How do i validate if the incoming JSON request body is a valid JSON (not against the schema) in Azure Logic App?

Question

How do i validate if the incoming JSON request body is a valid JSON (not against the schema) in Azure Logic App?

Sanjana Pushkar 201 Microsoft Employee

Hi, I have a Service Bus trigger which gets triggered every time a message is added to the topic. I need to validate if the incoming message is a valid JSON (not against the schema), and if not, it is passed to another service bus queue.

I can't seem to find a proper way to do that using logic apps, can someone help me in how it can be done.

Help would be much appreciated!

Accepted answer

0 additional answers

Your answer

Answer 1

MayankBargali-MSFT 70,936 Moderator

@Anonymous Thanks for reaching out. You can leverage the Parse JSON action to validate if the message content is valid JSON or not.

In the below workflow I have leveraged the Parse JSON action and, in the content, I am converting my message content to base64ToString and for Schema specifying the empty JSON schema.

Now in my condition I am checking whether my Parse JSON action failed or succeeded. I have configured run after behavior on my condition, so it is executed in both failed and successful scenario of my previous Parse JSON action. For actions please refer to this action.

Syntax: actions('your action name').status

Example: actions('Parse_JSON').status

If my message content is valid JSON then the true condition will be executed and for not valid JSON false condition will be executed and you can further write your logic on true and false condition.

User's image

Let me know if you need any assistance.

Please accept as "Yes" if the answer is helpful so that it can help others in the community. If you need any help/clarification/concerns/follow up questions, then please click on "Add Comment" on my answer and provide more details.

Sanjana Pushkar 201 Reputation points Microsoft Employee

2023-03-03T06:45:37.8266667+00:00

Thanks for the help @MayankBargali-MSFT .

I tried doing the same, but the below error keeps popping up.

The JSON body that i'm validating is:

{

"firstname":"name",

"lastname":"xyz"

}
MayankBargali-MSFT 70,936 Reputation points Moderator

2023-03-03T07:24:58.6466667+00:00

@Anonymous Please share the screenshot (as I have shared the second screenshot in my answer) for your ParseJSON action so I can check what content (share the exact value that you have specified as I my case it is base64ToString(triggerbody)?['ContentData']) you are specifying along with what schema you have defined?
Sanjana Pushkar 201 Reputation points Microsoft Employee

2023-03-03T08:13:38.2+00:00

@MayankBargali-MSFT Please find the screenshots below
MayankBargali-MSFT 70,936 Reputation points Moderator

2023-03-03T08:31:25.56+00:00

@Anonymous Thanks for sharing the screenshot. As per the screenshot I can see that you are using the standard logic app with build in service bus trigger "When a message are available in a topic". The output for this action for the ContentData is already in the string format so you don't need to convert in to base64String.

You can simply use it as below and rest of the steps remain same as I mentioned before.

Let me know if you need any assistance/
Sanjana Pushkar 201 Reputation points Microsoft Employee

2023-03-09T05:42:22.26+00:00

Hi @MayankBargali-MSFT , when I am passing a JSON body without brackets, it is taking it as a valid JSON. I even tried using json(triggerOutputs()?['body']?['contentData']) , but it is taking missing brackets as a valid json, and is not failing. Can you suggest me something on this?
MayankBargali-MSFT 70,936 Reputation points Moderator

2023-03-09T08:30:15.3333333+00:00
@Anonymous Please use the schema as below

{ "type": "object", "properties": {} }
Sanjana Pushkar 201 Reputation points Microsoft Employee

2023-03-09T09:13:58.85+00:00

Thanks for the suggestion @MayankBargali-MSFT , but it isn't getting failed and taking it as a valid JSON. Is there any other way to validate the JSON body?
MayankBargali-MSFT 70,936 Reputation points Moderator

2023-03-09T09:31:02.4466667+00:00

Sanjana Pushkar Can you share yor message content. For me it is getting failed for invalid json. Tested with multiple input.
Sanjana Pushkar 201 Reputation points Microsoft Employee

2023-03-09T10:11:54.7166667+00:00

@MayankBargali-MSFT This is the message content that i'm sending and the Parse JSON is getting succeeded
MayankBargali-MSFT 70,936 Reputation points Moderator

2023-03-09T10:26:35.5966667+00:00

Sanjana Pushkar The above should fail as this is not the valid JSON object. I will reach out to my team. For now, either you can check your message content if it is ending with } in the condition with the endsWith function reference. For other string as below is getting failed and only one condition it passe if it doesn't have the closing curly bracket.

"firstname" : "name", "lastname": "xyz"}

The alternative is to offload this function azure function and verify if your text is valid json object or not.
Sanjana Pushkar 201 Reputation points Microsoft Employee

2023-03-09T10:44:46.5266667+00:00

@MayankBargali-MSFT Try removing single bracket, instead of both.

{

"firstname":"name",

"lastname":"xyz"
Sanjana Pushkar 201 Reputation points Microsoft Employee

2023-03-09T10:48:33.2333333+00:00

@MayankBargali-MSFT Thank you so much for the help, i will try using that.

Share via

How do i validate if the incoming JSON request body is a valid JSON (not against the schema) in Azure Logic App?

0 additional answers

Your answer