91 lines
2.8 KiB
Go
91 lines
2.8 KiB
Go
/*
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* Copyright (c) 2021 IBM Corp and others.
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*
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* All rights reserved. This program and the accompanying materials
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* are made available under the terms of the Eclipse Public License v2.0
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* and Eclipse Distribution License v1.0 which accompany this distribution.
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*
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* The Eclipse Public License is available at
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* https://www.eclipse.org/legal/epl-2.0/
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* and the Eclipse Distribution License is available at
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* http://www.eclipse.org/org/documents/edl-v10.php.
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*
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* Contributors:
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* Seth Hoenig
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* Allan Stockdill-Mander
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* Mike Robertson
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*/
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package mqtt
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import (
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"errors"
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"strings"
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)
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// ErrInvalidQos is the error returned when an packet is to be sent
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// with an invalid Qos value
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var ErrInvalidQos = errors.New("invalid QoS")
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// ErrInvalidTopicEmptyString is the error returned when a topic string
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// is passed in that is 0 length
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var ErrInvalidTopicEmptyString = errors.New("invalid Topic; empty string")
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// ErrInvalidTopicMultilevel is the error returned when a topic string
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// is passed in that has the multi level wildcard in any position but
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// the last
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var ErrInvalidTopicMultilevel = errors.New("invalid Topic; multi-level wildcard must be last level")
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// Topic Names and Topic Filters
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// The MQTT v3.1.1 spec clarifies a number of ambiguities with regard
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// to the validity of Topic strings.
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// - A Topic must be between 1 and 65535 bytes.
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// - A Topic is case sensitive.
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// - A Topic may contain whitespace.
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// - A Topic containing a leading forward slash is different than a Topic without.
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// - A Topic may be "/" (two levels, both empty string).
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// - A Topic must be UTF-8 encoded.
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// - A Topic may contain any number of levels.
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// - A Topic may contain an empty level (two forward slashes in a row).
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// - A TopicName may not contain a wildcard.
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// - A TopicFilter may only have a # (multi-level) wildcard as the last level.
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// - A TopicFilter may contain any number of + (single-level) wildcards.
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// - A TopicFilter with a # will match the absence of a level
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// Example: a subscription to "foo/#" will match messages published to "foo".
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func validateSubscribeMap(subs map[string]byte) ([]string, []byte, error) {
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if len(subs) == 0 {
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return nil, nil, errors.New("invalid subscription; subscribe map must not be empty")
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}
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var topics []string
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var qoss []byte
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for topic, qos := range subs {
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if err := validateTopicAndQos(topic, qos); err != nil {
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return nil, nil, err
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}
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topics = append(topics, topic)
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qoss = append(qoss, qos)
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}
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return topics, qoss, nil
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}
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func validateTopicAndQos(topic string, qos byte) error {
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if len(topic) == 0 {
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return ErrInvalidTopicEmptyString
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}
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levels := strings.Split(topic, "/")
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for i, level := range levels {
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if level == "#" && i != len(levels)-1 {
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return ErrInvalidTopicMultilevel
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}
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}
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if qos > 2 {
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return ErrInvalidQos
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}
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return nil
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}
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