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

tools/router/buffer_with_file_test.go

@@ -0,0 +1,193 @@
+package router
+
+import (
+	"errors"
+	"io"
+	"io/fs"
+	"os"
+	"testing"
+)
+
+func TestNewBufferWithFile(t *testing.T) {
+	t.Parallel()
+
+	scenarios := []struct {
+		name     string
+		limit    int64
+		expected int64
+	}{
+		{"negative limit", -1, DefaultMaxMemory},
+		{"zero limit", 0, DefaultMaxMemory},
+		{"> 0", 1, 1},
+	}
+
+	for _, s := range scenarios {
+		t.Run(s.name, func(t *testing.T) {
+			b := newBufferWithFile(s.limit)
+
+			if b.file != nil {
+				t.Fatalf("Expected no file descriptor to be open, got %v", b.file)
+			}
+
+			if b.buf == nil {
+				t.Fatal("Expected buf to be initialized, got nil")
+			}
+
+			if b.memoryLimit != s.expected {
+				t.Fatalf("Expected %d limit, got %d", 10, b.memoryLimit)
+			}
+		})
+	}
+}
+
+func TestBufferWithFile_WriteReadClose(t *testing.T) {
+	t.Parallel()
+
+	b := newBufferWithFile(4)
+
+	t.Run("write under limit", func(t *testing.T) {
+		n, err := b.Write([]byte("ab"))
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if n != 2 {
+			t.Fatalf("Expected %d bytes to be written, got %v", 2, n)
+		}
+
+		if l := b.buf.Len(); l != 2 {
+			t.Fatalf("Expected memory buf lenth %d, got %d", 2, l)
+		}
+
+		if b.file != nil {
+			t.Fatalf("Expected temp file to remain nil, got %v", b.file)
+		}
+	})
+
+	t.Run("write under limit (again)", func(t *testing.T) {
+		n, err := b.Write([]byte("c"))
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if n != 1 {
+			t.Fatalf("Expected %d bytes to be written, got %v", 1, n)
+		}
+
+		if l := b.buf.Len(); l != 3 {
+			t.Fatalf("Expected memory buf lenth %d, got %d", 3, l)
+		}
+
+		if b.file != nil {
+			t.Fatalf("Expected temp file to remain nil, got %v", b.file)
+		}
+	})
+
+	t.Run("write beyound limit (aka. skip memory buf and write into file)", func(t *testing.T) {
+		n, err := b.Write([]byte("de"))
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if n != 2 {
+			t.Fatalf("Expected %d bytes to be written, got %v", 2, n)
+		}
+
+		if l := b.buf.Len(); l != 3 {
+			t.Fatalf("Expected memory buf lenth to be unchanged (%d), got %d", 3, l)
+		}
+
+		if b.file == nil {
+			t.Fatal("Expected temp file to be initialized")
+		}
+	})
+
+	t.Run("read 0 bytes fromm non-empty buffer", func(t *testing.T) {
+		temp := []byte{}
+
+		n, err := b.Read(temp)
+		if err != nil { // should return nil for consistency with bytes.Buffer
+			t.Fatalf("Expected nil, got %v", err)
+		}
+
+		if n != 0 {
+			t.Fatalf("Expected 0 bytes to be read, got %d (%q)", n, temp)
+		}
+	})
+
+	t.Run("read under limit", func(t *testing.T) {
+		expected := "ab"
+		temp := make([]byte, 2)
+
+		n, err := b.Read(temp)
+		if err != nil && err != io.EOF {
+			t.Fatal(err)
+		}
+
+		if n != len(temp) {
+			t.Fatalf("Expected %d bytes to be read, got %d (%q)", len(temp), n, temp)
+		}
+
+		if str := string(temp); str != expected {
+			t.Fatalf("Expected to read %q, got %q", expected, str)
+		}
+	})
+
+	t.Run("read beyound limit", func(t *testing.T) {
+		expected := "cde"
+		temp := make([]byte, 3)
+
+		n, err := b.Read(temp)
+		if err != nil && err != io.EOF {
+			t.Fatal(err)
+		}
+
+		if n != len(temp) {
+			t.Fatalf("Expected %d bytes to be read, got %d (%q)", len(temp), n, temp)
+		}
+
+		if str := string(temp); str != expected {
+			t.Fatalf("Expected to read %q, got %q", expected, str)
+		}
+	})
+
+	t.Run("read from empty buffers", func(t *testing.T) {
+		temp := make([]byte, 3)
+
+		n, err := b.Read(temp)
+		if err != io.EOF {
+			t.Fatalf("Expected EOF, got %v", err)
+		}
+
+		if n != 0 {
+			t.Fatalf("Expected 0 bytes to be read, got %d (%q)", n, temp)
+		}
+	})
+
+	t.Run("close cleanup", func(t *testing.T) {
+		if b.file == nil {
+			t.Fatal("Expected temp file to be initialized, got nil")
+		}
+
+		filename := b.file.Name()
+
+		_, err := os.Stat(filename)
+		if err != nil || errors.Is(err, fs.ErrNotExist) {
+			t.Fatalf("Expected the temp file to exist and be accessible, got %v", err)
+		}
+
+		err = b.Close()
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		info, err := os.Stat(filename)
+		if err == nil {
+			t.Fatalf("Expected the temp file to be deleted after close, got %v", info)
+		}
+
+		if b.buf != nil || b.file != nil {
+			t.Fatal("Expected the internal buffers to be nil after close")
+		}
+	})
+}