func unmarshalError(r *request.Request) {
	defer r.HTTPResponse.Body.Close()

	if r.HTTPResponse.ContentLength == int64(0) {
		// No body, use status code to generate an awserr.Error
		r.Error = awserr.NewRequestFailure(
			awserr.New(strings.Replace(r.HTTPResponse.Status, " ", "", -1), r.HTTPResponse.Status, nil),
			r.HTTPResponse.StatusCode,
			"",
		)
		return
	}

	resp := &xmlErrorResponse{}
	err := xml.NewDecoder(r.HTTPResponse.Body).Decode(resp)
	if err != nil && err != io.EOF {
		r.Error = awserr.New("SerializationError", "failed to decode SimpleDB XML error response", nil)
	} else if len(resp.Errors) == 0 {
		r.Error = awserr.New("MissingError", "missing error code in SimpleDB XML error response", nil)
	} else {
		// If there are multiple error codes, return only the first as the aws.Error interface only supports
		// one error code.
		r.Error = awserr.NewRequestFailure(
			awserr.New(resp.Errors[0].Code, resp.Errors[0].Message, nil),
			r.HTTPResponse.StatusCode,
			resp.RequestID,
		)
	}
}

func unmarshalError(req *request.Request) {
	bodyBytes, err := ioutil.ReadAll(req.HTTPResponse.Body)
	if err != nil {
		req.Error = awserr.New("UnmarshaleError", req.HTTPResponse.Status, err)
		return
	}
	if len(bodyBytes) == 0 {
		req.Error = awserr.NewRequestFailure(
			awserr.New("UnmarshaleError", req.HTTPResponse.Status, fmt.Errorf("empty body")),
			req.HTTPResponse.StatusCode,
			"",
		)
		return
	}
	var jsonErr jsonErrorResponse
	if err := json.Unmarshal(bodyBytes, &jsonErr); err != nil {
		req.Error = awserr.New("UnmarshaleError", "JSON unmarshal", err)
		return
	}
	req.Error = awserr.NewRequestFailure(
		awserr.New(jsonErr.Code, jsonErr.Message, nil),
		req.HTTPResponse.StatusCode,
		"",
	)
}

// UnmarshalError unmarshals a response error for the REST JSON protocol.
func UnmarshalError(r *request.Request) {
	code := r.HTTPResponse.Header.Get("X-Amzn-Errortype")
	bodyBytes, err := ioutil.ReadAll(r.HTTPResponse.Body)
	if err != nil {
		r.Error = awserr.New("SerializationError", "failed reading REST JSON error response", err)
		return
	}
	if len(bodyBytes) == 0 {
		r.Error = awserr.NewRequestFailure(
			awserr.New("SerializationError", r.HTTPResponse.Status, nil),
			r.HTTPResponse.StatusCode,
			"",
		)
		return
	}
	var jsonErr jsonErrorResponse
	if err := json.Unmarshal(bodyBytes, &jsonErr); err != nil {
		r.Error = awserr.New("SerializationError", "failed decoding REST JSON error response", err)
		return
	}

	if code == "" {
		code = jsonErr.Code
	}

	code = strings.SplitN(code, ":", 2)[0]
	r.Error = awserr.NewRequestFailure(
		awserr.New(code, jsonErr.Message, nil),
		r.HTTPResponse.StatusCode,
		r.RequestID,
	)
}

// Build builds the REST component of a service request.
func Build(r *request.Request) {
	if r.ParamsFilled() {
		v := reflect.ValueOf(r.Params).Elem()
		buildLocationElements(r, v)
		buildBody(r, v)
	}
}

// UnmarshalMeta unmarshals the REST metadata of a response in a REST service
func UnmarshalMeta(r *request.Request) {
	r.RequestID = r.HTTPResponse.Header.Get("X-Amzn-Requestid")
	if r.DataFilled() {
		v := reflect.Indirect(reflect.ValueOf(r.Data))
		unmarshalLocationElements(r, v)
	}
}

func assertMD5(t *testing.T, req *request.Request) {
	err := req.Build()
	assert.NoError(t, err)

	b, _ := ioutil.ReadAll(req.HTTPRequest.Body)
	out := md5.Sum(b)
	assert.NotEmpty(t, b)
	assert.Equal(t, base64.StdEncoding.EncodeToString(out[:]), req.HTTPRequest.Header.Get("Content-MD5"))
}

func addAccountID(r *request.Request) {
	if !r.ParamsFilled() {
		return
	}

	v := reflect.Indirect(reflect.ValueOf(r.Params))
	if f := v.FieldByName("AccountId"); f.IsNil() {
		f.Set(reflect.ValueOf(&defaultAccountID))
	}
}

