Reconnection Recovery

State fields tagged lvt:"persist" survive WebSocket disconnects, server restarts, and full page reloads — the framework restores them from the session store via the group cookie before the first render after reconnect. The counter and notes here are both persisted; the notes textarea also uses lvt-form:preserve so in-progress typing isn't lost when another action re-renders the page.

Reconnection Recovery

Counter: 0 (lvt:"persist")

Try: Increment a few times and save some notes, then reload the page. State is restored before the first render. Why both tags on Notes? lvt:"persist" (server-side) survives reconnect. lvt-form:preserve (client-side) keeps your in-progress text in the DOM across re-renders that other actions trigger — without it, typing while the Counter is incrementing would lose the textarea draft.

Template

A persisted counter and a persisted notes textarea — reload the page and both come back.

{{define "content"}} <article> <h3>Reconnection Recovery</h3> <p><small>State fields tagged <code>lvt:"persist"</code> survive WebSocket disconnects, server restarts, and full page reloads — the framework restores them from the session store via the group cookie before the first render after reconnect.</small></p> <p>Counter: <strong>{{.Counter}}</strong> <small>(<code>lvt:"persist"</code>)</small></p> <form method="POST"> <button name="increment">Increment</button> </form> <form method="POST" lvt-form:preserve> <label> Notes <small>(<code>lvt:"persist"</code> + <code>lvt-form:preserve</code>)</small> <textarea name="notes" rows="3" placeholder="Type something…">{{.Notes}}</textarea> </label> <button name="saveNotes">Save Notes</button> </form> <p><small><strong>Try:</strong> Increment a few times and save some notes, then reload the page. State is restored before the first render. <strong>Why both tags on Notes?</strong> <code>lvt:"persist"</code> (server-side) survives reconnect. <code>lvt-form:preserve</code> (client-side) keeps your in-progress text in the DOM across re-renders that other actions trigger — without it, typing while the Counter is incrementing would lose the textarea draft.</small></p> </article> {{end}}

Handler & state

The actions are ordinary mutations; persistence comes entirely from the lvt:"persist" struct tags.

type ReconnectionController struct{} func (c *ReconnectionController) Increment(state ReconnectionState, ctx *livetemplate.Context) (ReconnectionState, error) { state.Counter++ return state, nil } func (c *ReconnectionController) SaveNotes(state ReconnectionState, ctx *livetemplate.Context) (ReconnectionState, error) { // Notes is a free-form textarea — leading/trailing whitespace AND // internal newlines are deliberate user content. Unlike Send/Join // inputs (which use TrimSpace to reject all-whitespace submissions), // SaveNotes preserves whatever the user typed verbatim. state.Notes = ctx.GetString("notes") return state, nil } func reconnectionHandler() http.Handler { tmpl := newLayoutTmpl("templates/layout.tmpl", "templates/realtime/reconnection.tmpl") return tmpl.Handle(&ReconnectionController{}, livetemplate.AsState(&ReconnectionState{ Title: "Reconnection Recovery", Category: "Real-Time & Multi-User", })) }

type ReconnectionState struct { Title string Category string Counter int `lvt:"persist"` Notes string `lvt:"persist"` }

Reconnection Recovery