Creates an instance of AgvClient.
the identity of the AGV this client represents
configuration options for the client
the identity of the AGV this client represents
Readonly clientGets the client's unique client ID to be used for logging purposes, etc.
Readonly debugGets a debugger function associated with this client instance.
Used to log informational, debug, and error messages. The first argument
is a formatter string with printf-style formatting supporting the
following directives: %O (object multi-line), %o (object
single-line), %s (string), %d (number), %j (JSON), %% (escape).
To turn on debug output for this library, set the DEBUG environment
variable to vda-5050:*. To enable low-level MQTT debugging, use
vda-5050:*,mqttjs*. Use * to debug all debug-enabled modules in your
application.
Gets the client configuration options as a readonly object.
Protected isDetermines whether the client has been started.
true if client has been started; false otherwise
Gets the semantic version of the VDA 5050 protocol this implementation conforms to.
a string in the format
"<major-version-number>.<minor-version-number>.<patch-version-number>"
Protected getRegister a last will message at the broker that triggers publication of a connection topic for broken connection state whenever the connection is interrupted unexpectedly.
Protected getGets the semantic version of the VDA 5050 protocol this implementation conforms to.
To be overridden by subclasses that provide VDA 5050 extensions. The
default version returned by the base method is the standard VDA 5050
protocol version this Client class implements.
a string in the format
"<major-version-number>.<minor-version-number>.<patch-version-number>"
Protected onProtected onPublishes the given VDA 5050 core or extension object on the given VDA 5050 communication topic.
On successful publication, this async function resolves a promise
containing a copy of the given headerless object including all header
properties as it has been published. If the publication is dropped
according to the dropIfOffline publish option, the promise resolves
with an undefined value.
a promise that resolves the published object if publication
succeeds or undefined if message should be dropped while offline
synchronously if client is not started, if topic is not valid, if object validation fails
the VDA 5050 communication topic to publish on
a VDA 5050 core or extension object without header properties
Optional options: ClientPublishOptionsclient publish options (optional)
Protected publishPublishes the given VDA 5050 core or extension object on the given VDA 5050 communication topic related to the given AGV subject.
The AgvId subject is used to automatically fill in header properties of
the object to be published. Each of its properties must specify a
non-empty string and must be valid as an MQTT topic level.
On successful publication, this async function resolves a promise
containing a copy of the given headerless object including all header
properties as it has been published. If the publication is dropped
according to the dropIfOffline publish option, the promise resolves
with an undefined value.
a promise that resolves the published object if publication
succeeds or undefined if message should be dropped while offline
synchronously if client is not started, if topic or subject is not valid, if object validation fails
the VDA 5050 communication topic to publish on
identity of the AGV which is related to this publication
a VDA 5050 core or extension object without header properties
Optional options: ClientPublishOptionsclient publish options (optional)
Register a callback function invoked whenever the client's connection state changes.
Upon registration, the given callback is invoked immediately with the current connection state.
You can only register one callback per client; any previously registered callback is discarded.
a callback function
Registers a custom VDA 5050 communication topic with a validator function to check structure and constraints of corresponding extension objects at runtime.
The asInbound and asOutbound parameters indicate whether the
registered extension topic should be allowed for inbound communication
and/or outbound communication. If inbound communication is not allowed,
subscribing to the topic will fail. Likewise, if outbound communication
is not allowed, publishing on the topic will fail.
The validator function is invoked on inbound and/or outbound messages
with a registered extension topic according to the client option
topicObjectValidation.
The validator function should throw a TypeError synchronously if the
passed extension object structure does not conform to the passed
extension topic and the direction of the message (inbound, outbound).
If the given topic is already registered, its registration will be overridden with the new parameters.
Use the function createValidators in the create-validators script
provided by this package to generate JS validation functions for your
custom JSON schemas. Use these functions in this method override.
a custom VDA 5050 communication topic
whether topic should be allowed on inbound communication
whether topic should be allowed on outbound communication
a function that validates message objects against the given extension topic
Protected resetStarts client interaction by connecting to the configured MQTT broker.
If client is already started, this operation is a noop.
Always await this operation before invoking other operations on this client instance.
a promise resolved when client is initially connected, and rejected when connection fails
Stops client interaction by disconnecting from the MQTT broker and cleaning up all active subscriptions and registered extension topics.
