In web browser, I want to compute sha1 checksum of a huge file in the local filesystem without sending it to a server.
File API supports to read files from local disk but I guess it reads the entire of the file and put all of them into the memory. It may occur a problem if the file is larger than system memory.
Streams API seems to be useful to solve this problem but I couldn't find how to read a file using the API.
The file api provides a slice method, so you should be able to read chunks of data
var blob = file.slice(startingByte, endindByte);
The Sha1 class in google's crypto api provides a update method, you should be able to feed the update method with your chunks