Struct LightstreamerClient 

pub struct LightstreamerClient {
    pub connection_details: ConnectionDetails,
    pub connection_options: ConnectionOptions,
    pub subscription_sender: Sender<SubscriptionRequest>,
    /* private fields */
}

Facade class for the management of the communication to Lightstreamer Server. Used to provide configuration settings, event handlers, operations for the control of the connection lifecycle, Subscription handling and to send messages.

An instance of LightstreamerClient handles the communication with Lightstreamer Server on a specified endpoint. Hence, it hosts one “Session”; or, more precisely, a sequence of Sessions, since any Session may fail and be recovered, or it can be interrupted on purpose. So, normally, a single instance of LightstreamerClient is needed.

However, multiple instances of LightstreamerClient can be used, toward the same or multiple endpoints.

You can listen to the events generated by a session by registering an event listener, such as ClientListener or SubscriptionListener. These listeners allow you to handle various events, such as session creation, connection status, subscription updates, and server messages. However, you should be aware that the event notifications are dispatched by a single thread, the so-called event thread. This means that if the operations of a listener are slow or blocking, they will delay the processing of the other listeners and affect the performance of your application. Therefore, you should delegate any slow or blocking operations to a dedicated thread, and keep the listener methods as fast and simple as possible. Note that even if you create multiple instances of LightstreamerClient, they will all use a single event thread, that is shared among them.

Parameters

• server_address: the address of the Lightstreamer Server to which this LightstreamerClient will connect to. It is possible to specify it later by using None here. See ConnectionDetails.setServerAddress() for details.
• adapter_set: the name of the Adapter Set mounted on Lightstreamer Server to be used to handle all requests in the Session associated with this LightstreamerClient. It is possible not to specify it at all or to specify it later by using None here. See ConnectionDetails.setAdapterSet() for details.

Raises

• IllegalArgumentException: if a not valid address is passed. See ConnectionDetails.setServerAddress() for details.

Fields

connection_details: ConnectionDetails

Data object that contains the details needed to open a connection to a Lightstreamer Server. This instance is set up by the LightstreamerClient object at its own creation. Properties of this object can be overwritten by values received from a Lightstreamer Server.

connection_options: ConnectionOptions

Data object that contains options and policies for the connection to the server. This instance is set up by the LightstreamerClient object at its own creation. Properties of this object can be overwritten by values received from a Lightstreamer Server.

subscription_sender: Sender<SubscriptionRequest>

The sender that can be used to subscribe/unsubscribe

Implementations

impl LightstreamerClient

pub const LIB_NAME: &'static str = "rust_client"

A constant string representing the name of the library.

pub const LIB_VERSION: &'static str = "0.1.0"

A constant string representing the version of the library.

pub const SEC_WEBSOCKET_KEY: &'static str = "PNDUibe9ex7PnsrLbt0N4w=="

WebSocket key used in the WebSocket handshake process. This is a base64-encoded value that is used to establish the WebSocket connection.

pub const SEC_WEBSOCKET_PROTOCOL: &'static str = "TLCP-2.4.0.lightstreamer.com"

WebSocket protocol identifier for the TLCP protocol used by Lightstreamer. This identifies the specific subprotocol used over the WebSocket connection.

pub const SEC_WEBSOCKET_VERSION: &'static str = "13"

WebSocket version used for the connection. Version 13 is the standard version used in modern WebSocket implementations.

pub const SEC_WEBSOCKET_UPGRADE: &'static str = "websocket"

WebSocket upgrade header value. Used to indicate that the client wishes to upgrade from HTTP to WebSocket protocol.

pub const TLCP_VERSION: &'static str = "TLCP-2.4.0"

A constant string representing the version of the TLCP protocol used by the library.

pub fn add_cookies(_uri: &str, _cookies: &Cookie<'_>)

Static method that can be used to share cookies between connections to the Server (performed by this library) and connections to other sites that are performed by the application. With this method, cookies received by the application can be added (or replaced if already present) to the cookie set used by the library to access the Server. Obviously, only cookies whose domain is compatible with the Server domain will be used internally.

This method should be invoked before calling the LightstreamerClient.connect() method. However it can be invoked at any time; it will affect the internal cookie set immediately and the sending of cookies on the next HTTP request or WebSocket establishment.

Parameters

• uri: the URI from which the supplied cookies were received. It cannot be None.
• cookies: an instance of http.cookies.SimpleCookie.

See also getCookies()

pub fn add_listener(&mut self, listener: Box<dyn ClientListener>)

Adds a listener that will receive events from the LightstreamerClient instance.

The same listener can be added to several different LightstreamerClient instances.

