httptransport: implement apiError using the new details package

Signed-off-by: Hank Donnay <[email protected]>

httptransport/error.go

@@ -1,89 +1,40 @@
 package httptransport
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
-	"errors"
 	"fmt"
 	"net/http"
 
-	"github.com/quay/zlog"
+	"github.com/quay/clair/v4/httptransport/internal/details"
 )
 
-// StatusClientClosedRequest is a nonstandard HTTP status code used when the
-// client has gone away.
-//
-// This convention is cribbed from Nginx.
-const statusClientClosedRequest = 499
-
-// ApiError writes an untyped (that is, "application/json") error with the
-// provided HTTP status code and message.
+// ApiError writes an error with the provided HTTP status code and message.
 //
 // ApiError does not return, but instead causes the goroutine to exit.
+//
+// Deprecated: This is implemented via [details.Error], which provides a
+// richer API.
 func apiError(ctx context.Context, w http.ResponseWriter, code int, f string, v ...interface{}) {
-	const errheader = `Clair-Error`
-	disconnect := false
-	select {
-	case <-ctx.Done():
-		disconnect = true
-	default:
-	}
-	if ev := zlog.Debug(ctx); ev.Enabled() {
-		ev.
-			Bool("disconnect", disconnect).
-			Int("code", code).
-			Str("error", fmt.Sprintf(f, v...)).
-			Msg("http error response")
-	} else {
-		ev.Send()
-	}
-	if disconnect {
-		// Exit immediately if there's no client to read the response, anyway.
-		w.WriteHeader(statusClientClosedRequest)
-		panic(http.ErrAbortHandler)
+	err := genericError{
+		status: code,
+		err:    fmt.Errorf(f, v...),
 	}
+	details.Error(ctx, w, &err)
+}
+
+type genericError struct {
+	status int
+	err    error
+}
 
-	h := w.Header()
-	h.Del("link")
-	h.Set("content-type", "application/json")
-	h.Set("x-content-type-options", "nosniff")
-	h.Set("trailer", errheader)
-	w.WriteHeader(code)
+func (e *genericError) Error() string {
+	return e.err.Error()
+}
 
-	var buf bytes.Buffer
-	buf.WriteString(`{"code":"`)
-	switch code {
-	case http.StatusBadRequest:
-		buf.WriteString("bad-request")
-	case http.StatusMethodNotAllowed:
-		buf.WriteString("method-not-allowed")
-	case http.StatusNotFound:
-		buf.WriteString("not-found")
-	case http.StatusTooManyRequests:
-		buf.WriteString("too-many-requests")
-	default:
-		buf.WriteString("internal-error")
-	}
-	buf.WriteByte('"')
-	if f != "" {
-		buf.WriteString(`,"message":`)
-		b, _ := json.Marshal(fmt.Sprintf(f, v...)) // OK use of encoding/json.
-		buf.Write(b)
-	}
-	buf.WriteByte('}')
+func (e *genericError) Unwrap() error {
+	return e.err
+}
 
-	if _, err := buf.WriteTo(w); err != nil {
-		h.Set(errheader, err.Error())
-	}
-	switch err := http.NewResponseController(w).Flush(); {
-	case errors.Is(err, nil):
-	case errors.Is(err, http.ErrNotSupported):
-		// Skip
-	default:
-		zlog.Warn(ctx).
-			Err(err).
-			Msg("unable to flush http response")
-	}
-	panic(http.ErrAbortHandler)
+func (e *genericError) ErrorStatus() int {
+	return e.status
 }

httptransport/error_test.go

@@ -52,7 +52,7 @@ func TestClientDisconnect(t *testing.T) {
 	}
 
 	<-handlerDone
-	if got, want := status, statusClientClosedRequest; got != want {
+	if got, want := status, 499; got != want {
 		t.Errorf("bad status code recorded: got: %d, want: %d", got, want)
 	}
 }