71 lines
1.7 KiB
Go
71 lines
1.7 KiB
Go
package main
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import (
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"bytes"
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"encoding/binary"
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"errors"
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"regexp"
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)
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var ExtractKeyParseError = errors.New("ExtractKey: parse error, possibly because seprator was not found")
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// Marshal keys
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func validObj(obj string) bool {
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return obj == "bite" || obj == "user"
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}
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// TODO: ensure security of regexp
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var validConversationRegexp = regexp.MustCompile(`^[a-zA-Z0-9-]+$`)
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func validConversation(conversation string) bool {
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return validConversationRegexp.MatchString(conversation)
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}
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const conversationSeprator = '@'
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const objSeprator = '+'
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func MarshalKey(obj, conversation string, start uint64) ([]byte, error) {
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prefixBytes, err := MarshalKeyPrefix(obj, conversation)
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if err != nil {
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return nil, err
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}
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startBytes := make([]byte, 8)
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binary.BigEndian.PutUint64(startBytes, start)
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return append(prefixBytes, startBytes...), nil
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}
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func MarshalKeyPrefix(obj, conversation string) ([]byte, error) {
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if !validObj(obj) || !validConversation(conversation) {
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return nil, errors.New("main: FormatKey: bad obj or conversation")
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}
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return []byte(obj + string(objSeprator) + conversation + string(conversationSeprator)), nil
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}
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func ExtractKey(b []byte) (string, string, uint64, error) {
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startStart := bytes.LastIndexByte(b, conversationSeprator) + 1
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if startStart < 0 {
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return "", "", 0, ExtractKeyParseError
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}
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startBytes := b[startStart:]
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convStart := bytes.LastIndexByte(b[:startStart-1], objSeprator) + 1
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if convStart < 0 {
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return "", "", 0, ExtractKeyParseError
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}
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convBytes := b[convStart : startStart-1]
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objStart := 0
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if objStart < 0 {
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return "", "", 0, ExtractKeyParseError
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}
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objBytes := b[objStart : convStart-1]
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obj := string(objBytes)
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conv := string(convBytes)
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start := binary.BigEndian.Uint64(startBytes)
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return obj, conv, start, nil
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}
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