ESP32 HTTPClient Library – setTimeout

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Description

The setTimeout method in the ESP32 HTTPClient Library is used to set the timeout duration (in milliseconds) for HTTP operations, such as connecting to a server or waiting for a response. This method helps manage how long the ESP32 will wait before aborting an HTTP request if no response is received, making it a critical tool for ensuring robust IoT applications.

Please note the differences between setTimeout and setConnectTimeout in the ESP32 HTTPClient Library:

Purpose

• setTimeout: Sets the overall timeout for the HTTP request operations after a connection is established, including waiting for the server to respond and reading the response data.
• setConnectTimeout: Sets the timeout specifically for establishing the initial connection to the server (i.e., the time allowed for the TCP handshake or SSL negotiation to complete).

Scope

• setTimeout: Applies to the entire HTTP transaction once connected, such as delays in receiving headers or body data from the server.
• setConnectTimeout: Applies only to the connection phase, determining how long the client waits to establish a connection before giving up.

Syntax and Usage

The setTimeout method is straightforward and has a single way of usage. Below is how to use it:

Using the method with an argument: 

http.setTimeout(timeout);

This is the only way to use setTimeout. You provide a timeout value in milliseconds as an argument to specify how long the HTTP client should wait for a response before timing out.

Argument(s)

• timeout: An unsigned 16-bit integer (uint16_t) representing the timeout duration in milliseconds. This value determines how long the HTTP client will wait for a response before considering the operation timed out. For example, setting it to 5000 means a 5-second timeout.

Return Value

The setTimeout method does not return a value. It is a void function that simply configures the timeout property of the HTTPClient object for subsequent HTTP operations.

Example Codes

Making an HTTP GET Request with a Custom Timeout

This example shows how to use setTimeout to set a 5-second timeout for an HTTP GET request to www.example.com. The ESP32 connects to a Wi-Fi network and attempts to fetch data, with the timeout ensuring the request doesn’t hang indefinitely if the server is unresponsive.

/*
 * Author: Avant Maker
 * Date: February 21, 2025
 * Version: 1.0
 * Description: This example code demonstrates how to 
 * use the ESP32 HTTPClient Library's setTimeout to set 
 * a 5-second timeout for an HTTP GET request to www.example.com.
 * The ESP32 connects to a Wi-Fi network and attempts to 
 * fetch data, with the timeout ensuring the request doesn't
 * hang indefinitely if the server is unresponsive.
 *
 * License: MIT 
 * 
 * Code Source: This example code is sourced from the Comprehensive 
 * Guide to the ESP32 Arduino Core Library, accessible on 
 * AvantMaker.com. For additional code examples and in-depth 
 * documentation related to the ESP32 Arduino Core Library, 
 * please visit:
 *
 * https://avantmaker.com/references/esp32-arduino-core-index/
 *
 * AvantMaker.com, your premier destination for all things 
 * DIY, AI, IoT, Smart Home, and STEM projects. We are dedicated 
 * to empowering makers, learners, and enthusiasts with the resources
 * they need to bring their innovative ideas to life.
 */

#include <WiFi.h>
#include <HTTPClient.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(500);
        Serial.print(".");
    }
    Serial.println("\nConnected to WiFi");
}

void loop() {
    if (WiFi.status() == WL_CONNECTED) {
        HTTPClient http;

        http.begin("http://www.example.com");
        http.setTimeout(5000); // Set timeout to 5 seconds

        int httpCode = http.GET();

        if (httpCode > 0) {
            String payload = http.getString();
            Serial.println("Response: " + payload);
        } else {
            Serial.println("Error on HTTP request: " + String(httpCode));
        }

        http.end();
    }
    delay(10000); // Wait 10 seconds before next request
}