Spider Silk

App app = new App();    // jte over classpath:/jte, and classpath:/public served at /

// Server-side rendering
app.get("/decks/{deckId}", req -> {
    long deckId = req.pathParamLong("deckId");  // non-numeric input becomes a 400
    return WebResponse.template("deck", model); // classpath:/jte/deck.jte
});

// JSON API: you state in code what goes out (no automatic serialization)
app.get("/api/decks", req -> WebResponse.json(
        Json.arr().add(Json.obj().put("id", 1L).put("name", "English"))));

app.post("/api/decks", req -> {
    String name = req.bodyJson().asObject().getString("name");
    return WebResponse.json(Json.obj().put("name", name)).status(HttpStatus.CREATED);
});

// Routes sharing a prefix: the group is an argument, not ambient state
app.path("/api/decks", group -> {
    group.before(req -> requireApiKey(req));    // covers /api/decks and everything under it
    group.get("", api::listDecks);              // GET  /api/decks
    group.get("/{deckId}", api::showDeck);      // GET  /api/decks/{deckId}
});

// Exception-to-response mapping
app.exception(IllegalArgumentException.class,
        (e, req) -> WebResponse.text(e.getMessage()).status(HttpStatus.NOT_FOUND));

// One place for a styled error page, whatever produced the status
app.error(HttpStatus.NOT_FOUND, req -> WebResponse.template("not-found", Map.of("path", req.path())));

app.start(8080);                                // embedded Jetty, sessions on