A listener can be added at any time. A call to add a listener already present will be ignored.

Parameters

• listener: An object that will receive the events as documented in the ClientListener interface.

See also removeListener()

pub async fn connect( &mut self, shutdown_signal: Arc<Notify>, ) -> Result<(), Box<dyn Error + Send + Sync>>

Operation method that requests to open a Session against the configured Lightstreamer Server.

When connect() is called, unless a single transport was forced through ConnectionOptions.setForcedTransport(), the so called “Stream-Sense” mechanism is started: if the client does not receive any answer for some seconds from the streaming connection, then it will automatically open a polling connection.

A polling connection may also be opened if the environment is not suitable for a streaming connection.

Note that as “polling connection” we mean a loop of polling requests, each of which requires opening a synchronous (i.e. not streaming) connection to Lightstreamer Server.

Note that the request to connect is accomplished by the client in a separate thread; this means that an invocation to getStatus() right after connect() might not reflect the change yet.

When the request to connect is finally being executed, if the current status of the client is not DISCONNECTED, then nothing will be done.

Raises

• IllegalStateException: if no server address was configured.

See also getStatus()

See also disconnect()

See also ClientListener.onStatusChange()

See also ConnectionDetails.setServerAddress()

pub async fn disconnect(&mut self)

Operation method that requests to close the Session opened against the configured Lightstreamer Server (if any).

When disconnect() is called, the “Stream-Sense” mechanism is stopped.

Note that active Subscription instances, associated with this LightstreamerClient instance, are preserved to be re-subscribed to on future Sessions.

Note that the request to disconnect is accomplished by the client in a separate thread; this means that an invocation to getStatus() right after disconnect() might not reflect the change yet.

When the request to disconnect is finally being executed, if the status of the client is “DISCONNECTED”, then nothing will be done.

See also connect()

pub fn get_cookies(_uri: Option<&str>) -> Cookie<'_>

Static inquiry method that can be used to share cookies between connections to the Server (performed by this library) and connections to other sites that are performed by the application. With this method, cookies received from the Server can be extracted for sending through other connections, according with the URI to be accessed.

See addCookies() for clarifications on when cookies are directly stored by the library and when not.

Parameters

• uri: the URI to which the cookies should be sent, or None.

Returns

A list with the various cookies that can be sent in a HTTP request for the specified URI. If a None URI was supplied, all available non-expired cookies will be returned.

pub fn get_listeners(&self) -> &Vec<Box<dyn ClientListener>>

Returns a list containing the ClientListener instances that were added to this client.

Returns

A list containing the listeners that were added to this client.

See also addListener()

pub fn get_status(&self) -> &ClientStatus

Inquiry method that gets the current client status and transport (when applicable).

Returns

The current client status. It can be one of the following values:

• "CONNECTING": the client is waiting for a Server’s response in order to establish a connection;
• "CONNECTED:STREAM-SENSING": the client has received a preliminary response from the server and is currently verifying if a streaming connection is possible;
• "CONNECTED:WS-STREAMING": a streaming connection over WebSocket is active;
• "CONNECTED:HTTP-STREAMING": a streaming connection over HTTP is active;
• "CONNECTED:WS-POLLING": a polling connection over WebSocket is in progress;
• "CONNECTED:HTTP-POLLING": a polling connection over HTTP is in progress;
• "STALLED": the Server has not been sending data on an active streaming connection for longer than a configured time;
• "DISCONNECTED:WILL-RETRY": no connection is currently active but one will be opened (possibly after a timeout);
• "DISCONNECTED:TRYING-RECOVERY": no connection is currently active, but one will be opened as soon as possible, as an attempt to recover the current session after a connection issue;
• "DISCONNECTED": no connection is currently active.

See also ClientListener.onStatusChange()

pub fn get_subscriptions(&self) -> &Vec<Subscription>

Inquiry method that returns a list containing all the Subscription instances that are currently “active” on this LightstreamerClient.

Internal second-level Subscription are not included.

Returns

A list, containing all the Subscription currently “active” on this LightstreamerClient. The list can be empty.

See also subscribe()

pub fn new( server_address: Option<&str>, adapter_set: Option<&str>, username: Option<&str>, password: Option<&str>, ) -> Result<LightstreamerClient, Box<dyn Error>>

Creates a new instance of LightstreamerClient.

The constructor initializes the client with the server address and adapter set, if provided. It sets up the connection details and options for the client. If no server address or adapter set is specified, those properties on the client will be None. This allows for late configuration of these details before connecting to the Lightstreamer server.

