I have read this question but it doesn't exactly answer my question.
Unfortunately, it looks like things have changed in in the XHR object since I last looked at AJAX, so it is no longer possible to directly access responseText before it is finished being populated.
I have to write a page that uses AJAX (preferably jQuery, but I am open to suggestions) to retrieve CSV data via HTTP from a server I have no control over. The response data could be quite large; a megabyte of text is not uncommon.
The server is stream-friendly. Is there still any way to get access to a stream of data as it is being returned, directly from JavaScript?
I do have the option of writing some PHP code that lives in the middle and uses some sort of "Comet" tech (long-polling, EventSource, etc), but I would prefer to avoid that if possible.
In case it is relevant, assume for this question that users have the latest version of Firefox/Chrome/Opera and old browser compatibility is not an issue.
You're going to want to use straight up javascript for this. The reason is that you're going to want to continuously poll and not wait for the callbacks to fire. You don't need jQuery for this, it's pretty simple. They have some nice source code for this on the Ajax Patterns website.
Essentially, you'll just want to keep track of your last position in the response and periodically poll for more text past that location. The difference in your case is that you can subscribe to the complete event and stop your polling.