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package gmi
import (
"bytes"
"context"
"io"
"sync"
"git.sr.ht/~adnano/go-gemini"
"dev.mediocregopher.com/mediocre-blog.git/src/cache"
)
type cacheRW struct {
gemini.ResponseWriter
status gemini.Status
mediaType string
buf []byte
}
func (c *cacheRW) SetMediaType(mediaType string) {
c.mediaType = mediaType
c.ResponseWriter.SetMediaType(mediaType)
}
func (c *cacheRW) WriteHeader(status gemini.Status, meta string) {
c.status = status
c.ResponseWriter.WriteHeader(status, meta)
}
func (c *cacheRW) Write(b []byte) (int, error) {
c.buf = append(c.buf, b...)
return c.ResponseWriter.Write(b)
}
func cacheMiddleware(cache cache.Cache) func(h gemini.Handler) gemini.Handler {
type entry struct {
mediaType string
body []byte
}
pool := sync.Pool{
New: func() interface{} { return new(bytes.Reader) },
}
return func(h gemini.Handler) gemini.Handler {
return gemini.HandlerFunc(func(
ctx context.Context,
rw gemini.ResponseWriter,
r *gemini.Request,
) {
id := r.URL.String()
if value := cache.Get(id); value != nil {
entry := value.(entry)
if entry.mediaType != "" {
rw.SetMediaType(entry.mediaType)
}
reader := pool.Get().(*bytes.Reader)
defer pool.Put(reader)
reader.Reset(entry.body)
io.Copy(rw, reader)
return
}
cacheRW := &cacheRW{
ResponseWriter: rw,
status: gemini.StatusSuccess,
}
h.ServeGemini(ctx, cacheRW, r)
if cacheRW.status == gemini.StatusSuccess {
cache.Set(id, entry{
mediaType: cacheRW.mediaType,
body: cacheRW.buf,
})
}
})
}
}
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