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// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
package cache
import (
"bufio"
"bytes"
"net/http"
"net/http/httputil"
"path/filepath"
"strings"
"github.com/philippta/flyscrape"
)
func init() {
flyscrape.RegisterModule(Module{})
}
type Module struct {
Cache string `json:"cache"`
store Store
}
func (Module) ModuleInfo() flyscrape.ModuleInfo {
return flyscrape.ModuleInfo{
ID: "cache",
New: func() flyscrape.Module { return new(Module) },
}
}
func (m *Module) Provision(ctx flyscrape.Context) {
switch {
case m.Cache == "file":
file := replaceExt(ctx.ScriptName(), ".cache")
m.store = NewBoltStore(file)
case strings.HasPrefix(m.Cache, "file:"):
m.store = NewBoltStore(strings.TrimPrefix(m.Cache, "file:"))
}
}
func (m *Module) AdaptTransport(t http.RoundTripper) http.RoundTripper {
if m.store == nil {
return t
}
return flyscrape.RoundTripFunc(func(r *http.Request) (*http.Response, error) {
if nocache(r) {
return t.RoundTrip(r)
}
key := r.Method + " " + r.URL.String()
if b, ok := m.store.Get(key); ok {
if resp, err := http.ReadResponse(bufio.NewReader(bytes.NewReader(b)), r); err == nil {
return resp, nil
}
}
resp, err := t.RoundTrip(r)
if err != nil {
return resp, err
}
// Avoid caching when running into rate limits or
// when the page errored.
if resp.StatusCode < 200 || resp.StatusCode > 299 {
return resp, err
}
encoded, err := httputil.DumpResponse(resp, true)
if err != nil {
return resp, err
}
m.store.Set(key, encoded)
return resp, nil
})
}
func (m *Module) Finalize() {
if v, ok := m.store.(interface{ Close() }); ok {
v.Close()
}
}
func nocache(r *http.Request) bool {
if r.Header.Get(flyscrape.HeaderBypassCache) != "" {
r.Header.Del(flyscrape.HeaderBypassCache)
return true
}
return false
}
func replaceExt(filePath string, newExt string) string {
ext := filepath.Ext(filePath)
if ext != "" {
fileNameWithoutExt := filePath[:len(filePath)-len(ext)]
newFilePath := fileNameWithoutExt + newExt
return newFilePath
}
return filePath + newExt
}
type Store interface {
Get(key string) ([]byte, bool)
Set(key string, value []byte)
}
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