Mqtt topic allowed characters. Valid and invalid topic names.

Mqtt topic allowed characters For context: I'm running ZWaveJS2MQTT which connects to mosquitto. First, your wildcard topic patterns are not valid. Every department/team used a different Topic structure leading to massive integration challenges. Topic strings can include empty spaces to allow for more readable or descriptive topics. Jul 6, 2016 · There seem to be some best practices concerning MQTT topics. Capability discovery Clients can discover the capabilities of the MQTT server, for example, the maximum packet size that is accepted. In the ASCII character set: \ = 0x5C. discovery] Received message on illegal Topics & Best Practices. May 5, 2022 · The problem. Topic IDs. In subscribe topics, the number sign (#) can only be used as the last character in the topic string, and must be the only character in that level. The origin functions as an MQTT client that receives messages, generating a record for each message. ActiveMQ is compatible with several protocols like MQTT, Stomp, etc So ActiveMQ handle his own protocol based on the other. We will deal with them later. org is very active (at the time of this posting). Wildcard Subscriptions. Specify a different encoding using the LABE Based on this MQTT topic, you can design a system that captures any data related to the entire application using the identifier, hv100, but also can target different areas of interest for subscribing to messages, such as the building location. Now the client is receiving the message which he was sending to the broker, because he is subscribed to this Jan 12, 2023 · What you can use the MQTT topic wildcards. The default is the hardware type_serial number. In the current code, I send an "action" key in the JSON: "start" or "stop". e. The use of the topic level separator is significant when the two wildcard characters are encountered in topics specified by subscribers. Example: CR1000X/CR1000Xe _123. Of course, brokers can restrict topics, if they like. MQTT Topics In MQTT, the word topic refers to an UTF-8 string that the broker uses to filter messages for each connected client. String data type, maximum number of characters is 256 Feb 10, 2023 · To describe multiple topic names and topic filters in the resource attribute of a policy, use the ‘*’ and ‘?’ wildcard characters in place of the MQTT wildcard characters. See full list on cedalo. 2-2]. #ifndef MQTT_MAX_PACKET_SIZE #define MQTT_MAX_PACKET_SIZE 255 #endif second, and better solution is use this function to reset buffer size (default value is 255) boolean PubSubClient::setBufferSize(uint16_t size Feb 16, 2022 · (rc, mid) = self. conf in the inputs. mosquitto. Feb 11, 2022 · Learn about MQTT topics. A topic level ID MAY ONLY contain lowercase letters from a to z, numbers from 0 to 9 as well as the hyphen character (-). The paho js client in this app publish and subscribe to the same topic. Feb 10, 2021 · hello, I have this Warning in log: WARNING - PAI. The requirements are as follows: Much be at least 1 character long (^. setCallback(new MqttCallbackHandler(BaseApplication. Each topic must have at least 1 character and at most 65535 bytes. It is expected to be the same as "client ID" used to connect to MQTT broker. Hi @MrRoundRobin, thanks a lot for doing this useful tool. who publish this 5 respective topic. Protocol. The number of topics is going to be set by the number of topics that clients subscribe to as this list is what is searched when a new message is published, so assuming this list is kept I some kind of tree structure (which is very likely due to the hierarchical nature of topics) then the limit Jul 21, 2020 · MQTT通配符. This may be a later addition to the MQTT standard but MQTT5 does include a "response topic" optional field in the PUBLISH message. Topic names They can represent a hierarchy of information by using the forward slash (/) character to separate the levels of the hierarchy. 1 and v5 have the same statement). Asking for help, clarification, or responding to other answers. If the publisher stops publishing data on a topic the subscribers will stop receiving data on that topic but there is nothing to remove. alas after following the install instructions I get this: [10:43 AM]Matt Webb: Event Mqtt threw exception The character '#' is not allowed in topics. App User name, in association with MQTTPassword, used to connect to MQTT broker. . May 2, 2019 · No, you can only wildcard at a sub topic level. In JMS topics, these characters are allowed anywhere in a topic string, but use them with caution. I Oct 18, 2020 · Note that this is also covered in the mqtt spec "The Topic Name in the PUBLISH packet MUST NOT contain wildcard characters [MQTT-3. In comparison to a message queue, MQTT topics are very lightweight. Topics are case-sensitive, meaning "myhome/temperature" and "MyHome/Temperature" are considered as two different topics. your_topic/msg1 and your_topic/msg2. There is the possibility of receiving message in the topics x / start and x / stop, and depending on the topic, it performs an action. 