How to iterate over the headers in an Azure Logic App? - azure-logic-apps

Question

In a http triggered Logic App I'd like to iterate over the incoming http headers and use only the x-... headers. These headers should be appended to a JSON message.
I know how to access the headers using triggerOutputs()['headers'], how to iterate over collections and how to construct a JSON message using compose. But how to iterate over the headers?
Note: I don't know the x-... header names and I'd like to append any x-... header into the message, I don't want to update the Logic App if a new header is being added or one is removed.
I tried to create a ForEach that iterates over triggerOutputs()['headers'], but that's not a collection.
The header content:
{
"Cache-Control": "no-cache",
"Connection": "keep-alive",
"Accept": "*/*",
"Accept-Encoding": "br,gzip,deflate",
"Host": "prod-42.westeurope.logic.azure.com:443",
"x-batch-uuid": "e74f68b9-d69e-4d50-bfe2-65bd6b38dd45",
"x-event": "12361",
"x-sequence": "1",
"x-trigger-id": "sample-trigger-id",
"x-trigger-time": "1672935303",
"x-uuid": "66fa9513-ab42-4f31-90ff-b44582f7d72f",
"Content-Length": "308",
"Content-Type": "application/json"
}
Current version with static x-header copy action
{
"definition": {
"$schema": "https://schema.management.azure.com/providers/Microsoft.Logic/schemas/2016-06-01/workflowdefinition.json#",
"actions": {
"MessageBody": {
"inputs": {
"data": "#triggerBody()",
"meta": "#outputs('X-Headers')"
},
"runAfter": {
"X-Headers": [
"Succeeded"
]
},
"type": "Compose"
},
"Send_message": {
"inputs": {
"body": {
"ContentData": "#{base64(outputs('MessageBody'))}"
},
"host": {
"connection": {
"name": "#parameters('$connections')['servicebus']['connectionId']"
}
},
"method": "post",
"path": "/#{encodeURIComponent(encodeURIComponent('schedule-events'))}/messages"
},
"runAfter": {
"MessageBody": [
"Succeeded"
]
},
"type": "ApiConnection"
},
"X-Headers": {
"inputs": {
"x-batch-uuid": "#{triggerOutputs()?['headers']?['x-batch-uuid']}",
"x-event": "#{triggerOutputs()?['headers']?['x-event']}",
"x-sequence": "#{triggerOutputs()?['headers']?['x-sequence']}",
"x-trigger-id": "#{triggerOutputs()?['headers']?['x-trigger-id']}",
"x-trigger-time": "#{triggerOutputs()?['headers']?['x-trigger-time']}",
"x-uuid": "#{triggerOutputs()?['headers']?['x-uuid']}"
},
"runAfter": {},
"type": "Compose"
}
},
"contentVersion": "1.0.0.0",
"outputs": {},
"parameters": {
"$connections": {
"defaultValue": {},
"type": "Object"
}
},
"triggers": {
"manual": {
"inputs": {
"schema": {
"properties": {
"person": {
"properties": {
"href": {
"type": "string"
},
"personId": {
"type": "string"
}
},
"type": "object"
}
},
"type": "object"
}
},
"kind": "Http",
"type": "Request"
}
}
},
"parameters": {
"$connections": {
"value": {
"servicebus": {
"connectionId": "/subscriptions/.../resourceGroups/.../providers/Microsoft.Web/connections/servicebus-1",
"connectionName": "servicebus-1",
"id": "/subscriptions/.../providers/Microsoft.Web/locations/westeurope/managedApis/servicebus"
}
}
}
}
}

Answer 1

As mentioned by #skin, you cannot iterate for each loop over an object. Headers is an object, and we can iterate for each loop for array only. As a workaround I have tried a below method. Kindly try if it helps in your case.
Created logic app as shown below,
In for each loop, taken condition as shown below
if(startsWith(item(),'-x'),true,false)
Logic app ran successfully as shown below,