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api_version_header.go
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/
api_version_header.go
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// Copyright (C) 2015-Present Pivotal Software, Inc. All rights reserved.
// This program and the accompanying materials are made available under
// the terms of the under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package middlewares
import (
"encoding/json"
"errors"
"fmt"
"net/http"
"code.cloudfoundry.org/lager"
)
const ApiVersionInvalidKey = "broker-api-version-invalid"
type APIVersionMiddleware struct {
LoggerFactory lager.Logger
}
type ErrorResponse struct {
Description string
}
func (m APIVersionMiddleware) ValidateAPIVersionHdr(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
logger := m.LoggerFactory.Session("version-header-check", lager.Data{})
err := checkBrokerAPIVersionHdr(req)
if err != nil {
logger.Error(ApiVersionInvalidKey, err)
w.Header().Set("Content-type", "application/json")
statusResponse := http.StatusPreconditionFailed
w.WriteHeader(statusResponse)
errorResp := ErrorResponse{
Description: err.Error(),
}
err = json.NewEncoder(w).Encode(errorResp)
if err != nil {
logger.Error("encoding response", err, lager.Data{"status": statusResponse, "response": errorResp})
}
return
}
next.ServeHTTP(w, req)
})
}
func checkBrokerAPIVersionHdr(req *http.Request) error {
var version struct {
Major int
Minor int
}
apiVersion := req.Header.Get("X-Broker-API-Version")
if apiVersion == "" {
return errors.New("X-Broker-API-Version Header not set")
}
if n, err := fmt.Sscanf(apiVersion, "%d.%d", &version.Major, &version.Minor); err != nil || n < 2 {
return errors.New("X-Broker-API-Version Header must contain a version")
}
if version.Major != 2 {
return errors.New("X-Broker-API-Version Header must be 2.x")
}
return nil
}