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Tag: SAP

CAP

[CAP] Get subdomain in a multitenant scenario

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Until recently, I was always decoded the JWT to get the subdomain of a subscribed tenant like this:

const jwt = retrieveJwt(req)
const subdomain = decodeJwt(jwt).ext_attr.zdn

I now noticed that you can also use the original request object and the getSubdomain function of the authInfo object. It’s provided by @sap/xssec and is only available when using XSUAA, means not with mocked authentication. This way you can get the subdomain in a single line:

const subdomain = req.http.req.authInfo.getSubdomain()

And there are some more helpful functions, that are documented here:

CAP

[CAP] Get service and approuter URLs of your running CAP application in a service handler

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In your mta.yaml you can define environment variables, which are filled during deployment. They can be filled with MTA Development and Deployment Parameters. Click here for an overview.

To get the URL of your deployed CAP service, simply use the ${default-url} parameter and pass the value to a variable below the properties attribute, e.g. SRV_URL. The approuter has to provide its default-url, which can then be used in the service for a variable, e.g. APPROUTER_URL.

  #####################################################################################################################
  # Approuter
  #####################################################################################################################
  - name: approuter
    type: approuter.nodejs
    path: app/approuter
    provides: 
      - name: app-api 
        properties:
          app-url: ${default-url}   # <---------------------------- provides approuter url
          app-uri: ${default-uri}   # <---------------------------- provides approuter uri/hostname
          app-protocol: ${protocol} # <---------------------------- provides approuter protocol

  #####################################################################################################################
  # Business Service Module
  #####################################################################################################################
  - name: mySrv
    type: nodejs
    path: gen/srv
    requires:
      - name: app-api # <---------------------------------------- required to access the provided variables of the approuter
    properties:
      SRV_URL: ${default-url}
      APPROUTER_URL: ~{app-api/app-url}
      SUBSCRIPTION_URL: ~{app-api/app-protocol}://\${tenant_subdomain}-~{app-api/app-uri}

After deployment, you can now access the URL via process.env.SRV_URL in a service handler. During development, simply use the .env file to provide the SRV_URL value.

You can check all the variables via the BTP Cockpit: Subaccount → Space → Select application → User-Provided Variables

Fiori / SAPUI5

[SAPUI5] Add your own Logout functionality to the Launchpad Sandbox

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Use the attachLogoutEvent of the ushell container to trigger your approuter logout endpoint, that needs to be configured in your xs-app.json. The code in my launchpad.html looks like this:

    <script>
        sap.ui.getCore().attachInit(() => {

            sap.ushell.Container.createRenderer('fiori2', true).then(renderer => renderer.placeAt("content"))

            sap.ushell.Container.attachLogoutEvent(e => {
                e.preventDefault()
                window.location.replace('/do/logout')
            }, false)

        })
    </script>

This way, you can reuse the default logout dialog logic the launchpad provides.

For completeness, find also my approuter configuration and custom logout page below.

My xs-app.json:

{
  "welcomeFile": "index.html",
  "authenticationMethod": "route",
  "logout": {
    "logoutEndpoint": "/do/logout",
    "logoutPage": "/logged-out.html"
  },
  "sessionTimeout": 60,
  "routes": [
    {
      "source": "^/logged-out.html$",
      "localDir": ".",
      "authenticationType": "none"
    },
    {
      "source": "^/launchpad.html$",
      "localDir": ".",
      "authenticationType": "xsuaa",
      "cacheControl": "no-cache, no-store, must-revalidate"
    },
    {
      "source": "^/appconfig/(.*)$",
      "localDir": ".",
      "authenticationType": "xsuaa"
    },
    {
      "source": "^/user-api(.*)",
      "target": "$1",
      "service": "sap-approuter-userapi",
      "authenticationType": "xsuaa"
    },
...
  ]
}

My logged-out.html file, placed in the approuter folder next to the launchpad.html:

<!DOCTYPE html>
<html>

<head>
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta http-equiv="Content-Type" content="text/html;charset=UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Logged out</title>
    <style>
        h2 {
            font-family: "Arial", sans-serif;
        }
        .centered {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
        }
    </style>
</head>

<body>
    <div class="centered">
        <h2>You are now logged out</h2>
    </div>
</body>

</html>
CAP, Fiori / SAPUI5

[SAPUI5] Add custom header parameter to all oData queries

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Simply go to your Component.js file and add this line to the init function:

this.getModel().setHeaders({"myCustomParameter": "test"})

In a CAP Backend, you get this parameter from the express req object, which can be accessed via the req.http property:

req.http.req.headers['myCustomParameter']

And here is a nice code snippet, on how to read this header parameter in an ABAP system: https://answers.sap.com/answers/425621/view.html

Fiori / SAPUI5

[SAPUI5] Suppress default oData error message / display meaningful error messages

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Create a separate ErrorHandler.js file, like it is described here and either do your own error handler implementation, or take the sample from here. To avoid displaying multiple errors at once, follow this chapter.

Thanks to the provided dsag sample, this is takes only a few minutes and improves the user experience a lot!

ABAP

[ABAP] xsdbool

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Somehow I always forget that there is a boolean function in ABAP. That’s why I’m writing this post to hopefully remember it better. 🙂

If you just want to check something for truthiness, you can do it in the following three ways:

IF sy-subrc = 0.
  result = abap_true.
ELSE.
  result = abap_false.
ENDIF.

result = SWITCH #( sy-subrc WHEN 0 THEN abap_true
                                   ELSE abap_false ).

result = xsdbool( sy-subrc = 0 )