When uploading big file (>100M) to server, PHP always accept entire data POST from browser first. We cannot inject into the process of uploading.
For example, check
It sounds like you're trying to stream the upload and need to validate before processing: Does this help? http://debuggable.com/posts/streaming-file-uploads-with-node-js:4ac094b2-b6c8-4a7f-bd07-28accbdd56cb
http://www.componentix.com/blog/13/file-uploads-using-nodejs-once-again