78 lines
1.6 KiB
Go
78 lines
1.6 KiB
Go
package nostr
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import (
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"context"
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"sync"
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)
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type Subscription struct {
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id string
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conn *Connection
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mutex sync.Mutex
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Relay *Relay
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Filters Filters
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Events chan *Event
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EndOfStoredEvents chan struct{}
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Context context.Context
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stopped bool
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emitEose sync.Once
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}
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type EventMessage struct {
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Event Event
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Relay string
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}
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// Unsub closes the subscription, sending "CLOSE" to relay as in NIP-01.
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// Unsub() also closes the channel sub.Events.
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func (sub *Subscription) Unsub() {
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sub.mutex.Lock()
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defer sub.mutex.Unlock()
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sub.conn.WriteJSON([]interface{}{"CLOSE", sub.id})
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if sub.stopped == false && sub.Events != nil {
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close(sub.Events)
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}
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sub.stopped = true
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}
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// Sub sets sub.Filters and then calls sub.Fire(ctx).
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func (sub *Subscription) Sub(ctx context.Context, filters Filters) {
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sub.Filters = filters
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sub.Fire(ctx)
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}
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// Fire sends the "REQ" command to the relay.
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// When ctx is cancelled, sub.Unsub() is called, closing the subscription.
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func (sub *Subscription) Fire(ctx context.Context) {
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ctx, cancel := context.WithCancel(ctx)
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sub.Context = ctx
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message := []interface{}{"REQ", sub.id}
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for _, filter := range sub.Filters {
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message = append(message, filter)
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}
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sub.conn.WriteJSON(message)
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// the subscription ends once the context is canceled
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go func() {
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<-ctx.Done()
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sub.Unsub()
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}()
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// or when the relay connection is closed
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go func() {
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<-sub.Relay.ConnectionContext.Done()
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// this will close the Events channel,
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// which can be used by an external reader to learn the subscription has stopped
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sub.Unsub()
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// we also cancel the context
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cancel()
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}()
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}
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