6 and 8. For AWS IoT, one of the first considerations when using MQTT is the design strategy of your MQTT topics. MQTT Topics. Sep 27, 2023 · EMQブログにご覧になってください目次MQTT ワイルドカード$で始まるトピックさまざまなシナリオのトピックMQTT トピックに関するよくある質問MQTT トピックは、メッセージを識別… Jul 13, 2021 · As mentioned by @chrislondon, you can have subtopics: e. Mar 12, 2020 · Some special characters have different values between the ASCII character set and the GSM character set. foo/+/bar matches foo/one/bar and foo/HelloWorld/bar Jul 27, 2017 · I have created a MQTT topic from Python client on the RabbitMQ broker installed in localhost . An MQTT topic acts as a matching mechanism between publishers and subscribers. A subscriber can subscribe to a topic that no messages have ever been published on and that is fine, the broker will send then any messages that may be sent in the future. 1 specification says: Topic Names and Topic Filters are case sensitive; Topic Names and Topic Filters can include the space character; Topic Names and Topic Filters are UTF-8 encoded strings, they MUST NOT encode to more than 65535 bytes PubSub+ event brokers interpret special characters in MQTT topic names and filters as follows: If the event broker receives the "+" or "#" characters in a topic name in a publish packet, it treats them as literal characters. The only supported wildcards are # and + # matches 1 or more sub topics but can not be used in the middle of a topic. Generated on Thu Sep 13 2018 13:40:20 for Paho MQTT C Client Library by 1. This is a limit imposed by the mqtt spec, you can't change it. Subscribe to them, using client. It is a key element May 20, 2016 · Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand May 29, 2019 · Generic MQTT Background With MQTT the sender and receiver are not aware of each other – the broker handles the messaging. Feb 23, 2018 · I'm trying to get a regex in C# to parse an mqtt topic to know which action to perform for each topic type we defined in our system. For information about supported versions, see Supported Systems and Versions. this code in SubPubClint. 04. It is allowed to include any UTF-8 string (even non printable ones and the empty char or space char). (Hass integration) Homeassistant discovery topic - homeassistant Home Assistant status topic - homeassistant/status z2m conf. message_callback_add("your_topic/msg1", on_message_msg1) and client. 201. Hi All, after every restart I receive the previous warning message, but the result is that i do not see the RPI parameter (see figure) Feb 24, 2017 · I have a microcontroller with a thermostat sending its data over Raspberry Pi to my computer using MQTT protocol. foo/+/bar will match foo/1/bar and foo/something/bar Feb 28, 2021 · for a sensor monitoring prototype, I am currently trying to set up a MQTT(mosquitto) + Telegraf + InfluxDB stack on Ubuntu 20. Topic patterns can only contain a single '#' character and it can only appear at the end of a topic e. This allows the messages to be separated in space, time, and intensity. sensor/+/foo/+/json This will match: sensor/1/foo/temp/json sensor/2/foo Aug 23, 2022 · As noted elsewhere there is no single "best practice". Oct 2, 2015 · Concrete example with existing MQTT server. Jan 9, 2023 · MQTT Topic Allowed Characters As mentioned earlier, MQTT topics use UTF-8 characters and are considered valid if they contain at least one UTF-8 character. Jul 10, 2014 · Do you know by chance if as per mqtt standards, is mqtt supposed to accept topics with a "/" somehow escaped on their names? If so, I may try to push a change in the broker source (or change it myself), otherwise I should not try to convince it here not use such such topic names Jul 6, 2019 · The MQTT spec (v3 and v5) says a topic can only use the '#` once in a topic and it must be at the end. _mqttClient. 85. String data type, maximum number of characters is 64; MQTTEnable (Enable or disable MQTT) By default, MQTT is disabled. 