[Docs] Calling other APIs Page

[virkt25]

Description / Steps to reproduce / Feature proposal

As I was working on loopbackio/loopback4-example-shopping#20 I was referencing our docs https://loopback.io/doc/en/lb4/Calling-other-APIs-and-web-services.html and I found it to be a bit confusing ...

• Creating the datasource using lb4 datasource prompts for a baseUrl which is not respected by loopback-connector-rest.
• The Service Interface section was confusing -- we should aim for 1 section showing a weakly typed example first and then an alternative stongly typed example.
• @serviceProxy decorator usage doesn't explain what it takes in -- is the string the name of the datasource (what I got from code), name of service, etc. and how is it determined by the booter?
• Get an instance of your controller section is at a really weird place and confusing. What's the intent of this section?
• Under Make service proxies easier to test, the code should be reviewed. For example, the following is wrong. -- we are initializing the service instead of letting DI do it. This entire section seems a bit incomplete to me.

@inject('datasources.geoService')
    protected datasource: juggler.DataSource = new GeocoderDataSource(),

Current Behavior

Expected Behavior

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[marioestradarosa]

I think this section should be updated. Considering that now we have a basic lb4 service CLI option.

[dhmlau]

#2128 and #1766 are about the same docs page. @nabdelgadir , could you please take a look and see if there are duplicate requirements and whether we can close one and continue the discussion on one of them? Thanks.

[dhmlau]

From what @nabdelgadir described:
#1766 - about fixing/updating the existing content
#2128 - about adding new content for calling other REST APIs.

[dhmlau]

Looking at the content in https://loopback.io/doc/en/lb4/Calling-other-APIs-and-web-services.html, it seems to be that we no longer need to install the service-proxy directly?

I'm thinking that we should rewrite this page as below:

• goal is to call other REST/SOAP API

  • there are lots of REST APIs out there, we can pick one, say https://swapi.co/
  • If we want to stick with SOAP, perhaps we can use the one that @raymondfeng created and deployed.

• the steps would be:

1. scaffold an LB4 app
2. add datasource using lb4 datasource command. Select REST / SOAP connector depends what is decided
3. add a service using lb4 service command.
4. add controller

@strongloop/loopback-maintainers, what do you think?