Formatting Phone Numbers with Genesys Cloud Architect Expressions

What You Will Build

• You will build a Genesys Cloud Architect flow that accepts an E.164 formatted phone number string and transforms it into a standard US North American Numbering Plan format: (XXX) XXX-XXXX.
• You will use the Genesys Cloud Architect API and Expression Language to perform string manipulation without external webhooks.
• The tutorial covers Python for API interaction and pure Architect Expression syntax for the transformation logic.

Prerequisites

• OAuth Client Type: A Service Account or Public Client with the contact-center:custom-object:read and contact-center:interaction:write scopes if you intend to write the result back to an interaction attribute. For pure flow testing, admin or flow:read is sufficient.
• SDK Version: Genesys Cloud Python SDK genesyscloud (version 130.0.0 or higher).
• Language/Runtime: Python 3.8+ for the API verification script; Genesys Cloud Architect for the expression logic.
• External Dependencies: pip install genesyscloud

Authentication Setup

Genesys Cloud uses OAuth 2.0 for API access. The Python SDK handles token acquisition automatically when configured with the AuthMethod object. You must provide your client_id and client_secret.

from genesyscloud.auth import AuthMethod, OAuthClientCredentials
from genesyscloud.rest import Configuration
import os

def get_configuration():
    # Retrieve credentials from environment variables
    client_id = os.getenv("GENESYS_CLIENT_ID")
    client_secret = os.getenv("GENESYS_CLIENT_SECRET")
    base_url = "https://api.mypurecloud.com" # Adjust for your region

    if not client_id or not client_secret:
        raise ValueError("GENESYS_CLIENT_ID and GENESYS_CLIENT_SECRET must be set")

    # Configure the OAuth flow
    auth_method = AuthMethod(
        OAuthClientCredentials(
            client_id=client_id,
            client_secret=client_secret,
            base_url=base_url
        )
    )

    # Initialize the global configuration
    configuration = Configuration(base_url=base_url)
    configuration.auth_methods = [auth_method]
    
    return configuration

This configuration object is passed to API clients to ensure every request includes a valid Bearer token. The SDK automatically refreshes tokens when they expire.

Implementation

Step 1: Understanding the Expression Language Constraints

Genesys Cloud Architect expressions are evaluated at runtime within the flow engine. You cannot use Python, JavaScript, or external libraries directly inside the expression builder. You must use the built-in string functions.

The target format is (XXX) XXX-XXXX. The input is +1XXXXXXXXXX (11 characters).

The logic requires three operations:

1. Extract the area code (characters at index 2 to 4).
2. Extract the prefix (characters at index 5 to 7).
3. Extract the line number (characters at index 8 to 11).
4. Concatenate these substrings with parentheses, spaces, and hyphens.

The relevant built-in functions are:

• substring(string, start, length): Extracts a portion of the string.
• concat(string1, string2, ...): Joins strings together.

Note that substring uses zero-based indexing.

• Input: +12125551234
• Index 0: +
• Index 1: 1
• Index 2: 2 (Start of Area Code)
• Index 5: 5 (Start of Prefix)
• Index 8: 1 (Start of Line Number)

Step 2: Constructing the Expression

You will construct the expression in two parts for clarity, though a single nested expression is also valid. For robustness in Architect, it is often cleaner to use intermediate variables, but for a single action, a nested concat is efficient.

The expression string is:

concat(
  "(",
  substring(to_string(${interaction.contact.phone_number}), 2, 3),
  ") ",
  substring(to_string(${interaction.contact.phone_number}), 5, 3),
  "-",
  substring(to_string(${interaction.contact.phone_number}), 8, 4)
)

Critical Parameter Explanation:

• to_string(...): This is essential. Phone numbers in Genesys interactions can sometimes be stored as integers or specific phone objects. The substring function requires a string type. If the input is not explicitly cast to a string, the expression will fail with a type mismatch error.
• substring(..., 2, 3): Starts at index 2 (the first digit of the area code) and takes 3 characters.
• substring(..., 5, 3): Starts at index 5 (the first digit of the prefix) and takes 3 characters.
• substring(..., 8, 4): Starts at index 8 (the first digit of the line number) and takes 4 characters.