1 but hasn't changed in v5) the size of the topic length is represented by 2 bytes so can be up to 65,535 chars. I can see data in mqtt via mqtt explorer but no Teams device nor entities appears in Devices or Entities list in HA. foo/+/bar will match foo/one/bar or foo/two/bar # This matches multiple whole MQTT topic levels, but can only be used at the end of the topic pattern. com Feb 20, 2024 · Here’re some best practices for using MQTT Topics: Each topic must contain at least one character. Dec 30, 2015 · Without looking at the source for mosca I'm going to make a general statement about a generic broker. MQTT topic is a string used in the MQTT protocol to identify and route messages. We'll examine special cases like topics beginning with '$', discuss how to apply these concepts in various real-world scenarios, and address frequently asked questions to deepen your understanding of these essential MQTT components. Homie communicates through MQTT and is hence based on the basic principles of MQTT topic publication and subscription. I will look into this in try to come up with a more intuitive solution. 0. Unfortunately, I have problem using Autodiscover in HA. New ("at least one character long [MQTT-4. There are 2 wild card characters. 1”协议版本） 4. This is a nice smoke test for a MQTT subscriber linux device: mosquitto_sub -h test. In our application, we use Mosquitto as an MQTT broker, is it possible to do the topic transform in Mosquitto broker? I think Mosquitto has full knowledge of topics and can do the topic mapping and transformation easily. String data type, maximum number of characters is 256; MQTTWillMessage (MQTT last will message) Message published on last will topic by broker if disconnected without a disconnect command. Shared Apr 14, 2022 · + This matches a single MQTT topic level and can appear at any location in the topic pattern. MQTT supports 2 types of wildcard. Any limit you are hitting is most likely to be a constraint of the MQTT client you are using. 0”协议版本和MQTT“3. Most MQTT APIs do not allow these characters in topic names, in accordance with the MQTT specification. If a user is typing in somthing, the onchange event occurs and publish the new value to the topic. A topic is typically leveled and separated with a slash / between the levels. I created this guide to Feb 15, 2023 · The Problem Moin, mein HA gibt mir seit dem 14. Share Improve this answer The MQTT 3. The topic consists of one or more topic levels. sports/tennis/# is valid but sports/#/courtA is not. I wonder how I can identify if it's coming up in the start or stop topic. 4 with MQTT Engine 4. paradox. Again, this is defined by the spec. foo/# matches foo/bar and foo/bar/baz + which matches a single topic element and can appear anywhere in the topic. However in practice, using shorter length topic names and fewer levels means less resource consumption. getAppContext(), broker, MQTT_CLIENT_ID); //Set call back class mqttClient. The payload of the message is limited to 268,435,456 bytes. In comparison to a Apr 5, 2016 · Amazon MQTT cloud server have n number of topic, I trying stay connect/subscribe with dynamic 5 topic and callback to me. 3-1]") // ErrMultiLevelWildcardNotLast shows `#` multi-level wildcard is not // allowed at top or middle of Topic Topic Names and Topic Filters are subject to the following guidelines: It is important to note that each topic must contain at least one character and that the topic string allows for empty spaces. ErrAtLeastOneCharacter = errors . The forward slash (/) is used to separate each level within a topic tree and provide a hierarchical structure to the topic space. hardware. Is there any example to migrate to the new way?? I receive this warning in log: configuration variable "json_attributes" is deprecated, replace with "json_attributes_topic" But, if I change only this name, I receive this: Invalid config for [sensor. Some are laid out on the hivemq website (amongst other things): Don’t use a leading forward slash Don’t use spaces in a topic Kee Hello, I am having some trouble trying to make a regex pattern to validate mqtt topics. stack at MQTTnet. The receiver can pick up the messages at… Publishers are not allowed to use the wildcard characters in their topic names. mosquitto. # which has to appear at the end of a topic patten and can match multiple topic sections. Topic names; Topic-ids; Short topic names (2 characters) Pre-defined topic IDs. mqtt]: value should be a string for QMqttTopicFilter is a thin wrapper around a QString providing an expressive data type for MQTT topic filters. 56. stumbled into this but keen to try make it work. As you said this change might be breaking, this change should happen in a major release. " (v3. 7. Feb 20, 2024 · Here’re some best practices for using MQTT Topics: Each topic must contain at least one character. 3. It is also worth noting that the topic is encoded with utf-8, so you may have less than 65536 characters available. mqtt_consumer section with: Apr 21, 2021 · In using 8. 