Update vendor, move to labstack/echo/v4 Fixes #698

vendor/github.com/labstack/echo/v4/response.go

@@ -0,0 +1,101 @@
+package echo
+
+import (
+	"bufio"
+	"net"
+	"net/http"
+)
+
+type (
+	// Response wraps an http.ResponseWriter and implements its interface to be used
+	// by an HTTP handler to construct an HTTP response.
+	// See: https://golang.org/pkg/net/http/#ResponseWriter
+	Response struct {
+		echo        *Echo
+		beforeFuncs []func()
+		afterFuncs  []func()
+		Writer      http.ResponseWriter
+		Status      int
+		Size        int64
+		Committed   bool
+	}
+)
+
+// NewResponse creates a new instance of Response.
+func NewResponse(w http.ResponseWriter, e *Echo) (r *Response) {
+	return &Response{Writer: w, echo: e}
+}
+
+// Header returns the header map for the writer that will be sent by
+// WriteHeader. Changing the header after a call to WriteHeader (or Write) has
+// no effect unless the modified headers were declared as trailers by setting
+// the "Trailer" header before the call to WriteHeader (see example)
+// To suppress implicit response headers, set their value to nil.
+// Example: https://golang.org/pkg/net/http/#example_ResponseWriter_trailers
+func (r *Response) Header() http.Header {
+	return r.Writer.Header()
+}
+
+// Before registers a function which is called just before the response is written.
+func (r *Response) Before(fn func()) {
+	r.beforeFuncs = append(r.beforeFuncs, fn)
+}
+
+// After registers a function which is called just after the response is written.
+// If the `Content-Length` is unknown, none of the after function is executed.
+func (r *Response) After(fn func()) {
+	r.afterFuncs = append(r.afterFuncs, fn)
+}
+
+// WriteHeader sends an HTTP response header with status code. If WriteHeader is
+// not called explicitly, the first call to Write will trigger an implicit
+// WriteHeader(http.StatusOK). Thus explicit calls to WriteHeader are mainly
+// used to send error codes.
+func (r *Response) WriteHeader(code int) {
+	if r.Committed {
+		r.echo.Logger.Warn("response already committed")
+		return
+	}
+	for _, fn := range r.beforeFuncs {
+		fn()
+	}
+	r.Status = code
+	r.Writer.WriteHeader(code)
+	r.Committed = true
+}
+
+// Write writes the data to the connection as part of an HTTP reply.
+func (r *Response) Write(b []byte) (n int, err error) {
+	if !r.Committed {
+		r.WriteHeader(http.StatusOK)
+	}
+	n, err = r.Writer.Write(b)
+	r.Size += int64(n)
+	for _, fn := range r.afterFuncs {
+		fn()
+	}
+	return
+}
+
+// Flush implements the http.Flusher interface to allow an HTTP handler to flush
+// buffered data to the client.
+// See [http.Flusher](https://golang.org/pkg/net/http/#Flusher)
+func (r *Response) Flush() {
+	r.Writer.(http.Flusher).Flush()
+}
+
+// Hijack implements the http.Hijacker interface to allow an HTTP handler to
+// take over the connection.
+// See [http.Hijacker](https://golang.org/pkg/net/http/#Hijacker)
+func (r *Response) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	return r.Writer.(http.Hijacker).Hijack()
+}
+
+func (r *Response) reset(w http.ResponseWriter) {
+	r.beforeFuncs = nil
+	r.afterFuncs = nil
+	r.Writer = w
+	r.Size = 0
+	r.Status = http.StatusOK
+	r.Committed = false
+}