package server import ( "errors" "strconv" ) type parsedQuery struct { infohashes []string params map[string]string } func (pq *parsedQuery) getUint64(key string) (uint64, bool) { str, exists := pq[key] if !exists { return 0, false } val, err := strconv.Uint64(str, 10, 64) if err != nil { return 0, false } return val, true } func parseQuery(query string) (*parsedQuery, error) { var ( keyStart, keyEnd int valStart, valEnd int firstInfohash string onKey = true hasInfohash = false pq = &parsedQuery{ infohashes: nil, params: make(map[string]string), } ) for i, length := 0, len(query); i < length; i++ { separator := query[i] == '&' || query[i] == ';' || query[i] == '?' if separator || i == length-1 { if onKey { keyStart = i + 1 continue } if i == length-1 && !separator { if query[i] == '=' { continue } valEnd = i } keyStr, err := url.QueryUnescape(query[keyStart : keyEnd+1]) if err != nil { return err } valStr, err := url.QueryUnescape(query[valStart : valEnd+1]) if err != nil { return err } pq.params[keyStr] = valStr if keyStr == "info_hash" { if hasInfohash { // Multiple infohashes if pq.infohashes == nil { pq.infohashes = []string{firstInfoHash} } pq.infohashes = append(pq.infohashes, valStr) } else { firstInfohash = valStr hasInfohash = true } } onKey = true keyStart = i + 1 } else if query[i] == '=' { onKey = false valStart = i + 1 } else if onKey { keyEnd = i } else { valEnd = i } } return } func validateParsedQuery(pq *parsedQuery) error { infohash, ok := pq["info_hash"] if infohash == "" { return errors.New("infohash does not exist") } peerId, ok := pq["peer_id"] if peerId == "" { return errors.New("peerId does not exist") } port, ok := pq.getUint64("port") if ok == false { return errors.New("port does not exist") } uploaded, ok := pq.getUint64("uploaded") if ok == false { return errors.New("uploaded does not exist") } downloaded, ok := pq.getUint64("downloaded") if ok == false { return errors.New("downloaded does not exist") } left, ok := pq.getUint64("left") if ok == false { return errors.New("left does not exist") } return nil }