133 lines
2.9 KiB
Go
133 lines
2.9 KiB
Go
// Copyright 2016 The Chihaya Authors. All rights reserved.
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// Use of this source code is governed by the BSD 2-Clause license,
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// which can be found in the LICENSE file.
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// Package query implements a simple, fast URL parser designed to be used to
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// parse parameters sent from BitTorrent clients. The last value of a key wins,
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// except for they key "info_hash".
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package query
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import (
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"errors"
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"net/url"
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"strconv"
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"strings"
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"github.com/chihaya/chihaya"
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)
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// ErrKeyNotFound is returned when a provided key has no value associated with
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// it.
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var ErrKeyNotFound = errors.New("query: value for the provided key does not exist")
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// ErrInvalidInfohash is returned when parsing a query encounters an infohash
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// with invalid length.
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var ErrInvalidInfohash = errors.New("query: invalid infohash")
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// Query represents a parsed URL.Query.
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type Query struct {
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query string
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params map[string]string
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infoHashes []chihaya.InfoHash
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}
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// New parses a raw URL query.
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func New(query string) (*Query, error) {
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var (
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keyStart, keyEnd int
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valStart, valEnd int
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onKey = true
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q = &Query{
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query: query,
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infoHashes: nil,
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params: make(map[string]string),
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}
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)
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for i, length := 0, len(query); i < length; i++ {
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separator := query[i] == '&' || query[i] == ';' || query[i] == '?'
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last := i == length-1
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if separator || last {
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if onKey && !last {
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keyStart = i + 1
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continue
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}
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if last && !separator && !onKey {
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valEnd = i
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}
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keyStr, err := url.QueryUnescape(query[keyStart : keyEnd+1])
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if err != nil {
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return nil, err
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}
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var valStr string
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if valEnd > 0 {
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valStr, err = url.QueryUnescape(query[valStart : valEnd+1])
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if err != nil {
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return nil, err
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}
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}
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if keyStr == "info_hash" {
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if len(valStr) != 20 {
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return nil, ErrInvalidInfohash
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}
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q.infoHashes = append(q.infoHashes, chihaya.InfoHashFromString(valStr))
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} else {
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q.params[strings.ToLower(keyStr)] = valStr
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}
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valEnd = 0
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onKey = true
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keyStart = i + 1
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} else if query[i] == '=' {
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onKey = false
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valStart = i + 1
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valEnd = 0
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} else if onKey {
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keyEnd = i
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} else {
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valEnd = i
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}
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}
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return q, nil
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}
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// String returns a string parsed from a query. Every key can be returned as a
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// string because they are encoded in the URL as strings.
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func (q *Query) String(key string) (string, error) {
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val, exists := q.params[key]
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if !exists {
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return "", ErrKeyNotFound
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}
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return val, nil
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}
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// Uint64 returns a uint parsed from a query. After being called, it is safe to
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// cast the uint64 to your desired length.
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func (q *Query) Uint64(key string) (uint64, error) {
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str, exists := q.params[key]
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if !exists {
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return 0, ErrKeyNotFound
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}
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val, err := strconv.ParseUint(str, 10, 64)
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if err != nil {
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return 0, err
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}
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return val, nil
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}
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// InfoHashes returns a list of requested infohashes.
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func (q *Query) InfoHashes() []chihaya.InfoHash {
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return q.infoHashes
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}
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