====== The Concepts : Flow Execution Key ======

The flow execution key is a random string of 64 alphanumeric characters. It allows the ActionFlow [[Session Handler]] to restore a given [[state]] and continue a [[flow]] execution from the correct [[state]] hash snapshot.

The flow execution key always has to be returned to the controller after the execution of a view by the user. Each submission of data has to be related to a flow key. If you submit data to an ActionFlow controller without providing a key, the controller will assume that you are requesting a new flow chain execution and will call the step mapped by the ''start_with'' instruction.

===== Structure of the key =====

The key is constructed as follows.
  * **Characters 1 to 8 inclusively** \\ The characters identify a given flow execution sequence. It is also called a [[flow]] id.
  * **Characters 9 to 64 inclusively** \\ Those identify the [[state]] hash to restore the session data from.

<note tip>
The case used in the key is important. Only upper-case and numeric characters are used.
</note>

~~DISCUSSION~~