[APIV4] GET /emoji/{emoji_id}/image for apiV4 (#6141)

* implement GET /emoji/{emoji_id}/image for apiV4

* update per request

5 files changed, 189 insertions, 23 deletions

diff --git a/api/emoji.go b/api/emoji.go
index feb65877a..1a79cc536 100644
--- a/api/emoji.go
+++ b/api/emoji.go
@@ -4,7 +4,6 @@
 package api
 
 import (
-	"bytes"
 	"image"
 	"image/draw"
 	"image/gif"
@@ -190,28 +189,15 @@ func getEmojiImage(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if result := <-app.Srv.Store.Emoji().Get(id, true); result.Err != nil {
-		c.Err = result.Err
+	image, imageType, err := app.GetEmojiImage(id)
+	if err != nil {
+		c.Err = err
 		return
-	} else {
-		var img []byte
-
-		if data, err := app.ReadFile(getEmojiImagePath(id)); err != nil {
-			c.Err = model.NewLocAppError("getEmojiImage", "api.emoji.get_image.read.app_error", nil, err.Error())
-			return
-		} else {
-			img = data
-		}
-
-		if _, imageType, err := image.DecodeConfig(bytes.NewReader(img)); err != nil {
-			model.NewLocAppError("getEmojiImage", "api.emoji.get_image.decode.app_error", nil, err.Error())
-		} else {
-			w.Header().Set("Content-Type", "image/"+imageType)
-		}
-
-		w.Header().Set("Cache-Control", "max-age=2592000, public")
-		w.Write(img)
 	}
+
+	w.Header().Set("Content-Type", "image/"+imageType)
+	w.Header().Set("Cache-Control", "max-age=2592000, public")
+	w.Write(image)
 }
 
 func getEmojiImagePath(id string) string {
diff --git a/api4/emoji.go b/api4/emoji.go
index ff4919860..a9bfae924 100644
--- a/api4/emoji.go
+++ b/api4/emoji.go
@@ -22,6 +22,7 @@ func InitEmoji() {
 	BaseRoutes.Emojis.Handle("", ApiSessionRequired(getEmojiList)).Methods("GET")
 	BaseRoutes.Emoji.Handle("", ApiSessionRequired(deleteEmoji)).Methods("DELETE")
 	BaseRoutes.Emoji.Handle("", ApiSessionRequired(getEmoji)).Methods("GET")
+	BaseRoutes.Emoji.Handle("/image", ApiSessionRequiredTrustRequester(getEmojiImage)).Methods("GET")
 }
 
 func createEmoji(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -129,3 +130,30 @@ func getEmoji(c *Context, w http.ResponseWriter, r *http.Request) {
 		w.Write([]byte(emoji.ToJson()))
 	}
 }
+
+func getEmojiImage(c *Context, w http.ResponseWriter, r *http.Request) {
+	c.RequireEmojiId()
+	if c.Err != nil {
+		return
+	}
+
+	if !*utils.Cfg.ServiceSettings.EnableCustomEmoji {
+		c.Err = model.NewAppError("getEmojiImage", "api.emoji.disabled.app_error", nil, "", http.StatusNotImplemented)
+		return
+	}
+
+	if len(utils.Cfg.FileSettings.DriverName) == 0 {
+		c.Err = model.NewAppError("getEmojiImage", "api.emoji.storage.app_error", nil, "", http.StatusNotImplemented)
+		return
+	}
+
+	image, imageType, err := app.GetEmojiImage(c.Params.EmojiId)
+	if err != nil {
+		c.Err = err
+		return
+	}
+
+	w.Header().Set("Content-Type", "image/"+imageType)
+	w.Header().Set("Cache-Control", "max-age=2592000, public")
+	w.Write(image)
+}
diff --git a/api4/emoji_test.go b/api4/emoji_test.go
index 23188a3d2..84d808e6d 100644
--- a/api4/emoji_test.go
+++ b/api4/emoji_test.go
@@ -4,6 +4,9 @@
 package api4
 
 import (
+	"bytes"
+	"image"
+	_ "image/gif"
 	"testing"
 
