@abap2ui5/embed-control

@abap2ui5/embed-control

Run abap2UI5 apps inside any UI5 app.

abap2UI5 builds UI5 apps purely in ABAP: an ABAP class implementing z2ui5_if_app decides the view and handles every event. This package puts such an app into your UI5 app as an ordinary control, next to your own controls:

<mvc:View xmlns:mvc="sap.ui.core.mvc" xmlns:z2ui5="z2ui5.embed">
  <z2ui5:Container app="Z2UI5_CL_UI5_APP_HI_WORLD" height="400px"/>
</mvc:View>

The package is the control and nothing else. The abap2UI5 frontend it wraps comes from the abap2UI5 installation the app talks to - so it always has the version of that backend, and your app never carries a copy of it.

Install

npm install @abap2ui5/embed-control

Then two entries in your app. ui5.yaml - so ui5 build copies the control into your app (ui5 serve serves it anyway):

builder:
  settings:
    includeDependency:
      - "@abap2ui5/embed-control"

manifest.json - where the control's namespace lives:

"sap.ui5": {
  "resourceRoots": { "z2ui5.embed": "./thirdparty/z2ui5/embed/" }
}

The build puts it into dist/thirdparty/z2ui5/embed/ and your deployment takes it along like every other file of the app. Not under resources/: an app deployed to an ABAP system answers every <app>/resources/ path from the UI5 library of the system. The relative resource root holds in a standalone page and in the SAP Fiori launchpad alike.

Nothing else is deployed anywhere: the control is a plain module (no component, no library), so no app index entry of an ABAP system is involved, and any number of apps can carry their own copy.

Use

In an XML view, as above, or in code:

sap.ui.require(["z2ui5/embed/Container"], (Container) => {
  new Container({
    app: "ZCL_MY_ABAP2UI5_APP",
    params: { customer: "4711" },
    height: "600px",
  }).placeAt("content");
});

Every control is its own abap2UI5 session - two controls with the same class do not share state. Changing app, endpoint or params ends the running session and starts a new one; restart() does the same with the values as they are; destroying the control ends it too. All three are ordinary properties, so they can be bound to your model - params is compared by value with what the running app was started with, so a binding that hands over the same parameters in a new object does not restart the app, and an endpoint that names the same place in another spelling (a trailing slash, a relative path) does not either.

Both events arrive asynchronously, after the rendering that started the app - a refused endpoint included. A start that failed is not repeated by itself: change one of the three properties, or call restart(). An invisible control (visible="false") starts nothing until it is shown; an app that runs keeps running, with its state, while its control is hidden.

Examples

Complete examples that use the package are in abap2UI5/samples-embed-control, on its branch standard, all taking the package from npm:

• freestyle/ - a UI5 freestyle app with three controls, also as the BSP Z2UI5_HOST to try it on a system with a plain abapGit pull
• fiori-elements/ - a Fiori elements app with the control in a custom section of its object page: the abap2UI5 app gets the key of the object on the page as a parameter
• fiori-elements-v2/ - a Fiori elements app for OData V2 with the control in an object page extension, and the RAP service it reads; on the branch rap, all of it for one abapGit pull on a system with RAP
• card/ - a UI Integration Card for SAP Build Work Zone that runs any abap2UI5 app: the class is a card parameter, the backend a card destination

Its README walks through the places the package is wired in.

Backend

The app runs on an ABAP system with abap2UI5 installed and its HTTP service (by default /sap/bc/z2ui5) active. The control needs abap2UI5 1.145.0 or later, whose service answers ?z2ui5-bundle - in Node that is @abap2ui5/node-runtime 1.145.0, in CAP @cap2ui5/cds-plugin 0.3.1, which runs on it:

GET  /sap/bc/z2ui5?z2ui5-bundle   the frontend as one script - loaded once per page
POST /sap/bc/z2ui5                the roundtrips, one session per control
GET  /sap/bc/z2ui5                abap2UI5's own page, unchanged

An older abap2UI5 answers with its page; the control then fires componentFailed ("no abap2UI5 frontend at ...") instead of starting.

What 1.145.0 does not do yet. abap2UI5 1.146.0 fixes all of these; with 1.145.0 itself plan for them:

• The URL hash is the frontend's. 1.145.0 clears the host's hash with the first roundtrip and after every one: a Fiori elements object page goes back to its list, SAP Build Work Zone leaves the page a card sits on. And a host hash shaped like abap2UI5's own deep link, #/app/<CLASS>, wins over the app property - that class starts instead. A host that routes by the hash - a Fiori elements app, an app with a UI5 router, SAP Build Work Zone - needs 1.146.0 or later, whose frontend knows it is embedded and leaves the hash to your app (abap2UI5 677e71b, #2808).
• No CSRF token handshake. An SAP approuter route checks CSRF tokens by default (cds add approuter generates such a route), and 1.145.0 sends none - every roundtrip is refused with 403 "X-CSRF-Token: Required". Give the route to the service "csrfProtection": false; abap2UI5's own origin check stays in place. 1.146.0 fetches the token on that 403 (abap2UI5 #2802).

