[#7575] use memory+file buffer when rereading the request body (fix #7572)

tools/router/rereadable_read_closer_test.go

@@ -1,28 +1,69 @@
-package router_test
+package router
 
 import (
+	"errors"
 	"io"
+	"io/fs"
+	"os"
+	"strconv"
 	"strings"
 	"testing"
-
-	"github.com/pocketbase/pocketbase/tools/router"
 )
 
 func TestRereadableReadCloser(t *testing.T) {
 	content := "test"
 
-	rereadable := &router.RereadableReadCloser{
+	rereadable := &RereadableReadCloser{
 		ReadCloser: io.NopCloser(strings.NewReader(content)),
+		MaxMemory:  2, // should store the rest 2 bytes in temp file
 	}
 
-	// read multiple times
-	for i := 0; i < 3; i++ {
-		result, err := io.ReadAll(rereadable)
-		if err != nil {
-			t.Fatalf("[read:%d] %v", i, err)
-		}
-		if str := string(result); str != content {
-			t.Fatalf("[read:%d] Expected %q, got %q", i, content, result)
+	totalRereads := 5
+
+	tempFilenames := make([]string, 0, totalRereads)
+
+	// reread multiple times
+	for i := 0; i < totalRereads; i++ {
+		t.Run("run_"+strconv.Itoa(i), func(t *testing.T) {
+			if i > 3 {
+				// test allso with manual Reread calls to ensure that
+				// r.copy is reseted and written to only when there are n>0 bytes
+				rereadable.Reread()
+			}
+
+			result, err := io.ReadAll(rereadable)
+			if err != nil {
+				t.Fatalf("[read:%d] %v", i, err)
+			}
+			if str := string(result); str != content {
+				t.Fatalf("[read:%d] Expected %q, got %q", i, content, result)
+			}
+
+			b, ok := rereadable.ReadCloser.(*bufferWithFile)
+			if !ok {
+				t.Fatalf("Expected bufferWithFile replacement, got %v", b)
+			}
+
+			if b.file != nil {
+				tempFilenames = append(tempFilenames, b.file.Name())
+			}
+		})
+	}
+
+	if v := len(tempFilenames); v != totalRereads {
+		t.Fatalf("Expected %d temp files to have been created during the previous rereads, got %d", totalRereads, v)
+	}
+
+	err := rereadable.Close()
+	if err != nil {
+		t.Fatalf("Expected no close errors, got %v", err)
+	}
+
+	// ensure that no lingering temp files are left after close
+	for _, name := range tempFilenames {
+		info, err := os.Stat(name)
+		if err == nil || !errors.Is(err, fs.ErrNotExist) {
+			t.Fatalf("Expected file name %q to be deleted, got %v (%v)", name, info, err)
 		}
 	}
 }