Fix: stop panic on TCP broken pipe

internal/webserver/utils.go

@@ -11,11 +11,13 @@ import (
 	"io/ioutil"
 	"math"
 	"mime"
+	"net"
 	"net/http"
 	nurl "net/url"
 	"os"
 	fp "path/filepath"
 	"strings"
+	"syscall"
 	"time"
 
 	"github.com/disintegration/imaging"
@@ -183,7 +185,19 @@ func createTemplate(filename string, funcMap template.FuncMap) (*template.Templa
 }
 
 func checkError(err error) {
-	if err != nil {
+	if err == nil {
-		panic(err)
+		return
 	}
+
+	// Check for a broken connection, as it is not really a
+	// condition that warrants a panic stack trace.
+	if ne, ok := err.(*net.OpError); ok {
+		if se, ok := ne.Err.(*os.SyscallError); ok {
+			if se.Err == syscall.EPIPE || se.Err == syscall.ECONNRESET {
+				return
+			}
+		}
+	}
+
+	panic(err)
 }