Scripting

• Introduction
• Model Expressions/Scripts
  • Model Expressions
  • Model Listeners
• Execution Listeners
  • Task Listeners
• Application Listener
• Scripts Scope and variables
• Item Scope
• Execution Scope
• Application Listener

Introduction

Scripting is using NodeJs JavaScript engine. scripts have full access to the running working full, as well as your application logic in: - AppDelegate class; as a general entry point - AppServices class; that responds to Service Tasks - AppUtils class; general purpose class to make your scripts more powerfull

Scripting is used to add logic to your workflow and is achieved by:

Model Expressions/Scripts

Model Expressions

conditional flow examples:

    data.approval=='Approved'
  or 
    (data.approval=='Approved')
    (this.data.v1 + this.data.v2)
    (this.data.v1 == this.data.v2)
    (this.data.v1 + this.data.v2)>0
    (this.data.v1 + this.data.v2)<4

timers examples:

For duration timers

    $appServices.dateAdd(item.dateStarted,10,'days')

Input/Output

Type	Example Value
Text/String	hello
List	[ 'str1', 'str2', item.data.myExistingVar ]
Map	\{ 'key1': 'val1', 'key2': 'val2' \}
JavaScript	data.item.myExistingVar
JavaScript	\{ 'key1': 'val1', 'key2': 'val2' , 'key3': [item.data.myExistingVar, 'hello'], 'key4': \{ 'ikey5': item.data.myExistingVar\}\}

Assignment properties

User Task Assignment properties can be JavaScript expression, in this case they must start with '$'

For example:

assignee $(this.data.requester)

Model Listeners

Inside your model, you can attach Listeners to various nodes as JavaScript Listeners

These are similar to expressions above but can invoke async functions and can include more complete Javascript

No syntax required for these scripts

Examples

    let userManager=await appServices.retrieveManagerForUser(item.userName);

    data.manager=userManager;

    if (data.var1>5) {
        data.message='any text here';
    }

Execution Listeners

These are for all node types and processes

event	Description
start	is fired at the start of item execution
end	is fired at the end of item execution

Task Listeners

These are for User Tasks only

event	Description
assign	invoked after assign command is issued
validate	invoked after assign or invoke command is issued

validate scripts have a special handling, that they can stop execution by raising errors, to return errors to the execution:

    // do some checking here
    return {error:'Not a valid Input'};

As a result execution will raise an exception and the command will fail.

Application Listener

You can place a listener in your application delegate or your execution scripts class to listen to all events Example:

    const api = new BPMNAPI(new BPMNServer(configuration,new Logger({ toConsole: false}),{cron:false}));

    let options= {option1:1234}; //,option2:SystemUser};

    api.server.listener.on('all', async function ({ context, event, }) {
        if (event=='process.restored')
            {
            context.options=options;
            context.options['restored']=true;
            }
        if (event.startsWith('process.'))
            console.log('---Event: -->' + event , context.options);
        else 
            console.log('---Event: -->'+event, 'item:',context.item.elementId,context.options );
    });

Scripts Scope and variables

Item Scope

Items Expressions and Listeners have the following variables

Variable	Description
item	reference the current item
this	same as item
data	item data object
input	item input
output	item output
appDelegate	reference to appDelegate object
appServices	reference to appServices object
appUtils	reference to appUtils object

• Common Item properties:

      id;                 
      options;
      context;    //execution options
      elementId;  // Model Node Id
  

• Item methods

      log(msg)        // issues a log message into the logger
      info(msg)       // issues an information message
  

• Execution (context) properties

      instance: InstanceObject;
      tokens = new Map();
      definition: IDefinition;
      process : Process;
      item;
      messageMatchingKey;
      userName;
      servicesProvider;
      options;
      operation;
  

Execution Scope

Expressions and Listeners have the following variables

Variable	Description
this	refers to execution object
appDelegate	reference to appDelegate object
appServices	reference to appServices object
appUtils	reference to appUtils object

Application Listener

You can place a listener in your application delegate or your execution scripts class to listen to all events Example:

    const api = new BPMNAPI(new BPMNServer(configuration,new Logger({ toConsole: false}),{cron:false}));

    let options= {option1:1234}; //,option2:SystemUser};

    api.server.listener.on('all', async function ({ context, event, }) {
        if (event=='process.restored')
            {
            context.options=options;
            context.options['restored']=true;
            }
        if (event.startsWith('process.'))
            console.log('---Event: -->' + event , context.options);
        else 
            console.log('---Event: -->'+event, 'item:',context.item.elementId,context.options );
    });