Step 3: Implementing via API (Python SDK)

To automate this change or deploy it as part of a CI/CD pipeline, you must update the Architect flow definition. You will retrieve the existing flow, modify the specific action that contains the expression, and save the flow.

First, define the expression string in Python.

FORMATTED_PHONE_EXPRESSION = """concat("(", substring(to_string(${interaction.contact.phone_number}), 2, 3), ") ", substring(to_string(${interaction.contact.phone_number}), 5, 3), "-", substring(to_string(${interaction.contact.phone_number}), 8, 4))"""

Next, use the FlowsApi to update a specific action. In this example, you will update a “Set Interaction Attribute” action.

from genesyscloud.flows import FlowsApi, Flow, FlowAction
from genesyscloud.rest import ApiException

def update_flow_expression(flow_id: str, action_id: str, configuration: Configuration):
    flows_api = FlowsApi(configuration=configuration)
    
    try:
        # Retrieve the current flow definition
        flow, response = flows_api.get_flow(
            flow_id=flow_id,
            expand=["actions"]
        )
        
        # Locate the specific action to update
        target_action = None
        for action in flow.actions:
            if action.id == action_id:
                target_action = action
                break
        
        if not target_action:
            raise ValueError(f"Action ID {action_id} not found in flow {flow_id}")
        
        # Update the expression in the action's result or value field
        # Assuming this is a SetInteractionAttribute action
        if hasattr(target_action, 'set_result') and target_action.set_result:
            target_action.set_result.expression = FORMATTED_PHONE_EXPRESSION
        elif hasattr(target_action, 'value'):
             target_action.value = FORMATTED_PHONE_EXPRESSION

        # Save the updated flow
        # Note: You must provide the correct revision number if strict versioning is enabled
        updated_flow, response = flows_api.put_flow(
            flow_id=flow_id,
            body=flow
        )
        
        print(f"Flow {flow_id} updated successfully. New version: {updated_flow.revision}")
        return updated_flow

    except ApiException as e:
        print(f"Exception when calling FlowsApi->put_flow: {e}")
        print("Status Code: " + str(e.status))
        print("Reason: " + str(e.reason))
        print("Response Headers: " + str(e.headers))
        print("Response Body: " + e.body)
        raise

Step 4: Validating the Expression Logic

Before applying this to a live flow, you should verify the expression logic. While Genesys does not provide a public “Expression Evaluator” API endpoint, you can validate the logic using the same substring logic in Python to ensure the indices are correct for your specific input format.

def validate_phone_format(input_phone: str) -> str:
    """
    Simulates the Genesys Architect expression logic in Python.
    Input: +12125551234
    Output: (212) 555-1234
    """
    if not input_phone.startswith("+1") or len(input_phone) != 11:
        raise ValueError("Input must be E.164 US format: +1XXXXXXXXXX")
    
    # Simulate to_string()
    phone_str = str(input_phone)
    
    # Simulate substring(start, length)
    area_code = phone_str[2:2+3] # Index 2, length 3
    prefix = phone_str[5:5+3]    # Index 5, length 3
    line_number = phone_str[8:8+4] # Index 8, length 4
    
    # Simulate concat
    formatted = f"({area_code}) {prefix}-{line_number}"
    return formatted

# Test
test_input = "+12125551234"
result = validate_phone_format(test_input)
assert result == "(212) 555-1234", f"Expected (212) 555-1234, got {result}"
print(f"Validation Passed: {test_input} -> {result}")

Complete Working Example

The following script combines authentication, flow retrieval, and expression injection. It assumes you have a flow ID and an action ID where you want to place the formatted phone number.

import os
import sys
from genesyscloud.auth import AuthMethod, OAuthClientCredentials
from genesyscloud.rest import Configuration, ApiException
from genesyscloud.flows import FlowsApi

