Homelab, Linux, JS & ABAP (~˘▾˘)~
 

Tag: CAP

CAP

[CAP] Get subdomain in a multitenant scenario

 , , , , , , ,

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

 , , , , , , , , , , ,

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

CAP, Fiori / SAPUI5

[SAPUI5] Add custom header parameter to all oData queries

 , , , , ,

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

CAP

[CAP] Select max with group by

 , , , , , , ,

https://www.w3resource.com/sql/aggregate-functions/Max-with-group-by.php

https://answers.sap.com/questions/13081527/simple-count-aggregation-on-caps-cql.html?childToView=13079907&answerPublished=true

entity myEntity {
        key ID: Integer;
        key seqNr: Integer;
        key createdAt: DateTime;
        ...
    }

@readonly
entity myEntityMaxSeqNr 
        as select from myEntity {
            ID, 
            count(seqNr) as maxSeqNr: Integer
            createdAt,
            ...
            } 
        group by 
            ID,
            createdAt;

This can also be done using CQL like here.