SolidJS•4mo ago

Keeping data and code secure and on the server (restrict code to initial render)

Hi, I have questions regarding SSR & "use server"; What already works: 1. OAuth authentication where the client only has a uuid session but not any of the OAuth keys/tokens 2. When the client fetches a page, server action ... the server resolves the OAuth tokens based on the session UUID What i want to archive: 3. I can use the OAuth tokens to fetch data for components only on initial server render without exposing tokens to the client or code that deals with theese tokens

16 Replies

NitonFxOP•4mo ago

What i currently have is this inside a component

const authentication = useAuthentication();

const authentication = useAuthentication();

and use Authentication is

export function useAuthentication(): Accessor<UserData> {
    const fallbackUserRoles: UserData = { roles: [], user: null };
    const fetchUser = async () => {
        const idToken = await getUserIdentity();
        if (idToken === null) {
            return fallbackUserRoles;
        }
        return {
            user: idToken.name,
            roles: [],
        } satisfies UserData;
    };
    const res = createAsync<UserData>(fetchUser, {
        deferStream: true,
    });
    return () => res() ?? fallbackUserRoles;
}

export function useAuthentication(): Accessor<UserData> {
    const fallbackUserRoles: UserData = { roles: [], user: null };
    const fetchUser = async () => {
        const idToken = await getUserIdentity();
        if (idToken === null) {
            return fallbackUserRoles;
        }
        return {
            user: idToken.name,
            roles: [],
        } satisfies UserData;
    };
    const res = createAsync<UserData>(fetchUser, {
        deferStream: true,
    });
    return () => res() ?? fallbackUserRoles;
}

Where getUserIdentity() is a use server my problem is that 1. this code exposes the identity token to the client 2. Authentication related code is in client alto it wont and should never be used Making useAuthentication "use server" doesn't work since the function cannot be serialized While i can add the mapping from idToken to UserData to the server (getUserIdentity) i cannot remove the dead code from the frontend I would search for a solution where the server just returns the HTML with all the values already inlined (this already works!) but without the code that makes it dynamic since its not the clients concern So i suppose i am searching for something "use init"; or something along the lines

Brendonovich•4mo ago

what about this?

const fallbackUserRoles: UserData = { roles: [], user: null };
const fetchUser = async () => {
    "use server";
    const idToken = await getUserIdentity();
    if (idToken === null) {
        return fallbackUserRoles;
    }
    return {
        user: idToken.name,
        roles: [],
    } satisfies UserData;
};

export function useAuthentication(): Accessor<UserData> {
    const res = createAsync<UserData>(fetchUser, {
        deferStream: true,
    });
    return () => res() ?? fallbackUserRoles;
}

const fallbackUserRoles: UserData = { roles: [], user: null };
const fetchUser = async () => {
    "use server";
    const idToken = await getUserIdentity();
    if (idToken === null) {
        return fallbackUserRoles;
    }
    return {
        user: idToken.name,
        roles: [],
    } satisfies UserData;
};

export function useAuthentication(): Accessor<UserData> {
    const res = createAsync<UserData>(fetchUser, {
        deferStream: true,
    });
    return () => res() ?? fallbackUserRoles;
}

NitonFxOP•4mo ago

I mean thats what i meant with

While i can add the mapping from idToken to UserData to the server (getUserIdentity) i cannot remove the dead code from the frontend

But yes that hides the token from the client (altho the code is still in the sourcemap but thats ok for dev) While it leaves the dead code in the frontend this would be ok if no other solution exists

Brendonovich•4mo ago

which dead code?

NitonFxOP•4mo ago

everything inside useAuthentication() should never be called on the client the user can/will never change besides on page reload

Brendonovich•4mo ago

could use middleware but i wouldn't recommend it

NitonFxOP•4mo ago

Or do i understand it wrong and useAuthentication will also be called by the client?

Brendonovich•4mo ago

yeah useAuthentication will be called on the client Start only does SSR for the initial page load, in the browser it becomes an SPA

NitonFxOP•4mo ago

but it doesn't cause a RPC call because of solid magic?

Brendonovich•4mo ago

on initial load yeah it reuses the server data instead of doing another fetch

NitonFxOP•4mo ago

Hmmm ok because the problem i have is i have an api client this api client object contains the api key (oath access token) i wanted to do something like

const myClient = useMyClient();
<div>{myClient.getFooBar("lorem ipsum")}</div>

const myClient = useMyClient();
<div>{myClient.getFooBar("lorem ipsum")}</div>

the problem i dont know how to do this without exposing the apiKey from the myClient to the frontend ofc i could write a own use server function for every method in MyClient but i am looking at an autogenerated API client with ~100 API endpoints & growing of which i use quite a few

Brendonovich•4mo ago

are you using cookies or something to authenticate the client to the backend instead of the api key?

NitonFxOP•4mo ago

Yes As I said I have a session cookie and only the backend knows the access token Backend being solid start server

Brendonovich•4mo ago

i think i'd try use one server function that wraps the api client and use some typescript magic to do something like apiClientServerFunction('getFooBar', ['lorem ipsum']) or is it possible to use the api client in the browser and provide a custom transport that resolves the api key on the backend

NitonFxOP•4mo ago

Oh like a path /api/myapi/[...path] With like a generic handler that replaces the session with API key and relays it to the real API? Altho I probably would have to be quite careful since well requests have quite a lot to them🤔 Or is the mechanism you mean something different? But there is no way in general to render something initially on the server and leave it static once on the client I am not saying that it is unreasonable to not have such a feature given the already high complexity of meta frameworks

Brendonovich•4mo ago

you could use NoHydration but it's a bit extreme

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Keeping data and code secure and on the server (restrict code to initial render)