New ESP8266HTTPUpdate feature

[hmueller01]

Hi,
I like to add a new feature to ESP8266HTTPUpdate called "getAvailableVersion". It queries the server and returns the available firmware version on the update server. IMHO there are two possibilities to achieve this:

1. Add this feature to ESP8266httpUpdate.cpp
2. Extend the ESP8266HTTPUpdate class e.g.

class ESP8266HTTPUpdateAdv : public ESP8266HTTPUpdate {
 private:

 public:
  ESP8266HTTPUpdateAdv(void) : ESP8266HTTPUpdate() {};  // Constructor
  ESP8266HTTPUpdateAdv(int http_client_timeout) : ESP8266HTTPUpdate(http_client_timeout) {};

  HTTPUpdateResult getAvailableVersion(WiFiClient& client, const String& host, uint16_t port, const String& uri, const String& current_version, String& available_version);
};

Unfortunately this does not work without modifying ESP8266httpUpdate.h

--- a/libraries/ESP8266httpUpdate/src/ESP8266httpUpdate.h
+++ b/libraries/ESP8266httpUpdate/src/ESP8266httpUpdate.h
@@ -153,10 +153,10 @@ protected:
     String _password;
     String _auth;
     String _md5Sum;
-private:
+
     int _httpClientTimeout;
     followRedirects_t _followRedirects = HTTPC_DISABLE_FOLLOW_REDIRECTS;
-
+private:
     // Callbacks
     HTTPUpdateStartCB    _cbStart;
     HTTPUpdateEndCB      _cbEnd;

as I need _httpClientTimeout and _followRedirects protected that I can use it in the inherited class as follows:

/**
 * @brief  Get avialable firmware version from update server
 * @author Holger Mueller
 * @date   2023-07-29
 * 
 * @param  client WiFiClient to use (see HTTPClient::begin)
 * @param  host Update host name or IP (see HTTPClient::begin)
 * @param  port Port on host (see HTTPClient::begin)
 * @param  uri Update URI on server (see HTTPClient::begin)
 * @param  current_version Current firmware version
 * @param  available_version Firmware version available on update server
 * @return ESP8266HTTPUpdate::HTTPUpdateResult, HTTP_UPDATE_OK in case of success
 */
HTTPUpdateResult ESP8266HTTPUpdateAdv::getAvailableVersion(WiFiClient& client, const String& host, uint16_t port, const String& uri, const String& current_version, String& available_version) {
  HTTPUpdateResult ret = HTTP_UPDATE_FAILED;
  HTTPClient http;
  http.begin(client, host, port, uri);

  // use HTTP/1.0 for update since the update handler not support any transfer Encoding
  http.useHTTP10(true);
  http.setTimeout(_httpClientTimeout);
  http.setFollowRedirects(_followRedirects);
  http.setUserAgent(F("ESP8266-http-Update"));
  http.addHeader(F("x-ESP8266-Chip-ID"), String(ESP.getChipId()));
  http.addHeader(F("x-ESP8266-STA-MAC"), WiFi.macAddress());
  http.addHeader(F("x-ESP8266-AP-MAC"), WiFi.softAPmacAddress());
  http.addHeader(F("x-ESP8266-free-space"), String(ESP.getFreeSketchSpace()));
  http.addHeader(F("x-ESP8266-sketch-size"), String(ESP.getSketchSize()));
  http.addHeader(F("x-ESP8266-sketch-md5"), String(ESP.getSketchMD5()));
  http.addHeader(F("x-ESP8266-chip-size"), String(ESP.getFlashChipRealSize()));
  http.addHeader(F("x-ESP8266-sdk-version"), ESP.getSdkVersion());

  http.addHeader(F("x-ESP8266-mode"), F("version"));

  if (current_version && current_version[0] != 0x00) {
    http.addHeader(F("x-ESP8266-version"), current_version);
  }

  if (!_user.isEmpty() && !_password.isEmpty()) {
    http.setAuthorization(_user.c_str(), _password.c_str());
  }

  if (!_auth.isEmpty()) {
    http.setAuthorization(_auth.c_str());
  }

  const char* headerkeys[] = {"x-MD5", "x-version"};
  size_t headerkeyssize = sizeof(headerkeys) / sizeof(char*);

