Is it possible, when exporting a Google Spreadsheet into a CSV, to apply this operation only to filtered set of rows?
I need to get in CSV exactly the rows which are visible on the sheet after a filter is applied to it.
Open a Gdocs spreadsheet, look at the menu item: 'Tools::Script Gallery', do a search for csv, and you'll find a script that takes an arbitrary named range, converts it to to csv and emails the result to you. I can't vouch for the script at all, but it seems to work.
If you look at it in the Gdocs Script Editor, you can see that it builds a CSV by actually parsing the spreadsheet data rather than using an internal export function, so it may not work perfectly for all cases. If it doesn't do what you want out of the box, it looks like this would be pretty easy to modify. I haven't tried it on filtered data, but it gets its data from a call to 'SpreadsheetApp.getActiveSpreadsheet()' which has a '.getActiveSelection()' method, so you might be able to bypass the whole named range thing.