ESP32 https OTA #watchy #esp32

wifi_update_client.c

#include <wifi_update_client.h>

#include <esp_log.h>
#include <esp32-hal.h>
#include <esp_https_ota.h>

static const char *LOG_TAG = "wifi_update_client";

const char *url = "https://raw.githubusercontent.com/sqfmi/Watchy/master/examples/WatchFaces/7_SEG/7_SEG.bin";

// Thanks to Elder Scroll on the Watchy discord:
// echo "" | openssl s_client -showcerts -connect raw.githubusercontent.com:443 | sed -n "1,/Root/d; /BEGIN/,/END/p" | openssl x509 -outform PEM > raw.githubusercontent.com.pem
// The certificate should be in the file raw.githubusercontent.com.pem

const char *github_cert =
    "-----BEGIN CERTIFICATE-----\n"
    "MIIEsTCCA5mgAwIBAgIQBOHnpNxc8vNtwCtCuF0VnzANBgkqhkiG9w0BAQsFADBs\n"
    "MQswCQYDVQQGEwJVUzEVMBMGA1UEChMMRGlnaUNlcnQgSW5jMRkwFwYDVQQLExB3\n"
    "d3cuZGlnaWNlcnQuY29tMSswKQYDVQQDEyJEaWdpQ2VydCBIaWdoIEFzc3VyYW5j\n"
    "ZSBFViBSb290IENBMB4XDTEzMTAyMjEyMDAwMFoXDTI4MTAyMjEyMDAwMFowcDEL\n"
    "MAkGA1UEBhMCVVMxFTATBgNVBAoTDERpZ2lDZXJ0IEluYzEZMBcGA1UECxMQd3d3\n"
    "LmRpZ2ljZXJ0LmNvbTEvMC0GA1UEAxMmRGlnaUNlcnQgU0hBMiBIaWdoIEFzc3Vy\n"
    "YW5jZSBTZXJ2ZXIgQ0EwggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQC2\n"
    "4C/CJAbIbQRf1+8KZAayfSImZRauQkCbztyfn3YHPsMwVYcZuU+UDlqUH1VWtMIC\n"
    "Kq/QmO4LQNfE0DtyyBSe75CxEamu0si4QzrZCwvV1ZX1QK/IHe1NnF9Xt4ZQaJn1\n"
    "itrSxwUfqJfJ3KSxgoQtxq2lnMcZgqaFD15EWCo3j/018QsIJzJa9buLnqS9UdAn\n"
    "4t07QjOjBSjEuyjMmqwrIw14xnvmXnG3Sj4I+4G3FhahnSMSTeXXkgisdaScus0X\n"
    "sh5ENWV/UyU50RwKmmMbGZJ0aAo3wsJSSMs5WqK24V3B3aAguCGikyZvFEohQcft\n"
    "bZvySC/zA/WiaJJTL17jAgMBAAGjggFJMIIBRTASBgNVHRMBAf8ECDAGAQH/AgEA\n"
    "MA4GA1UdDwEB/wQEAwIBhjAdBgNVHSUEFjAUBggrBgEFBQcDAQYIKwYBBQUHAwIw\n"
    "NAYIKwYBBQUHAQEEKDAmMCQGCCsGAQUFBzABhhhodHRwOi8vb2NzcC5kaWdpY2Vy\n"
    "dC5jb20wSwYDVR0fBEQwQjBAoD6gPIY6aHR0cDovL2NybDQuZGlnaWNlcnQuY29t\n"
    "L0RpZ2lDZXJ0SGlnaEFzc3VyYW5jZUVWUm9vdENBLmNybDA9BgNVHSAENjA0MDIG\n"
    "BFUdIAAwKjAoBggrBgEFBQcCARYcaHR0cHM6Ly93d3cuZGlnaWNlcnQuY29tL0NQ\n"
    "UzAdBgNVHQ4EFgQUUWj/kK8CB3U8zNllZGKiErhZcjswHwYDVR0jBBgwFoAUsT7D\n"
    "aQP4v0cB1JgmGggC72NkK8MwDQYJKoZIhvcNAQELBQADggEBABiKlYkD5m3fXPwd\n"
    "aOpKj4PWUS+Na0QWnqxj9dJubISZi6qBcYRb7TROsLd5kinMLYBq8I4g4Xmk/gNH\n"
    "E+r1hspZcX30BJZr01lYPf7TMSVcGDiEo+afgv2MW5gxTs14nhr9hctJqvIni5ly\n"
    "/D6q1UEL2tU2ob8cbkdJf17ZSHwD2f2LSaCYJkJA69aSEaRkCldUxPUd1gJea6zu\n"
    "xICaEnL6VpPX/78whQYwvwt/Tv9XBZ0k7YXDK/umdaisLRbvfXknsuvCnQsH6qqF\n"
    "0wGjIChBWUMo0oHjqvbsezt3tkBigAVBRQHvFwY+3sAzm2fTYS5yh+Rp/BIAV0Ae\n"
    "cPUeybQ=\n"
    "-----END CERTIFICATE-----\n";

static const char *event_to_str(esp_http_client_event_id_t id) {
    switch (id) {
        case HTTP_EVENT_ERROR:        return "HTTP_EVENT_ERROR";
        case HTTP_EVENT_ON_CONNECTED: return "HTTP_EVENT_ON_CONNECTED";
        case HTTP_EVENT_HEADER_SENT:  return "HTTP_EVENT_HEADER_SENT";
        case HTTP_EVENT_ON_HEADER:    return "HTTP_EVENT_ON_HEADER";
        case HTTP_EVENT_ON_DATA:      return "HTTP_EVENT_ON_DATA";
        case HTTP_EVENT_ON_FINISH:    return "HTTP_EVENT_ON_FINISH";
        case HTTP_EVENT_DISCONNECTED: return "HTTP_EVENT_DISCONNECTED";
        default: return "HTTP_EVENT_unknown";
    }
}

esp_err_t http_event_handler(esp_http_client_event_t *evt) {
    ESP_LOGI(LOG_TAG, "Download event %s (%d)", event_to_str(evt->event_id), evt->data_len);
    yield();
    return ESP_OK;
}

const char *wifi_update_client() {
    ESP_LOGI(LOG_TAG, "Starting image download from %s", url);
    disableCore0WDT();
    esp_http_client_config_t config = {
        .method = HTTP_METHOD_GET,
        .url = url,
        .cert_pem = github_cert,
        .event_handler = http_event_handler,
    };
    esp_err_t err = esp_https_ota(&config);
    if (err == ESP_OK) {
        ESP_LOGI(LOG_TAG, "Download OK - restarting");
        esp_restart();
        return NULL;
    }
    return esp_err_to_name(err);
}

wifi_update_client.h

#ifndef WIFI_UPDATE_CLIENT_H__
#define WIFI_UPDATE_CLIENT_H__

#  ifdef __cplusplus
extern "C" {
#  endif

const char *wifi_update_client();

#  ifdef __cplusplus
}
#  endif

#endif // WIFI_UPDATE_CLIENT_H__