// Unmarshal unmarshals a response body for the EC2 protocol.
func Unmarshal(r *request.Request) {
	defer r.HTTPResponse.Body.Close()
	if r.DataFilled() {
		decoder := xml.NewDecoder(r.HTTPResponse.Body)
		err := xmlutil.UnmarshalXML(r.Data, decoder, "")
		if err != nil {
			r.Error = awserr.New("SerializationError", "failed decoding EC2 Query response", err)
			return
		}
	}
}

func populateLocationConstraint(r *request.Request) {
	if r.ParamsFilled() && aws.StringValue(r.Service.Config.Region) != "us-east-1" {
		in := r.Params.(*CreateBucketInput)
		if in.CreateBucketConfiguration == nil {
			r.Params = awsutil.CopyOf(r.Params)
			in = r.Params.(*CreateBucketInput)
			in.CreateBucketConfiguration = &CreateBucketConfiguration{
				LocationConstraint: r.Service.Config.Region,
			}
		}
	}
}

// Build builds a request payload for the REST XML protocol.
func Build(r *request.Request) {
	rest.Build(r)

	if t := rest.PayloadType(r.Params); t == "structure" || t == "" {
		var buf bytes.Buffer
		err := xmlutil.BuildXML(r.Params, xml.NewEncoder(&buf))
		if err != nil {
			r.Error = awserr.New("SerializationError", "failed to encode rest XML request", err)
			return
		}
		r.SetBufferBody(buf.Bytes())
	}
}

// updatePredictEndpoint rewrites the request endpoint to use the
// "PredictEndpoint" parameter of the Predict operation.
func updatePredictEndpoint(r *request.Request) {
	if !r.ParamsFilled() {
		return
	}

	r.Service.Endpoint = *r.Params.(*PredictInput).PredictEndpoint

	uri, err := url.Parse(r.Service.Endpoint)
	if err != nil {
		r.Error = err
		return
	}
	r.HTTPRequest.URL = uri
}

// UnmarshalError unmarshals an error response for an AWS Query service.
func UnmarshalError(r *request.Request) {
	defer r.HTTPResponse.Body.Close()

	resp := &xmlErrorResponse{}
	err := xml.NewDecoder(r.HTTPResponse.Body).Decode(resp)
	if err != nil && err != io.EOF {
		r.Error = awserr.New("SerializationError", "failed to decode query XML error response", err)
	} else {
		r.Error = awserr.NewRequestFailure(
			awserr.New(resp.Code, resp.Message, nil),
			r.HTTPResponse.StatusCode,
			resp.RequestID,
		)
	}
}

func buildGetBucketLocation(r *request.Request) {
	if r.DataFilled() {
		out := r.Data.(*GetBucketLocationOutput)
		b, err := ioutil.ReadAll(r.HTTPResponse.Body)
		if err != nil {
			r.Error = awserr.New("SerializationError", "failed reading response body", err)
			return
		}

		match := reBucketLocation.FindSubmatch(b)
		if len(match) > 1 {
			loc := string(match[1])
			out.LocationConstraint = &loc
		}
	}
}

// Sign requests with signature version 4.
//
// Will sign the requests with the service config's Credentials object
// Signing is skipped if the credentials is the credentials.AnonymousCredentials
// object.
func Sign(req *request.Request) {
	// If the request does not need to be signed ignore the signing of the
	// request if the AnonymousCredentials object is used.
	if req.Service.Config.Credentials == credentials.AnonymousCredentials {
		return
	}

	region := req.Service.SigningRegion
	if region == "" {
		region = aws.StringValue(req.Service.Config.Region)
	}

	name := req.Service.SigningName
	if name == "" {
		name = req.Service.ServiceName
	}

	s := signer{
		Request:     req.HTTPRequest,
		Time:        req.Time,
		ExpireTime:  req.ExpireTime,
		Query:       req.HTTPRequest.URL.Query(),
		Body:        req.Body,
		ServiceName: name,
		Region:      region,
		Credentials: req.Service.Config.Credentials,
		Debug:       req.Service.Config.LogLevel.Value(),
		Logger:      req.Service.Config.Logger,
	}

