traefik/vendor/github.com/emicklei/go-restful/response.go

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2017-02-07 21:33:23 +00:00
package restful
// Copyright 2013 Ernest Micklei. All rights reserved.
// Use of this source code is governed by a license
// that can be found in the LICENSE file.
import (
"encoding/json"
"encoding/xml"
"net/http"
"strings"
)
// DEPRECATED, use DefaultResponseContentType(mime)
var DefaultResponseMimeType string
//PrettyPrintResponses controls the indentation feature of XML and JSON
//serialization in the response methods WriteEntity, WriteAsJson, and
//WriteAsXml.
var PrettyPrintResponses = true
// Response is a wrapper on the actual http ResponseWriter
// It provides several convenience methods to prepare and write response content.
type Response struct {
http.ResponseWriter
requestAccept string // mime-type what the Http Request says it wants to receive
routeProduces []string // mime-types what the Route says it can produce
statusCode int // HTTP status code that has been written explicity (if zero then net/http has written 200)
contentLength int // number of bytes written for the response body
prettyPrint bool // controls the indentation feature of XML and JSON serialization. It is initialized using var PrettyPrintResponses.
err error // err property is kept when WriteError is called
}
// Creates a new response based on a http ResponseWriter.
func NewResponse(httpWriter http.ResponseWriter) *Response {
return &Response{httpWriter, "", []string{}, http.StatusOK, 0, PrettyPrintResponses, nil} // empty content-types
}
// If Accept header matching fails, fall back to this type, otherwise
// a "406: Not Acceptable" response is returned.
// Valid values are restful.MIME_JSON and restful.MIME_XML
// Example:
// restful.DefaultResponseContentType(restful.MIME_JSON)
func DefaultResponseContentType(mime string) {
DefaultResponseMimeType = mime
}
// InternalServerError writes the StatusInternalServerError header.
// DEPRECATED, use WriteErrorString(http.StatusInternalServerError,reason)
func (r Response) InternalServerError() Response {
r.WriteHeader(http.StatusInternalServerError)
return r
}
// PrettyPrint changes whether this response must produce pretty (line-by-line, indented) JSON or XML output.
func (r *Response) PrettyPrint(bePretty bool) {
r.prettyPrint = bePretty
}
// AddHeader is a shortcut for .Header().Add(header,value)
func (r Response) AddHeader(header string, value string) Response {
r.Header().Add(header, value)
return r
}
// SetRequestAccepts tells the response what Mime-type(s) the HTTP request said it wants to accept. Exposed for testing.
func (r *Response) SetRequestAccepts(mime string) {
r.requestAccept = mime
}
// WriteEntity marshals the value using the representation denoted by the Accept Header (XML or JSON)
// If no Accept header is specified (or */*) then return the Content-Type as specified by the first in the Route.Produces.
// If an Accept header is specified then return the Content-Type as specified by the first in the Route.Produces that is matched with the Accept header.
// If the value is nil then nothing is written. You may want to call WriteHeader(http.StatusNotFound) instead.
// Current implementation ignores any q-parameters in the Accept Header.
func (r *Response) WriteEntity(value interface{}) error {
if value == nil { // do not write a nil representation
return nil
}
for _, qualifiedMime := range strings.Split(r.requestAccept, ",") {
mime := strings.Trim(strings.Split(qualifiedMime, ";")[0], " ")
if 0 == len(mime) || mime == "*/*" {
for _, each := range r.routeProduces {
if MIME_JSON == each {
return r.WriteAsJson(value)
}
if MIME_XML == each {
return r.WriteAsXml(value)
}
}
} else { // mime is not blank; see if we have a match in Produces
for _, each := range r.routeProduces {
if mime == each {
if MIME_JSON == each {
return r.WriteAsJson(value)
}
if MIME_XML == each {
return r.WriteAsXml(value)
}
}
}
}
}
if DefaultResponseMimeType == MIME_JSON {
return r.WriteAsJson(value)
} else if DefaultResponseMimeType == MIME_XML {
return r.WriteAsXml(value)
} else {
if trace {
traceLogger.Printf("mismatch in mime-types and no defaults; (http)Accept=%v,(route)Produces=%v\n", r.requestAccept, r.routeProduces)
}
r.WriteHeader(http.StatusNotAcceptable) // for recording only
r.ResponseWriter.WriteHeader(http.StatusNotAcceptable)
if _, err := r.Write([]byte("406: Not Acceptable")); err != nil {
return err
}
}
return nil
}
// WriteAsXml is a convenience method for writing a value in xml (requires Xml tags on the value)
