(request *Request, response *Response) {
17 if f.Index < len(f.Filters) {
19 f.Filters[f.Index-1](request, response, f)
21 f.Target(request, response)
25 // FilterFunction definitions must call ProcessFilter on the FilterChain to pass on the control and eventually call the RouteFunction
26 type FilterFunction func(*Request, *Response, *FilterChain)
28 // NoBrowserCacheFilter is a filter function to set HTTP headers that disable browser caching
29 // See examples/restful-no-cache-filter.go for usage
30 func NoBrowserCacheFilter(req *Request, resp *Response, chain *FilterChain) {
31 resp.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate") // HTTP 1.1.
32 resp.Header().Set("Pragma", "no-cache") // HTTP 1.0.
33 resp.Header().Set("Expires", "0") // Proxies.
34 chain.ProcessFilter(req, resp)