NPM SOAP package - client as singleton?

Question

I'm using this npm package: https://www.npmjs.com/package/soap

I could not find an answer in the documentation, as I'm wondering if the best practice for SOAP client is to create a single client as startup and use for all requests (similar to database client), or create a new one per request.

Answer 1

It depends on your use case and application requirements.

After reading up on the code of the node-soap, the following happens when createClient() is called:

• createClient(url, options, cb) internally creates a wsdl handler for the particular url in question (wsdl.open_wsdl())
• the wsdl handler is cached with the url as key (unless options.disableCache is true)
• createClient() calls back with Client() which wraps the wsdl handler

So, unless your url changes, it should be ok for you to use it as a singleton, since there's no need to run the setup code for wsdl yet again.

If your url changes (or if you aren't sure if it changes), use createClient() for each call. The wsdl setup will still be cached, so there's no overhead for you in this case (except for the first time the wsdl is created).