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mirror of https://github.com/dutchcoders/transfer.sh.git synced 2020-11-18 19:53:40 -08:00
2019-03-17 20:19:56 +01:00

80 lines
2.6 KiB
Go

// Copyright 2015 Google Inc. All rights reserved.
//
// 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 header
import (
"fmt"
"net/http"
"strings"
"github.com/google/martian"
)
// NewBadFramingModifier makes a best effort to fix inconsistencies in the
// request such as multiple Content-Lengths or the lack of Content-Length and
// improper Transfer-Encoding. If it is unable to determine a proper resolution
// it returns an error.
//
// http://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-14#section-3.3
func NewBadFramingModifier() martian.RequestModifier {
return martian.RequestModifierFunc(
func(req *http.Request) error {
cls := req.Header["Content-Length"]
if len(cls) > 0 {
var length string
// Iterate over all Content-Length headers, splitting any we find with
// commas, and check that all Content-Lengths are equal.
for _, ls := range cls {
for _, l := range strings.Split(ls, ",") {
// First length, set it as the canonical Content-Length.
if length == "" {
length = strings.TrimSpace(l)
continue
}
// Mismatched Content-Lengths.
if length != strings.TrimSpace(l) {
return fmt.Errorf(`bad request framing: multiple mismatched "Content-Length" headers: %v`, cls)
}
}
}
// All Content-Lengths are equal, remove extras and set it to the
// canonical value.
req.Header.Set("Content-Length", length)
}
tes := req.Header["Transfer-Encoding"]
if len(tes) > 0 {
// Extract the last Transfer-Encoding value, and split on commas.
last := strings.Split(tes[len(tes)-1], ",")
// Check that the last, potentially comma-delimited, value is
// "chunked", else we have no way to determine when the request is
// finished.
if strings.TrimSpace(last[len(last)-1]) != "chunked" {
return fmt.Errorf(`bad request framing: "Transfer-Encoding" header is present, but does not end in "chunked"`)
}
// Transfer-Encoding "chunked" takes precedence over
// Content-Length.
req.Header.Del("Content-Length")
}
return nil
})
}