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fbb72869b3
* echo.context.cjson should encode the JSON before writing the status code #1334 : `response.Write` automatically sets status to `200` if a response code wasn't committed yet. This is convenient, but it ignores the fact that `response.Status` is a public field that may be set separately/before `response.Write` has been called A `response.Status` is by default `0`, or `200` if the response was reset, so `response.Write` should fallback to `200` only if a code wasn't set yet. * echo.context.cjson should encode the JSON before writing the status code #1334 : Writing the response code before encoding the payload is prone to error. If JSON encoding fails, the response code is already committed, the server is able to only modify the response body to reflect the error and the user receives an awkward response where the status is successful but the body reports an error. Instead - set the desired code on `c.response.Status`. If writing eventually takes place, the desired code is committed. If an error occurs, the server can still change the response.
105 lines
3.0 KiB
Go
105 lines
3.0 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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)
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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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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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}
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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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if r.Status == 0 {
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r.Status = http.StatusOK
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}
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r.WriteHeader(r.Status)
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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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for _, fn := range r.afterFuncs {
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fn()
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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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func (r *Response) reset(w http.ResponseWriter) {
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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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