ns-limp
by H.Qasim Ali | v6.1.0-dev
Nativescript SDK for LIMP
npm i --save ns-limp
  • Version: 6.1.0-dev
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ns-limp

Official NativeScript Angular SDK for LIMP.

Quick Start

The current SDK has two dependencies:

  • jsrasgin
  • nativescript-websockets The dependencies should be automatically installed with the library.

Install ns-limp for NativeScript

tns plugin add ns-limp

How to Use

  1. Initiate the API, in your component, using :
import { Component, OnInit } from '@angular/core';

import { ApiService, Res } from 'ns-limp/api.service';

@Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css']
})
export class AppComponent implements OnInit {

constructor(private api: ApiService) {}

ngOnInit() {
this.api.init({
api: 'ws://localhost:8081/ws',
anonToken: '__ANON',
authAttrs: ['email']
});
}
}

SDK Config

When initialising the SDK, you should pass an object matching the interface SDKConfig, which has the following attributes:

  1. api (Required): The URI of LIMP app you are connecting to.
  2. anonToken (Required): LIMP app ANON_TOKEN.
  3. authAttrs (Required): As of LIMP APIv5.8, LIMP apps don't have strict User module attrs structure. This includes the authentication attrs that are set per app. This attribute represents an Array<string> referring to the same authentication attrs of the app.
  4. debug (Optional): A Boolean representing the debug mode status on the SDK. If true, you would see verbose messages in the browser console about messages transferred are received. Default false.
  5. fileChunkSize (Optional): A Number representing the chunk size in bytes of the files being uploaded as part of the process of pushing binary data to LIMP app. Default 512000.
  6. authHashLevel (Optional): Either 5.0 or 5.6. With the change to auth hash generation introduced in APIv5.6 of LIMP, some legacy apps are left without the ability to upgrade to APIv5.6 and beyond due to hashes difference. SDKv5.7 is adding authHashLevel to allow developers to use higher APIs and SDKs with legacy apps. Default 5.6;

Best Practices

You can use the SDK 100% per your style of development, however we have some tips:

Session Reauth

The best practice to handle a reauth scenario is by attempting to checkAuth as soon as the connection with LIMP app is made. This can be made by subscribing to inited$ subject which notifies subscriptions about any changes to SDK initialisation status reflected as inited attribute in the SDK. Which can be done like:

this.api.inited$.subscribe((init: boolean) => {
if (init) {
// SDK is inited and ready for your calls:
try {
// Wrap in try..catch to handle error thrown if no credentials cached
this.api.checkAuth();
} catch { }
}
}, (err: Res<Doc>) => {
console.log('inited$.err', err);
});

Auth State Detection

Although, you can detect the user auth state in the subscription of the calls auth, reauth and checkAuth, the best practice is to use the global authed$ state Subject. You can do this by subscripting to authed$ in the same component (usually AppComponent) you are initiating the SDK at. This assures a successful checkAuth as part of the api.init subscription can be handled. The model suggested is:

this.api.authed$.subscribe((session: Doc) => {
if (session) {
console.log('We are having an `auth` condition with session:', session);
} else {
console.log('We just got unauthenticated');
}
});

Reconnecting on Disconnects

Websockets are always-alive connections. A lot can go wrong here resulting in the connection with your LIMP app. To make sure you can always get reconnected recall SDK init method upon SDK becoming not inited:

import { Component, OnInit } from '@angular/core';

import { ApiService, Res } from 'ns-limp/api.service';

@Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css']
})
export class AppComponent implements OnInit {

constructor(private api: ApiService) {
this.api.inited$.subscribe((init: boolean) => {
if (init) {
// SDK is inited and ready for your calls:
try {
// Wrap in try..catch to handle error thrown if no credentials cached
this.api.checkAuth();
} catch { }
} else {
// SDK just got not inited, let's init SDK again:
this.init();
}
}, (err: Res<Doc>) => {
console.log('
inited$.err', err);
});
}

ngOnInit() {
this.init();
}

init(): void {
this.api.init({
api: '
ws://localhost:8081/ws',
anonToken: '
__ANON',
authAttrs: ['
email']
});
}
}

API Reference

debug

A Boolean representing the debug mode status on the SDK. If true, you would see verbose messages in the browser console about messages transferred are received. Default false.

fileChunkSize

A Number representing the chunk size in bytes of the files being uploaded as part of the process of pushing binary data to LIMP app. Default 512000.

session

A Doc object representing the current session. It has value only when the user is authenticated.

authed

A Boolean storing the current state of user authentication.

authed$

A Subject<Boolean | Doc> you can subscribe to handle changes to state of user authentication.

init()

The base method to initiate a connection with LIMP app. This method returns an Observable for chain subscription if for any reason you need to read every message being received from the API, however subscribing to it is not required. Method definition:

init(api: String, anonToken: String): Observable<Res<Doc>> { /*...*/ }

close()

The method to close current connection with LIMP app. This method returns an Observable for chain subscription if for any reason you need to read the resposne of the close call, however subscribing to it is not required. Method definition:

close(): Observable<Res<Doc>> { /*...*/ }

auth()

The method you can use to authenticate the user. This method returns an Observable for chain subscription if for any reason you need to read the response of the auth call, however subscribing to it is not required. Method definition:

auth(authVar: string, authVal: string, password: string): Observable<Res<Doc>> { /*...*/ }

reauth()

The method you can use to reauthenticate the user. The method would fail if no sid and token attrs are cached from earlier successful authentication call. This method is not supposed to be called directly, rather use checkAuth(). This method returns an Observable for chain subscription if for any reason you need the response of the reauth call, however subscribing to it is not required. Method definition:

reauth(sid: string = this.cache.get('sid'), token: string = this.cache.get('token')): Observable<Res<Doc>> { /*...*/ }

signout()

The method you can use to signout the current user. Upon success, this methods removes all the cached attrs of the session. This method returns an Observable for chain subscription if for any reason you need the response of the signout call, however subscribing to it is not required. Method definition:

signout(): Observable<Res<Doc>> { /*...*/ }

checkAuth()

The method to check whether there is a cached session and attempt to reauthenticate the user. This method would throw an error if no credentials are cached, thus you need to always wrap it in try..catch. This method returns an Observable for chain subscription if for any reason you need the response of the checkAuth call, however subscribing to it is not required. Method definition:

checkAuth(): Observable<Res<Doc>> { /*...*/ }

generateAuthHash()

The method to use to generate authentication hashes. This is used internally for the auth() call. However, you also need this to generate the values when creating a user. Method definition:

generateAuthHash(authVar: string, authVal: string, password: string): string { /*...*/ }

deleteWatch()

The method to delete a watch in progress. You can pass the watch ID you want to delete or __all to delete all watches. This method returns an Observable for chain subscription if for any reason you need the response of the deleteWatch call, however subscribing to it is not required. Method definition:

deleteWatch(watch: string | '__all'): Observable<Res<Doc>> { /*...*/ }

call()

The most important method in the SDK. This is the method you use to call different endpoints in your LIMP app. Although the callArgs object in the params is having full definition of all call attrs, you still usually only need to pass either query and/or doc in most of the cases. Third param awaitAuth specify wheter the call should be queued until session is authed. Method definition:

call(endpoint: string, callArgs: callArgs, awaitAuth: boolean = false): Observable<Res<Doc>> { /*...*/ }

Contribution Guidelines

Thank you for your interest in ns-limp.

Please refer to Contribution Guidelines for more details on contributing to this project.