ValueEnricher¶

The ValueEnricher enables docproc to add new content to a message or to modify existing content of the message. It uses a simple rules engine to conditionally modify or add content.

Configuration¶

The ValueEnricher requires the following configuration entries:

[valueenricher-config]
type  = ValueEnricher
rules = /path/to/a/rules/set

type: To configure a ValueEnricher, use ValueEnricher as type.
rules: rules refers to a file on disk containing the rules to be executed on the message content. A rule consists of one or more conditions and a target value to set.

Defining Rules¶

The rules to be executed are kept in a simple JSON-based list.

[
    {
        "name": "First rule",
        "path": "NET",
        "op": "less than",
        "value": 0,
        "targetpath": "DOCTYPE",
        "targetvalue": "CREDIT_NOTE"
    },
    {
        "name": "Second rule",
        "path": "ZIP",
        "op": "exists",
        "targetpath": "HAS_ZIP",
        "targetvalue": true
    }
]

A rule to be used for the ValueEnricher consists of the following fields:

name, path, op, value
targetpath - specific to the ValueEnricher
targetvalue - specific to the ValueEnricher

See Operating the Rules Engine for more details about how to configure rules. Rules being used by the ValueEnricher contain two additional fields:

targetpath

Defines the path to use for writing the provided targetvalue. If the given path does not exist, it will be created. Similarily to the path, the targetpath can be nested using a dotted notation.

Accessing arrays is currently not possible.

targetvalue

The value to write into targetpath. The value can contain portions of the existing message’s content using a ${<sourcepath>} notation.

Defining Target Paths¶

Target paths to write content to can be defined in the same way as the source paths for comparison. A target path can refer to an existing path, causing it to be overwritten with the new value on evaluating the rule successfully. The target path can also be a completely new path, that will be created, if the rule is successful.

Let’s add a city name based on the provided shortcut for the following message.

Message:

{
    "content": {
        "city_sc": "NY"
    }
}

Rule:

{
    "path": "city_sc",
    "op": "equals",
    "value": "NY",
    "targetpath": "city",
    "targetvalue": "New York"
}

Resulting Message:

{
    "content": {
        "city_sc": "NY",
        "city": "New York"
    }
}

Overwrite the city’s shortcut with the city name

Message:

{
    "content": {
        "city": "NY"
    }
}

Rule:

{
    "path": "city",
    "op": "equals",
    "value": "NY",
    "targetpath": "city",
    "targetvalue": "New York"
}

Resulting Message:

{
    "content": {
        "city": "New York"
    }
}

Add an address block containing the city name.

Message:

{
    "content": {
        "city_sc": "NY"
    }
}

Rule:

{
    "path": "city_sc",
    "op": "equals",
    "value": "NY",
    "targetpath": "address.city",
    "targetvalue": "New York"
}

Resulting Message:

{
    "content": {
        "city_sc": "NY",
        "address": {
            "city": "New York"
        }
    }
}

Defining Target Values¶

Target value can be any kind of atomic value types, such as integers, decimal numbers, boolean values or strings. More complex values, such as JSON objects, maps or arrays are not supported.

Message:

{
    "content": {
        "CITY": "New York",
        "ZIP": "10006",
    }
}

Rule:

{
    "path": "ZIP",
    "op": "exists",
    "targetpath": "HAS_ZIP",
    "targetvalue": true
}

{
    "content": {
        "CITY": "New York",
        "ZIP": "NY-10006",
        "HAS_ZIP": true
    }
}

Furthermore, target values can copy the values from existing paths, as long as those contain atomic value types. To refer to an existing path, use ${}.

Prefix the ZIP code with state information for New York:

Message:

{
    "content": {
        "CITY": "New York",
        "ZIP": "10006",
    }
}

Rule:

{
    "path": "CITY",
    "op": "equals",
    "value": "New York",
    "targetpath": "ZIP",
    "targetvalue": "NY-${ZIP}"
}

Resulting Message:

{
    "content": {
        "CITY": "New York",
        "ZIP": "NY-10006"
    }
}