LogicApp - How to check if collection is empty - azure-logic-apps

Question

What I would like to do it if there is addOn array, I would like to append the word "xxx" to the end of the name.
Schema applied to message.
{
"properties": {
"appointment": {
"properties": {
"id": {
"type": "integer"
},
"lines": {
"items": {
"properties": {
"addOn": {
"items": {
"properties": {
"id": {
"type": "integer"
},
"name": {
"type": "string"
}
},
"required": [
"id",
"name"
],
"type": "object"
},
"type": "array"
},
"id": {
"type": "integer"
},
"price": {
"type": "integer"
}
},
"required": [
"id",
"price"
],
"type": "object"
},
"type": "array"
}
},
"type": "object"
},
"messageId": {
"type": "string"
}
},
"type": "object"
}
Message 1
{
"messageId": "11",
"appointment": {
"id": 22,
"lines": [
{
"id": 33,
"price": 125.0,
"addOn": [
{
"id": 44,
"name": "test"
}
]
}
]
}
}
Message 2
{
"messageId": "11",
"appointment": {
"id": 22,
"lines": [
{
"id": 33,
"price": 125.0
}
]
}
}
Message 1 works fine but whenever I try and use length or Parse Array I get a message that addOn is null.
How can I put a proper Condition express to not get any errors or do nothing when there is no addOn array.
Logic App.
Message1 - Okay
Message2 - Error
Code View.
{
"definition": {
"$schema": "https://schema.management.azure.com/providers/Microsoft.Logic/schemas/2016-06-01/workflowdefinition.json#",
"actions": {
"For_each": {
"actions": {
"For_each_2": {
"actions": {
"Condition_3": {
"actions": {},
"expression": {
"and": [
{
"equals": [
"#empty(items('For_each_2'))",
"True"
]
}
]
},
"runAfter": {},
"type": "If"
}
},
"foreach": "#items('For_each')['addOn']",
"runAfter": {},
"type": "Foreach"
}
},
"foreach": "#body('Parse_JSON')?['appointment']?['lines']",
"runAfter": {
"Parse_JSON": [
"Succeeded"
]
},
"type": "Foreach"
},
"Parse_JSON": {
"inputs": {
"content": "#triggerBody()",
"schema": {
"properties": {
"appointment": {
"properties": {
"id": {
"type": "integer"
},
"lines": {
"items": {
"properties": {
"addOn": {
"items": {
"properties": {
"id": {
"type": "integer"
},
"name": {
"type": "string"
}
},
"required": [
"id",
"name"
],
"type": "object"
},
"type": "array"
},
"id": {
"type": "integer"
},
"price": {
"type": "integer"
}
},
"required": [
"id",
"price"
],
"type": "object"
},
"type": "array"
}
},
"type": "object"
},
"messageId": {
"type": "string"
}
},
"type": "object"
}
},
"runAfter": {},
"type": "ParseJson"
}
},
"contentVersion": "1.0.0.0",
"outputs": {},
"parameters": {},
"triggers": {
"manual": {
"inputs": {
"schema": {
"properties": {
"appointment": {
"properties": {
"id": {
"type": "integer"
},
"lines": {
"items": {
"properties": {
"addOn": {
"items": {
"properties": {
"id": {
"type": "integer"
},
"name": {
"type": "string"
}
},
"required": [
"id",
"name"
],
"type": "object"
},
"type": "array"
},
"id": {
"type": "integer"
},
"price": {
"type": "integer"
}
},
"required": [
"id",
"price",
"addOn"
],
"type": "object"
},
"type": "array"
}
},
"type": "object"
},
"messageId": {
"type": "string"
}
},
"type": "object"
}
},
"kind": "Http",
"type": "Request"
}
}
},
"parameters": {}
}
Steve

