The WebServer class found in ESP8266WebServer.h header, is a simple web server that knows how to handle HTTP requests such as GET and POST and can only support one simultaneous client.

Usage

Class Constructor

ESP8266WebServer server(80);

Creates the ESP8266WebServer class object.

Parameters:

host IP address: IPaddress addr (optional)

host port number: int port (default is the standard HTTP port 80)

Basic Operations

Starting the server

void begin();

Handling incoming client requests

void handleClient();

Disabling the server

void close();
void stop();

Both methods function the same

Client request handlers

void on();
void addHandler();
void onNotFound();
void onFileUpload();

Example:

server.on("/", handlerFunction);
server.onNotFound(handlerFunction); // called when handler is not assigned
server.onFileUpload(handlerFunction); // handle file uploads

Sending responses to the client

void send();
void send_P();

Parameters:

code - HTTP response code, can be 200 or 404, etc.

content_type - HTTP content type, like "text/plain" or "image/png", etc.

content - actual content body

Advanced Options

Getting information about request arguments

const String & arg();
const String & argName();
int args();
bool hasArg();

arg - get request argument value

argName - get request argument name

args - get arguments count

hasArg - check if argument exist

Getting information about request headers

const String & header();
const String & headerName();
const String & hostHeader();
int headers();
bool hasHeader();

header - get request header value

headerName - get request header name

hostHeader - get request host header if available, else empty string

headers - get header count

hasHeader - check if header exist

Authentication

bool authenticate();
void requestAuthentication();

authenticate - server authentication, returns true if client is authenticated else false

requestAuthentication - sends authentication failure response to the client

Example Usage:

if(!server.authenticate(username, password)){
  server.requestAuthentication();
}

Other Function Calls

const String & uri(); // get the current uri
HTTPMethod  method(); // get the current method 
WiFiClient client(); // get the current client
HTTPUpload & upload(); // get the current upload
void setContentLength(); // set content length
void sendHeader(); // send HTTP header
void sendContent(); // send content
void sendContent_P(); 
void collectHeaders(); // set the request headers to collect
void serveStatic();
size_t streamFile();

For code samples enter here .