# Define the Genesys Cloud Architect Expression
# This string is copied directly into the Architect expression builder
PHONE_FORMAT_EXPRESSION = """concat("(", substring(to_string(${interaction.contact.phone_number}), 2, 3), ") ", substring(to_string(${interaction.contact.phone_number}), 5, 3), "-", substring(to_string(${interaction.contact.phone_number}), 8, 4))"""

def main():
    # 1. Setup Authentication
    client_id = os.getenv("GENESYS_CLIENT_ID")
    client_secret = os.getenv("GENESYS_CLIENT_SECRET")
    base_url = os.getenv("GENESYS_BASE_URL", "https://api.mypurecloud.com")
    
    if not client_id or not client_secret:
        print("Error: Set GENESYS_CLIENT_ID and GENESYS_CLIENT_SECRET environment variables.")
        sys.exit(1)

    auth_method = AuthMethod(
        OAuthClientCredentials(
            client_id=client_id,
            client_secret=client_secret,
            base_url=base_url
        )
    )
    configuration = Configuration(base_url=base_url)
    configuration.auth_methods = [auth_method]

    # 2. Initialize API Client
    flows_api = FlowsApi(configuration=configuration)
    
    # 3. Define Target
    flow_id = os.getenv("TARGET_FLOW_ID")
    action_id = os.getenv("TARGET_ACTION_ID")
    
    if not flow_id or not action_id:
        print("Error: Set TARGET_FLOW_ID and TARGET_ACTION_ID environment variables.")
        sys.exit(1)

    try:
        print(f"Fetching flow: {flow_id}")
        # Expand actions to get the full action definitions
        flow, _ = flows_api.get_flow(flow_id=flow_id, expand=["actions"])
        
        # 4. Locate and Update Action
        action_found = False
        for action in flow.actions:
            if action.id == action_id:
                print(f"Found action: {action.name}")
                
                # Depending on the action type, the field might be 'set_result', 'value', or 'expression'
                # For a generic Set Interaction Attribute, it is usually in the 'set_result' object
                if hasattr(action, 'set_result') and action.set_result:
                    print("Updating set_result.expression")
                    action.set_result.expression = PHONE_FORMAT_EXPRESSION
                elif hasattr(action, 'value'):
                    print("Updating value")
                    action.value = PHONE_FORMAT_EXPRESSION
                else:
                    print("Warning: Action type does not support standard expression update.")
                
                action_found = True
                break
        
        if not action_found:
            print(f"Error: Action ID {action_id} not found.")
            sys.exit(1)

        # 5. Save Flow
        print("Saving flow changes...")
        updated_flow, response = flows_api.put_flow(flow_id=flow_id, body=flow)
        print(f"Success. Flow version updated to: {updated_flow.revision}")

    except ApiException as e:
        print(f"API Error: {e.status} - {e.reason}")
        print(f"Body: {e.body}")
        sys.exit(1)

if __name__ == "__main__":
    main()

Common Errors & Debugging

Error: TypeError: argument of type 'NoneType' is not iterable or Expression Evaluation Failure

• Cause: The interaction.contact.phone_number attribute is null or undefined at the time the expression is evaluated. This happens if the flow action executes before the contact data is fully populated or if the phone number field is empty.
• Fix: Add a condition in Architect to check if the phone number is not null before executing the formatting action. Alternatively, wrap the expression in a null-check if available in newer expression versions, but explicit flow control is more reliable.
• Code Fix (Flow Design): Add a “Condition” node before the “Set Interaction Attribute” node. Condition: ${interaction.contact.phone_number} != null.

Error: IndexError or Incorrect Output (12) 345-6789

• Cause: The input phone number does not match the expected E.164 format +1XXXXXXXXXX. For example, if the input is 12125551234 (missing the +), the indices shift by one.
• Fix: Ensure the input source provides E.164. If the input might vary, use a regex-based cleaning step first, or adjust the substring start indices.
• Debugging: Print the raw phone number to a log attribute before formatting to verify the string content and length.

Error: ApiException: 409 Conflict

• Cause: The flow was modified by another user or process after you retrieved it, resulting in a version mismatch.
• Fix: The SDK handles revision numbers. If you encounter a 409, re-fetch the flow and retry the update. In production scripts, implement a retry loop with a short delay.

Error: Expression syntax error in Architect UI

• Cause: Mismatched parentheses or incorrect function arguments in the expression string.
• Fix: Verify the concat arguments are separated by commas and that all substring calls have exactly three arguments: (string, start, length). Ensure to_string is applied to the dynamic variable.

Official References

• Genesys Cloud Architect Expression Language Reference
• Genesys Cloud Python SDK Documentation
• Flows API Reference
• Set Interaction Attribute Action