`@sap-ux/preview-middleware`

The @sap-ux/preview-middleware is a Custom UI5 Server Middleware for previewing an application in a local Fiori launchpad . It can be used either with the ui5 serve or the fiori run commands. It hosts a local Fiori launchpad based on your configuration as well as offers an API to modify flex changes in your project. The API is available at /preview/api and additional client code required for the preview is available at /preview/client.

When this middleware is used together with the reload-middleware, then the order in which the middlewares are loaded is important. The reload-middleware needs to be loaded before the preview-middleware. Hence the configuration in the ui5.yaml needs to look e.g. like this:

- name: reload-middleware
  afterMiddleware: compression
- name: preview-middleware
  afterMiddleware: reload-middleware

Configuration Options

Option	Type	Default Value	Description
`flp`			Optional configuration object for the local Fiori launchpad
`flp.path`	`string`	`/test/flp.html`	The mount point of the local Fiori launchpad.
`flp.init`	`string`	`undefined`	Optional UI5 module/script to be executed after the standard initialization
`flp.intent`			Optional intent to be used for the application
`flp.intent.object`	`string`	`app`	Optional intent object
`flp.intent.action`	`string`	`preview`	Optional intent action
`flp.apps`	`array`	`undefined`	Optional additional local apps that are available in local Fiori launchpad
`flp.libs`	`boolean`	`undefined`	Optional flag to add a generic script fetching the paths of used libraries not available in UI5. To disable set it to `false`, if not set, then the project is checked for a `load-reuse-libs` script and if available the libraries are fetched as well.
`flp.theme`	`string`	`undefined`	Optional flag for setting the UI5 Theme.
`adp.target`			Required configuration for adaptation projects defining the connected backend
`adp.ignoreCertErrors`	`boolean`	`false`	Optional setting to ignore certification validation errors when working with e.g. development systems with self signed certificates
`rta`			Optional configuration allowing to add mount points for runtime adaptation
`rta.layer`	`string`	`(calculated)`	Optional property for defining the runtime adaptation layer for changes (default is `CUSTOMER_BASE` or read from the project for adaptation projects)
`rta.editors`	`array`	`undefined`	Optional list of mount points for editing
`test`	`array`	`undefined`	Optional list of configurations for automated testing.
`debug`	`boolean`	`false`	Enables debug output

`flp.apps`

Array of additional application configurations:

Option	Type	Default Value	Description
`target`	`string`		Target path of the additional application
`local` or `componentId`	`string`		Either a local path to a folder containing the application or the `componentId` of a remote app is required
`intent`			Optional intent to be used for the application
`intent.object`	`string`	`(calculated)`	Optional intent object, if it is not provided then it will be calculated based on the application id
`intent.action`	`string`	`preview`	Optional intent action

`adp.target`

Option	Type	Description
`url`	`string` mandatory (local)	Mandatory URL pointing to the backend system. *Not required if destination is provided and the proxy is running SAP Business Application Studio
`destination`	`string` mandatory (if no url)	Required if the backend system is available as destination in SAP Business Application Studio.
`client`	`string` optional	sap-client parameter
`scp`	`boolean` optional	If set to true the proxy will execute the required OAuth routine for the ABAP environment on SAP BTP

`rta.editors`

Option	Type	Description
`path`	`string` mandatory	The mount point to be used for the editor.
`developerMode`	`boolean` optional	Enables/disables the runtime adaptation developer mode (only supported for adaptation projects)

`test`

Option	Type	Description
`framework`	`string` mandatory	Currently `OPA5`, `QUnit` (only QUnit 2.3.2 provided as third-party module via OpenUI5/SAPUI5) and `Testsuite` are supported. `Testsuite` will generate a testsuite for all configured frameworks that can be be used with a test runner (like e.g. karma)
`path`	`string` optional	The mount point to be used for test suite. By default `/test/opaTests.qunit.html` is used for `OPA5`, `/test/unitTests.qunit.html` is used for `QUnit` and `/test/testsuite.qunit.html` is used for `Testsuite`
`init`	`string` optional	The mount point to be used for custom test runner script
`pattern`	`string` optional	Optional glob pattern to find the tests. By default `/test/*/Journey.` is used for `OPA5` and `/test//Test.*` is used for `QUnit` (n.a. for `Testsuite`)

Usage

The middleware can be used without configuration. However, since the middleware intercepts a few requests that might otherwise be handled by a different middleware, it is strongly recommended to run other file serving middlewares after the preview-middleware e.g. backend-proxy-middleware and ui5-proxy-middleware (and the corresponding middlewares in the @sap/ux-ui5-tooling). Example: ./test/fixtures/simple-app/ui5.yaml

