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
- Subscription data received
 
{
  "type": "subscriptions.data",
  "event": {
    "subscription_id": "shh_0x01",
    "data": {
        <whisper envelope 01>,
        <whisper envelope 02>,
        ...
    }
}
- Subscription error received
 
{
  "type": "subscriptions.error",
  "event": {
    "subscription_id": "shh_0x01",
    "error_message": "can not find filter with id: 0x01"
  }
}