OpenCalculationEngine

Description

OpenBilling is a .NET project designed to handle customizable billing calculation.

The operations are defined with an excel-like language.

Installation

git clone https://github.com/darrrio/open-calculationengine.git
cd open-calculationengine
dotnet restore
dotnet build

Usage

Syntax for expression and inputFile

The CalculateExpression method in the EngineController class requires two parameters: expression and inputFile.

expression Parameter

• Type: string
• Description: The formula or expression to be evaluated.
• Format: The expression should be a string that can include operators and functions recognized by the ExpressionNode class.
• Examples:
  • "$OP.SUM(1;2;3)"
  • "$OP.MULTIPLY(4;5)"
  • "$FN.TARIFF()"
  • More to be added...

inputFile Parameter

• Type: Hashtable
• Description: A hashtable containing the base data used for the calculation.
• Format: The input file should be a JSON object that can be serialized into a JsonObject. The keys should be strings, and the values can be nested JSON objects, arrays, or primitive types (e.g., string, number).
• Example:

  {
    "key1": "value1",
    "key2": {
      "nestedKey1": "nestedValue1",
      "nestedKey2": 123
    },
    "key3": [
      {
        "arrayKey1": "arrayValue1"
      },
      {
        "arrayKey2": "arrayValue2"
      }
    ]
  }

Available Operators and Functions

Operators

• Addition: $OP.SUM
• Multiplication: $OP.MULTIPLY
• Division: $OP.DIVIDE

Functions

• GetTariff(): $FN.TARIFF

Naming Convention in JSON Object and Expression

• Format: The keys in the JSON object should be named according to the following convention:
• Operators: The key should be named $OP.<OPERATOR_NAME>.
• Functions: The key should be named $FN.<FUNCTION_NAME>.
• Operators with Parameters: Can be used only 2 parameters. The parameters should be separated by a semicolon (;).
• Functions with Parameters: Can be used only 1 or 2 parameters. The parameters should be separated by a semicolon (;) even with only 1 parameter. eg. $FN.TARIFF($PRM.PARAM1;) or $FN.TARIFF($PRM.PARAM1;$PRM.PARAM2;)

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.