Bug fix: Image caching (#172)

src/internal/imgcache/cache.go

@@ -0,0 +1,178 @@
+package imgcache
+
+import (
+  "fmt"
+  "io"
+  "io/ioutil"
+  "net/http"
+  "net/url"
+  "os"
+  "path/filepath"
+  "strings"
+  "sync"
+)
+
+// Cache : Cache strcut
+type Cache struct {
+  path     string
+  cacheURL string
+  caching  bool
+  images   map[string]string
+  Queue    []string
+  Cache    []string
+  Image    imageFunc
+  sync.RWMutex
+}
+
+type imageFunc struct {
+  GetURL  func(string) string
+  Caching func()
+  Remove  func()
+}
+
+// New : New cahce
+func New(path, chacheURL string, caching bool) (c *Cache, err error) {
+
+  c = &Cache{}
+
+  c.images = make(map[string]string)
+  c.path = path
+  c.cacheURL = chacheURL
+  c.caching = caching
+  c.Queue = []string{}
+  c.Cache = []string{}
+
+  var queue []string
+
+  c.Image.GetURL = func(src string) (cacheURL string) {
+
+    c.Lock()
+    defer c.Unlock()
+
+    src = strings.Trim(src, "\r\n")
+
+    if c.caching == false {
+      return src
+    }
+
+    u, err := url.Parse(src)
+    if err != nil || len(filepath.Ext(u.Path)) == 0 {
+      return src
+    }
+
+    var filename = fmt.Sprintf("%s%s", strToMD5(src), filepath.Ext(u.Path))
+    if cacheURL, ok := c.images[fmt.Sprintf("%s%s", strToMD5(src), filepath.Ext(u.Path))]; ok {
+      return cacheURL
+    }
+
+    if indexOfString(filename, c.Cache) == -1 {
+
+      if indexOfString(src, c.Queue) == -1 {
+        c.Queue = append(c.Queue, src)
+      }
+
+    } else {
+      c.images[filename] = c.cacheURL + filename
+      src = c.cacheURL + filename
+    }
+
+    /*
+       if _, err := os.Stat(c.path + filename); err != nil {
+         //c.images[filename] = c.cacheURL + filename
+         if indexOfString(src, c.Queue) == -1 {
+           c.Queue = append(c.Queue, src)
+         }
+       } else {
+         c.images[filename] = c.cacheURL + filename
+       }
+    */
+
+    return src
+  }
+
+  c.Image.Caching = func() {
+
+    c.Lock()
+    defer c.Unlock()
+
+    var filename string
+
+    for _, src := range c.Queue {
+
+      resp, err := http.Get(src)
+      if err != nil {
+        continue
+      }
+      defer resp.Body.Close()
+
+      if resp.StatusCode != http.StatusOK {
+        continue
+      }
+
+      filename = fmt.Sprintf("%s%s%s%s", c.path, string(os.PathSeparator), strToMD5(src), filepath.Ext(src))
+
+      file, err := os.Create(filename)
+      if err != nil {
+        continue
+      }
+
+      defer file.Close()
+
+      _, err = io.Copy(file, resp.Body)
+      if err != nil {
+        continue
+      }
+
+      u, err := url.Parse(src)
+      if err == nil {
+        c.images[fmt.Sprintf("%s%s", strToMD5(src), filepath.Ext(u.Path))] = c.cacheURL + filename
+      }
+
+      queue = append(queue, src)
+
+    }
+
+    for _, q := range queue {
+      c.Queue = removeStringFromSlice(q, c.Queue)
+    }
+
+  }
+
+  c.Image.Remove = func() {
+
+    c.Lock()
+    defer c.Unlock()
+
+    files, err := ioutil.ReadDir(c.path)
+    if err != nil {
+      return
+    }
+
+    for _, file := range files {
+
+      switch c.caching {
+
+      case true:
+        if _, ok := c.images[file.Name()]; !ok {
+          os.RemoveAll(c.path + file.Name())
+        }
+
+      case false:
+        os.RemoveAll(c.path + file.Name())
+      }
+
+    }
+
+  }
+
+  files, err := ioutil.ReadDir(c.path)
+  if err != nil {
+    return
+  }
+
+  for _, file := range files {
+    c.Cache = append(c.Cache, file.Name())
+  }
+
+  return
+}

src/internal/imgcache/tools.go

@@ -0,0 +1,34 @@
+package imgcache
+
+import (
+  "crypto/md5"
+  "encoding/hex"
+)
+
+func strToMD5(str string) string {
+  md5Hasher := md5.New()
+  md5Hasher.Write([]byte(str))
+  return hex.EncodeToString(md5Hasher.Sum(nil))
+}
+
+func indexOfString(str string, slice []string) int {
+
+  for i, v := range slice {
+    if str == v {
+      return i
+    }
+  }
+
+  return -1
+}
+
+func removeStringFromSlice(str string, slice []string) []string {
+
+  var i = indexOfString(str, slice)
+
+  if i != -1 {
+    slice = append(slice[:i], slice[i+1:]...)
+  }
+
+  return slice
+}