status-go/services/subscriptions

Signal Subscriptions

This package implements subscriptions mechanics using signal package.

It defines 3 new RPC methods in the eth namespace and 2 signals.

Methods

###eth_subscribeSignal Creates a new filter and subscribes to its changes via signals.

Parameters: receives the method name and parameters for the filter that is created.

Example 1:

{
  "jsonrpc": "2.0", 
  "id": 1,
  "method": "eth_subscribeSignal", 
  "params": ["eth_newPendingTransactionFilter", []]
}

Example 2:

{
  "jsonrpc": "2.0", 
  "id": 2,
  "method": "eth_subscribeSignal", 
  "params": [
    "shh_newMessageFilter",
    [{ "symKeyID":"abcabcabcabc", "topics": ["0x12341234"] }]
  ]
}

Supported filters: shh_newMessageFilter, eth_newFilter, eth_newBlockFilter, eth_newPendingTransactionFilter (see Ethereum documentation for respective parameters).

Returns: error or subscriptionID.

###eth_unsubscribeSignal Unsubscribes and removes one filter by its ID. NOTE: Unsubscribing from a filter removes it.

Parameters: subscriptionID obtained from eth_subscribeSignal Returns: error if something went wrong while unsubscribing.

Signals

1. Subscription data received

{
  "type": "subscriptions.data",
  "event": {
    "subscription_id": "shh_0x01",
    "data": {
        <whisper envelope 01>,
        <whisper envelope 02>,
        ...
    }
}

2. Subscription error received

{
  "type": "subscriptions.error",
  "event": {
    "subscription_id": "shh_0x01",
    "error_message": "can not find filter with id: 0x01"
  }
}