subscriptions

Documentation

Index

• type Broker
  • func NewBroker() *Broker
  • func (b *Broker) ClientById(clientId string) (Client, error)
  • func (b *Broker) Clients() map[string]Client
  • func (b *Broker) Register(client Client)
  • func (b *Broker) Unregister(clientId string)
• type Client
• type DefaultClient
  • func NewDefaultClient() *DefaultClient
  • func (c *DefaultClient) Channel() chan Message
  • func (c *DefaultClient) Discard()
  • func (c *DefaultClient) Get(key string) any
  • func (c *DefaultClient) HasSubscription(sub string) bool
  • func (c *DefaultClient) Id() string
  • func (c *DefaultClient) IsDiscarded() bool
  • func (c *DefaultClient) Send(m Message)
  • func (c *DefaultClient) Set(key string, value any)
  • func (c *DefaultClient) Subscribe(subs ...string)
  • func (c *DefaultClient) Subscriptions(prefixes ...string) map[string]SubscriptionOptions
  • func (c *DefaultClient) Unset(key string)
  • func (c *DefaultClient) Unsubscribe(subs ...string)
• type Message
• type SubscriptionOptions

Types

type Broker

type Broker struct {
	// contains filtered or unexported fields
}

Broker defines a struct for managing subscriptions clients.

func NewBroker

func NewBroker() *Broker

NewBroker initializes and returns a new Broker instance.

func (*Broker) ClientById

func (b *Broker) ClientById(clientId string) (Client, error)

ClientById finds a registered client by its id.

Returns non-nil error when client with clientId is not registered.

func (*Broker) Clients

func (b *Broker) Clients() map[string]Client

Clients returns a shallow copy of all registered clients indexed with their connection id.

func (*Broker) Register

func (b *Broker) Register(client Client)

Register adds a new client to the broker instance.

func (*Broker) Unregister

func (b *Broker) Unregister(clientId string)

Unregister removes a single client by its id.

If client with clientId doesn't exist, this method does nothing.

type Client

type Client interface {
	// Id Returns the unique id of the client.
	Id() string

	// Channel returns the client's communication channel.
	Channel() chan Message

	// Subscriptions returns a shallow copy of the the client subscriptions matching the prefixes.
	// If no prefix is specified, returns all subscriptions.
	Subscriptions(prefixes ...string) map[string]SubscriptionOptions

	// Subscribe subscribes the client to the provided subscriptions list.
	//
	// Each subscription can also have "options" (json serialized SubscriptionOptions) as query parameter.
	//
	// Example:
	//
	// 	Subscribe(
	// 	    "subscriptionA",
	// 	    `subscriptionB?options={"query":{"a":1},"headers":{"x_token":"abc"}}`,
	// 	)
	Subscribe(subs ...string)

	// Unsubscribe unsubscribes the client from the provided subscriptions list.
	Unsubscribe(subs ...string)

	// HasSubscription checks if the client is subscribed to `sub`.
	HasSubscription(sub string) bool

	// Set stores any value to the client's context.
	Set(key string, value any)

	// Unset removes a single value from the client's context.
	Unset(key string)

	// Get retrieves the key value from the client's context.
	Get(key string) any

	// Discard marks the client as "discarded", meaning that it
	// shouldn't be used anymore for sending new messages.
	//
	// It is safe to call Discard() multiple times.
	Discard()

	// IsDiscarded indicates whether the client has been "discarded"
	// and should no longer be used.
	IsDiscarded() bool

	// Send sends the specified message to the client's channel (if not discarded).
	Send(m Message)
}

Client is an interface for a generic subscription client.

type DefaultClient

type DefaultClient struct {
	// contains filtered or unexported fields
}

DefaultClient defines a generic subscription client.

func NewDefaultClient

func NewDefaultClient() *DefaultClient

NewDefaultClient creates and returns a new DefaultClient instance.

func (*DefaultClient) Channel

func (c *DefaultClient) Channel() chan Message

Channel implements the [Client.Channel] interface method.

func (*DefaultClient) Discard

func (c *DefaultClient) Discard()

Discard implements the [Client.Discard] interface method.

func (*DefaultClient) Get

func (c *DefaultClient) Get(key string) any

Get implements the [Client.Get] interface method.

func (*DefaultClient) HasSubscription

func (c *DefaultClient) HasSubscription(sub string) bool

HasSubscription implements the [Client.HasSubscription] interface method.

func (*DefaultClient) Id

func (c *DefaultClient) Id() string

Id implements the [Client.Id] interface method.

func (*DefaultClient) IsDiscarded

func (c *DefaultClient) IsDiscarded() bool

IsDiscarded implements the [Client.IsDiscarded] interface method.

func (*DefaultClient) Send

func (c *DefaultClient) Send(m Message)

Send sends the specified message to the client's channel (if not discarded).

func (*DefaultClient) Set

func (c *DefaultClient) Set(key string, value any)

Set implements the [Client.Set] interface method.

func (*DefaultClient) Subscribe

func (c *DefaultClient) Subscribe(subs ...string)

Subscribe implements the [Client.Subscribe] interface method.

Empty subscriptions (aka. "") are ignored.

func (*DefaultClient) Subscriptions

func (c *DefaultClient) Subscriptions(prefixes ...string) map[string]SubscriptionOptions

Subscriptions implements the [Client.Subscriptions] interface method.

It returns a shallow copy of the the client subscriptions matching the prefixes. If no prefix is specified, returns all subscriptions.

func (*DefaultClient) Unset

func (c *DefaultClient) Unset(key string)

Unset implements the [Client.Unset] interface method.

func (*DefaultClient) Unsubscribe

func (c *DefaultClient) Unsubscribe(subs ...string)

Unsubscribe implements the [Client.Unsubscribe] interface method.

If subs is not set, this method removes all registered client's subscriptions.

type Message

type Message struct {
	Name string `json:"name"`
	Data []byte `json:"data"`
}

Message defines a client's channel data.

type SubscriptionOptions

type SubscriptionOptions struct {
	Query   map[string]any `json:"query"`
	Headers map[string]any `json:"headers"`
}

SubscriptionOptions defines the request options (query params, headers, etc.) for a single subscription topic.