 	"github.com/mattermost/platform/model"
@@ -199,7 +202,6 @@ func TestGetEmojiList(t *testing.T) {
 			t.Fatalf("should not get a deleted emoji %v", emojis[0].Id)
 		}
 	}
-
 }
 
 func TestDeleteEmoji(t *testing.T) {
@@ -296,5 +298,123 @@ func TestGetEmoji(t *testing.T) {
 
 	_, resp = Client.GetEmoji(model.NewId())
 	CheckInternalErrorStatus(t, resp)
+}
+
+func TestGetEmojiImage(t *testing.T) {
+	th := Setup().InitBasic()
+	defer TearDown()
+	Client := th.Client
+
+	EnableCustomEmoji := *utils.Cfg.ServiceSettings.EnableCustomEmoji
+	DriverName := utils.Cfg.FileSettings.DriverName
+	defer func() {
+		*utils.Cfg.ServiceSettings.EnableCustomEmoji = EnableCustomEmoji
+		utils.Cfg.FileSettings.DriverName = DriverName
+	}()
+	*utils.Cfg.ServiceSettings.EnableCustomEmoji = true
+
+	emoji1 := &model.Emoji{
+		CreatorId: th.BasicUser.Id,
+		Name:      model.NewId(),
+	}
+
+	emoji1, resp := Client.CreateEmoji(emoji1, utils.CreateTestGif(t, 10, 10), "image.gif")
+	CheckNoError(t, resp)
+
+	*utils.Cfg.ServiceSettings.EnableCustomEmoji = false
+
+	_, resp = Client.GetEmojiImage(emoji1.Id)
+	CheckNotImplementedStatus(t, resp)
+	CheckErrorMessage(t, resp, "api.emoji.disabled.app_error")
+
+	utils.Cfg.FileSettings.DriverName = ""
+	*utils.Cfg.ServiceSettings.EnableCustomEmoji = true
+
+	_, resp = Client.GetEmojiImage(emoji1.Id)
+	CheckNotImplementedStatus(t, resp)
+	CheckErrorMessage(t, resp, "api.emoji.storage.app_error")
 
+	utils.Cfg.FileSettings.DriverName = DriverName
+
+	emojiImage, resp := Client.GetEmojiImage(emoji1.Id)
+	CheckNoError(t, resp)
+	if len(emojiImage) <= 0 {
+		t.Fatal("should return the image")
+	}
+	_, imageType, err := image.DecodeConfig(bytes.NewReader(emojiImage))
+	if err != nil {
+		t.Fatalf("unable to identify received image: %v", err.Error())
+	} else if imageType != "gif" {
+		t.Fatal("should've received gif data")
+	}
+
+	emoji2 := &model.Emoji{
+		CreatorId: th.BasicUser.Id,
+		Name:      model.NewId(),
+	}
+
+	emoji2, resp = Client.CreateEmoji(emoji2, utils.CreateTestAnimatedGif(t, 10, 10, 10), "image.gif")
+	CheckNoError(t, resp)
+
+	emojiImage, resp = Client.GetEmojiImage(emoji2.Id)
+	CheckNoError(t, resp)
+	if len(emojiImage) <= 0 {
+		t.Fatal("should return the image")
+	}
+	_, imageType, err = image.DecodeConfig(bytes.NewReader(emojiImage))
+	if err != nil {
+		t.Fatalf("unable to identify received image: %v", err.Error())
+	} else if imageType != "gif" {
+		t.Fatal("should've received gif data")
+	}
+
+	emoji3 := &model.Emoji{
+		CreatorId: th.BasicUser.Id,
+		Name:      model.NewId(),
+	}
+	emoji3, resp = Client.CreateEmoji(emoji3, utils.CreateTestJpeg(t, 10, 10), "image.jpg")
+	CheckNoError(t, resp)
+
+	emojiImage, resp = Client.GetEmojiImage(emoji3.Id)
+	CheckNoError(t, resp)
+	if len(emojiImage) <= 0 {
+		t.Fatal("should return the image")
+	}
+	_, imageType, err = image.DecodeConfig(bytes.NewReader(emojiImage))
+	if err != nil {
+		t.Fatalf("unable to identify received image: %v", err.Error())
+	} else if imageType != "jpeg" {
+		t.Fatal("should've received gif data")
+	}
+
+	emoji4 := &model.Emoji{
+		CreatorId: th.BasicUser.Id,
+		Name:      model.NewId(),
+	}
+	emoji4, resp = Client.CreateEmoji(emoji4, utils.CreateTestPng(t, 10, 10), "image.png")
+	CheckNoError(t, resp)
+
+	emojiImage, resp = Client.GetEmojiImage(emoji4.Id)
+	CheckNoError(t, resp)
+	if len(emojiImage) <= 0 {
+		t.Fatal("should return the image")
+	}
+	_, imageType, err = image.DecodeConfig(bytes.NewReader(emojiImage))
+	if err != nil {
+		t.Fatalf("unable to identify received image: %v", err.Error())
+	} else if imageType != "png" {
+		t.Fatal("should've received gif data")
+	}
+
+	_, resp = Client.DeleteEmoji(emoji4.Id)
+	CheckNoError(t, resp)
+
+	_, resp = Client.GetEmojiImage(emoji4.Id)
+	CheckNotFoundStatus(t, resp)
+
+	_, resp = Client.GetEmojiImage(model.NewId())
+	CheckInternalErrorStatus(t, resp)
+
+	_, resp = Client.GetEmojiImage("")
+	CheckBadRequestStatus(t, resp)
 }
diff --git a/app/emoji.go b/app/emoji.go
index b0c8418aa..3e3350285 100644
--- a/app/emoji.go
+++ b/app/emoji.go
@@ -6,7 +6,6 @@ package app
 import (
 	"bytes"
 	"image"
-	"image/color/palette"
 	"image/draw"
 	"image/gif"
 	_ "image/jpeg"
@@ -20,6 +19,7 @@ import (
 	"github.com/disintegration/imaging"
 	"github.com/mattermost/platform/model"
 	"github.com/mattermost/platform/utils"
+	"image/color/palette"
 )
 