  // track these headers
  http.collectHeaders(headerkeys, headerkeyssize);

  int code = http.GET();
  int len = http.getSize();

  if (code <= 0) {
    DEBUG_HTTP_UPDATE("[httpUpdate] HTTP error: %s\n", http.errorToString(code).c_str());
    _setLastError(code);
    http.end();
    return HTTP_UPDATE_FAILED;
  }

  DEBUG_HTTP_UPDATE("[httpUpdate] Header read fin.\n");
  DEBUG_HTTP_UPDATE("[httpUpdate] Server header:\n");
  DEBUG_HTTP_UPDATE("[httpUpdate]  - code: %d\n", code);
  DEBUG_HTTP_UPDATE("[httpUpdate]  - len: %d\n", len);
  if (code != HTTP_CODE_OK) {
    DEBUG_HTTP_UPDATE("[httpUpdate]  - payload: %s\n", http.getString().c_str());
  }

  String md5;
  if (_md5Sum.length()) {
    md5 = _md5Sum;
  } else if (http.hasHeader("x-MD5")) {
    md5 = http.header("x-MD5");
  }
  if (md5.length()) {
    DEBUG_HTTP_UPDATE("[httpUpdate]  - MD5: %s\n", md5.c_str());
  }

  DEBUG_HTTP_UPDATE("[httpUpdate] ESP8266 info:\n");

  switch (code) {
    case HTTP_CODE_OK:  ///< OK (check for version)
      if (http.hasHeader("x-version")) {
        available_version = http.header("x-version");
        ret = HTTP_UPDATE_OK;
        DEBUG_HTTP_UPDATE("[httpUpdate]  - server version: %s\n", available_version.c_str());
      } else {
        _setLastError(HTTP_UE_SERVER_NOT_REPORT_SIZE); // TODO might not be the perfect error code, lacking better one
        ret = HTTP_UPDATE_FAILED;
        DEBUG_HTTP_UPDATE("[httpUpdate] Content-Length was 0 or wasn't set by Server?!\n");
      }
      break;
    case HTTP_CODE_NOT_MODIFIED:
      ///< Not Modified (No updates)
      ret = HTTP_UPDATE_NO_UPDATES;
      break;
    case HTTP_CODE_NOT_FOUND:
      _setLastError(HTTP_UE_SERVER_FILE_NOT_FOUND);
      ret = HTTP_UPDATE_FAILED;
      break;
    case HTTP_CODE_FORBIDDEN:
      _setLastError(HTTP_UE_SERVER_FORBIDDEN);
      ret = HTTP_UPDATE_FAILED;
      break;
    case HTTP_CODE_UNAUTHORIZED:
      _setLastError(HTTP_UE_SERVER_UNAUTHORIZED);
      ret = HTTP_UPDATE_FAILED;
      break;
    default:
      _setLastError(HTTP_UE_SERVER_WRONG_HTTP_CODE);
      ret = HTTP_UPDATE_FAILED;
      DEBUG_HTTP_UPDATE("[httpUpdate] HTTP Code is (%d)\n", code);
      // http.writeToStream(&Serial1);
      break;
  }

  http.end();
  return ret;
}

Which solution do you prefer (and what kind of PR should I make)?

[hmueller01]

@Links2004 What do you think? I've seen you as an author of ESP8266HTTPUpdate ...

[d-a-v]

A pull request with point 1 should be quickly merged.

[hmueller01]

@d-a-v Ok, this is good news. I'll update my code (currently implemented option 2) and update the documentation http-server
Furthermore I have to add a new error code
_setLastError(HTTP_UE_SERVER_NOT_REPORT_SIZE); // TODO might not be the perfect error code, lacking better one
...
When finished I'll raise a PR.