Arguments

• server_address - An optional reference to a string slice that represents the server address to connect to. If None, the server address must be set later.
• adapter_set - An optional reference to a string slice that specifies the adapter set name. If None, the adapter set must be set later.

Returns

A result containing the new LightstreamerClient instance if successful, or an IllegalStateException if the initialization fails due to invalid state conditions.

Panics

Does not panic under normal circumstances. However, unexpected internal errors during the creation of internal components could cause panics, which should be considered when using this function in production code.

pub fn remove_listener(&mut self, _listener: Box<dyn ClientListener>)

Removes a listener from the LightstreamerClient instance so that it will not receive events anymore.

A listener can be removed at any time.

Parameters

• listener: The listener to be removed.

See also addListener()

pub fn send_message( &mut self, message: &str, sequence: Option<&str>, _delay_timeout: Option<u64>, listener: Option<Box<dyn ClientMessageListener>>, enqueue_while_disconnected: bool, )

Operation method that sends a message to the Server. The message is interpreted and handled by the Metadata Adapter associated to the current Session. This operation supports in-order guaranteed message delivery with automatic batching. In other words, messages are guaranteed to arrive exactly once and respecting the original order, whatever is the underlying transport (HTTP or WebSockets). Furthermore, high frequency messages are automatically batched, if necessary, to reduce network round trips.

Upon subsequent calls to the method, the sequential management of the involved messages is guaranteed. The ordering is determined by the order in which the calls to sendMessage are issued.

If a message, for any reason, doesn’t reach the Server (this is possible with the HTTP transport), it will be resent; however, this may cause the subsequent messages to be delayed. For this reason, each message can specify a “delayTimeout”, which is the longest time the message, after reaching the Server, can be kept waiting if one of more preceding messages haven’t been received yet. If the “delayTimeout” expires, these preceding messages will be discarded; any discarded message will be notified to the listener through ClientMessageListener.onDiscarded(). Note that, because of the parallel transport of the messages, if a zero or very low timeout is set for a message and the previous message was sent immediately before, it is possible that the latter gets discarded even if no communication issues occur. The Server may also enforce its own timeout on missing messages, to prevent keeping the subsequent messages for long time.

Sequence identifiers can also be associated with the messages. In this case, the sequential management is restricted to all subsets of messages with the same sequence identifier associated.

Notifications of the operation outcome can be received by supplying a suitable listener. The supplied listener is guaranteed to be eventually invoked; listeners associated with a sequence are guaranteed to be invoked sequentially.

The “UNORDERED_MESSAGES” sequence name has a special meaning. For such a sequence, immediate processing is guaranteed, while strict ordering and even sequentialization of the processing is not enforced. Likewise, strict ordering of the notifications is not enforced. However, messages that, for any reason, should fail to reach the Server whereas subsequent messages had succeeded, might still be discarded after a server-side timeout, in order to ensure that the listener eventually gets a notification.

Moreover, if “UNORDERED_MESSAGES” is used and no listener is supplied, a “fire and forget” scenario is assumed. In this case, no checks on missing, duplicated or overtaken messages are performed at all, so as to optimize the processing and allow the highest possible throughput.

Since a message is handled by the Metadata Adapter associated to the current connection, a message can be sent only if a connection is currently active. If the special enqueueWhileDisconnected flag is specified it is possible to call the method at any time and the client will take care of sending the message as soon as a connection is available, otherwise, if the current status is “DISCONNECTED*”, the message will be abandoned and the ClientMessageListener.onAbort() event will be fired.

Note that, in any case, as soon as the status switches again to “DISCONNECTED*”, any message still pending is aborted, including messages that were queued with the enqueueWhileDisconnected flag set to true.

Also note that forwarding of the message to the server is made in a separate thread, hence, if a message is sent while the connection is active, it could be aborted because of a subsequent disconnection. In the same way a message sent while the connection is not active might be sent because of a subsequent connection.

Parameters

• message: a text message, whose interpretation is entirely demanded to the Metadata Adapter associated to the current connection.
• sequence: an alphanumeric identifier, used to identify a subset of messages to be managed in sequence; underscore characters are also allowed. If the “UNORDERED_MESSAGES” identifier is supplied, the message will be processed in the special way described above. The parameter is optional; if set to None, “UNORDERED_MESSAGES” is used as the sequence name.
• delay_timeout: a timeout, expressed in milliseconds. If higher than the Server configured timeout on missing messages, the latter will be used instead. The parameter is optional; if a negative value is supplied, the Server configured timeout on missing messages will be applied. This timeout is ignored for the special “UNORDERED_MESSAGES” sequence, although a server-side timeout on missing messages still applies.
• listener: an object suitable for receiving notifications about the processing outcome. The parameter is optional; if not supplied, no notification will be available.
• enqueue_while_disconnected: if this flag is set to true, and the client is in a disconnected status when the provided message is handled, then the message is not aborted right away but is queued waiting for a new session. Note that the message can still be aborted later when a new session is established.

pub fn set_logger_provider()

Static method that permits to configure the logging system used by the library. The logging system must respect the LoggerProvider interface. A custom class can be used to wrap any third-party logging system.

