Web API - create a CSV from data store query

There is a built in template for this, try creating another new Web API but select the "Basic - CSV Download" template. You can then combine the two examples to query from the DB and create a csv output.

Hi Tim, 

Thanks for the response, I've tried to combine the two templates to achieve what I wanted but I'm getting the following error when I call the API: A null parameter has been passed as parameter 2.

I noticed in the CSV templateis uses 'User.firstName' etc. to write to the CSV, however I can't work out how to reference specific columns from my dataset. This is my current code:

with(
  /*
  * Run the "queryEntity()" function on "cons!API_Response_test" to retrieve data for the
  * first 50 data store entities and store this in a local variable named
  * "local!entities".
  */
  local!entities: a!queryEntity(
    entity: cons!API_Response_test,
    query: a!query(
      pagingInfo: a!pagingInfo(
        startIndex: 1,
        batchSize: 50
      )
    ),
    fetchTotalCount: true
  ).data,


  a!httpResponse(
    headers: {
      a!httpHeader(
        name: "Content-Disposition",
        value: "attachment; filename=" & char(34) & "testApiResponse" & ".csv" & char(34)
      )
    },

    body: {
      "api_name" & char(10) &
      joinarray(
        /*column name*/
        {a!queryEntity("API_Name")},
        ","
      )
    }
  )
)

Hi Tim, 

Thanks for the response, I've tried to combine the two templates to achieve what I wanted but I'm getting the following error when I call the API: A null parameter has been passed as parameter 2.

I noticed in the CSV templateis uses 'User.firstName' etc. to write to the CSV, however I can't work out how to reference specific columns from my dataset. This is my current code:

with(
  /*
  * Run the "queryEntity()" function on "cons!API_Response_test" to retrieve data for the
  * first 50 data store entities and store this in a local variable named
  * "local!entities".
  */
  local!entities: a!queryEntity(
    entity: cons!API_Response_test,
    query: a!query(
      pagingInfo: a!pagingInfo(
        startIndex: 1,
        batchSize: 50
      )
    ),
    fetchTotalCount: true
  ).data,


  a!httpResponse(
    headers: {
      a!httpHeader(
        name: "Content-Disposition",
        value: "attachment; filename=" & char(34) & "testApiResponse" & ".csv" & char(34)
      )
    },

    body: {
      "api_name" & char(10) &
      joinarray(
        /*column name*/
        {a!queryEntity("API_Name")},
        ","
      )
    }
  )
)

The data from the a!queryEntity is now in your local variable local!entities - assuming this is a standard queryEntity response then you'll have a construct of local!entities.API_Name

This works, thank you Paul!