81 lines
2.2 KiB
Go
81 lines
2.2 KiB
Go
// This file is an adaptation of https://github.com/markusthoemmes/goautoneg.
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// The copyright and license header are reproduced below.
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//
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// Copyright [yyyy] [name of copyright owner]
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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package httpd
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import (
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"mime"
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"sort"
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"strconv"
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"strings"
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)
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// accept is a structure to represent a clause in an HTTP Accept Header.
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type accept struct {
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Type, SubType string
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Q float64
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Params map[string]string
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}
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// parseAccept parses the given string as an Accept header as defined in
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// https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.1.
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// Some rules are only loosely applied and might not be as strict as defined in the RFC.
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func parseAccept(headers []string) []accept {
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var res []accept
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for _, header := range headers {
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parts := strings.Split(header, ",")
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for _, part := range parts {
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mt, params, err := mime.ParseMediaType(part)
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if err != nil {
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continue
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}
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accept := accept{
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Q: 1.0, // "[...] The default value is q=1"
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Params: params,
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}
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// A media-type is defined as
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// "*/*" | ( type "/" "*" ) | ( type "/" subtype )
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types := strings.Split(mt, "/")
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switch {
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// This case is not defined in the spec keep it to mimic the original code.
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case len(types) == 1 && types[0] == "*":
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accept.Type = "*"
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accept.SubType = "*"
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case len(types) == 2:
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accept.Type = types[0]
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accept.SubType = types[1]
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default:
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continue
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}
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if qVal, ok := params["q"]; ok {
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// A parsing failure will set Q to 0.
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accept.Q, _ = strconv.ParseFloat(qVal, 64)
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delete(params, "q")
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}
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res = append(res, accept)
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}
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}
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sort.SliceStable(res, func(i, j int) bool {
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return res[i].Q > res[j].Q
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})
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return res
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}
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