If no logging system is specified, all the generated log is discarded.

The following categories are available to be consumed:

• lightstreamer.stream: logs socket activity on Lightstreamer Server connections; at INFO level, socket operations are logged; at DEBUG level, read/write data exchange is logged.
• lightstreamer.protocol: logs requests to Lightstreamer Server and Server answers; at INFO level, requests are logged; at DEBUG level, request details and events from the Server are logged.
• lightstreamer.session: logs Server Session lifecycle events; at INFO level, lifecycle events are logged; at DEBUG level, lifecycle event details are logged.
• lightstreamer.subscriptions: logs subscription requests received by the clients and the related updates; at WARN level, alert events from the Server are logged; at INFO level, subscriptions and unsubscriptions are logged; at DEBUG level, requests batching and update details are logged.
• lightstreamer.actions: logs settings / API calls.

Parameters

• provider: A LoggerProvider instance that will be used to generate log messages by the library classes.

pub fn set_trust_manager_factory()

Provides a mean to control the way TLS certificates are evaluated, with the possibility to accept untrusted ones.

May be called only once before creating any LightstreamerClient instance.

Parameters

• factory: an instance of ssl.SSLContext

Raises

• IllegalArgumentException: if the factory is None
• IllegalStateException: if a factory is already installed

pub async fn subscribe( subscription_sender: Sender<SubscriptionRequest>, subscription: Subscription, )

Adds a subscription to the LightstreamerClient instance.

Active subscriptions are subscribed to through the server as soon as possible (i.e. as soon as there is a session available). Active Subscription are automatically persisted across different sessions as long as a related unsubscribe call is not issued.

Subscriptions can be given to the LightstreamerClient at any time. Once done the Subscription immediately enters the “active” state.

Once “active”, a Subscription instance cannot be provided again to a LightstreamerClient unless it is first removed from the “active” state through a call to unsubscribe().

Also note that forwarding of the subscription to the server is made in a separate thread.

A successful subscription to the server will be notified through a SubscriptionListener.onSubscription() event.

Parameters

• subsrciption_sender: A Sender object that sends a SubscriptionRequest to the LightstreamerClient
• subscription: A Subscription object, carrying all the information needed to process real-time values.

See also unsubscribe()

pub async fn subscribe_get_id( subscription_sender: Sender<SubscriptionRequest>, subscription: Subscription, ) -> Result<usize, Box<dyn Error + Send + Sync>>

If you want to be able to unsubscribe from a subscription, you need to keep track of the id of the subscription. This blocking method allows you to wait for the id of the subscription to be returned.

Parameters

• subscription_sender: A Sender object that sends a SubscriptionRequest to the LightstreamerClient
• subscription: A Subscription object, carrying all the information needed to process real-time

pub async fn unsubscribe( subscription_sender: Sender<SubscriptionRequest>, subscription_id: usize, )

Operation method that removes a Subscription that is currently in the “active” state.

By bringing back a Subscription to the “inactive” state, the unsubscription from all its items is requested to Lightstreamer Server.

Subscription can be unsubscribed from at any time. Once done the Subscription immediately exits the “active” state.

Note that forwarding of the unsubscription to the server is made in a separate thread.

The unsubscription will be notified through a SubscriptionListener.onUnsubscription() event.

Parameters

• subsrciption_sender: A Sender object that sends a SubscriptionRequest to the LightstreamerClient
• subscription_id: The id of the subscription to be unsubscribed from. instance.

pub fn set_logging_type(&mut self, logging: LogType)

Method setting enum for the logging of this instance.

Default logging type is StdLogs, corresponding to stdout

LightstreamerClient has methods for logging that are compatible with the Tracing crate. Enabling logging for the Tracing crate requires implementation of a tracing subscriber and its configuration and formatting.

Parameters

• logging: An enum declaring the logging type of this LightstreamerClient instance.

pub fn make_log(&mut self, loglevel: Level, log: &str)

Method for logging messages

Match case wraps log types. loglevel param ignored in StdLogs case, all output to stdout.

Parameters

• loglevel Enum determining use of stdout or Tracing subscriber.

Trait Implementations

impl Debug for LightstreamerClient

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.