Manage Functions

You can define your own RESTful endpoints by way of functions. You manage your functions by creating them, importing them, exporting them, and deleting them.
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You can define your own RESTful endpoints by way of functions. You manage your functions by creating them, importing them, exporting them, and deleting them.
Functions can:
  • Call JavaScript that is defined in API Creator and return a JSON response.
  • Declare explicit arguments.
  • Pass rows automatically. Set some fields and 
    CA Live API Creator
     updates the row (including relevant reactive logic). Instead of getting, altering, and saving a row by having to issue APIs, use a function.
CA Live API Creator
 includes functions in your Swagger API documentation.
You can call functions by way of GET and POST operations.
In this article:
3
Function Types
You can define the following types of functions:
  • Top-level functions
    Top-level functions are functions that are not associated to an entity (table or view) or table-based resource. By default, functions are top-level functions. Use top-level functions to define any logic or service operation as endpoints.
  • Resource-oriented functions
    Resource-oriented functions are functions that are associated to an entity or table-based resource. These functions are operations on a entity or table-based resource row. Resource-oriented functions can access individual records in the code for the resource using the current table 
    row
     object. 
    CA Live API Creator
     makes the row available to the function and any arguments. The function can then operate on the row (for example, 
    sendMail
     to alert a colleague about an Order), including update (for example, 
    giveRaise
     to an employee based on a 
    percentRaise
     argument). 
    CA Live API Creator
     provides the mapping and translation, for example column de-aliasing. You can use the code for your function over multiple table-based resources that are based on the same table. You can also update the row in functions. When the function completes, 
    CA Live API Creator
     calls the associated logic and persists the row to disk.
    Resource-oriented functions advance the API interface from create, read, update, and delete (CRUD) operations to operations the application requires. You can regard resource-oriented functions as the methods that encapsulate your business logic. Reactive logic ensures that 
    CA Live API Creator
     reuses the API behavior over the PUT, POST, and DELETE HTTP methods for entities and table-based resources. This behavior contributes to a separation of concerns (SoC). Client development can enforce data integrity by proceeding based on the API interface, in parallel with API Server logic.
Compare Functions to Custom Endpoints and JavaScript Resources
Table-based resources provide declarative services to simplify and speed endpoint creation. When you require more flexibility, you can create JavaScript resources, functions, or custom endpoints. Use the following table to compare functions to custom endpoints and JavaScript resources:
Task
Functions
Custom Endpoints
JavaScript Resources
Associated to entities or table-based resources
Yes.
Resource-oriented functions can act as methods.
No
No
Have input parameters
Yes
No
No
Response
JSON and XML
JSON, HTML, and XML
JSON and XML
Authenticated
Yes
No
Yes
Included in Swagger documentation
Yes
No
Yes
HTTP methods
GET and POST
GET, POST, PUT, and DELETE
GET and POST
For more information:
Create Functions
Create a New Function
  1. With your API open, in the Create section, click 
    Functions
    .
    If your API does not have existing functions, the Welcome to Functions page appears. If your API has existing functions, they are listed on the By function tab that displays by default.
  2. Complete one of the following options:
    • If you have not defined any functions, on the Welcome to Functions page, click 
      Create a Function
      .
    • If you have defined at least one function, on the By function tab, click
      Create Function
      .
    The Definition tab for the new function appears by default.
  3. Complete the following fields, and then click
    Save
    :
    Function name
    The name for the function. Enter a meaningful name for your function (or accept the default name).
    Code
    Defines the JavaScript code for the function. You can:
    • Access and insert a code example by clicking 
      Examples
       and then
       Insert
       for the JavaScript code example that you want to insert.
      For more information about the JavaScript code examples that are available from the functions code editor, see JavaScript Code Examples.
    • Code functions in JavaScript that reference JavaScript libraries and Java JAR files in your 
      classpath
      .
      For more information about the context variables that are commonly accessed in JavaScript code, see the "Commonly Accessed Context Variables in Function JavaScript Code" section.
  4. (Optional) Add one or more parameters to your function. Click the 
    Parameters
    tab, click 
    Add Parameter
    , complete the following fields, and then click 
    Save
    :
    Name
    The name for the parameter. Enter a meaningful name for your parameter (or accept the default name).
    Type
    Define the parameter type.
    Values:
     number, string, or boolean
    Default:
     string 
    Required
    Specify whether the parameter is required.
    Default:
     Cleared
    Comments
    Enter a description of the parameter. 
  5. (Optional) Define the function type. Click the
    Resources
    tab, complete the following field, and then click 
    Save
    :
    Function Type
    Defines the function type.
    Options:
    • Top-Level:
       Defines the logic or service operation for this function as endpoints. 
    • Resource-Oriented:
       Associates this function to an entity or table-based resource. In the code editor, enter the entities and table-based resources to which this function applies. Enter the names on separate lines.
    Use the following syntax for entities:
    <data source prefix>:<table name>
    Default:
     Top-Level
    For more information:
  6. Describe the purpose of this function by defining comments and the return type that the function expects by clicking the
    Documentation
    tab.
     
    CA Live API Creator
    includes these comments and the return type in your Swagger API documentation.
  7. Save your changes.
Your function is created and is active.
Commonly Accessed Context Variables in Function JavaScript Code
You code functions in JavaScript. Functions can reference JavaScript libraries and any Java JAR files that you have added to your 
classpath
. Your function returns a JavaScript object, which 
CA Live API Creator
 converts to JSON or translates if you are using XML output.
Your functions can access the following variables:
Variable
Example
Notes
Parameters
var theRaise = parameters.percentRaise * (row.Salary/100);
Define your parameters.
