Shelly Plus Plug: Sending POST Request When Switch Unavailable

Title: Sending POST Request with Shelly Plus Plug: Handling Switch Unavailability

In this article, we will discuss how to send a POST request using the Shelly Plus Plug, even when the switch becomes unavailable. This guide will cover key concepts, provide detailed context on the topic, and ensure the article is at least 800 words long.

Understanding the Shelly Plus Plug

The Shelly Plus Plug is a versatile Wi-Fi relay module that allows users to control various home appliances remotely. It can be programmed to send HTTP requests, including POST requests, to control devices.

The Issue: Switch Unavailability

Sometimes, the switch on the Shelly Plus Plug may become unavailable, preventing the device from sending the POST request. This issue can occur due to network instability, power outages, or other factors.

Sending POST Requests with Shelly Plus Plug

To send a POST request with the Shelly Plus Plug, you need to use the http_post function in the Shelly script. Here's a basic example:

#include <ESP8266WiFi.h>
#include <ESP8266HTTPClient.h>

const char* ssid = "your_SSID";
const char* password = "your_PASSWORD";

void setup() {
  Serial.begin(115200);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");
}

void loop() {
  if (Shelly.isOnline()) {
    HTTPClient http;
    http.begin("http://example.com/api/post");
    http.addHeader("Content-Type", "application/x-www-form-urlencoded");

    int httpCode = http.POST("param1=value1&param2=value2");

    if (httpCode > 0) {
      // HTTP request was successful
      String response = http.getString();
      Serial.println(httpCode);
      Serial.println(response);
    } else {
      // HTTP request failed
      Serial.print("Error on sending POST: ");
      Serial.println(http.errorToString(httpCode).c_str());
    }

    http.end();
  } else {
    // Switch is unavailable
    Serial.println("Shelly is offline");
  }

  delay(5000);
}

Replace "your_SSID" and "your_PASSWORD" with your Wi-Fi credentials. The http.POST() function sends the POST request with the specified parameters.

Handling Switch Unavailability

To handle switch unavailability, you can wrap the POST request code within an if statement that checks if the Shelly is online. If the switch is unavailable, the code will not execute the POST request, and you can log this event for troubleshooting purposes.

Troubleshooting and References

• Shelly Plus User Manual
• ESP8266WiFi Library
• ESP8266HTTPClient Library

This article provides a basic example of sending a POST request with the Shelly Plus Plug and handling switch unavailability. For more complex scenarios, you may need to adjust the code according to your specific requirements.