117 lines
3.5 KiB
Go
117 lines
3.5 KiB
Go
package echo
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import (
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"bufio"
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"net"
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"net/http"
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"strconv"
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)
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type (
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// Response wraps an http.ResponseWriter and implements its interface to be used
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// by an HTTP handler to construct an HTTP response.
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// See: https://golang.org/pkg/net/http/#ResponseWriter
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Response struct {
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echo *Echo
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contentLength int64
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beforeFuncs []func()
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afterFuncs []func()
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Writer http.ResponseWriter
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Status int
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Size int64
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Committed bool
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}
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)
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// NewResponse creates a new instance of Response.
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func NewResponse(w http.ResponseWriter, e *Echo) (r *Response) {
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return &Response{Writer: w, echo: e}
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}
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// Header returns the header map for the writer that will be sent by
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// WriteHeader. Changing the header after a call to WriteHeader (or Write) has
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// no effect unless the modified headers were declared as trailers by setting
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// the "Trailer" header before the call to WriteHeader (see example)
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// To suppress implicit response headers, set their value to nil.
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// Example: https://golang.org/pkg/net/http/#example_ResponseWriter_trailers
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func (r *Response) Header() http.Header {
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return r.Writer.Header()
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}
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// Before registers a function which is called just before the response is written.
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func (r *Response) Before(fn func()) {
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r.beforeFuncs = append(r.beforeFuncs, fn)
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}
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// After registers a function which is called just after the response is written.
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// If the `Content-Length` is unknown, none of the after function is executed.
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func (r *Response) After(fn func()) {
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r.afterFuncs = append(r.afterFuncs, fn)
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}
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// WriteHeader sends an HTTP response header with status code. If WriteHeader is
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// not called explicitly, the first call to Write will trigger an implicit
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// WriteHeader(http.StatusOK). Thus explicit calls to WriteHeader are mainly
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// used to send error codes.
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func (r *Response) WriteHeader(code int) {
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if r.Committed {
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r.echo.Logger.Warn("response already committed")
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return
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}
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for _, fn := range r.beforeFuncs {
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fn()
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}
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r.Status = code
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r.Writer.WriteHeader(code)
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r.Committed = true
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r.contentLength, _ = strconv.ParseInt(r.Header().Get(HeaderContentLength), 10, 0)
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}
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// Write writes the data to the connection as part of an HTTP reply.
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func (r *Response) Write(b []byte) (n int, err error) {
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if !r.Committed {
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r.WriteHeader(http.StatusOK)
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}
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n, err = r.Writer.Write(b)
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r.Size += int64(n)
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if r.Size == r.contentLength {
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for _, fn := range r.afterFuncs {
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fn()
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}
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}
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return
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}
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// Flush implements the http.Flusher interface to allow an HTTP handler to flush
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// buffered data to the client.
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// See [http.Flusher](https://golang.org/pkg/net/http/#Flusher)
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func (r *Response) Flush() {
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r.Writer.(http.Flusher).Flush()
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}
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// Hijack implements the http.Hijacker interface to allow an HTTP handler to
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// take over the connection.
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// See [http.Hijacker](https://golang.org/pkg/net/http/#Hijacker)
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func (r *Response) Hijack() (net.Conn, *bufio.ReadWriter, error) {
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return r.Writer.(http.Hijacker).Hijack()
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}
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// CloseNotify implements the http.CloseNotifier interface to allow detecting
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// when the underlying connection has gone away.
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// This mechanism can be used to cancel long operations on the server if the
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// client has disconnected before the response is ready.
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// See [http.CloseNotifier](https://golang.org/pkg/net/http/#CloseNotifier)
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func (r *Response) CloseNotify() <-chan bool {
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return r.Writer.(http.CloseNotifier).CloseNotify()
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}
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func (r *Response) reset(w http.ResponseWriter) {
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r.contentLength = 0
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r.beforeFuncs = nil
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r.afterFuncs = nil
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r.Writer = w
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r.Size = 0
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r.Status = http.StatusOK
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r.Committed = false
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}
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