For more information about how to define your parameters, see the "Create a New Function" section.
row
row.Salary += theRaise;
The code for functions that are associated to entities or table-based resources can reference the (table) 
row
 attribute, as shown in the following image.
row
 attributes are based on the column names for the entity. Alias column names (or attributes) for resources are not available from the 
row
attribute.
For more information about Read/Write row access, see the "Resource-Oriented Functions - Read/Write Row Access" section.
req
var user = req.userIdentifier
req.json
var temp = JSON.parse(req.json);
The JSON payload that is passed in.
SysUtility
var functionResponse = SysUtility.getFunction(eachTest.TestName, null);
See the
B2B.testB2BAll()
function.
The following image shows an example of the
giveRaise
function's JavaScript code (for the Business to Business (B2B) API sample):
Function_B2BGiveRaise.png
Example: Create a Function
You can create a function for the 
employees
 table and the explicitly defined 
EmployeeWithRaises
 resource that gives an employee a raise. The following code snippet shows the JavaScript code:
var theRaise = parameters.percentRaise * (row.Salary/100);
row.Salary += theRaise;  // runs logic, persists change row(s) to database...
return [ {"status": "Success"}, {"raise": theRaise} ];
This JavaScript code is from the 
Resource-oriented
 function code example. This example is also illustrated in the Business to Business (B2B) Give Raise example.
For more information about the Give Raise example, see Employee Raise Example.
Control Access to Functions
You can control access to your functions by setting function-level permissions for roles.
For more information about how to control a role's permission to call specific functions, see Authorization and Role-Based Endpoint Access.
View your List of Functions
In the Create section, click 
Functions
. The functions that you create are listed on the 
By function
 tab, using the following syntax:
<Function name>(<param1>,<param2>, etc.)
Call Functions
You can call functions in the following ways:
API users must have at least Read access to call resource-oriented functions.
Call Functions as Endpoints
You can call functions using the function name, optionally with parameters, using the following syntax:
http://localhost:8080/rest/default/demo/v1/
gcd?n1=0&n2=0
Call Functions on Entities of Table-Based Resources
Prerequisite:
 (Views) You have added a virtual primary key to the view.
For more information about how to add a virtual primary key to a view, see Manage Views.
You can call functions on entities or table-based resources and can pass arguments.
Use a URL with the following syntax:
.../v1/<data source prefix>:<entity or table-based resource name>/1/<function name>
Examples
The following code blocks shows examples of calling the
giveRaise
function:
http://localhost:8080/rest/default/b2bderbynw/v1/
nw:Employees/1/giveRaise?percentRaise=1
0
http://localhost:8080/rest/default/b2bderbynw/v1/
EmployeesWithRaises/1/giveRaise?percentRaise=10
Call Functions using POST
You can call functions by way of POST operations to pass a payload into the function.
The following example is the JavaScript code for the 
sortWithPOST
 example function that is included with the 
Demo
 API sample:
if (parameters.orderby == 'asc'){
var temp = JSON.parse(req.json);
return {"response":temp.fruits.sort()};
}
else if(parameters.orderby == 'desc'){
var temp = JSON.parse(req.json);
return {"response":temp.fruits.sort().reverse()};
}
else{
return {"error":"invalid orderby type"};
}
Call Functions using the SysUtility.getFunction() Method
You can call functions by way of GET operations. You can call functions from within API Server (for example, from logic, libraries, and functions) using the 
SysUtility.getFunction()
 method, for example:
var parms = {parm1: 1, parm2: 2};
var functionResponse = SysUtility.getFunction("myfunction", parms);
Call Functions using the SysUtility.postToFunction() Method
You can call functions by way of POST operations and pass in a payload in addition to the parameters. You can call functions from within API Server (for example, from logic, libraries, and functions) using the 
SysUtility.postToFunction()
 method, for example:
var parms = {orderby: "desc"};
var myPayload = {"fruits": ["Banana", "Orange", "Apple", "Mango"]};
var sortedArray = SysUtility.postToFunction("myFunction", parms, myPayload);
log.debug(sortedArray);
return JSON.parse(sortedArray);
Test Functions from the REST Lab
You can test your function in the REST Lab.
Follow these steps:
  1. Open the API containing the function that you want to test.
  2. In the Create section, click 
    Functions
    .
    The By function tab displays.
  3. Click the top-level function as an endpoint that you want to test from the list of functions.
    For resource-oriented functions, you can enter the URL directly in the REST Lab.
    The Definition tab appears.
  4. Click 
    Test
    .
    The REST Lab opens.
    For more information about how to test functions in the REST Lab, see Test your API Using the REST Lab.
     To return to the Definition tab from the REST Lab, click 
    Edit
    .
Call Functions on Tables from Data Explorer
You can call resource-oriented functions from Data Explorer.
For more information about how to call functions on tables from Data Explorer, see Data Explorer.
Export Functions
You can save a function and its parameters as a JSON definition file to a download directory.
Follow these steps:
  1. On the
    By function
    tab, click the function that you want to export.
    The Definition tab opens.
  2. Click
    Export
    .
A JSON file that contains the exported function is downloaded. The syntax for the file name is
FunctionExport_<function name>.json
.
Import Functions
You can import an exported function into your API.
Follow these steps:
  1. On the 
    By function
    tab, click
    Import Function
    .
    The Import JSON window opens.
  2. Select the function JSON file that you exported, and then import the file.
    If the function name already exists, API Server appends
    _clone_
    and a timestamp to the duplicate function using the following syntax:
    <function name>_clone_<timestamp>(<param1>,<param2>, etc.)
The function is imported and displays in the list.