tracker/server/http/query/query.go

126 lines
2.7 KiB
Go

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