Minimal Configuration

With no configuration provided, the local FLP will be available at /test/flp.html and the log level is info.

server:
  customMiddleware:
  - name: preview-middleware
    afterMiddleware: compression

Different Path and Debugging enabled

With this configuration, the local FLP will be available at /test/myFLP.html and the log level is debug.

server:
  customMiddleware:
  - name: preview-middleware
    afterMiddleware: compression
    configuration:
      flp: 
        path: /test/myFLP.html
      debug: true

Additional Applications

If you want to test cross application navigation, then you can add additional applications into the local FLP. With this configuration, an application that is locally available in ../local-folder will be available at /apps/other-app and will also be added as tile to the local FLP as well as one of the UI5 sample apps will be bound to the intent TheOther-preview.

server:
  customMiddleware:
  - name: preview-middleware
    afterMiddleware: compression
    configuration:
      apps:
        - target: /apps/other-app
          local: ../local-folder
          intent: 
            object: TheLocal
            action: preview
        - target: /test-resources/sap/ushell/demoapps/AppNavSample
          componentId: sap.ushell.demo.AppNavSample
          intent: 
            object: TheOther
            action: preview

Runtime Adaptation Support

If you want to create variants as part of your application, then you can create an additional mount point allowing to create and edit variants.

server:
  customMiddleware:
  - name: preview-middleware
    afterMiddleware: compression
    configuration:
      rta:
        layer: CUSTOMER_BASE
        editors:
          - path: /test/variant-editor.html

This mount path can be used with a run script that looks as follows.

"start-variants-management": "ui5 serve --open \"test/variant-editor.html.html#app-preview\""

Test Suites

If you want to also generate generic test suites and test runners for QUnit or OPA5 tests then you can use the following minimum configurations

server:
  customMiddleware:
  - name: preview-middleware
    afterMiddleware: compression
    configuration:
      test:
        - framework: Testsuite
        - framework: QUnit
        - framework: OPA5

Adaptation Project

If you want to use the middleware in an adaption project, the additional adp object needs to be configured. This example would preview a local adaptation project merged with its reference application from the target system at http://sap.example and it will ignore certification validation errors. For adaptation projects, it is also recommended to add the rta configuration allowing to edit the project.

server:
  customMiddleware:
  - name: preview-middleware
    afterMiddleware: compression
    configuration:
      adp: 
        target: 
          url: http://sap.example
        ignoreCertErrors: true
      rta:
        editors:
          - path: /test/adaptation-editor.html
            developerMode: true

When the middleware is used in an adaptation project together with a middleware proxying requests to the backend e.g. the backend-proxy-middleware, then it is critically important that the preview-middleware is handling requests before the backend proxy because it intercepts requests to the manifest.json of the original application and merges it with the local variant.

- name: preview-middleware
  afterMiddleware: rcompression
- name: backend-proxy-middleware
  afterMiddleware: preview-middleware

Programmatic Usage

Alternatively you can use the underlying middleware fuction programmatically, e.g. for the case when you want to incorporate the preview-middleware functionality in your own middleware.

import { FlpSandbox } from '@sap-ux/preview-middleware';
const flp = new FlpSandbox(flpConfig, rootProject, middlewareUtil, logger);
const files = await resources.rootProject.byGlob('/manifest.json');
flp.init(JSON.parse(await files[0].getString()));

return flp.router

flpConfig - the middleware configuration
rootProject - Reader to access the resources of the root project
middlewareUtil - MiddlewareUtil of the UI5 server
logger - Logger instance to be used in the middleware.

Migration

If you have no custom modifications in the local Fiori Launchpad sandbox files (webapp/test/flpSandbox.html or webapp/test/flpSandboxMockserver.html), the conversion is finished.

If you have custom modifications in the local Fiori Launchpad sandbox files, you need to migrate them into a custom .js or .ts file (depending on your setup) and integrate this file as a custom init script into the configuration options of the middleware.

Sample:

from custom modification in flpSandbox.html:

<script type="text/javascript">
    sap.ui.getCore().attachInit(function () {
        console.log('my custom code');
    });
</script>

to custom test/init.ts:

console.log('my custom code');

integrated via ui5.yaml:

server:
  customMiddleware:
  - name: preview-middleware
    afterMiddleware: compression
    configuration:
      flp:
        init: /test/init # <-- path to your custom init script