59 lines
1.4 KiB
Go
Vendored
59 lines
1.4 KiB
Go
Vendored
package middleware
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// Ported from Goji's middleware, source:
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// https://github.com/zenazn/goji/tree/master/web/middleware
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import (
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"net/http"
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"time"
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)
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// Unix epoch time
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var epoch = time.Unix(0, 0).Format(time.RFC1123)
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// Taken from https://github.com/mytrile/nocache
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var noCacheHeaders = map[string]string{
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"Expires": epoch,
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"Cache-Control": "no-cache, no-store, no-transform, must-revalidate, private, max-age=0",
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"Pragma": "no-cache",
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"X-Accel-Expires": "0",
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}
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var etagHeaders = []string{
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"ETag",
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"If-Modified-Since",
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"If-Match",
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"If-None-Match",
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"If-Range",
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"If-Unmodified-Since",
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}
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// NoCache is a simple piece of middleware that sets a number of HTTP headers to prevent
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// a router (or subrouter) from being cached by an upstream proxy and/or client.
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//
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// As per http://wiki.nginx.org/HttpProxyModule - NoCache sets:
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// Expires: Thu, 01 Jan 1970 00:00:00 UTC
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// Cache-Control: no-cache, private, max-age=0
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// X-Accel-Expires: 0
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// Pragma: no-cache (for HTTP/1.0 proxies/clients)
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func NoCache(h http.Handler) http.Handler {
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fn := func(w http.ResponseWriter, r *http.Request) {
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// Delete any ETag headers that may have been set
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for _, v := range etagHeaders {
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if r.Header.Get(v) != "" {
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r.Header.Del(v)
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}
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}
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// Set our NoCache headers
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for k, v := range noCacheHeaders {
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w.Header().Set(k, v)
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}
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h.ServeHTTP(w, r)
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}
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return http.HandlerFunc(fn)
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}
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