14 Dec 30, 2015 · The length of the actual topic string is at most 65536 bytes. MqttAndroidClient mqttClient = new MqttAndroidClient(BaseApplication. Prefix your MQTT topics to distinguish data topics from command topics. The MQTT 3. foo/bar/# is valid, #/foo is not. I saw companies struggling with MQTT because they lacked a standardized approach to the MQTT Topic definition. The MQTT 3. Oct 5, 2022 · You signed in with another tab or window. MqttTopicValidator. How they are created. I handle all messages Jan 4, 2010 · My acl_file says: user openhab topic readwrite +/cmnd/POWER2 topic readwrite device-a/cmnd/+ The log says: 1576575835: Received PUBLISH from openhab (d0, q1, r0, m20, 'device-a/cmnd/POWER2', . 2 Topics beginning with $) May 17, 2018 · I have a temperature sensor connected to raspberry via MQTT on ESP32 controller, it display correctly temperature in Arduino IDE serial monitor also in Home Assistant webpage. Oct 22, 2022 · An MQTT topic is a UTF-8 encoded string that is the basis for message routing in the MQTT protocol. Aug 13, 2016 · For android I have used Paho Android project, very simple to use, here are the steps: Intialize a client, set required options and connect. All messages related to device temperature are published on topics device/1/temerature, device/2/temperature, etc. 2 times in the last 5 minutes Feb 23, 2017 · Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. The allowed topic. However, I uninstalled IOTLink a few years ago from my Windows PC. A topic name is an UTF-8 string containing one or more levels separated by a forward slash character (/). 1 OASIS Standard , July 8, 2016. Dec 11, 2022 · stefan123t changed the title Home-Assistant illegal discovery topic Home-Assistant illegal discovery topic, contains not allowed characters, Leerzeichen/Space Dec 13, 2022 stefan123t added bug Something isn't working documentation Improvements or additions to documentation enhancement New feature or request good first issue Good for newcomers Before you create a topic namespace for your system, review the characteristics of MQTT topics to create the hierarchy of topic names that works best for your IoT system. Dec 27, 2023 · In either case it MUST be the last character specified in the Topic Filter [MQTT-4. I am publishing few messages in this topic and able to see those in MQTTLens Chrome plug-in also from the Subscriber written in Python. Topic Names. Beyond this point, some special characters must be entered using a specific way, such as a 2-byte representation. Does anyone have an idea or information for this? There is no concept of removing a topic. The above exception was the direct cause of the following exception: Aug 10, 2022 · The topic of publication and subscription are different now. Subscription Identifier. e. I configured telegraf. Provide details and share your research! But avoid …. dest_id is client ID of the "destination" unit, i. You switched accounts on another tab or window. Deciding on your topic hierarchy is an important step in your system design. The topic is not valid. This technique is especially useful when sending numerous small messages over extensive topic names in real time, offering two primary advantages: It amplifies performance while significantly reducing May 22, 2016 · In mqtt, is there any limitation or performance issue on the maximum number of topic that a client can subscribe ? Let say i have posted 1000 comment on 1000 post. Almost any character or symbol on your keyboard would be MQTT topic-allowed characters, including blank spaces. In MQTT, the word topic refers to an UTF-8 string that the broker uses to filter messages for each connected client. i. Defines if MQTT clients are allowed to use wildcard characters in a topic filter. {1,}$) If there is # there can only be one and it must be the last character If there is + and its the only character then it passes Oct 30, 2019 · will allow the client testuser to subscribe to topics a/b/c and d/e/f/# only, while admin is allowed to publish and subscribe these topics. Try not to use more topic levels “just because I can”. CHECK Will mess topic - homeassistant/status z2m conf. Long data type, allowed values: first, define MQTT_MAX_PACKET_SIZE before including SubPubClient. Each topic level is separated by a forward slash (topic level separator). Topic naming and structure and how to use wildcards. Kura is installed and working on the Raspberry. It allows quick ACL control to check whether the client is allowed to publish specific topic. 