Every release is tested against abap2UI5's main and against 1.145.0 (@abap2ui5/node-runtime 1.145.0) - there without what needs the hash. The package records the floor in its package.json (abap2ui5.minBackend), and that is the version the test installs.

The page and the service have to share an origin. abap2UI5 rejects a POST whose Origin names another host than its own (its CSRF defense), and the control loads the frontend only from a path on this server - an endpoint that resolves to another origin is refused, because what comes back is code that runs in your page. So the browser reaches the service through your app's origin:

• deployed - the app is served from the same system (BSP, launchpad), or an approuter / destination routes /sap/bc/z2ui5 to it
• ui5 serve - a proxy middleware forwards /sap to the system, like ui5-middleware-simpleproxy in the examples. It rewrites Host and tells the backend the dev server's host in X-Forwarded-Host, which abap2UI5 compares the browser's Origin with (trusted by default; check_trust_forwarded_host in the user exit)

Content-Security-Policy: the frontend is a <script src> of your own origin, and every module in it is a function - nothing is evaluated from a string. A host with script-src 'self' and no 'unsafe-eval' needs nothing extra (UI5 1.71 itself still needs 'unsafe-eval').

UI5 libraries

The embedded app loads whatever UI5 library its ABAP view names. With the UI5 CLI serving the framework (framework: in ui5.yaml), list every library your ABAP apps use there, not only the ones your own views use - the hello world app, for instance, needs sap.ui.layout - and sap.ui.codeeditor, which abap2UI5's developer tools (Ctrl+F12 in the embedded app) need. A library missing there fails in the browser console with a script load error; an app deployed to a system has every library of that system.

Supported UI5 versions

The same floor as abap2UI5: OpenUI5 / SAPUI5 1.71 and later. The freestyle example is tested on 1.71 and 1.136, the Fiori elements examples for OData V4 and V2 on SAPUI5 1.136, the card on OpenUI5 1.136.

Your app's tooling: UI5 CLI 3 or 4 - the package's ui5.yaml is specVersion 3.0, and every release is built with both.

Known limitations

• One frontend per page: the first control that starts decides which endpoint the frontend comes from; every control still sends its roundtrips to its own endpoint. A control that shared that load with another endpoint of its own, and saw it fail, tries its own endpoint once. A bundle the host loaded itself - a <script src="<endpoint>?z2ui5-bundle"> of its page, to have it warm - is taken as it is, not loaded again.
• The host page's mobile setup, with abap2UI5 1.146.0 and earlier. sap.m.App, the root of the embedded frontend, runs UI5's sap/ui/util/Mobile.init when it is created - once per page, with the settings of whoever calls it first. On a host page without a sap.m.App of its own that puts height: 100% on <html>, adds a viewport meta tag that disables zooming and a format-detection meta tag, and on iOS turns native scrolling off (position: fixed on <html>) and hides the browser's UI. abap2UI5 1.147.0 makes that call first, with everything off, so the host keeps its page; what stays on a phone or tablet is the web-app-capable meta tag sap.m.App sets on every rendering. From 1.147.0 on the root of an embedded app is a sap.m.NavContainer, which sets none of it; with ownsPage the root is the sap.m.App again, as on a page of the app's own. A host with a sap.m.App of its own is not affected on any release.
• Custom controls from the sibling BSPs z2ui5_cci / z2ui5_ccc (abap2UI5-addons/custom-controls, the customer's own library) behind a proxy that puts the system under a prefix of its own - SAP Build Work Zone's destination proxy, an approuter route with a prefix - need abap2UI5 1.147.0. Until then the bundle names their paths as the system has them, /sap/bc/ui5_ui5/sap/z2ui5_cci, which the host's origin does not have; from then on its bundle names the node it was requested under, and the frontend puts the prefix of the control's endpoint in front of the roots. Nothing in the control changes with it.
• abap2UI5 was built to own the whole page. Its embedded mode leaves the URL to your app (from 1.146.0 on) - unless ownsHash hands the hash back (from 1.147.0 on) - and, from 1.147.0 on as well, the document title, the favicon, the busy indicator and the "leave page?" prompt as well, unless ownsPage hands the page back; before that an embedded app shows the global busy indicator during a roundtrip and may set the document title and favicon when the ABAP app asks for it. The rest is still to come (backlog item). Up to 1.146.0 an embedded app renders its root as sap.m.App, the full-screen root: the theme's background of its own, and a height of 100% on every ancestor up to the control's area. From 1.147.0 on it is a sap.m.NavContainer that only fills the area, unless ownsPage hands the page back. Before 1.146.0 the app also takes the focus when it starts, from wherever it is in your app - the root focuses the first field of its first page, and the ABAP app may set the focus as well.
• Page-wide behaviour of the embedded frontend. Its error dialog's "Restart" - and "Refresh" on its fatal error screen - reloads the whole page, your app included. Its developer tools wrap the window.console methods while an app runs (the browser console keeps working; its source links point to the wrapper) and listen for Ctrl+F12 on the document.
• Keep-alive. The embedded app's component belongs to your app's component, the owner of the control, and the abap2UI5 frontend does not support keep-alive: an app that declares it (sap.ui5/keepAlive, UI5 1.88+) reports no keep-alive support while it has an embedded app, as UI5 does for every nested component without it.

What is inside

License

MIT