← Subir ficheros de la SD desde un PLC ESP32 por HTTP POST

Subir ficheros de la SD desde un PLC ESP32 por HTTP POST — ejemplo completo

Recupera datos de máquina en búfer: un PLC ESP32 sube ficheros de log de la tarjeta SD a un servidor por HTTP POST con basic auth y entrega confirmada.

Programa completo y ejecutable para el ESP32 PLC (sd-file-upload-http-post.ino): incluye cabecera de conexionado, requisitos y notas de integración.

Vista de solo lectura.

/*
 * COMPLETE EXAMPLE — SD file upload over HTTP POST with authentication
 *
 * Hardware: ESP32 PLC (Industrial Shields, with WiFi + microSD slot)
 * Based on: textile monitoring project, modul_MQTT.h
 *
 * Network:
 *   The Node-RED concentrator listens on http://:1880/get_data
 *   with basic authentication. The PLC uploads the daily files from the SD
 *   card (created by the datalogging module) to fill the gaps left by a
 *   network outage.
 *
 * Architecture:
 *   1. uploadFile(name): opens the file on the SD card and streams it
 *      (without loading it into RAM) over HTTP POST
 *   2. Basic auth with HTTP_USER/HTTP_PASS and X-File-Name header so
 *      Node-RED knows which day it is receiving
 *   3. The file is only deleted/renamed if the server returns 200
 *   4. Triggered on demand: here via Serial; in production it arrives as
 *      an MQTT command ("upload 2026-06-10.json")
 *
 * Works together with other catalog examples:
 *   - sd-daily-file-datalogging.ino (source of the files)
 *   - mqtt-remote-commands.ino (remote trigger)
 *   - node-red-multi-plant-concentrator.js (/get_data endpoint)
 */

#include 
#include 
#include 

const char *WIFI_SSID  = "WIFI_SSID";
const char *WIFI_PASS  = "WIFI_PASS";
const char *SERVER     = "CONCENTRADOR_IP";   // Node-RED host
const int   PORT       = 1880;
const char *HTTP_USER  = "HTTP_USER";
const char *HTTP_PASS  = "HTTP_PASS";

// ------------------------------------------------- Streaming upload
// Returns true if the server confirmed reception (HTTP 200)
bool uploadFile(const String &fileName) {
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("No WiFi: cannot upload " + fileName);
    return false;
  }

  File file = SD.open(fileName, FILE_READ);
  if (!file) {
    Serial.println("Not found on SD: " + fileName);
    return false;
  }

  HTTPClient http;
  http.begin("http://" + String(SERVER) + ":" + String(PORT) + "/get_data");
  http.setAuthorization(HTTP_USER, HTTP_PASS);          // basic auth
  http.addHeader("Content-Type", "text/plain");
  http.addHeader("X-File-Name", fileName);              // which day is uploaded
  http.setTimeout(15000);                               // large files

  // The file is streamed directly from the SD card
  int code = http.sendRequest("POST", &file, file.size());
  size_t bytes = file.size();
  file.close();
  http.end();

  Serial.println("POST " + fileName + " (" + String(bytes) +
                 " bytes) -> HTTP " + String(code));
  return code == 200;
}

// After a confirmed upload, mark the file as sent
void markAsUploaded(const String &fileName) {
  String destination = "/uploaded" + fileName;
  SD.mkdir("/uploaded");
  if (SD.rename(fileName, destination))
    Serial.println("Moved to " + destination);
}

void setup() {
  Serial.begin(115200);

  SD.begin();
  WiFi.mode(WIFI_STA);
  WiFi.begin(WIFI_SSID, WIFI_PASS);
  uint32_t t0 = millis();
  while (WiFi.status() != WL_CONNECTED && millis() - t0 < 15000) delay(500);

  Serial.println("Ready. Type the name of the file to upload,");
  Serial.println("e.g.: /2026-06-10.json");
}

void loop() {
  // Console demo; in production this is triggered by an MQTT command
  if (Serial.available()) {
    String name = Serial.readStringUntil('\n');
    name.trim();
    if (name.length() == 0) return;
    if (!name.startsWith("/")) name = "/" + name;

    if (uploadFile(name)) {
      markAsUploaded(name);         // only if the server confirmed (200)
    } else {
      Serial.println("Upload failed: the file stays on the SD for retry");
    }
  }

  delay(20);
}