Is there a way to make a blocking call in Node.Js?

Question

It's few times harder to program using continuations (callbacks) rather than in model of straight sequential execution. Can NodeJs do blocking calls?

Answer 1

Yes, it can. For example you can read a file with fs.readFileSync() rather than fs.readFile(). Each library usually provides a xxxSync method for synchronous/blocking methods.

But you should NOT use the sync method very often. Remember that Node.js uses a single thread of execution for JavaScript code. If you block this thread you block it for everybody (unlike C#/Java where a new thread will be created for each request.)

If the asynch approach is too much for you you might want to use another platform (Ruby, Python, PHP).

Answer 2

Yes, node.js 0.11.x can do blocking calls inside if a generator. By "blocking call" I mean stopping execution of current function for a while. Look at co library.

This is the only recommended way to do blocking calls.

Other than that, you can look at fibers , but it needs to be used carefully, and not in general-purpose libraries.

There are also a couple of *Sync calls mentioned before, but please avoid using them entirely unless you're writing one-liner.