ArduinoHttpClient

ArduinoHttpClient does not provide networking itself. It requires a networking hardware module and a corresponding transport-specific Client library. You must include a library that provides a Client instance, such as:

• WiFiNINA
• WiFi101
• Ethernet
• MKRGSM
• MKRNB
• WiFi
• GSM

For requests requiring custom headers (like Authorization), use the beginRequest() / endRequest() pattern. This allows you to manually inject headers before the body is sent.

client.beginRequest();
client.sendHeader("Custom-Header", "Custom-Value");
client.sendBasicAuth("user", "pass");
client.endRequest();

// If sending a body, use beginBody()
client.beginBody();
client.write("body data");

To use HttpClient, you must provide an existing Client instance (such as WiFiClient or EthernetClient), the server name, and optionally the port. The default port is kHttpPort (80).

// Using a string for server name
HttpClient client(wifiClient, "example.com");

// Using a char array for server name
HttpClient client(wifiClient, "example.com", 80);

// Using an IPAddress
HttpClient client(wifiClient, IPAddress(192, 168, 1, 1), 80);

You can retrieve the response body in two ways:

1. As a String: Use responseBody() to get the entire body as a String. This automatically skips headers if they haven't been read.
2. As a Stream: Use read() to read the body byte-by-byte. This is more memory-efficient for large responses.

// Method 1: Get as String
String body = client.responseBody();

// Method 2: Read byte-by-byte
while (client.available()) {
    char c = client.read();
    // process c
}

Use ping() to send a WebSocket ping frame to the server to keep the connection alive or check connectivity. Returns 0 if successful, or an error code.

int status = ws.ping();

The get() method connects to the server and sends a GET request to the specified URL path. It returns HTTP_SUCCESS (0) if successful, or an error code if the connection or request fails.

int result = client.get("/api/data");
if (result == HTTP_SUCCESS) {
    // Handle success
}

After making a request, use responseStatusCode() to get the HTTP status (e.g., 200, 404). To read headers, you must call headerAvailable() in a loop, then use readHeaderName() and readHeaderValue(). This must be done after checking the status code but before reading the body.

int status = client.responseStatusCode();
if (status == 200) {
    while (client.headerAvailable()) {
        String name = client.readHeaderName();
        String value = client.readHeaderValue();
    }
}

The URLEncoder utility provides static methods to percent-encode strings, making them safe for use in URL query parameters. You can pass either a C-style string (const char*) or an Arduino String object to the encode method. It returns a new String containing the encoded version of the input.

// Using a C-style string
String encodedStr = URLEncoder::encode("hello world!");

// Using an Arduino String object
String myString = "data & more";
String encodedString = URLEncoder::encode(myString);

To use WebSockets, instantiate a WebSocketClient by providing an existing Client object (such as a WiFiClient or EthernetClient), the server name (hostname or IP), and the server port. The default port is HttpClient::kHttpPort.

// Example using a WiFiClient
WiFiClient client;
WebSocketClient ws(&client, "example.com", 80);