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Scripting#

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:#

![flow-conditin](images/flow-condition.png)
    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#

TypeExample Value
Text/Stringhello
List[ 'str1', 'str2', item.data.myExistingVar ]
Map\{ 'key1': 'val1', 'key2': 'val2' \}
JavaScriptdata.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| Also at the process level, start and end are triggered ![flow-conditin](images/execution%20listener.png)

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 );
    });