Imperative Apex call under guest user results in List has no rows for assignment to SObject, anonymous execution works fine

Question

I have the following Apex Method which is called in the Experience Cloud under unauthenticated guest user:

@AuraEnabled(cacheable=true)
public static string test(String ref) {
    try {
        Some_Object__c o = [Select Id, Blah__c from Some_Object__c where Blah__c =: ref];
        return o.Id;
    } catch (Exception e) {
        System.debug(e.getMessage());
        throw new AuraHandledException(e.getMessage());
    }
}

Which is called by this LWC:

import { LightningElement, wire, track } from 'lwc';
import { CurrentPageReference } from "lightning/navigation";
import getTest from "@salesforce/apex/SomeController.test";
export default class HelloWorld extends LightningElement {
    @track ref;
    @track blah;

    @wire(CurrentPageReference)

    getStateParameters(currentPageReference) {
        if (currentPageReference) {
            const urlValue = currentPageReference.state.ref;
            if (urlValue) {
                this.ref = urlValue;
            }
        }
    }

    connectedCallback(){
        this.loadData;
    }

    get loadData(){
         getTest({ref: this.ref})
            .then(result => {
                this.blah = result;
            })
            .catch(error => {
                console.log(error);
            })
     }
}

The important part of this code is the loadData() method.

Calling SomeController.Test() from this LWC results in List has no rows for assignment to SObject. If I run this query in the developer console, I can see the value I'm passing in is there (and matches). If I run this same method anonymously, I recieve the correct result.

The parameter is populated (with some debug logs I can see it's there). If I attempt to return all rows, the list has a size of 0 (like so: List<Focus_Application__c> applications = [Select Id, Reference_Id__c from Focus_Application__c];). I've triple checked that the custom object is definitely populated in this org.

This perhaps points to permissions on the object? But I can't see anything out of place.

Answer 1

Don't use a getter for this purpose. They can, and will, be called multiple times in a semi-unpredictable order. You can call the method directly from your wire handler:

@wire(CurrentPageReference)
getStateParameters(currentPageReference) {
    if (currentPageReference) {
        const urlValue = currentPageReference.state.ref;
        if (urlValue) {
            this.ref = urlValue;
            getTest({ref: this.ref})
            .then(result => {
                this.blah = result;
            })
            .catch(error => {
                console.log(error);     
            })
        }
    }
}

Answer 2

The problem is with Guest User access.

The topic started has deleted her answer:

This was due to field level security on the guest user:

To fix:

1. Click the gear icon, then Setup.
2. Go to Digital Experiences > All Sites > Workspaces.
3. View the guest profile for this site.
4. Administration > Pages > Go to Force.com > Public access settings.
5. Scroll down to field level security.
6. Add access to the specific fields you need.