go-omaha/omaha/parse.go
Michael Marineau a6290c1b4f protocol: add ParseRequest and ParseResponse functions
For parsing and verification of of HTTP request and response bodies,
including optional checking the Content-Type field which the handler
previously didn't do.
2017-05-04 13:25:46 -07:00

71 lines
1.7 KiB
Go

// Copyright 2017 CoreOS, Inc.
//
// Licensed 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 omaha
import (
"encoding/xml"
"fmt"
"io"
"mime"
"strings"
)
// checkContentType verifies the HTTP Content-Type header properly
// declares the document is XML and UTF-8. Blank is assumed OK.
func checkContentType(contentType string) error {
if contentType == "" {
return nil
}
mType, mParams, err := mime.ParseMediaType(contentType)
if err != nil {
return err
}
if mType != "text/xml" && mType != "application/xml" {
return fmt.Errorf("unsupported content type %q", mType)
}
charset, _ := mParams["charset"]
if charset != "" && strings.ToLower(charset) != "utf-8" {
return fmt.Errorf("unsupported content charset %q", charset)
}
return nil
}
// parseReqOrResp parses Request and Response objects.
func parseReqOrResp(r io.Reader, v interface{}) error {
decoder := xml.NewDecoder(r)
if err := decoder.Decode(v); err != nil {
return err
}
var protocol string
switch v := v.(type) {
case *Request:
protocol = v.Protocol
case *Response:
protocol = v.Protocol
default:
panic(fmt.Errorf("unexpected type %T", v))
}
if protocol != "3.0" {
return fmt.Errorf("unsupported omaha protocol: %q", protocol)
}
return nil
}