Basic routing

A route pairs an HTTP method and a path with a handler. An App named app registers routes in setup() and processes incoming clients in loop(), as in the complete hello world sketches.

The following are partial examples: place the handler functions above setup() in a hello world sketch and add their registrations before server.begin().

void readHome(Request& req, Response& res) {
  res.print("Hello World!");
}

void createUser(Request& req, Response& res) {
  res.status(201);
  res.print("Created a user");
}

void updateUser(Request& req, Response& res) {
  res.print("Updated the user");
}

void removeUser(Request& req, Response& res) {
  res.sendStatus(204);
}

// Add inside setup().
app.get("/", readHome);
app.post("/user", createUser);
app.put("/user", updateUser);
app.del("/user", removeUser);

Use del() for DELETE because delete is a C++ keyword. The supported route methods are get, head, post, put, patch, del, and options. HEAD needs its own registration; aWOT suppresses its response body. app.use(handler) runs for every supported method and path. app.use("/user", handler) matches that route pattern for every method.

Multiple handlers and continuation

Register the same route more than once to run several handlers in order. Each handler must call req.next() if it wants dispatch to continue. This partial example logs a request before producing the response:

void logUser(Request& req, Response& res) {
  Serial.println(req.path());
  req.next();
}

void readUser(Request& req, Response& res) {
  res.print("User details");
}

// Add inside setup().
app.get("/user", logUser);
app.get("/user", readUser);

Returning without req.next() stops routing. res.end() marks the response as ended and also prevents subsequent route handlers, even if req.next() was called. aWOT finalizes the output when process() returns; the caller then closes or retains the client.

See routing for parameters and mounted routers, and middleware for logging and authentication.