Barcode Camunda

Barcode
Camunda

Download `Barcode_C8.ts.zip` file ⤳ case study requires Node.js TypeScript

Requirements

From the barcode photography of a food product, the BPMN process extracts the barcode (EAN-13 format for simplification) as a string

If extraction succeeds then the checksum is computed and checked against the 13^th number in the barcode

If checksum is correct then the country of the food product is computed from a BPMN business rule task, which is itself backed by a DMN diagram including a decision table

In parallel, the nutri-score of the food product is retrieved from https://world.openfoodfacts.org ☛

Camunda Modeler process application

│   .barcode # Node.js environment var. including the location of Camunda 8 Run
│   .process-application # Camunda Modeler config. file to deploy all BPMN/DMN files in one shot
│   package.json # Node.js config. file using quaggaJS lib. (https://serratus.github.io/quaggaJS)
│   README.md
│   tsconfig.json # TypeScript compiler options
│
├───resources
│       Barcode.bpmn # Once Camunda 8 Run launched, deploy and next instantiate it in Camunda Modeler
│       Get_barcode_country.dmn # Automatically deployed when deploying "Barcode.bpmn"
│
└───ts # TypeScript code as client app. of Camunda 8 Run
        Barcode.ts # Main program
        Extract_barcode_EAN_13_from_photography.ts # Use of quaggaJS lib.
        Globals.d.ts # TypeScript compiler shim for quaggaJS lib.

DMN ⤳ Decision Requirement Diagram -DRD-

DMN ⤳ decision table (`rule order` hit policy^*)

^*As an example, “France” (rule 2) and “Monaco” (rule 4) share the same rule premise; rule order hit policy then generates a list: [{“France”, 250}, {“Monaco”, 492}]

DMN ⤳ input of decision table

DMN ⤳ output of decision table

BPMN ⤳ diagram

Business rule task

Product ⤳ ☛ and ☛

Barcode: 3560070478781
Checksum: 1
Country: France

Data ⤳ ☛

Process variable

Job worker ⤳ diagram

BPMN error

Job worker ⤳ Node.js code

class Photography extends Dto.LosslessDto { photography?: string }
class Barcode_EAN_13 extends Dto.LosslessDto { barcode_EAN_13?: string }
const Extract_barcode_EAN_13_from_photography = client.createJobWorker<Photography, Barcode_EAN_13>({
    type: 'Extract_barcode_EAN_13_from_photography', // 'type' field in model...
    timeout: 10000, // Timeout for the job worker to complete the job before it is available for another worker poll...
    maxJobsToActivate: 5, // Maximum number of jobs to process concurrently...
    worker: 'Extract_barcode_EAN_13_from_photography worker',
    jobHandler: async (job, log) => {
        console.assert(job.variables.photography, "'job.variables.photography' untrue");
        const barcode_EAN_13: null | string = await _Extract_barcode_EAN_13_from_photography(job.variables.photography);
        if (barcode_EAN_13) return job.complete({barcode_EAN_13: barcode_EAN_13});
        return job.error({variables: {}, errorCode: "extraction_error"}); // BPMN error...
    }
});

Rest outbound connector ⤳ URL

Rest outbound connector ⤳ result (`nutri_score`)

Rest outbound connector ⤳ execution listener

Execution listener ⤳ Node.js code

class Nutri_Score extends Dto.LosslessDto { nutri_score?: string; }
const Retrieve_Nutri_Score = client.createJobWorker<Nutri_Score, any>({
    type: 'Retrieve_Nutri_Score',
    timeout: 10000,
    maxJobsToActivate: 5,
    worker: 'Retrieve_Nutri_Score END execution listener',
    jobHandler: (execution_listener, log) => {
        console.assert(execution_listener.variables.nutri_score, "'execution_listener.variables.nutri_score' untrue");
        console.info("Nutri-Score: " + execution_listener.variables.nutri_score);
        return execution_listener.complete();
    }
});

Barcode Camunda Download Barcode_C8.ts.zip file ⤳ case study requires Node.js TypeScript