74 lines
1.4 KiB
Go
74 lines
1.4 KiB
Go
package main
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import (
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"net/http"
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)
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type Response struct {
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Code int
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Headers map[string][]string
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Body []byte
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}
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func (r Response) WriteResponse(rw http.ResponseWriter) {
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for k, vs := range r.Headers {
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for _, v := range vs {
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rw.Header().Add(k, v)
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}
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}
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rw.WriteHeader(r.Code)
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rw.Write(r.Body)
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}
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// implements ResponseWriter to collect HTTP responses
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type ResponseCollector struct {
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Response
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}
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func (rc *ResponseCollector) Header() http.Header {
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return rc.Headers
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}
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func (rc *ResponseCollector) Write(bs []byte) (int, error) {
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rc.Body = append(rc.Body, bs...)
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return len(bs), nil
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}
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func (rc *ResponseCollector) WriteHeader(code int) {
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rc.Code = code
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}
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func (rc *ResponseCollector) CollectResponse() Response {
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return rc.Response
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}
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type cacheEntry struct {
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r Response
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}
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func Cache(h http.Handler) http.Handler {
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c := make(map[string]cacheEntry)
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return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
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if r.Method != "GET" {
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rw.WriteHeader(403)
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rw.Write([]byte("invalid request type"))
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return
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}
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entry, exists := c[r.URL.String()]
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if exists {
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entry.r.WriteResponse(rw)
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} else {
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rc := ResponseCollector{}
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// copy request in case they modify it
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req := *r
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h.ServeHTTP(&rc, &req)
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resp := rc.CollectResponse()
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c[r.URL.String()] = cacheEntry{resp}
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resp.WriteResponse(rw)
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}
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// TODO bookkeeping for the cache here
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})
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}
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