1-2] Non normative comment “sport/#” also matches the singular “sport”, since # includes the parent level. MqttTopicValidator Jul 19, 2017 · If you are new to MQTT topics, the Eclipse Foundation's Paho project provides good information here on the basics of wildcards. Only allowing the characters you suggest May 29, 2016 · The topic does not match an allowed rule 2 times in the last 5 minutes May 29, 2016 8:36:46 AM Closed connection from 217. This can be used anywhere in the topic (between /) and matches a single level of topic. publish(topic=topic, payload=payload, qos=qos) File "C:\Python\lib\site-packages\paho\mqtt\client. message_callback_add("your_topic/msg2", on_message_msg2), and execute your custom logic in case msg1 or msg2 arrives to the subscriber - in on_message_msg1() and on Mar 6, 2024 · The Topic Alias feature of MQTT comes to the fore in these instances, replacing lengthy and complicated topic strings with single integers. Scale 1\\xd2 P' using the utf-8 encoding. – user4856296 Commented Apr 7, 2016 at 6:27 Mar 6, 2018 · Is it possible to deny a subscription to all topics in the configuration? If topics start with a $ chr then the issue is solved but the MQTT-spec says: 'Applications cannot use a topic with a leading $ character for their own purposes. Jan 7, 2019 · The client is subscribed to a x / # topic. The MQTT topics are case sensitive May 20, 2019 · MQTT allows all UTF-8 characters as topic, with '/' being the level seperator. Conceptually, an MQTT topic behaves like an ephemeral notification channel. Topic alias is used to decrease the number of bytes that are sent across the network by encoding long topic names into a short integer encoding. Avoid camel case. to whom the message is intended. I used to use an mqtt client called IOTLINK with it. (MQTT) Base Topic - homeassistant Jul 6, 2022 · In this post, we focus on MQTT topics, wildcards, and best practices. 主题层级（topic level）分隔符用于将结构化引入主题名。如果存在分隔符，它将主题名分割为多个主题层级 topic level 。 Jun 2, 2023 · Discoveryprefix - homeassistant Enable Birth mess. An MQTT topic consists of one or more topic levels, separated by the slash character (/). mqtt. Jan 13, 2018 · src_id is the ID of the mqtt client that publishes the message. May 16, 2024 · Clients can use wildcards (special characters) in an MQTT topic to subscribe to multiple MQTT topics. 132. Unfortunately, after each reboot of Home Assistant, I’m still getting the warning log messages below. Apr 5, 2017 · Subscriptions can be made to topics that contain wild cards which can help if you want to match more than just a single topic. The MQTT Subscriber origin subscribes to topics on an MQTT broker to read messages from the broker. ' (4. May 8, 2016 · The application uses a specific mqtt topic like "app/form/notes". A topic name must not contain any wildcard characters ( + and # )! Topic names are usabe both in publish and subscribe operations. We have two topics that must be differentiated: cd/hl/projects/{ Topic aliases can be used instead of long topics to reduce the packet size. I'm having no problems with receiv Jul 15, 2016 · Topic Names and Topic Filters MUST NOT include the null character (Unicode U+0000) Topic Names and Topic Filters are UTF-8 encoded strings, they MUST NOT encode to more than 65535 bytes Retrieved from the MQTT Version 3. From the documentation (see the "Topic exchange" subsection): There can be as many words in the routing key as you like, up to the limit of 255 bytes. As per MQTT 3. sensor/data/foo/# There is a second wildcard character which is +. and for each new comment on any of these post i should be notified so to do this i want to subscribe to all 1000 topic. We should wisely use that compelling feature. Jun 22, 2021 · Home assistant is unable to auto discover devices if their MQTT discovery topic contains any of the Norwegian/Scandinavian letters: Æ, Ø or Å (might be that some other non-ascii characters are also included). MQTT topics must balance current device communications, cloud side operations, and Oct 17, 2022 · MQTT Topics FAQ What is the maximum level and length of an MQTT topic? MQTT topic is UTF-8 encoded strings, and it MUST NOT be more than 65535 bytes. 3 with MQTT Engine 4. Answers generated by artificial intelligence tools are not allowed on Stack A superhuman character only damaged by a Jul 7, 2022 · The maximum length of a topic exchange's routing key is 255 bytes. +/tennis/courtA and sports/+/courtA are both valid. A topic is typically leveled and separated with a slash / between the levels such as chat/room/1. _mqtt_client. To learn more about MQTT topics and wildcards, check out this guide . 2022-07-15 04:06:45 WARNING (MainThread) [homeassistant. 