hmpps-probation-frontend-components

hmpps-probation-frontend-components is a Node.js client library to simplify the process of incorporating global components within PDS applications. We welcome feedback on this Slack channel here in order to improve it.

Contents

1. Using the library
2. For library developers

Using the library

Prerequisites

The package assumes adherance to the standard hmpps-template-typescript project. It requires:

• a user object to be available on res.locals containing a token and displayName.
• nunjucks to be setup
• the environment variable COMPONENT_API_URL to be set for each environment
• the environment variables AUTH_CODE_CLIENT_ID and AUTH_CODE_CLIENT_SECRET to be set to allow authenticating with the dev environment locally
• the environment variable HMPPS_AUTH_URL to be set to https://sign-in-dev.hmpps.service.justice.gov.uk/auth to authenticate with the dev environment locally
• to be run AFTER helmet middleware

Installation

To install the package, run the following command:

npm install @ministryofjustice/hmpps-probation-frontend-components

Usage

Add environment variables to the helm_deploy/values-{env}.yaml files for COMPONENT_API_URL. Populate with the following values:

dev - https://probation-frontend-components-dev.hmpps.service.justice.gov.uk

preprod - https://probation-frontend-components-preprod.hmpps.service.justice.gov.uk

prod - https://probation-frontend-components.hmpps.service.justice.gov.uk

You can also add this to your .env or docker-compose files with the dev url, as follows:

- COMPONENT_API_URL=https://probation-frontend-components-dev.hmpps.service.justice.gov.uk

Add a block for the component library in the apis section of server/config.ts, for example:

probationApi: {
  url: get('COMPONENT_API_URL', 'https://probation-frontend-components-dev.hmpps.service.justice.gov.uk', requiredInProduction),
  healthPath: '/health/ping'
}

Currently, the package provides the header and the footer component.

To incorporate use the middleware for appropriate routes within your Express application (after the setUpCurrentUser middleware):

    import pdsComponents from '@ministryofjustice/hmpps-probation-frontend-components'

    ...

    app.use(pdsComponents.getPageComponents({
      pdsUrl: config.apis.probationApi.url,
      logger,
    }))

However, please 🙏 consider carefully whether you need the components for EVERY request.

It may be sufficient for you app to only request components for GET requests for example, in which case

    app.get('*', pdsComponents.getPageComponents({
      pdsUrl: config.apis.probationApi.url,
      logger,
    })
  )

Add the hmpps-probation-frontend-components path to the nunjucksSetup.ts file to enable css to be loaded:

    const njkEnv = nunjucks.configure(
  [
    path.join(__dirname, '../../server/views'),
    'node_modules/govuk-frontend/dist/',
    'node_modules/govuk-frontend/dist/components/',
    'node_modules/@ministryofjustice/frontend/',
    'node_modules/@ministryofjustice/frontend/moj/components/',
    'node_modules/@ministryofjustice/hmpps-probation-frontend-components/dist/assets/',
  ],
  {
    autoescape: true,
    express: app,
  },
)

Include the package scss within the index.scss file

  @import 'node_modules/@ministryofjustice/hmpps-probation-frontend-components/dist/assets/footer';
  @import 'node_modules/@ministryofjustice/hmpps-probation-frontend-components/dist/assets/header';

Include reference to the components in your layout.njk file:

{% for js in feComponents.jsIncludes %}
    <script src="{{ js }}" nonce="{{ cspNonce }}"></script>
{% endfor %}

{% for css in feComponents.cssIncludes %}
    <link href="{{ css }}" nonce="{{ cspNonce }}" rel="stylesheet" />
{% endfor %}

{% block header %}
  {{ feComponents.header | safe }}
{% endblock %}

{% block footer %}
    {{ feComponents.footer | safe }}
{% endblock %}

Extra calls

It may be that you need to add some extra requests for the page components for pages that do not fit the normal flow of routes. e.g. in setUpAuthentication.ts on the /autherror path:

     router.get(
      '/autherror',
      pdsComponents.getPageComponents({ pdsUrl: config.serviceUrls.digitalProbation }),
      (req, res) => {
        res.status(401)
        return res.render('autherror')
      },
  )

This will provide a stripped down header if there is no user object on res.locals.

CSP

The package updates the content-security-middleware to include references to the fe-components API. This package should be run after Helmet to prevent this being overwritten.

Note

In the event of a failure to retrieve the components, the package will populate the html fields with fallback components.

For library developers:

1. Publishing to NPM