Do not show non-image attachment in a <img> tag. Fixes #3215 (#3311)

conf/locale/locale_en-US.ini

@@ -500,6 +500,8 @@ issues.label_deletion = Label Deletion
 issues.label_deletion_desc = Deleting this label will remove its information in all related issues. Do you want to continue?
 issues.label_deletion_success = Label has been deleted successfully!
 issues.num_participants = %d Participants
+issues.attachment.open_tab = `Click to see "%s" in a new tab`
+issues.attachment.download = `Click to download "%s"`
 
 pulls.new = New Pull Request
 pulls.compare_changes = Compare Changes

modules/template/template.go

@@ -9,6 +9,8 @@ import (
 	"encoding/json"
 	"fmt"
 	"html/template"
+	"mime"
+	"path/filepath"
 	"runtime"
 	"strings"
 	"time"
@@ -103,6 +105,10 @@ func NewFuncMap() []template.FuncMap {
 		"ThemeColorMetaTag": func() string {
 			return setting.UI.ThemeColorMetaTag
 		},
+		"FilenameIsImage": func(filename string) bool {
+			mimeType := mime.TypeByExtension(filepath.Ext(filename))
+			return strings.HasPrefix(mimeType, "image/")
+		},
 	}}
 }
 

public/less/_repository.less

@@ -463,6 +463,13 @@
 							margin: 0;
 							vertical-align: middle;
 						}
+						span.ui.image {
+							font-size: 8vw;
+							color: #000000;
+						}
+						span.ui.image:hover {
+							color: #000000;
+						}
 					}
 				}
 

templates/repo/issue/view_content.tmpl

@@ -41,7 +41,13 @@
 						<div class="ui bottom attached segment">
 							<div class="ui small images">
 								{{range .Issue.Attachments}}
-									<a target="_blank" href="{{AppSubUrl}}/attachments/{{.UUID}}"><img class="ui image" src="{{AppSubUrl}}/attachments/{{.UUID}}"></a>
+									<a target="_blank" href="{{AppSubUrl}}/attachments/{{.UUID}}">
+										{{if FilenameIsImage .Name}}
+											<img class="ui image" src="{{AppSubUrl}}/attachments/{{.UUID}}" title='{{$.i18n.Tr "repo.issues.attachment.open_tab" .Name}}'>
+										{{else}}
+											<span class="ui image octicon octicon-desktop-download" title='{{$.i18n.Tr "repo.issues.attachment.download" .Name}}'></span>
+										{{end}}
+									</a>
 								{{end}}
 							</div>
 						</div>
@@ -96,7 +102,13 @@
 								<div class="ui bottom attached segment">
 									<div class="ui small images">
 										{{range .Attachments}}
-											<a target="_blank" href="{{AppSubUrl}}/attachments/{{.UUID}}"><img class="ui image" src="{{AppSubUrl}}/attachments/{{.UUID}}"></a>
+											<a target="_blank" href="{{AppSubUrl}}/attachments/{{.UUID}}">
+												{{if FilenameIsImage .Name}}
+													<img class="ui image" src="{{AppSubUrl}}/attachments/{{.UUID}}" title='{{$.i18n.Tr "repo.issues.attachment.open_tab" .Name}}'>
+												{{else}}
+													<span class="ui image octicon octicon-desktop-download" title='{{$.i18n.Tr "repo.issues.attachment.download" .Name}}'></span>
+												{{end}}
+											</a>
 										{{end}}
 									</div>
 								</div>