Caching policies added.

We used httpcache library to implement this. As it was not possible to support different policies, I mostly copied and modified it.

cache/diskcache/diskcache.go

@@ -0,0 +1,61 @@
+// Package diskcache provides an implementation of cache.Cache that uses the diskv package
+// to supplement an in-memory map with persistent storage
+//
+package diskcache
+
+import (
+	"bytes"
+	"crypto/md5"
+	"encoding/hex"
+	"github.com/peterbourgon/diskv"
+	"io"
+)
+
+// Cache is an implementation of cache.Cache that supplements the in-memory map with persistent storage
+type Cache struct {
+	d *diskv.Diskv
+}
+
+// Get returns the response corresponding to key if present
+func (c *Cache) Get(key string) (resp []byte, ok bool) {
+	key = keyToFilename(key)
+	resp, err := c.d.Read(key)
+	if err != nil {
+		return []byte{}, false
+	}
+	return resp, true
+}
+
+// Set saves a response to the cache as key
+func (c *Cache) Set(key string, resp []byte) {
+	key = keyToFilename(key)
+	_ = c.d.WriteStream(key, bytes.NewReader(resp), true)
+}
+
+// Delete removes the response with key from the cache
+func (c *Cache) Delete(key string) {
+	key = keyToFilename(key)
+	_ = c.d.Erase(key)
+}
+
+func keyToFilename(key string) string {
+	h := md5.New()
+	_, _ = io.WriteString(h, key)
+	return hex.EncodeToString(h.Sum(nil))
+}
+
+// New returns a new Cache that will store files in basePath
+func New(basePath string) *Cache {
+	return &Cache{
+		d: diskv.New(diskv.Options{
+			BasePath:     basePath,
+			CacheSizeMax: 100 * 1024 * 1024, // 100MB
+		}),
+	}
+}
+
+// NewWithDiskv returns a new Cache using the provided Diskv as underlying
+// storage.
+func NewWithDiskv(d *diskv.Diskv) *Cache {
+	return &Cache{d}
+}

cache/diskcache/diskcache_test.go

@@ -0,0 +1,18 @@
+package diskcache
+
+import (
+	"github.com/geziyor/geziyor/cache"
+	"io/ioutil"
+	"os"
+	"testing"
+)
+
+func TestDiskCache(t *testing.T) {
+	tempDir, err := ioutil.TempDir("", "cache")
+	if err != nil {
+		t.Fatalf("TempDir: %v", err)
+	}
+	defer os.RemoveAll(tempDir)
+
+	cache.PleaseCache(t, New(tempDir))
+}