Data Factory Expression - get a sas token from JSON

Question

I have an output from web activity in Azure Data Factory which generate a JSON containing SAS token for blob storage. I need to pass this SAS Token as an URL to an other Web Activity after every run, as it will expired after 5 minutes.

output example in JSON:

{
    "@odata.context":"https://<baseurl>/data/$metadata#Edm.String",
    "value": "{\"BlobId\":\"{<GUID>}\",\"BlobUrl\":\"https://<baseurl_id>.blob.core.windows.net/dmf/<uniqueFileName>?<SAS Token>\"}"    
}
}

The part that needs to be extracted:

https://<baseurl_id>.blob.core.windows.net/dmf/<uniqueFileName>?<SAS Token>

so far I tried this, by using dynamics content in second web activity:

@activity('web').output.value['BlobUrl']

Could you please support?

try @json(activity('web').output.value).BlobUrl , I usually use a SetVariable for testing if I am getting the proper value extracted. — Scott Mildenberger, Sep 21 '22 at 20:05
@ScottMildenberger thanks a lot - it works! And really great advise for testing. — Volume069, Sep 22 '22 at 09:19

score 2 · Accepted Answer · answered Sep 22 '22 at 13:28

Change to

@json(activity('web').output.value).BlobUrl

'value' is serialized json, you convert 'value' it to json with the @json function. Then you can access any of the properties easily as .BlobUrl shown above.

Whenever I am not sure how to extract a certain value from an output I use the SetVariable activity for testing, it can be removed once you have it figured it out.

Data Factory Expression - get a sas token from JSON

1 Answers1