Edouard Vanbelle
68 lines
2.2 KiB
TypeScript
68 lines
2.2 KiB
TypeScript
/**
|
|
* Reactive server-status store.
|
|
*
|
|
* Populated by the `apiFetch` wrapper, which reads the
|
|
* `x-server-status` header off every API response and calls
|
|
* `updateFromHeader(...)`. When no migration is running the header
|
|
* is absent and the store stays at its default (readonly=false, no
|
|
* migration info). See `middleware::server_status` on the server
|
|
* for the header spec.
|
|
*
|
|
* The AppShell subscribes to this store to show/hide the
|
|
* maintenance banner without polling — the state travels back to
|
|
* the client on the piggyback of whatever API request the user was
|
|
* making anyway. Zero extra network cost.
|
|
*/
|
|
|
|
/**
|
|
* JSON shape emitted in the `x-server-status` header. Optional
|
|
* `migration` field is present only while a migration is running.
|
|
*/
|
|
export interface ServerStatus {
|
|
readonly: boolean;
|
|
migration?: {
|
|
target: string;
|
|
migrated: number;
|
|
total: number;
|
|
percent: number;
|
|
};
|
|
}
|
|
|
|
const DEFAULT: ServerStatus = { readonly: false };
|
|
|
|
// Rune-based reactive state — `$state` in a `.svelte.ts` module.
|
|
let current = $state<ServerStatus>(DEFAULT);
|
|
|
|
/** Current server status. Reactively updates when apiFetch sees a new header. */
|
|
export function serverStatus(): ServerStatus {
|
|
return current;
|
|
}
|
|
|
|
/**
|
|
* Parse the raw header value and update the store. Silently
|
|
* tolerates a missing header (resets to default: nothing to
|
|
* broadcast means nothing wrong) and a malformed one (keeps the
|
|
* previous value rather than surface a parse error to users).
|
|
*
|
|
* Called by `apiFetch` after every response — see `client.ts`.
|
|
*/
|
|
export function updateFromHeader(rawHeader: string | null): void {
|
|
if (rawHeader == null) {
|
|
// No header on this response = server not in maintenance
|
|
// mode = reset the store to the default so any lingering
|
|
// banner disappears. Cheap idempotent write.
|
|
if (current.readonly || current.migration) current = DEFAULT;
|
|
return;
|
|
}
|
|
try {
|
|
const parsed = JSON.parse(rawHeader) as ServerStatus;
|
|
// Basic shape validation — server should never send a
|
|
// missing `readonly`, but be defensive.
|
|
if (typeof parsed.readonly === 'boolean') {
|
|
current = parsed;
|
|
}
|
|
} catch {
|
|
// Malformed header — keep previous state rather than churn.
|
|
}
|
|
}
|