1 主题通配符 Topic wildcards. + matches a single sub topic and can be placed anywhere in the topic. You signed out in another tab or window. . I am trying to get it Jan 10, 2019 · Hi, I have some mqtt sensors, but in HA 0. Jun 28, 2019 · The broker accepts valid topics without initialization. Beside the benefits of having a strong type preventing unintended misuse, QMqttTopicFilter provides convenient functions related to topic filters like isValid () or match (). org -t "#" -v The "#" is a wildcard for topics and returns all messages (topics): the server had a lot of traffic, so it returned a 'firehose' of Jun 21, 2019 · I wanted to know if there is a generic regex for MQTT topic validation. 7 I’m seeing the following issue: When the data comes in, two structures are created under the MQTTengine tag provider: 1) a nested directory hierarchy (expected) and 2) a directory where the groupID had the “” replaced with underscores (unexpected). + which matches a single element in a topic. ThrowIfInvalid(String topic) at MQTTnet. A wildcard subscription is a subscription with a topic filter containing one or more wildcard characters Jul 24, 2021 · it does this by using a variety of topic identifiers in place of standard topic name used in MQTT. 1. Then publish to these topics. The forward slash alone is a valid topic. The sender can send at the speed it wants, and the time it wants. Avoid blank spaces and special characters (except /). g. components. getAppContext())); MqttConnectOptions connOpts = new Hi @chkr1011, I instantiated a MqttClient object and called SubscribeAsync with a topic that includes a wildcard character (ie '+' or '#'), but I am not receiving any messages published that satisfy that topic. By default, ZJ2Q publishes discovery topics under node_x. CHECK Birth mess topic - homeassistant/status Enable Will mess. In MQTT-SN there are 4 possible topic Identifiers that can be used. ') ValueError: Publish topic cannot contain wildcards. Reload to refresh your session. Valid and invalid topic names. The null character cannot be used in topic names or topic filters. py", line 1233, in publish raise ValueError('Publish topic cannot contain wildcards. h, case prioritize your define variable. When designing MQTT topics, it’s important to follow best practices to ensure clarity, consistency, and manageability. For subscriptions, two wildcard characters are supported: A '#' character represents a complete sub-tree of the hierarchy and thus must be the last character in a subscription topic string, such as SENSOR/#. 8. Use lowercase letters consistently to avoid case-sensitivity confusion. 0, there is a new way to configure the old json_attributes list. (v3. 3 Release den folgenden Fehler beim Start. true. Ich habe in der Watermeter Config geschaut, konnte aber keine Fehler feststellen. In the GSM character set: Ö = 0x5C. Dec 9, 2022 · [10:42 AM]Matt Webb: hi all. 1-1]") // ErrAtLeastOneCharacter shows empty Topic Name or Filter are not allowed. Jul 30, 2019 · I have a MQTT client that wants to subscribe to the following topics node1/data/updates node1/data/delta node1/data Of course I have multiple nodes, so I have to use wildcards as explained here: Dec 12, 2018 · You are mixing protocols. To provide more flexibility, MQTT supports a hierarchical topic namespace. You can use the + character which is a single level wildcard character. Where to see the list of topics created in RabbitMQ broker? I have enabled web interface for this server . Topics are case-sensitive. foo/# will match foo/bar and foo/bar/one and foo/bar/one/two Let's say I've several devices each having a temperature. NO, the mentioned regex starts with an ^, so it listes the allowed characters. panel - Unable to properly decode label b'Sens. They are not explicitly forbidden, but they can cause confusion or errors. Also allows quick ACL MQTT topic name is a UTF-8 encoded string used for message routing. Sep 16, 2021 · As described in the MQTT specification (assumed v3. 1 a topic name is a UTF8-encoded string that can include wild card Aug 3, 2023 · MQTT Topics are highly flexible and do not force any structure. c#L138. Subscription identifiers are used by MQTT clients to associate received publishes with their subscriptions. This means a topic pattern of +/sensor/# will match each of the following: rpi1 Jul 15, 2022 · I currently use Home Assistant’s MQTT Broken addon. 话题名称和话题过滤器（MQTT“5. When choosing wildcard characters to use in a policy document, consider that the ‘*’ character is not confined to a single topic level as the ‘+’ character is MQTTClientID (MQTT client identifier) Unique identifier the data logger uses to connect to MQTT broker. </param util_topic. So wie ich das verstehe Apr 20, 2024 · New("wildcard characters MUST NOT be used within a Topic Name [MQTT-4. This is similar to Jan 4, 2015 · MQTT topic transform in Mosquitto. In MQTT topics, the number sign (#), and the plus sign (+) cannot be used in publish topics.