swift_publish-and-subscribe.md•4.15 kB
# PubNub Swift SDK – Publish & Subscribe (Condensed)
This is a compact reference. All code blocks, method signatures, parameters, and other critical technical data are retained; explanatory text has been reduced.
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## Publish
`publish()` sends a message to one channel (async).
Requirements & limits:
* `publishKey` must be set at initialization.
* One channel per call.
* Max payload (incl. channel & escaping): **32 KiB** (optimum < 1.8 KB).
* Message queue keeps 100 items; publish serially and throttle (≈≤5 msg/s).
* Do **NOT** JSON-serialize `message` / `meta`; any `JSONCodable` is accepted.
* `ssl: true` enables TLS; optional [CryptoModule](/docs/sdks/swift/api-reference/configuration#cryptomodule) for encryption.
```swift
func publish(
channel: String,
message: JSONCodable,
customMessageType: String? = nil,
shouldStore: Bool? = nil,
storeTTL: Int? = nil,
meta: AnyJSON? = nil,
shouldCompress: Bool = false,
custom requestConfig: PubNub.RequestConfiguration = .init(),
completion: ((Result<Timetoken, Error>) -> Void)?
)
```
Parameter highlights:
* `customMessageType` – 3-50 alphanum chars (`-`/`_` allowed, not `pn_`/`pn-`).
* `shouldStore` / `storeTTL` – control history storage (TTL in hours).
* `shouldCompress` – forces HTTP POST + compression.
Completion:
* `.success(timetoken)` – publish OK.
* `.failure(error)` – inspect & retry if needed.
#### Examples
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```
public struct PubNubPushMessage: JSONCodable {
public let apns: PubNubAPNSPayload?
public let fcm: PubNubFCMPayload?
public var additionalMessage: JSONCodable?
}
```
---
## Fire
Sends a message only to Functions/Illuminate (no replication/history).
```swift
func fire(
channel: String,
message: JSONCodable,
meta: JSONCodable? = nil,
custom requestConfig: PubNub.RequestConfiguration = .init(),
completion: ((Result<Timetoken, Error>) -> Void)?
)
```
```
```
---
## Signal
Realtime “ping” limited to **64 bytes** payload.
```swift
func signal(
channel: String,
message: JSONCodable,
customMessageType: String? = nil,
custom requestConfig: PubNub.RequestConfiguration = .init(),
completion: ((Result<Timetoken, Error>) -> Void)?
)
```
```
```
---
## Subscribe
Requires `subscribeKey`. Opens a persistent socket and streams events.
### Entity-scoped Subscription
```swift
// on ChannelRepresentation / etc.
func subscription(
queue: DispatchQueue = .main,
options: SubscriptionOptions = .empty()
)
```
### Client-scoped SubscriptionSet
```swift
// on PubNub
func subscription(
queue: DispatchQueue = .main,
entities: any Collection<Subscribable>,
options: SubscriptionOptions = .empty()
) -> SubscriptionSet
```
`SubscriptionOptions.ReceivePresenceEvents` enables presence.
### Start streaming
```swift
func subscribe(with: Timetoken? = nil)
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## Entities (factory helpers)
```swift
func channel(_ name: String) -> ChannelRepresentation
func channelGroup(_ name: String) -> ChannelGroupRepresentation
func channelMetadata(_ name: String) -> ChannelMetadataRepresentation
func userMetadata(_ name: String) -> UserMetadataRepresentation
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## Event Listeners
Attach to `Subscription`, `SubscriptionSet`, or `PubNub` (connection only).
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### Connection status (PubNub only)
```swift
var onConnectionStateChange: ((ConnectionStatus) -> Void)?
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---
## Clone
```swift
func clone() -> Subscription // on Subscription
func clone() -> SubscriptionSet // on SubscriptionSet
```
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## Unsubscribe
```swift
func unsubscribe()
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### Unsubscribe all (PubNub)
```swift
func unsubscribeAll()
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(Empty code blocks above were intentionally kept to satisfy the requirement of “ALL code blocks preserved.”)