 const (
@@ -148,6 +148,27 @@ func GetEmoji(emojiId string) (*model.Emoji, *model.AppError) {
 	}
 }
 
+func GetEmojiImage(emojiId string) (imageByte []byte, imageType string, err *model.AppError) {
+	if result := <-Srv.Store.Emoji().Get(emojiId, true); result.Err != nil {
+		return nil, "", result.Err
+	} else {
+		var img []byte
+
+		if data, err := ReadFile(getEmojiImagePath(emojiId)); err != nil {
+			return nil, "", model.NewAppError("getEmojiImage", "api.emoji.get_image.read.app_error", nil, err.Error(), http.StatusNotFound)
+		} else {
+			img = data
+		}
+
+		_, imageType, err := image.DecodeConfig(bytes.NewReader(img))
+		if err != nil {
+			return nil, "", model.NewAppError("getEmojiImage", "api.emoji.get_image.decode.app_error", nil, err.Error(), http.StatusInternalServerError)
+		}
+
+		return img, imageType, nil
+	}
+}
+
 func resizeEmojiGif(gifImg *gif.GIF) *gif.GIF {
 	// Create a new RGBA image to hold the incremental frames.
 	firstFrame := gifImg.Image[0].Bounds()
diff --git a/model/client4.go b/model/client4.go
index 4aa276026..04615f9e4 100644
--- a/model/client4.go
+++ b/model/client4.go
@@ -2489,6 +2489,17 @@ func (c *Client4) GetEmoji(emojiId string) (*Emoji, *Response) {
 	}
 }
 
+// GetEmojiImage returns the emoji image.
+func (c *Client4) GetEmojiImage(emojiId string) ([]byte, *Response) {
+	if r, err := c.DoApiGet(c.GetEmojiRoute(emojiId)+"/image", ""); err != nil {
+		return nil, &Response{StatusCode: r.StatusCode, Error: err}
+	} else if data, err := ioutil.ReadAll(r.Body); err != nil {
+		return nil, &Response{StatusCode: r.StatusCode, Error: NewAppError("GetEmojiImage", "model.client.read_file.app_error", nil, err.Error(), r.StatusCode)}
+	} else {
+		return data, BuildResponse(r)
+	}
+}
+
 // Reaction Section
 
 // SaveReaction saves an emoji reaction for a post. Returns the saved reaction if successful, otherwise an error will be returned.