	req.Error = s.sign()
}

func validateSSERequiresSSL(r *request.Request) {
	if r.HTTPRequest.URL.Scheme != "https" {
		p := awsutil.ValuesAtPath(r.Params, "SSECustomerKey||CopySourceSSECustomerKey")
		if len(p) > 0 {
			r.Error = errSSERequiresSSL
		}
	}
}

func unmarshalError(r *request.Request) {
	defer r.HTTPResponse.Body.Close()
	_, err := ioutil.ReadAll(r.HTTPResponse.Body)
	if err != nil {
		r.Error = awserr.New("SerializationError", "unable to unmarshal EC2 metadata error respose", err)
	}

	// TODO extract the error...
}

func unmarshalHandler(r *request.Request) {
	defer r.HTTPResponse.Body.Close()
	b, err := ioutil.ReadAll(r.HTTPResponse.Body)
	if err != nil {
		r.Error = awserr.New("SerializationError", "unable to unmarshal EC2 metadata respose", err)
	}

	data := r.Data.(*metadataOutput)
	data.Content = string(b)
}

func fillPresignedURL(r *request.Request) {
	if !r.ParamsFilled() {
		return
	}

	params := r.Params.(*CopySnapshotInput)

	// Stop if PresignedURL/DestinationRegion is set
	if params.PresignedUrl != nil || params.DestinationRegion != nil {
		return
	}

	// First generate a copy of parameters
	r.Params = awsutil.CopyOf(r.Params)
	params = r.Params.(*CopySnapshotInput)

	// Set destination region. Avoids infinite handler loop.
	// Also needed to sign sub-request.
	params.DestinationRegion = r.Service.Config.Region

	// Create a new client pointing at source region.
	// We will use this to presign the CopySnapshot request against
	// the source region
	config := r.Service.Config.Copy().
		WithEndpoint("").
		WithRegion(*params.SourceRegion)

	client := New(config)

	// Presign a CopySnapshot request with modified params
	req, _ := client.CopySnapshotRequest(params)
	url, err := req.Presign(300 * time.Second) // 5 minutes should be enough.

	if err != nil { // bubble error back up to original request
		r.Error = err
	}

	// We have our URL, set it on params
	params.PresignedUrl = &url
}

func unmarshalBody(r *request.Request, v reflect.Value) {
	if field, ok := v.Type().FieldByName("SDKShapeTraits"); ok {
		if payloadName := field.Tag.Get("payload"); payloadName != "" {
			pfield, _ := v.Type().FieldByName(payloadName)
			if ptag := pfield.Tag.Get("type"); ptag != "" && ptag != "structure" {
				payload := v.FieldByName(payloadName)
				if payload.IsValid() {
					switch payload.Interface().(type) {
					case []byte:
						b, err := ioutil.ReadAll(r.HTTPResponse.Body)
						if err != nil {
							r.Error = awserr.New("SerializationError", "failed to decode REST response", err)
						} else {
							payload.Set(reflect.ValueOf(b))
						}
					case *string:
						b, err := ioutil.ReadAll(r.HTTPResponse.Body)
						if err != nil {
							r.Error = awserr.New("SerializationError", "failed to decode REST response", err)
						} else {
							str := string(b)
							payload.Set(reflect.ValueOf(&str))
						}
					default:
						switch payload.Type().String() {
						case "io.ReadSeeker":
							payload.Set(reflect.ValueOf(aws.ReadSeekCloser(r.HTTPResponse.Body)))
						case "aws.ReadSeekCloser", "io.ReadCloser":
							payload.Set(reflect.ValueOf(r.HTTPResponse.Body))
						default:
							r.Error = awserr.New("SerializationError",
								"failed to decode REST response",
								fmt.Errorf("unknown payload type %s", payload.Type()))
						}
					}
				}
			}
		}
	}
}

// Unmarshal unmarshals a payload response for the REST XML protocol.
func Unmarshal(r *request.Request) {
	if t := rest.PayloadType(r.Data); t == "structure" || t == "" {
		defer r.HTTPResponse.Body.Close()
		decoder := xml.NewDecoder(r.HTTPResponse.Body)
		err := xmlutil.UnmarshalXML(r.Data, decoder, "")
		if err != nil {
			r.Error = awserr.New("SerializationError", "failed to decode REST XML response", err)
			return
		}
	} else {
		rest.Unmarshal(r)
	}
}