@aofl/resource-enumerate

Resource enumerate is a special case API call that returns the interface of the API code in a single endpoint. The response can contain server time, paths to resources, and other information based on application needs. An advantage of this technique is that it eliminates the need to hardcode paths/urls.

@aofl/resource-enumerate accepts a config object that defines the path to the production api server.

It also supports before() and after() hooks. See example below.

Api Documentation

Installation

``bash
npm i -S @aofl/resource-enumerate
`

Usage

`javascript
const resourceEnumerateConfig = {
apis: {
'awesome-apis': { // api namespace
url: '/apis/v1.0/resource-enumerate.json', // production url
requestOptions: { // options passed into fetch
method: 'GET',
cache: 'no-cache'
},
developmentVariables() { // return an object that is passed into the develpomentConfig function
return {
host: location.host
};
},
stageVariables() { // return an object that is passed into the stageConfig function
return {
host: location.host
};
},
invalidateCache() { // This function is invoked before each get() call and it controls whether or not a cached version is returned
return false;
}
}
},
developmentConfig: () => import('./dev-api-config'), // lazy-load dev config
stageConfig: () => import('./stage-api-config') // lazy-load stage config
};

export default resourceEnumerateConfig;
`

[development|stage]Config() export a function that takes api namespace and the returned object from [development|stage]Variables() and returns the path to the environment specific resource enumerate api call.

`javascript
// dev-api-config.js
export default (apiNs, {host}) => {
return //${host}/apis/dev/v1.0/resource-enumerate.json;
};
`

`javascript
// stage-api-config.js
export default (apiNs, {host}) => {
return //${host}/apis/stage/v1.0/resource-enumerate.json;
};
`

`javascript
import {ResourceEnumerate} from '@aofl/resource-enumerate';
import resourceEnumerateConfig from './__config/resource-enumerate-config';
import apiRequestInstance from 'apiRequestInstanceFile :)'; // see @aofl/api-request
import {getServerEnvironment} from '@aofl/server-environment';


const developmentRegex = /localhost|192\.168\.[\d|\.]+|172\.(1[6-9]|2[0-9]|3[01])\.[\d|\.]+|10\.([0-9]|[1-8][0-9]|9[0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.[\d|\.]+/; // localhost or all private ips
const stageRegex = /^stage\./; // match url starting with "stage."

const environment = getServerEnvironment(developmentRegex, stageRegex);
const resourceEnumerate = new ResourceEnumerate(environment);
const serverTime = {};

resourceEnumerate.before((request, response, next) => {
serverTime[request.namespace] = {
before: Date.now() // record time right before api call
};
next(response);
});

resourceEnumerate.after((request, response, next) => {
serverTime[request.namespace].after = Date.now(); // record end time immediately after the response comes back
serverTime[request.namespace].delta = response.serverTime - Math.round(
(servertime[request.namespace].before + servertime[request.namespace].after) / 2); // aproximate difference between server and local client time

next(response);
});

// making api call
resourceEnumerate.init(resourceEnumerateConfig)
.then(() => {
resourceEnumerate.get('awesome-apis')
.then((resourceEnumeratePayload) => {
apiRequestInstance
.request(resourceEnumeratePayload.api_url + resourceEnumeratePayload.endpoints.getPosts)
.then((response) => {
// do something with response
});
});
});
`

Caching


Calling get() will cache the api response by default. There are 2 ways to invalidate cache and fetch a new copy of the resource enumerate data.

1. By calling get() and passing false as the second argument (fromCache).
1. By implementing invalidateCache() in the config object. This function is invoked everytime get() is invoked and will return the cached data if it evaluates to false.

`javascript
...
'awesome-apis': {
url: '/apis/v1.0/resource-enumerate.json'
invalidateCache() { // add invalidateCache function
return Math.random() > 0.8;
}
}
...
``