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Flow Operations

Introduction

Flow operation data structures are the key containers for flow representation. Flows are stored as JSON within the N2ACD PostgreSQL database and are represented in JSON with the following key attributes:

Attribute	Type	Description
`always_present_calling`	Integer	[Privileged] This parameter causes the service logic to override the Presentation Indicator for the Calling Party Number. If `always_present_calling` is set to `1` then any AttemptTermination operations performed as part of this flow will always force the Calling Party Number Presentation Indicator to Presentation Allowed.
`operations`	Object	See the following section.

Note features marked as [Privileged] are not available to all users, and the API and GUI will perform appropriate checking when the flow is created or updated.

Example Flow

An example JSON representation of a flow and its operations could be as follows:

    {
        "operations": {
            "5": {
                "id": 5,
                "type": "Start",
                "base_node": 1,
                "exits": [ 4 ]
            },
            "4": {
               "id": 4,
               "base_node": 2,
               "type": "Location",
               "exits": [ 1, 2 ],
               "config": {
                    "rules": [
                        {
                            "geography_entry": "Auckland 2",
                            "exit_idx": 1
                        },
                        {
                            "geography_entry": "Gisborne 6",
                            "exit_idx": 1
                        },
                    ]
                }
            },
            "2": {
                "id": 2,
                "type": "AttemptTerminate",
                "base_node": 6,
                "exits": [ null ],
                "config": {
                    "destinations": [ { "number": "032420002" } ]
                }
            },
            "1": {
                "id": 1,
                "type": "AttemptTerminate",
                "base_node": 3,
                "exits": [ null ],
                "config": {
                    "destinations": [ { "number": "032420003" } ]
                }
            }
        }
    }

This represents a flow which performs geographic routing, and terminates to 032420002 for callers from Auckland/Gisborne and 032420003 otherwise.

Operation Attributes

The operations is a Hash of Operation Objects, keyed by the operation id. All Operation Objects have the following parameters.

Parameter	Type	Description
`id`	Integer	[Required] The numeric operation ID. This must match the Object's key in the `operations` hash.
`type`	String	[Required] Name of the operation type, e.g. `Start`, `Menu`, etc.
`exits`	Array of Integer	[Required] Array of all of the "next operation" IDs to which this operation is connected. Indexes into this array should be zero-based. The Array element may also be `null`, which indicates that this exit leads to the end of all processing. If the caller is still on the line when this exit is taken, the call will be disconnected by the switch.
`config`	Object	Most Operation Objects will have a `config` describing the particular configuration of this operation instance. The structure of this `config` depends on the operation `type`.

Announcement Attributes

Several operations have announcements as part of their config structure. All announcement configuration Objects have the following parameters:

Parameter	Type	Description
`set`	String	[Required] Name of the (public or private) announcement set which contains this announcement.
`entry`	String	[Required] Name of the announcement entry, which must be an announcement configured within the specified announcement set.
`repetition`	Integer	Number of times this announcement entry should be repeated. Support for this feature is specific to the individual announcement audio platform (IVR/UIP/SRP). (Default = 1).
`duration`	Integer	If specified to a value greater than zero, the announcement will be extended to the indicated duration in seconds. Support for this feature is specific to the individual announcement audio platform (IVR/UIP/SRP). (Default = 0).

Pattern Matching

Many nodes within flows offer pattern matching for validation of user input, etc. In all cases, this uses Lua syntax for pattern matching. This syntax is similar to regular expressions, but more limited.

The following character patterns are most often used in Lua pattern matching within N2ACD:

Pattern	Contents
`%a`	Letters
`%l`	Lower case letters
`%u`	Upper case letters
`%d`	Digits
`%w`	Alphanumeric characters
`%x`	Hexadecimal digits
`%p`	Punctuation characters
`%s`	Space characters

Some characters have special meanings in a pattern:

Character	Contents
`(` and `)`	Specify the start and stop of a capture group.
`.`	Matches any single character.
`+`	Matches one or more occurrences of the previous pattern.
`*`	Matches zero or more occurrencs of the previous pattern.
`-`	As for `*`, but matches the shortest match possible.
`?`	Matches zero or one occurrences of the previous pattern.
`[`	Specifies the start of a custom character class, and is terminated with `]`. This class matches any of the characters in it as a pattern.
`^`	Either used within a customer character class to invert the class, or used within a pattern to match the start of the string.
`$`	Matches the end of the string.
`%`	Escape character for other special characters.

Some examples of pattern matches are:

Pattern	Description	Example Matches
`021`	Match `021` exactly.	`021`
`0212*`	Match `021` followed by zero or more `2` digits.	`021` `0212` `02122`
`(021)*`	Match zero or more of the entire group `021`.	`<empty>` `021` `021021`
`[AB1-5]*`	Match zero or more `A` or `B` characters or digits within the range `1` to `5`.	`<empty>` `53B212` ``B1234A543` \|
`[^AB1-5]*`	Match zero or more characters that are not `A` or `B` characters or digits within the range `1` to `5`.	`<empty>` `F8976` `8879D`
`.*`	Match zero or more of any digit or character.	`<empty>` `02123B` `022335`
`.*021`	Match any number which ends in 012.	`021` `54321021`

For further details, refer to the official Lua pattern matching documentation.