func (r *Response) WriteAsXml(value interface{}) error {
var output []byte
var err error
if value == nil { // do not write a nil representation
return nil
}
if r.prettyPrint {
output, err = xml.MarshalIndent(value, " ", " ")
} else {
output, err = xml.Marshal(value)
}
if err != nil {
return r.WriteError(http.StatusInternalServerError, err)
}
r.Header().Set(HEADER_ContentType, MIME_XML)
if r.statusCode > 0 { // a WriteHeader was intercepted
r.ResponseWriter.WriteHeader(r.statusCode)
}
_, err = r.Write([]byte(xml.Header))
if err != nil {
return err
}
if _, err = r.Write(output); err != nil {
return err
}
return nil
}
// WriteAsJson is a convenience method for writing a value in json
func (r *Response) WriteAsJson(value interface{}) error {
return r.WriteJson(value, MIME_JSON) // no charset
}
// WriteJson is a convenience method for writing a value in Json with a given Content-Type
func (r *Response) WriteJson(value interface{}, contentType string) error {
var output []byte
var err error
if value == nil { // do not write a nil representation
return nil
}
if r.prettyPrint {
output, err = json.MarshalIndent(value, " ", " ")
} else {
output, err = json.Marshal(value)
}
if err != nil {
return r.WriteErrorString(http.StatusInternalServerError, err.Error())
}
r.Header().Set(HEADER_ContentType, contentType)
if r.statusCode > 0 { // a WriteHeader was intercepted
r.ResponseWriter.WriteHeader(r.statusCode)
}
if _, err = r.Write(output); err != nil {
return err
}
return nil
}
// WriteError write the http status and the error string on the response.
func (r *Response) WriteError(httpStatus int, err error) error {
r.err = err
return r.WriteErrorString(httpStatus, err.Error())
}
// WriteServiceError is a convenience method for a responding with a ServiceError and a status
func (r *Response) WriteServiceError(httpStatus int, err ServiceError) error {
r.WriteHeader(httpStatus) // for recording only
return r.WriteEntity(err)
}
// WriteErrorString is a convenience method for an error status with the actual error
func (r *Response) WriteErrorString(status int, errorReason string) error {
r.statusCode = status // for recording only
r.ResponseWriter.WriteHeader(status)
if _, err := r.Write([]byte(errorReason)); err != nil {
return err
}
return nil
}
// WriteHeader is overridden to remember the Status Code that has been written.
// Note that using this method, the status value is only written when
// calling WriteEntity,
// or directly calling WriteAsXml or WriteAsJson,
// or if the status is one for which no response is allowed:
//
// 202 = http.StatusAccepted
// 204 = http.StatusNoContent
// 206 = http.StatusPartialContent
// 304 = http.StatusNotModified
// 404 = http.StatusNotFound
//
// If this behavior does not fit your need then you can write to the underlying response, such as:
// response.ResponseWriter.WriteHeader(http.StatusAccepted)
func (r *Response) WriteHeader(httpStatus int) {
r.statusCode = httpStatus
// if 202,204,206,304,404 then WriteEntity will not be called so we need to pass this code
if http.StatusNotFound == httpStatus ||
http.StatusNoContent == httpStatus ||
http.StatusNotModified == httpStatus ||
http.StatusPartialContent == httpStatus ||
http.StatusAccepted == httpStatus {
r.ResponseWriter.WriteHeader(httpStatus)
}
}
// StatusCode returns the code that has been written using WriteHeader.
// If WriteHeader, WriteEntity or WriteAsXml has not been called (yet) then return 200 OK.
func (r Response) StatusCode() int {
if 0 == r.statusCode {
// no status code has been written yet; assume OK
return http.StatusOK
}
return r.statusCode
}
// Write writes the data to the connection as part of an HTTP reply.
// Write is part of http.ResponseWriter interface.
func (r *Response) Write(bytes []byte) (int, error) {
written, err := r.ResponseWriter.Write(bytes)
r.contentLength += written
return written, err
}
// ContentLength returns the number of bytes written for the response content.
// Note that this value is only correct if all data is written through the Response using its Write* methods.
// Data written directly using the underlying http.ResponseWriter is not accounted for.
func (r Response) ContentLength() int {
return r.contentLength
}
// CloseNotify is part of http.CloseNotifier interface
func (r Response) CloseNotify() <-chan bool {
return r.ResponseWriter.(http.CloseNotifier).CloseNotify()
}
// Error returns the err created by WriteError
func (r Response) Error() error {
return r.err
}