9.1

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Work with Groovy

Basic Level Video Lessons

65 Groovy Coding Samples

https://www.youtube.com/playlist?list=PLOGAj7tCqHx84a5oHMfLhE3-vKMM_6_nD

Advanced Groovy: Functional Programming

Comprehensive Groovy Book to learn

Code examples from this book - https://github.com/Dierk/GroovyInAction

Additional Learning Resourses

https://leanpub.com/groovytutorial/read

http://www.groovy-lang.org/documentation.html#gettingstarted

http://www.groovy-lang.org/documentation.html

Using Groovy for WorkFusion Bot Tasks

Pass Objects Between Groovy <script> Blocks

There are several options to pass an object or variable between script blocks:

  • Use the Web-Harvest sys object:

    sys.defineVariable("cc", simpleObject);

  • define a variable** without type** or without def:

    simpleObject = new SimpleClass();

  • Use the putAt() method of Groovy Binding API:

    binding.putAt("cc", simpleObject);


// or simple syntax:
putAt("new_column", export_info);

    If you need to create a Web-Harvest Node variable which can be passed to other plugins (except export), do not use the putAt() method.

Example

<?xml version="1.0" encoding="UTF-8"?>
<config xmlns="http://web-harvest.sourceforge.net/schema/1.0/config" scriptlang="groovy">
    
    <script><![CDATA[
        class SimpleClass {
            def printString() {
                println "  Simple Class Content";
            }
        }
        // static objects/variables having local scope, i.e. visible only inside <script> block where they were defined
        def simpleObject = new SimpleClass();
        simpleObject.printString();
        
        // to make static object/variable available in other <script> block add it to global context object 'binding'
        binding.putAt("cc", simpleObject);

        // dynamic variables having GLOBAL scope, i.e. available between <script> blocks and down in WebHarvest as well
        simpleGroovyString = "  hello"
        
        //creating a global variable using web-harvest sys object
        def localString = "  Var from script 1"
        sys.defineVariable("global_var", localString);
    ]]></script>

    <script><![CDATA[
        try {
            println(localString);
        } catch (Exception e) {
            cc.printString();
            println(simpleGroovyString);
            println(global_var);
        }
        
    ]]></script>

    <export include-original-data="true">
        <single-column name="cc_var" value="${cc}" />
        <single-column name="simplegroovystring_var" value="${simpleGroovyString}" />
        <single-column name="global_var" value="${global_var}" />
    </export>
</config>

Working with WebHarvest objects in Groovy

<config xmlns="http://web-harvest.sourceforge.net/schema/1.0/config" scriptlang="groovy">

<var-def name="jsonData">
  <http url="https://pub_demo.s3.amazonaws.com/trainings/bakery.json"/>
</var-def>

<script><![CDATA[

        import com.google.gson.JsonObject
        import com.google.gson.Gson
        import com.google.gson.JsonArray
        import com.google.gson.JsonElement
        import com.google.gson.JsonParser
        
        // http://web-harvest.sourceforge.net/doc/org/webharvest/runtime/variables/ListVariable.html
        println("Class of WebHarvest var jsonData : " + jsonData.getClass());     
        println("Class of jsonData wrapped object : " + jsonData.getWrappedObject().getClass());
        println("jsonData wrapped object : " + jsonData.getWrappedObject());
        
        
        JsonArray items = new Gson().fromJson(jsonData.toString(), JsonObject.class).getAt("Data");
        JsonParser parser = new JsonParser();

         for (int i = 0; i < items.size(); i++) {
             JsonElement value = items.get(i).get("name");
             JsonElement batters = parser.parse(items.get(i).get("batters").toString());
             JsonArray batter = batters.getAsJsonArray("batter");
             JsonArray topping = items.get(i).get("topping");
             
             println("batter - " + batter);
             println("topping - " + topping);
             println("\n\n\n");
         } 
         
]]></script>

    <export include-original-data="true"></export>

</config>

Assignments

1. Practice JSON Manipulations

Create simple BP with single Machine Task.

Load JSON from external file: https://pub_demo.s3.amazonaws.com/trainings/bakery.json

How to read file from HTTP

  <var-def name="jsonData">
    <http url="${json_url}"/>
  </var-def>

Get JSON with <http> webharvest tag into Java variable and parse it with com.google.gson.Gson library (import com.google.gson.Gson)

  • check online documentation how to use Gson library

Out of parsed data calculate:

  1. Count of available toppings for ‘Cakes'
  2. List 'Old Fashioned' available batter types
  3. Calculate sum of ppu’s for all donuts

Provide 3 calculations in export data of your MT

How to export data (simple way)

    <export include-original-data="true">
       <single-column name="topping_length" value="${toppingLength}"/>    
       <single-column name="batter_type" value="${batterType}"/>
       <single-column name="ppu" value="${ppu}"/>
    </export>

2. Use Groovy for parsing XML responses

  1. On input you have file with 30 companies
  2. Study Google Places API - https://developers.google.com/places/web-service/search
  3. Register and obtain your googleapikey
  4. Use Google Places API to verify: Address, Phone, Company Name. Also have API verification link in result data.
  5. When calling Google API expect XML as response type. Parse responses with Groovy.
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