functional-help.js

functional-help.js

console.clear()

const { matchPath } = require('react-router-dom');
const { isNil, trim, flow, identity } = require('lodash');

const patterns = [
  { path: '/' },
  { path: '/new' },
  { path: '/dashboard' },
  { path: '/details/:claimId' },
  { path: '/add-policy/:claimId' },
  { path: '/details/:claimId/documents' },
  { path: '/details/:claimId/claimants' },
  { path: '/details/:claimId/indicators' },
  { path: '/details/:claimId/indicators' },
  { path: '/details/:claimId/case-history' },
  { path: '/details/:claimId/communications' },
  { path: '/edit-policy/:claimId/:policyNumber' },
  { path: '/details/:claimid/claimants/:claimantId' },
];

const urls = [
  '/add-policy/',
  '/add-policy',
  '/add-policy/1',
  '/details/3/indicators',
]

const entitlements = {
  SOME_ROLE: {
    resources: {
      '/details/:id/indicators': ['GET', 'POST', 'DEL'],
      '/add-policy/:claimId': ['*'],
      '/details/:claimId/communications': [],
    },
  }
}

const patternFinder = (path, pattern) => matchPath(path, {
  path: pattern.path,
  exact: true,
  strict: false
})

const slashedUp = (route) => `/${trim(route, '/')}/`
const normalizedRoute = (route) => slashedUp(route).replace(/(?<=\/)(\:.*?)(?=\/)/gm, '*')
const normalizedResources = (resources) => 
  (Object.keys(resources).reduce((previous, current) => ({
    ...previous,
    [normalizedRoute(current)]: resources[current],
  }), {}))

/**
 * What is the best way, here, to get patterns?
 */
const match = index => (index >= 0) ? resources[normalizedRoute(patterns[index].path)] : []

/**
 * What is the best way, here, to get resources?
 */
const AuthZ = flow([
  identity,
  (path) => patterns.findIndex(pattern => !isNil(patternFinder(path, pattern))),
  match,
])

const resources = normalizedResources(entitlements.SOME_ROLE.resources)

for (const url of urls) {
  const methods = AuthZ(url, resources)

  /**
   * Output
   * []
   * []
   * [ '*' ]
   * [ 'GET', 'POST', 'DEL' ]
   */
  console.log(methods)
}

functional-help.v2.js

console.clear()

const { matchPath } = require('react-router-dom');
const { isNil, trim, flow, identity } = require('lodash');

const urls = [
  '/details/3/claimants',
  '/details/3/communications',
]

const patterns = [
  { path: '/' },
  { path: '/new' },
  { path: '/dashboard' },
  { path: '/details/:claimId' },
  { path: '/add-policy/:claimId' },
  { path: '/details/:claimId/documents' },
  { path: '/details/:claimId/claimants' },
  { path: '/details/:claimId/indicators' },
  { path: '/details/:claimId/indicators' },
  { path: '/details/:claimId/case-history' },
  { path: '/details/:claimId/communications' },
  { path: '/edit-policy/:claimId/:policyNumber' },
  { path: '/details/:claimid/claimants/:claimantId' },
];

const entitlements = {
  agent: {
    resources: {
      '/details/:id/indicators': ['GET', 'POST', 'DEL'],
      '/add-policy/:claimId': ['*'], // TODO: This isn't implimented, dunno if it's required yet
      '/details/:claimId/communications': ['GET', 'POST', 'DEL'],
      '/details/:claimId/claimants': ['POST', 'DEL'],
    }
  }
}

const patternFinder = (path, pattern) => matchPath(path, {
  path: pattern.path,
  exact: true,
  strict: false
})

// Remove and add the slashes back. To be, you know, safe.
const slashedUp = (route) => `/${trim(route, '/')}/`

// This replaces all :id (whatever the string is) with *
const normalizedRoute = (route) => slashedUp(route).replace(/(?<=\/)(\:.*?)(?=\/)/gm, '*')

// Go through all the resources and normalize them so that we can compare
const normalizedResources = (resources) => 
  (Object.keys(resources).reduce((previous, current) => ({
    ...previous,
    [normalizedRoute(current)]: resources[current],
  }), {}))

// Find a match against the global resources object.
const isMatched = (resources, patterns) => (index) => (index >= 0) ? resources[normalizedRoute(patterns[index].path)] : []

// Does user have access given the request method? Better with a Maybe.
const hasAccess = (request, methods) =>
  (isNil(methods))
    ? false
    : (request === '*') ? true : methods.includes(request)

/**
 * Get the methods one is allowed to access for a given route
 */
const AuthZ = flow([
  identity,
  (path) => patterns.findIndex(pattern => !isNil(patternFinder(path, pattern))),
  isMatched(normalizedResources(entitlements.agent.resources), patterns),
])

// -----------------------------------------------------------------------------
//                                  IMPURE
// -----------------------------------------------------------------------------
for (const url of urls) {
  const allowed = AuthZ(url)

  console.log(JSON.stringify({
    url,
    matches: allowed,
    allowed: hasAccess('GET', allowed),
  }, null, 2))
  console.log('\n\n--------------------------------------')
}