Problem Downloading File With Curl

I am using Curl to get json data, that works well.

I have a need to download a file using Curl. The API requires me to do a GET and pass an ID for the document.

I am uncertain how to deal with the file stream.

At the command line I do a redirect to create the file.

curl -X GET '' > foo.csv

Any suggestions how to deal with the stream? Based on what I understand of the curl function, I believe I want to use

curl -o foo.csv -X GET '' 

In Yii I am doing this:

 $jsonObject = Yii::app()->curl->setOption(CURLOPT_HTTPHEADER=>$auth)->get($report_url);

The extension is great, but not sure it handles this situation or if I need to extend it.

Any help is very appreciated !