Answer 1

I would like to append the word "xxx" to the end of the name.
For appending you can directly add while setting the "name" variable.
Alternatively, you can also use concat function as below.
concat(body('Parse_JSON')?['appointment']?['lines'][0]['addOn'][0]['name'],variables('xxx'))
where both cases would give the result as the following
How can I put a proper Condition express to not get any errors or do nothing when there is no addOn array.
You can do this in many ways where one of the workarounds would be using if the lines contain "addOn" or not.
"contains": ["#body('Parse_JSON')?['appointment']?['lines'][0]","addOn"]
MESSAGE1 RESULTS:
MESSAGE2 RESULTS:
You can reproduce the same in your logic app using the below codeview
{
"definition": {
"$schema": "https://schema.management.azure.com/providers/Microsoft.Logic/schemas/2016-06-01/workflowdefinition.json#",
"actions": {
"Compose": {
"inputs": "#variables('Message')",
"runAfter": {
"For_each": [
"Succeeded"
]
},
"type": "Compose"
},
"For_each": {
"actions": {
"Condition": {
"actions": {
"Set_variable": {
"inputs": {
"name": "Message",
"value": {
"appointment": {
"id": "#body('Parse_JSON')?['appointment']?['id']",
"lines": [
{
"addOn": "addOn is NULL",
"id": "#items('For_each')?['id']",
"price": "#items('For_each')?['price']"
}
]
},
"messageId": "#{body('Parse_JSON')?['messageId']}"
}
},
"runAfter": {},
"type": "SetVariable"
}
},
"else": {
"actions": {
"For_each_2": {
"actions": {
"Set_variable_2": {
"inputs": {
"name": "Message",
"value": {
"appointment": {
"id": "#body('Parse_JSON')?['appointment']?['id']",
"lines": [
{
"addOn": [
{
"id": "#items('For_each_2')?['id']",
"name": "#{concat(body('Parse_JSON')?['appointment']?['lines'][0]['addOn'][0]['name'],variables('xxx'))}"
}
],
"id": "#items('For_each')?['id']",
"price": "#items('For_each')?['price']"
}
]
},
"messageId": "#{body('Parse_JSON')?['messageId']}"
}
},
"runAfter": {},
"type": "SetVariable"
}
},
"foreach": "#items('For_each')['addOn']",
"runAfter": {},
"type": "Foreach"
}
}
},
"expression": {
"and": [
{
"not": {
"contains": [
"#body('Parse_JSON')?['appointment']?['lines'][0]",
"addOn"
]
}
}
]
},
"runAfter": {},
"type": "If"
}
},
"foreach": "#body('Parse_JSON')?['appointment']?['lines']",
"runAfter": {
"Initialize_variable_xxx": [
"Succeeded"
]
},
"type": "Foreach"
},
"Initialize_variable": {
"inputs": {
"variables": [
{
"name": "Message",
"type": "object"
}
]
},
"runAfter": {
"Parse_JSON": [
"Succeeded"
]
},
"type": "InitializeVariable"
},
"Initialize_variable_xxx": {
"inputs": {
"variables": [
{
"name": "xxx",
"type": "string",
"value": "xxx"
}
]
},
"runAfter": {
"Initialize_variable": [
"Succeeded"
]
},
"type": "InitializeVariable"
},
"Parse_JSON": {
"inputs": {
"content": "#triggerBody()",
"schema": {
"properties": {
"appointment": {
"properties": {
"id": {
"type": "integer"
},
"lines": {
"items": {
"properties": {
"addOn": {
"items": {
"properties": {
"id": {
"type": "integer"
},
"name": {
"type": "string"
}
},
"required": [
"id",
"name"
],
"type": "object"
},
"type": "array"
},
"id": {
"type": "integer"
},
"price": {
"type": "integer"
}
},
"required": [
"id",
"price"
],
"type": "object"
},
"type": "array"
}
},
"type": "object"
},
"messageId": {
"type": "string"
}
},
"type": "object"
}
},
"runAfter": {},
"type": "ParseJson"
}
},
"contentVersion": "1.0.0.0",
"outputs": {},
"parameters": {},
"triggers": {
"manual": {
"inputs": {
"schema": {
"properties": {
"appointment": {
"properties": {
"id": {
"type": "integer"
},
"lines": {
"items": {
"properties": {
"addOn": {
"items": {
"properties": {
"id": {
"type": "integer"
},
"name": {
"type": "string"
}
},
"required": [
"id",
"name"
],
"type": "object"
},
"type": "array"
},
"id": {
"type": "integer"
},
"price": {
"type": "integer"
}
},
"required": [
"id",
"price",
"addOn"
],
"type": "object"
},
"type": "array"
}
},
"type": "object"
},
"messageId": {
"type": "string"
}
},
"type": "object"
}
},
"kind": "Http",
"type": "Request"
}
}
},
"parameters": {}
}