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Rossum Formulas

This section covers both the Rossum Formula Fields and the Rossum Python flavor.

Installation​

Formula Fields or Rossum Python do not require any installation. It is available as a native Rossum functionality.

Formula Fields are available in the queue schema as a formula field type. Rossum Python is available in serverless functions. Both flavors are fundamentally similar and differ only in how they are used with minimal syntax differences.

In case you want to use the Rossum Python within the serverless functions, you need to enable following setting:

  1. Go to the settings of the Webhook (Serverless function)
  2. Scroll to Additional notification metadata
  3. Enable the Schemas option
  4. Save it and now you can work with the Rossum Python in your serverless function

Basic usage​

To start with Formula Fields, follow these steps:

  1. Create a new order_id_normalized field in the queue schema.
  2. Select the formula field type of the field.
  3. Write the formula in the formula field.

Your first formula can be as simple as (no returns, no imports):

field.order_id

This formula copies the order_id field into your newly created Formula Field.

Alternatively, you can create a new serverless (Python) function with the following boilerplate code that does the same thing:

from rossum_python import RossumPython

def rossum_hook_request_handler(payload):
    r = RossumPython.from_payload(payload)

    r.field.order_id_normalized = r.field.order_id # ←

    return r.hook_response()

Notice that it is a little bit more verbose, but it is still very similar. The main differences are that we need to wrap the functionality into rossum_hook_request_handler function and that we need to explicitly write into the order_id_normalized field.

Available functions and features​

Here is a list of available functions and features and their comparison between Formula Fields and Serverless Functions. Note that serverless functions examples always assume that the code is wrapped in rossum_hook_request_handler function and prefixed by r = RossumPython.from_payload(payload) call (see above).

Get datapoint value​

Formula field​

Can be either returned directly from the formula fields or stored in some temporary variable.

field.amount

Serverless function​

In case of serverless function, the value can never be returned directly and must be either used in some other function call, or stored in some temporary variable to be used later:

x = r.field.amount

Get datapoint metadata​

Formula field​

field.amount.id               # Datapoint system ID
field.amount.rir_confidence   # Confidence score

Serverless function​

r.field.amount.id
r.field.amount.rir_confidence

Write into datapoint value​

Formula field​

warning

Formula fields cannot write into any other fields. They simply return the value into the formula field itself.

Serverless function​

r.field.amount = 10

Check whether datapoint is set or not​

Formula field​

is_set(field.amount)     # Returns `true` if datapoint is set (has value)
is_empty(field.amount)   # Opposite of `is_set`

Serverless function​

from rossum_python import RossumPython, is_set, is_empty

# …

is_set(r.field.amount)
is_empty(r.field.amount)

Defaulting values​

Use the default value if the field is empty.

Formula field​

default_to(field.amount, 0)

Serverless function​

from rossum_python import RossumPython, default_to

# …

default_to(r.field.amount, 0)

Substitute​

Substitute is an alias for re.sub function (for convenience).

Formula field​

substitute(r"[^0-9]", r"", field.document_id)  # Remove non-digit characters

Could also be written as (re is imported automatically):

re.sub(r"[^0-9]", r"", field.document_id)

Serverless function​

from rossum_python import RossumPython, substitute

# …

substitute(r"[^0-9]", r"", field.document_id)

Show info/warning/error messages​

Formula field​

show_info("…")                    # Show global info message
show_info("…", field.amount)      # Show info message on the specified field

show_warning("…")                 # Show global warning message
show_warning("…", field.amount)   # Show warning message on the specified field

show_error("…")                   # Show global error message
show_error("…", field.amount)     # Show error message on the specified field

Serverless function​

note

Messages do not affect the automation behavior and, therefore, automation blockers must be set explicitly (see how to set automation blockers). The only exception is show_error which always blocks the automation.

r.show_info("…")
r.show_info("…", r.field.amount)

r.show_warning("…")
r.show_warning("…", r.field.amount)

r.show_error("…")
r.show_error("…", r.field.amount)

Set automation blockers​

note

Automation blockers must be set independently of the info/warning messages. Error messages block the automation by default (cannot be disabled).

Formula field​

automation_blocker("message", field.amount)

Serverless function​

r.automation_blocker("message", r.field.amount)