New in 0.19
A Context Storage plugin is a node.js module that exposes a function on its module.exports
that can be used to create new instances of the plugin. The object returned by the
function must have the following functions:
ContextStore.open()
Open the storage ready for use. This is called before any store values are accessed.
Returns a Promise that resolves when the store is ready for access.
ContextStore.close()
Called when the runtime is stopped so no further key values will be accessed.
Returns a Promise that resolves with the store is closed.
ContextStore.get(scope, key, [callback])
| Argument |
Description |
| scope |
the scope of the key |
| key |
the key, or array of keys, to return the value(s) for. |
| callback |
optional a callback function to invoke with the key value |
The key argument can be either a String identifying a single key, or an Array
of Strings identifying multiple keys to return the values for.
If the optional callback argument is provided, it must be a function that takes
two or more arguments:
function callback(error, value1, value2, ... ) {
}
If no callback is provided, and the store supports synchronous access, the
get function should return the individual value, or array of values for the keys.
If the store does not support synchronous access it should throw an error.
ContextStore.set(scope, key, value, [callback])
| Argument |
Description |
| scope |
the scope of the key |
| key |
the key, or array of keys, to set the value(s) for. |
| value |
the value, or array of values |
| callback |
optional a callback function to invoke when the value is set |
The key argument can be either a String identifying a single key, or an Array
of Strings identifying multiple keys to set.
key |
value |
Action |
| String |
Any |
Stores value under key |
| Array |
Array |
Stores each element of the value array under the corresponding key value. If value has fewer elements than key, it sets the missing values to null. |
| Array |
not-Array |
Stores value as the value of the first key - uses null for any remaining keys. |
If the optional callback argument is provided, it will be called when the value
has been stored. It takes a single argument, error, to indicate any errors hit
whilst storing the values.
function callback(error) {
}
If no callback is provided, and the store supports synchronous access, the
set function should return once the value is stored. If the store does not support
synchronous access it should throw an error.
ContextStore.keys(scope, [callback])
| Argument |
Description |
| scope |
the scope of the keys to return |
| callback |
optional a callback function to invoke with the list of keys |
Gets a list of all keys under the given scope.
If the optional callback argument is provided, it must be a function that takes
two or more arguments:
function callback(error, keys) {
}
If no callback is provided, and the store supports synchronous access, the
keys function should return the array of keys. If the store does not support
synchronous access it should throw an error.
ContextStore.delete(scope)
| Argument |
Description |
| scope |
the scope to delete |
ContextStore.clean(activeNodes)
| Argument |
Description |
| activeNodes |
a list of all node/flow ids that are still active |
Returns a promise that resolves when store has removed any context scopes that
are no longer required. The activeNodes list can be used to identify what nodes
and flows are still considered active.
