sap build code authorization error: Cannot read properties of undefined (reading '$count')

[mostafa4]

I am working on a CAP (Cloud Application Programming) model where I have an entity called booksService.books, and I am applying role-based access control to filter certain fields based on user roles.

entity books {
key ID : UUID;
title : String;
author : String;
Sales : Integer;
Price : Integer;
} 

User Roles and Their Permissions:

• AdminAll → Can see all data
• viewExSales → Can see all fields except sales 

I initially wrote this event handler to modify the query when a user has the "viewExSales" role, so they cannot see the Sales column:

/**
 * 
 * @On(event = { "READ" }, entity = "booksService.books")
 * @Param {Object} request - User information, tenant-specific CDS model, headers, and query parameters
 */
module.exports = async function (request) {
    if (request.user.is('viewExSales')) {
        // Remove the 'Sales' column from the query
        request.query.columns = request.query.columns.filter(column => column !== 'Sales');
    }
};

 i get error

[cds] - ❗️Uncaught TypeError: Cannot read properties of undefined (reading '$count')
    at all (/home/user/projects/books/node_modules/@sap/cds/libx/_runtime/fiori/lean-draft.js:982:80)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async cds.ApplicationService.handle (/home/user/projects/books/node_modules/@sap/cds/libx/_runtime/fiori/lean-draft.js:447:20)

So, I also tried implementing manual query filtering based on roles like this

module.exports = async function(request) {
    const { books } = cds.entities;
    const user = request.user;
    
    let columns = ['ID', 'title', 'author', 'Sales', 'Price'];

    if (user) {
        const userRoles = Array.isArray(user.roles) ? user.roles : Object.keys(user.roles);

        if (userRoles.includes('AdminAll')) {
            return await SELECT.from(books).columns(...columns);
        } 
        
        if (userRoles.includes('viewExSales')) {
            columns = columns.filter(col => col !== 'Sales');
        }

        return await SELECT.from(books).columns(...columns);
    } 

    return await SELECT.from(books).columns(...columns);
};

it works and returned the data correctly but there were issues in it

Issue:

1. Filters and searches applied via the generated Fiori UI are ignored.

• If I filter by title or author, the backend still returns the full dataset instead of the filtered results.
• It seems like my custom query is overriding the default behavior of CAP filtering.

[xinye]

Hi @mostafa4, regarding your question, I have tried to reproduce the same steps as yours. Have you added the corresponding role into your BTP user? I did it, and re-login the BTP subaccount and verified it after waiting for a few moments, the `Sales` column data is hidden as expected. Would you double check it?

[mostafa4]

hi @xinye sorry for the confusion the problem in the second code is that any additional queries will not work as I return the same book data. for example in the ui if i use the search field to search for a title or a author it will always return all the data and the same for the filters. I asked joule to generate code to help me but it code always gave me the error Uncaught TypeError: Cannot read properties of undefined (reading '$count').

[xinye]

Hi @mostafa4, thanks for the clarification, I got your point now. Per my testing, it looks your requirement can not be achieved from the custom logic. Have you tried the alternative option? For example, create a new service projection entity without `Sales`, and assign role to this new service entity only?