text: 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 (
  	"bufio"
  	"errors"
  	"net"
  	"net/http"
  )
  
  // DefaultResponseMimeType is DEPRECATED, use DefaultResponseContentType(mime)
  var DefaultResponseMimeType string
  
  //PrettyPrintResponses controls the indentation feature of XML and JSON serialization
  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 explicitly (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
  	hijacker      http.Hijacker // if underlying ResponseWriter supports it
  }
  
  // NewResponse creates a new response based on a http ResponseWriter.
  func NewResponse(httpWriter http.ResponseWriter) *Response {
  	hijacker, _ := httpWriter.(http.Hijacker)
  	return &Response{ResponseWriter: httpWriter, routeProduces: []string{}, statusCode: http.StatusOK, prettyPrint: PrettyPrintResponses, hijacker: hijacker}
  }
  
  // DefaultResponseContentType set a default.
  // If Accept header matching fails, fall back to this type.
  // 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
  }
  
  // Hijack implements the http.Hijacker interface.  This expands
  // the Response to fulfill http.Hijacker if the underlying
  // http.ResponseWriter supports it.
  func (r *Response) Hijack() (net.Conn, *bufio.ReadWriter, error) {
  	if r.hijacker == nil {
  		return nil, nil, errors.New("http.Hijacker not implemented by underlying http.ResponseWriter")
  	}
  	return r.hijacker.Hijack()
  }
  
  // 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
  }
  
  // EntityWriter returns the registered EntityWriter that the entity (requested resource)
  // can write according to what the request wants (Accept) and what the Route can produce or what the restful defaults say.
  // If called before WriteEntity and WriteHeader then a false return value can be used to write a 406: Not Acceptable.
  func (r *Response) EntityWriter() (EntityReaderWriter, bool) {
  	sorted := sortedMimes(r.requestAccept)
  	for _, eachAccept := range sorted {
  		for _, eachProduce := range r.routeProduces {
  			if eachProduce == eachAccept.media {
  				if w, ok := entityAccessRegistry.accessorAt(eachAccept.media); ok {
  					return w, true
  				}
  			}
  		}
  		if eachAccept.media == "*/*" {
  			for _, each := range r.routeProduces {
  				if w, ok := entityAccessRegistry.accessorAt(each); ok {
  					return w, true
  				}
  			}
  		}
  	}
  	// if requestAccept is empty
  	writer, ok := entityAccessRegistry.accessorAt(r.requestAccept)
  	if !ok {
  		// if not registered then fallback to the defaults (if set)
  		if DefaultResponseMimeType == MIME_JSON {
  			return entityAccessRegistry.accessorAt(MIME_JSON)
  		}
  		if DefaultResponseMimeType == MIME_XML {
  			return entityAccessRegistry.accessorAt(MIME_XML)
  		}
  		// Fallback to whatever the route says it can produce.
  		// https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
  		for _, each := range r.routeProduces {
  			if w, ok := entityAccessRegistry.accessorAt(each); ok {
  				return w, true
  			}
  		}
  		if trace {
  			traceLogger.Printf("no registered EntityReaderWriter found for %s", r.requestAccept)
  		}
  	}
  	return writer, ok
  }
  
  // WriteEntity calls WriteHeaderAndEntity with Http Status OK (200)
  func (r *Response) WriteEntity(value interface{}) error {
  	return r.WriteHeaderAndEntity(http.StatusOK, value)
  }
  
  // WriteHeaderAndEntity marshals the value using the representation denoted by the Accept Header and the registered EntityWriters.
  // If no Accept header is specified (or */*) then respond with the Content-Type as specified by the first in the Route.Produces.
  // If an Accept header is specified then respond with 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 no response is send except for the Http status. You may want to call WriteHeader(http.StatusNotFound) instead.
  // If there is no writer available that can represent the value in the requested MIME type then Http Status NotAcceptable is written.
  // Current implementation ignores any q-parameters in the Accept Header.
  // Returns an error if the value could not be written on the response.
  func (r *Response) WriteHeaderAndEntity(status int, value interface{}) error {
  	writer, ok := r.EntityWriter()
  	if !ok {
  		r.WriteHeader(http.StatusNotAcceptable)
  		return nil
  	}
  	return writer.Write(r, status, value)
  }
  
  // WriteAsXml is a convenience method for writing a value in xml (requires Xml tags on the value)
  // It uses the standard encoding/xml package for marshalling the value ; not using a registered EntityReaderWriter.
  func (r *Response) WriteAsXml(value interface{}) error {
  	return writeXML(r, http.StatusOK, MIME_XML, value)
  }
  
  // WriteHeaderAndXml is a convenience method for writing a status and value in xml (requires Xml tags on the value)
  // It uses the standard encoding/xml package for marshalling the value ; not using a registered EntityReaderWriter.
  func (r *Response) WriteHeaderAndXml(status int, value interface{}) error {
  	return writeXML(r, status, MIME_XML, value)
  }
  
  // WriteAsJson is a convenience method for writing a value in json.
  // It uses the standard encoding/json package for marshalling the value ; not using a registered EntityReaderWriter.
  func (r *Response) WriteAsJson(value interface{}) error {
  	return writeJSON(r, http.StatusOK, MIME_JSON, value)
  }
  
  // WriteJson is a convenience method for writing a value in Json with a given Content-Type.
  // It uses the standard encoding/json package for marshalling the value ; not using a registered EntityReaderWriter.
  func (r *Response) WriteJson(value interface{}, contentType string) error {
  	return writeJSON(r, http.StatusOK, contentType, value)
  }
  
  // WriteHeaderAndJson is a convenience method for writing the status and a value in Json with a given Content-Type.
  // It uses the standard encoding/json package for marshalling the value ; not using a registered EntityReaderWriter.
  func (r *Response) WriteHeaderAndJson(status int, value interface{}, contentType string) error {
  	return writeJSON(r, status, contentType, value)
  }
  
  // WriteError write the http status and the error string on the response. err can be nil.
  func (r *Response) WriteError(httpStatus int, err error) error {
  	r.err = err
  	if err == nil {
  		r.WriteErrorString(httpStatus, "")
  	} else {
  		r.WriteErrorString(httpStatus, err.Error())
  	}
  	return err
  }
  
  // WriteServiceError is a convenience method for a responding with a status and a ServiceError
  func (r *Response) WriteServiceError(httpStatus int, err ServiceError) error {
  	r.err = err
  	return r.WriteHeaderAndEntity(httpStatus, err)
  }
  
  // WriteErrorString is a convenience method for an error status with the actual error
  func (r *Response) WriteErrorString(httpStatus int, errorReason string) error {
  	if r.err == nil {
  		// if not called from WriteError
  		r.err = errors.New(errorReason)
  	}
  	r.WriteHeader(httpStatus)
  	if _, err := r.Write([]byte(errorReason)); err != nil {
  		return err
  	}
  	return nil
  }
  
  // Flush implements http.Flusher interface, which sends any buffered data to the client.
  func (r *Response) Flush() {
  	if f, ok := r.ResponseWriter.(http.Flusher); ok {
  		f.Flush()
  	} else if trace {
  		traceLogger.Printf("ResponseWriter %v doesn't support Flush", r)
  	}
  }
  
  // WriteHeader is overridden to remember the Status Code that has been written.
  // Changes to the Header of the response have no effect after this.
  func (r *Response) WriteHeader(httpStatus int) {
  	r.statusCode = httpStatus
  	r.ResponseWriter.WriteHeader(httpStatus)
  }
  
  // StatusCode returns the code that has been written using WriteHeader.
  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
  }
  