Generalize cache get with expire param

utils/cache.go

@@ -0,0 +1,66 @@
+package utils
+
+import (
+    "bytes"
+    "io"
+    "os"
+    "path/filepath"
+    "time"
+)
+
+
+func CacheStream( path string, readStream func() ( io.ReadCloser, error ), expires int ) ( *bytes.Buffer, error ) {
+
+    cache, err := os.Stat( path )
+
+    // Check if cache exists and not expired
+    if err == nil {
+        expired := cache.ModTime().Add( 60 * 1e9 )
+        if time.Now().Before( expired ) {
+            f, err := os.Open( path )
+            if err == nil {
+                defer f.Close()
+                writeBuff := bytes.NewBuffer( []byte{} )
+                _, err = io.Copy( writeBuff, f )
+                if err == nil {
+                    return writeBuff, nil
+                }
+            }
+        }
+    }
+
+    err = os.MkdirAll( filepath.Dir( path ), 0750 )
+    if err != nil {
+        return nil, err
+    }
+
+    writeBuff := bytes.NewBuffer( []byte{} )
+
+    // Get the reader that return new data
+    s, err := readStream()
+    if err != nil {
+        return nil, err
+    }
+
+    defer s.Close()
+
+    _, err = io.Copy( writeBuff, s )
+    if err != nil {
+        return nil, err
+    }
+
+    f, err := os.OpenFile( path, os.O_CREATE | os.O_WRONLY | os.O_TRUNC, 0644 )
+    if err != nil {
+        return nil, err
+    }
+
+    defer f.Close()
+
+    data := writeBuff.Bytes()
+    _, err = io.Copy( f, bytes.NewReader( data ) )
+    if err != nil {
+        return nil, err
+    }
+
+    return writeBuff, nil
+}