The lack of for n or while loops in Qlik's Application Automation, and a method
to create a for n loop was previously covered in creating a for n loop.
This post covers emulating a more adaptable while type approach using the label blocks.
Again, if you don't need to check state and want to run only a set number of iterations, then using the custom code block from the earlier post is easiest. It also has the advantage that all input linking works correctly, whereas with labels you will break lookups within the automation between sections.
While loop - via label and condition blocks
This automation retrieves a value from a public API (current timestamp), and does a simple check on the value.
By using a go to label and a condition block, we can evaluate the result, and either end the automation if true, or retry if false.
This approach is useful when used in conjunction with a sleep block to poll APIs.
To import this example, use the automation snippet below by copying the JSON and pasting it straight into a workspace.
Automation snippet:
{"blocks":[{"id":"A7049C5D-39CE-49CE-9153-278C72ED2748","type":"StartBlock","disabled":false,"name":"Start","displayName":"Start","comment":"","childId":"DD391D04-CE90-4FBD-BEB8-DB7C314675D5","inputs":[{"id":"run_mode","value":"manual","type":"select","structure":{}}],"settings":[],"collapsed":[{"name":"loop","isCollapsed":false}],"x":100,"y":100},{"id":"DCC7B8D4-28D9-4449-A8E8-72ACFA0DF3A3","type":"GotoBlock","disabled":false,"name":"goToLabel","displayName":"Go To Label","comment":"","childId":null,"inputs":[{"id":"label","value":"C75AC931-7BA3-4672-8BBF-2E9A0C0BCC2C","type":"select","displayValue":"whileLoop","structure":[]}],"settings":[],"collapsed":[{"name":"loop","isCollapsed":false}],"x":87.88671875,"y":340.31640625},{"id":"C75AC931-7BA3-4672-8BBF-2E9A0C0BCC2C","type":"LabelBlock","disabled":false,"name":"label","displayName":"Label - whileLoop","comment":"","childId":"8A4533EF-0492-46F0-B70D-EDCD031D26C4","inputs":[{"id":"name","value":"whileLoop","type":"string","structure":[]}],"settings":[],"collapsed":[{"name":"loop","isCollapsed":false}],"x":412.88671875,"y":174.31640625},{"id":"DD391D04-CE90-4FBD-BEB8-DB7C314675D5","type":"VariableBlock","disabled":false,"name":"targetApi","displayName":"Variable - targetApi","comment":"","childId":"DCC7B8D4-28D9-4449-A8E8-72ACFA0DF3A3","inputs":[],"settings":[],"collapsed":[{"name":"loop","isCollapsed":false}],"x":84.05859375,"y":193.79296875,"variableGuid":"56FD86DC-C2C4-43F7-8F46-7CCF22B7FE49","operations":[{"id":"set_value","key":"FF1A6796-D2FF-4C0D-985D-40D434976769","name":"Set value of { variable }","value":"https://worldtimeapi.org/api/timezone/Europe/London"}]},{"id":"3C80AC6A-1D75-42F1-AC9D-FE95E29F51A2","type":"GotoBlock","disabled":false,"name":"goToLabel2","displayName":"Go To Label 2","comment":"","childId":null,"inputs":[{"id":"label","value":"C75AC931-7BA3-4672-8BBF-2E9A0C0BCC2C","type":"select","displayValue":"whileLoop","structure":[]}],"settings":[],"collapsed":[{"name":"loop","isCollapsed":false}],"x":643.88671875,"y":598.31640625},{"id":"B792FCE5-46CA-4D96-8B39-D665599B16A4","type":"IfElseBlock","disabled":false,"name":"condition2","displayName":"Condition 2","comment":"","childId":null,"inputs":[{"id":"conditions","value":{"mode":"all","conditions":[{"input1":"{mod: {$.callURL.unixtime}, 2}","input2":"1","operator":"="}]},"type":"custom","structure":[]}],"settings":[],"collapsed":[{"name":"yes","isCollapsed":false},{"name":"no","isCollapsed":false}],"x":636,"y":400,"childTrueId":"D818C1FB-D5AA-453E-AE65-EBEED1D37FA3","childFalseId":"6346A1DB-527E-4BD0-B447-DC289F7F08FA"},{"id":"8A4533EF-0492-46F0-B70D-EDCD031D26C4","type":"CallUrlBlock","disabled":false,"name":"callURL","displayName":"Call URL","comment":"","childId":"B792FCE5-46CA-4D96-8B39-D665599B16A4","inputs":[{"id":"url","value":"{$.targetApi}","type":"string","structure":[]},{"id":"method","value":"GET","type":"select","displayValue":"GET","structure":[]},{"id":"timeout","value":"","type":"string","structure":[]},{"id":"params","value":null,"type":"object","mode":"keyValue","structure":[]},{"id":"headers","value":null,"type":"object","mode":"keyValue","structure":[]},{"id":"encoding","value":"","type":"string","structure":[]}],"settings":[{"id":"blendr_on_error","value":"stop","type":"select","structure":[]},{"id":"full_response","value":false,"type":"checkbox","structure":[]},{"id":"capitalize_headers","value":false,"type":"checkbox","structure":[]},{"id":"automations_censor_data","value":false,"type":"checkbox","structure":[]}],"collapsed":[{"name":"loop","isCollapsed":false}],"x":487,"y":270},{"id":"D818C1FB-D5AA-453E-AE65-EBEED1D37FA3","type":"ShowBlock","disabled":false,"name":"output","displayName":"Output","comment":"","childId":null,"inputs":[{"id":"input","value":"{$.callURL.unixtime} % 2 = 1, exit","type":"string","structure":[]}],"settings":[{"id":"display_mode","value":"add","type":"select","structure":[]}],"collapsed":[{"name":"loop","isCollapsed":false}],"x":585.80859375,"y":510.4296875},{"id":"6346A1DB-527E-4BD0-B447-DC289F7F08FA","type":"ShowBlock","disabled":false,"name":"output2","displayName":"Output 2","comment":"","childId":"3C80AC6A-1D75-42F1-AC9D-FE95E29F51A2","inputs":[{"id":"input","value":"{$.callURL.unixtime} % 2 did not equal 1, retry!","type":"string","structure":[]}],"settings":[{"id":"display_mode","value":"add","type":"select","structure":[]}],"collapsed":[{"name":"loop","isCollapsed":false}],"x":651.65234375,"y":640.31640625}],"variables":[{"guid":"56FD86DC-C2C4-43F7-8F46-7CCF22B7FE49","name":"targetApi","type":"string"}]}