BasicAuth - per-route HTTP Basic authentication

Layer: L6 Presentation · Build flags: PC_ENABLE_AUTH (on by default)

What this example teaches

The library protects a route with credentials via an auth-aware on() overload: you pass a realm, username, and password after the handler, and the handler runs only if the credentials check passes. Otherwise the server answers 401 with a WWW-Authenticate challenge automatically - you write no auth code.

Protecting one route. A public route uses the normal three-argument on(); a protected route adds the realm/user/password (digest defaults to false, i.e. Basic):

server.on("/", HttpMethod::HTTP_GET, [](uint8_t id, HttpReq *) { server.send(id, 200, "text/plain", "public page"); });
 
server.on("/secret", HttpMethod::HTTP_GET,
          [](uint8_t id, HttpReq *) { server.send(id, 200, "text/plain", "authenticated!"); },
          "Restricted", "admin", "s3cret");   // realm, user, pass

The handler body is reached only after a valid Authorization: Basic header.

‍Basic is base64, not encryption. The credentials are merely base64-encoded on the wire, so use Basic only over HTTPS or an SSH tunnel on untrusted networks. For a scheme where the password never crosses the wire, pass digest=true - see DigestAuth.

PC_ENABLE_AUTH is on by default; you only need to set it (to 0) to compile auth out.

Build and run

pio ci --board=esp32dev --project-option="framework=arduino" \
  --lib="." examples/L6-Presentation/BasicAuth/BasicAuth.ino

curl http://<ip>/                       # public
curl -u admin:s3cret http://<ip>/secret # 200; without -u you get a 401 challenge

Annotated source

The complete sketch (BasicAuth.ino), reproduced verbatim with added explanatory comments:

// Copyright (C) 2026 Douglas Quigg (dstroy0) <dquigg123@gmail.com>
// SPDX-License-Identifier: AGPL-3.0-or-later
 
#include "protocore.h"
#include "network_drivers/physical/physical.h"
 
static const char *SSID = "YOUR_SSID";
static const char *PASSWORD = "YOUR_PASSWORD";
 
PC server;
 
void setup()
{
    Serial.begin(115200);
    init_wifi_physical(SSID, PASSWORD);
    Serial.print("Connecting to WiFi");
    while (!wifi_ready())
    {
        delay(250);
        Serial.print('.');
    }
    uint32_t ip = pc_net_egress_ip(); // library egress IP (network byte order), no Arduino WiFi
    Serial.printf("IP: %u.%u.%u.%u\n", (unsigned)(ip & 0xFF), (unsigned)((ip >> 8) & 0xFF),
                  (unsigned)((ip >> 16) & 0xFF), (unsigned)((ip >> 24) & 0xFF));
 
    server.on("/", HttpMethod::HTTP_GET, [](uint8_t id, HttpReq *) { server.send(id, 200, "text/plain", "public page"); });
 
    // Basic auth (digest defaults to false): realm, username, password. A request
    // without valid credentials gets 401 + WWW-Authenticate before the handler runs.
    server.on(
        "/secret", HttpMethod::HTTP_GET, [](uint8_t id, HttpReq *) { server.send(id, 200, "text/plain", "authenticated!"); },
        "Restricted", "admin", "s3cret");
 
    server.begin(80);
}
 
void loop()
{
    server.handle();
}