From a848c0f49aecee9a6e246f3793da6ff45575e4a1 Mon Sep 17 00:00:00 2001
From: Patrice Tisserand <p.tisserand@gmail.com>
Date: Sun, 11 Nov 2018 23:13:48 +0100
Subject: [PATCH] Added support to resize remote image: #16

A path is 'remote' if net.url.Parse(path).Scheme is not empty.
TwoTier.RemoteLocalPath convert URL to local path which is then use for storage,cache and thumbnails.
---
 api/api.go       |  2 +-
 api/routes.go    |  3 ++-
 store/twotier.go | 45 +++++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 46 insertions(+), 4 deletions(-)

diff --git a/api/api.go b/api/api.go
index 37e21fb..973b11e 100644
--- a/api/api.go
+++ b/api/api.go
@@ -68,7 +68,7 @@ func NewApi(ready chan<- bool) *Api {
 		Thumbnails: thumbCache,
 		Tiers:      collections.NewSyncStrSet(),
 		Etags:      etags,
-		Router:     mux.NewRouter().StrictSlash(true),
+		Router:     mux.NewRouter().StrictSlash(true).SkipClean(true),
 	}
 	go api.initCacheLoader(ready)
 	api.initCacheManager()
diff --git a/api/routes.go b/api/routes.go
index 65104b0..fcd82f8 100644
--- a/api/routes.go
+++ b/api/routes.go
@@ -93,7 +93,8 @@ func (api *Api) serveThumbs() http.HandlerFunc {
 				vars["resizeOp"],
 				vars["options"])
 			path := vars["path"]
-			thumbPath := resizeTier + "/" + path
+			thumbPath, _ := api.Originals.RemoteToLocalPath(path)
+			thumbPath = resizeTier + "/" + thumbPath
 			api.Tiers.Add(resizeTier)
 			thumbBuf, _ := api.Thumbnails.Get(thumbPath)
 			if thumbBuf == nil {
diff --git a/store/twotier.go b/store/twotier.go
index d016f05..8beffd7 100644
--- a/store/twotier.go
+++ b/store/twotier.go
@@ -1,20 +1,46 @@
 package store
 
+import (
+	"errors"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"path/filepath"
+)
+
 type TwoTier struct {
 	Store Store
 	Cache Cache
 }
 
-func (s *TwoTier) Get(filename string) ([]byte, error) {
+func (s *TwoTier) Get(aurl string) ([]byte, error) {
 	var buf []byte
 	var err error
+	filename, isRemote := s.RemoteToLocalPath(aurl)
+
 	if s.Cache != nil {
 		buf, _ = s.Cache.Get(filename)
 	}
 	if buf == nil {
 		buf, err = s.Store.Get(filename)
 		if err != nil {
-			return nil, err
+			if !isRemote {
+				return nil, err
+			} else {
+				response, err := http.Get(aurl)
+				if err != nil {
+					return nil, err
+				}
+				if response.StatusCode >= 400 {
+					return nil, errors.New("(" + response.Request.URL.String() + ") HTTP Error: " + response.Status)
+				}
+				defer response.Body.Close()
+				buf, err = ioutil.ReadAll(response.Body)
+				if err != nil {
+					return nil, err
+				}
+				err = s.Store.Put(filename, buf)
+			}
 		}
 		if s.Cache != nil {
 			go s.Cache.Put(filename, buf)
@@ -54,3 +80,18 @@ func (s *TwoTier) LoadCache(walkFn func(item interface{}) error) error {
 	}
 	return s.Cache.LoadCache(walkFn)
 }
+
+func (s *TwoTier) RemoteToLocalPath(path string) (string, bool) {
+	var localPath string
+	var isRemote bool
+
+	aurl, _ := url.Parse(path)
+	if aurl.Scheme != "" {
+		isRemote = true
+		localPath = filepath.Join(aurl.Hostname(), aurl.EscapedPath())
+	} else {
+		isRemote = false
+		localPath = path
+	}
+	return localPath, isRemote
+}