If client is not started, this operation is a noop.
Always await this operation before invoking other operations on this
client instance, such as start.
After the client is stopped any publish, subscribe, and unsubscribe operations will throw an error until the client is restarted.
a promise resolved when client is disconnected from the underlying MQTT transport.
Subscribes to the given VDA 5050 communication topic and registers a handler function to be invoked when matching inbound publication messages are received by this client.
If multiple subscription handlers are registered for a given subscription, they are invoked synchronously in series, one after the other, but in arbitrary order.
A subscription handler should never perform long-lasting synchronous operations as it blocks processing of other handlers and incoming messages.
A subscription handler may also perform asynchronous operations but these are are not awaited and not synchronized with the invocation of other handlers.
A subscription handler is responsible for catching any errors. Uncaught errors result in "Uncaught Error" or "Unhandled Promise Rejection" reported by the runtime.
Take care to invoke Client.unsubscribe method on any subscription ID
that is no longer needed by the application to clean up the
subscription's handler function and to reduce network traffic.
Unsubscribing in a handler function is also possible; use the
corresponding subscription id passed as argument. If you want to keep a
subscription for the lifetime of the client, there is no need to
explicitely unsubscribe it before stopping the client.
a promise that resolves a unique subscription ID when subscription is set up successfully
synchronously if client is not started, if topic or subject is not valid
the VDA 5050 communication topic to subscribe to
a function invoked on any inbound message matching the subscription
Protected subscribeSubscribes to the given VDA 5050 communication topic for the given AGV subject and registers a handler function to be invoked when matching inbound publication messages are received by this client.
In the given partial AgvId subject, any property must either specify a
non-empty string which is valid as an MQTT topic level or be undefined
or excluded, to support wildcard subscriptions by control clients.
Otherwise, an error is thrown.
If multiple subscription handlers are registered for a given subscription, they are invoked synchronously in series, one after the other, but in arbitrary order.
A subscription handler should never perform long-lasting synchronous operations as it blocks processing of other handlers and incoming messages.
A subscription handler may also perform asynchronous operations but these are are not awaited and not synchronized with the invocation of other handlers.
A subscription handler is responsible for catching any errors. Uncaught errors result in "Uncaught Error" or "Unhandled Promise Rejection" reported by the runtime.
Take care to invoke Client.unsubscribe method on any subscription ID
that is no longer needed by the application to clean up the
subscription's handler function and to reduce network traffic.
Unsubscribing in a handler function is also possible; use the
corresponding subscription id passed as argument. If you want to keep a
subscription for the lifetime of the client, there is no need to
explicitely unsubscribe it before stopping the client.
a promise that resolves a unique subscription ID when subscription is set up successfully
synchronously if client is not started, if topic or subject is not valid
the VDA 5050 communication topic to subscribe to
identity of the AGV(s) which are related to this subscription
a function invoked on any inbound message matching the subscription
Unsubscribes the subscription issued for the given subscription ID.
The subscription's handler function will be cleaned up and no longer invoked. If there are no other active subscriptions on the associated VDA 5050 topic, the corresponding MQTT topic will also be unsubscribed to prevent unnecessary network traffic.
If the given subscription ID is already unsubscribed, it is silently ignored.
a promise that resolves on successful unsubscription
synchronously if client is not started
the subscription ID related to an issued subscription
Protected validatePerforms a runtime validation check of the given AGV identity to be used as subject of a subscription or publication.
For publications, all AgvId properties must be specified and valid. For
subscriptions, any property may be omitted, but existing properties must
have valid values.
a TypeError if validation check fails
(partial) identity of AGV
whether to validate as a subscription or publication subject
Protected validateValidate standard VDA 5050 topics at runtime with respect to the direction of information exchange. An AGV client can only publish on certain topics and only subscribe to certain topics.
Protected validatePerforms a runtime validation check of a VDA 5050 core or extension object with respect to a given VDA 5050 topic.
a TypeError if validation check fails
a VDA 5050 communication topic
a VDA 5050 core or extension object with header properties
Generated using TypeDoc
A client that implements a basic publish-subscribe communication abstraction layer of the vehicle plane (AGV) of VDA 5050 on top of the MQTT transport protocol.
Remarks
The counterpart of this component on the coordination plane is the class
MasterControlClient.