Maintaining request scope in Express/Node.js

Question

I am using Express to expose a REST API in my Node.js application. When a REST request comes in, I extract the user information from the HTTP headers. I would like this information to be available throughout the life of this request, no matter what function I am in. An obvious but kludgy way is to pass around the user information as parameters to all function calls. Is there a better way? So far I have found the following solutions, but I am not sure if they are ready for prime time:

StrongLoop Zone Library: Docs say "The zone library and documentation are still under development: there are bugs, missing features, and limited documentation."
Continuation-Local Storage: Not sure if this is slated to be part of Node.js. This issue at the end recommends looking at StrongLoop zone.
Node.js Domains: Does not look like this actually took off.

So you're looking for "requestable context"? So that whenever you need context that wasn't passed in directly, you can request it somehow? — Amit, Jul 31 '15 at 13:07
You can attach variables to `req` directly.Try adding the line `req.myObject = { color: "red" }` — prototype, Jul 31 '15 at 13:45
Well, in that case I will need to pass `req` around to all layers of the app, which is exactly what I am trying to avoid. — Naresh, Jul 31 '15 at 14:53

score 4 · Accepted Answer · answered Mar 10 '18 at 22:18

4

I'm not sure if you're still looking, but a while back I built express-http-context for this very purpose. It's an express middleware that sits on top of cls-hooks (formerly continuation-local-storage).

Full disclosure: this is an npm package that I built and maintain.

answered Mar 10 '18 at 22:18

Steve Konves

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Thanks, Steve. I am no longer looking for this solution, but I will keep express-http-context in mind. – Naresh Mar 10 '18 at 22:44

Maintaining request scope in Express/Node.js

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