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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
}
r.Status = code
for _, fn := range r.beforeFuncs {
fn()
}
r.Writer.WriteHeader(r.Status)
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 {
if r.Status == 0 {
r.Status = http.StatusOK
}
r.WriteHeader(r.Status)
}
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()
}
// Unwrap returns the original http.ResponseWriter.
// ResponseController can be used to access the original http.ResponseWriter.
// See [https://go.dev/blog/go1.20]
func (r *Response) Unwrap() http.ResponseWriter {
return r.Writer
}
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
}
|
