feat: handle empty get body (#3)

transport.go

@@ -1,6 +1,7 @@
 package httpr
 
 import (
+	"bytes"
 	"io"
 	"net/http"
 	"time"
@@ -51,9 +52,8 @@ func New(options ...Option) *Transport {
 // 408, 429, 500, 502, 503 and 504.
 var NewTransport = New
 
-// RoundTrip satisfies the http.RoundTripper interface and performs an
-// http request with the configured retry policy.
-func (tr *Transport) RoundTrip(r *http.Request) (*http.Response, error) {
+// setup sets the default values for the transport when they are not provided.
+func (tr *Transport) setup() {
 	if tr.tr == nil {
 		tr.tr = http.DefaultTransport
 	}
@@ -70,6 +70,17 @@ func (tr *Transport) RoundTrip(r *http.Request) (*http.Response, error) {
 			return 0
 		}
 	}
+}
+
+// RoundTrip satisfies the http.RoundTripper interface and performs an
+// http request with the configured retry policy.
+func (tr *Transport) RoundTrip(r *http.Request) (*http.Response, error) {
+	tr.setup()
+	if r.Body != nil && r.GetBody == nil {
+		if err := setGetBody(r); err != nil {
+			return nil, err
+		}
+	}
 	backoff := tr.rp.Backoff
 
 	retries := 0
@@ -127,3 +138,18 @@ func drainResponse(r *http.Response) error {
 	}
 	return nil
 }
+
+// setGetBody sets the GetBody method on the request
+func setGetBody(r *http.Request) error {
+	body, err := io.ReadAll(r.Body)
+	if err != nil {
+		return err
+	}
+	r.Body = io.NopCloser(bytes.NewReader(body))
+	r.ContentLength = int64(len(body))
+
+	r.GetBody = func() (io.ReadCloser, error) {
+		return io.NopCloser(bytes.NewReader(body)), nil
+	}
+	return nil
+}

transport_test.go

@@ -9,12 +9,64 @@ import (
 	"net"
 	"net/http"
 	"net/http/httptest"
+	"net/url"
 	"testing"
 	"time"
 
 	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
 )
 
+func TestNew(t *testing.T) {
+	var tests = []struct {
+		name  string
+		input []Option
+		want  *Transport
+	}{
+		{
+			name: "default transport",
+			want: &Transport{
+				tr: http.DefaultTransport,
+				rp: defaultRetryPolicy(),
+			},
+		},
+		{
+			name: "with retry policy",
+			input: []Option{
+				WithRetryPolicy(RetryPolicy{
+					ShouldRetry: StandardShouldRetry,
+					Backoff:     ExponentialBackoff(),
+					MaxRetries:  5,
+					MinDelay:    1 * time.Second,
+					MaxDelay:    10 * time.Second,
+					Jitter:      0.1,
+				}),
+			},
+			want: &Transport{
+				tr: http.DefaultTransport,
+				rp: RetryPolicy{
+					ShouldRetry: StandardShouldRetry,
+					Backoff:     ExponentialBackoff(),
+					MaxRetries:  5,
+					MinDelay:    1 * time.Second,
+					MaxDelay:    10 * time.Second,
+					Jitter:      0.1,
+				},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			got := New(test.input...)
+
+			if diff := cmp.Diff(test.want, got, cmp.AllowUnexported(Transport{}, http.Transport{}), cmpopts.IgnoreUnexported(http.Transport{}), cmpopts.IgnoreFields(RetryPolicy{}, "ShouldRetry", "Backoff"), cmpopts.IgnoreFields(http.Transport{}, "Proxy", "DialContext")); diff != "" {
+				t.Errorf("New() = unexpected result (-want +got)\n%s\n", diff)
+			}
+		})
+	}
+}
+
 func TestTransport_RoundTrip(t *testing.T) {
 	type input struct {
 		req         func() *http.Request
@@ -165,6 +217,33 @@ func TestTransport_RoundTrip(t *testing.T) {
 				body:       wantBodyPost,
 			},
 		},
+		{
+			name: "successful POST with retries - request literal",
+			input: input{
+				req: func() *http.Request {
+					u, _ := url.Parse("http://example.com")
+					req := &http.Request{
+						Method: http.MethodPost,
+						URL:    u,
+						Body:   io.NopCloser(bytes.NewReader(wantBodyPost)),
+					}
+					return req
+				},
+				retryPolicy: RetryPolicy{
+					ShouldRetry: StandardShouldRetry,
+					Backoff:     ExponentialBackoff(),
+					MaxRetries:  3,
+					MinDelay:    1 * time.Millisecond,
+					MaxDelay:    5 * time.Millisecond,
+				},
+				retries: 3,
+				err:     errors.New("error"),
+			},
+			want: want{
+				statusCode: http.StatusOK,
+				body:       wantBodyPost,
+			},
+		},
 	}
 
 	for _, test := range tests {