README.md

AsyncWebServer_ESP32_W5500 Library

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Table of contents

• Table of contents
• Important Note from v1.6.2
• Why do we need this AsyncWebServer_ESP32_W5500 library
  • Features
  • Why Async is better
  • Currently supported Boards
• Changelog
• Prerequisites
• Installation
  • Use Arduino Library Manager
  • Manual Install
  • VS Code & PlatformIO
• Important things to remember
• Principles of operation
  • The Async Web server
  • Request Life Cycle
  • Rewrites and how do they work
  • Handlers and how do they work
  • Responses and how do they work
  • Template processing
• Request Variables
  • Common Variables
  • Headers
  • GET, POST and FILE parameters
  • JSON body handling with ArduinoJson
• Responses
  • Redirect to another URL
  • Basic response with HTTP Code
  • Basic response with HTTP Code and extra headers
  • Basic response with string content
  • Basic response with string content and extra headers
  • Respond with content coming from a Stream
  • Respond with content coming from a Stream and extra headers
  • Respond with content coming from a Stream containing templates
  • Respond with content coming from a Stream containing templates and extra headers
  • Respond with content using a callback
  • Respond with content using a callback and extra headers
  • Respond with content using a callback containing templates
  • Respond with content using a callback containing templates and extra headers
  • Chunked Response
  • Chunked Response containing templates
  • Print to response
  • ArduinoJson Basic Response
  • ArduinoJson Advanced Response
• Param Rewrite With Matching
• Using filters
• Bad Responses
  • Respond with content using a callback without content length to HTTP/1.0 clients
• Async WebSocket Plugin
  • Async WebSocket Event
  • Methods for sending data to a socket client
  • Direct access to web socket message buffer
  • Limiting the number of web socket clients
• Async Event Source Plugin
  • Setup Event Source on the server
  • Setup Event Source in the browser
• Remove handlers and rewrites
• Setting up the server
  • Setup global and class functions as request handlers
  • Methods for controlling websocket connections
  • Adding Default Headers
  • Path variable
• How to connect W5500 to ESP32
• Examples
  • 1. Async_AdvancedWebServer
  • 2. Async_AdvancedWebServer_MemoryIssues_SendArduinoString
  • 3. Async_AdvancedWebServer_MemoryIssues_Send_CString
  • 4. Async_AdvancedWebServer_SendChunked
  • 5. Async_HelloServer
  • 6. Async_HelloServer2
  • 7. Async_HttpBasicAuth
  • 8. AsyncMultiWebServer_ESP32_W5500
  • 9. Async_PostServer
  • 10. Async_RegexPatterns_ESP32_W5500
  • 11. AsyncSimpleServer_ESP32_W5500
  • 12. AsyncWebServer_SendChunked
  • 13. Async_WebSocketsServer
  • 14. MQTTClient_Auth
  • 15. MQTTClient_Basic
  • 16. MQTT_ThingStream
• Example Async_AdvancedWebServer
• Debug Terminal Output Samples
  • 1. AsyncMultiWebServer_ESP32_W5500 on ESP32_DEV with ESP32_W5500
  • 2. Async_AdvancedWebServer_MemoryIssues_Send_CString on ESP32_DEV with ESP32_W5500
  • 3. Async_AdvancedWebServer_SendChunked on ESP32_DEV with ESP32_W5500
  • 4. AsyncWebServer_SendChunked on ESP32_DEV with ESP32_W5500
  • 5. Async_WebSocketsServer on ESP32_DEV with ESP32_W5500
  • 6. Async_HTTPBasicAuth on ESP32_DEV with ESP32_W5500
• Debug
• Troubleshooting
• Issues
• TO DO
• DONE
• Contributions and Thanks
• Contributing
• License
• Copyright

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Important Note from v1.6.2

The new v1.6.2+ has added a new and powerful feature to permit using CString to save heap to send very large data.

Check the marvelleous PRs of @salasidis in Portenta_H7_AsyncWebServer library

• request->send(200, textPlainStr, jsonChartDataCharStr); - Without using String Class - to save heap #8
• All memmove() removed - string no longer destroyed #11

and these new examples

1. Async_AdvancedWebServer_MemoryIssues_Send_CString
2. Async_AdvancedWebServer_MemoryIssues_SendArduinoString

If using Arduino String, to send a buffer around 30 KBytes, the used Max Heap is around 144,124 bytes

If using CString in regular memory, with the same 30 KBytes, the used Max Heap is around 111,828 bytes, saving around a buffer size (30 KBytes)

This is very critical in use-cases where sending very large data is necessary, without heap-allocation-error.

1. The traditional function used to send Arduino String is

void send(int code, const String& contentType = String(), const String& content = String());

such as

request->send(200, textPlainStr, ArduinoStr);

The required additional HEAP is about 3 times of the String size

2. To use CString with copying while sending. Use function

void send(int code, const String& contentType, const char *content, bool nonDetructiveSend = true);    // RSMOD

such as

request->send(200, textPlainStr, cStr);

The required additional HEAP is also about 2 times of the CString size because of unnecessary copies of the CString in HEAP. Avoid this unefficient way.

3. To use CString without copying while sending. Use function

void send(int code, const String& contentType, const char *content, bool nonDetructiveSend = true);    // RSMOD

such as

request->send(200, textPlainStr, cStr, false);

The required additional HEAP is about 1 times of the CString size. This way is the best and most efficient way to use by avoiding of unnecessary copies of the CString in HEAP

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Why do we need this AsyncWebServer_ESP32_W5500 library

Features

This library is based on, modified from:

1. Hristo Gochkov's ESPAsyncWebServer

to apply the better and faster asynchronous feature of the powerful ESPAsyncWebServer Library into (ESP32 + W5500).

Why Async is better

• Using asynchronous network means that you can handle more than one connection at the same time
• You are called once the request is ready and parsed
• When you send the response, you are immediately ready to handle other connections while the server is taking care of sending the response in the background
• Speed is OMG
• Easy to use API, HTTP Basic and Digest MD5 Authentication (default), ChunkedResponse
• Easily extensible to handle any type of content
• Supports Continue 100
• Async WebSocket plugin offering different locations without extra servers or ports
• Async EventSource (Server-Sent Events) plugin to send events to the browser
• URL Rewrite plugin for conditional and permanent url rewrites
• ServeStatic plugin that supports cache, Last-Modified, default index and more
• Simple template processing engine to handle templates

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Currently supported Boards

1. (ESP32 + W5500 Ethernet) boards

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Prerequisites

1. Arduino IDE 1.8.19+ for Arduino.
2. ESP32 Core 2.0.6+ for ESP32-based boards. ESP32 Latest Core
3. AsyncTCP library v1.1.1+.

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Installation

Use Arduino Library Manager

The best and easiest way is to use Arduino Library Manager. Search for AsyncWebServer_ESP32_W5500, then select / install the latest version. You can also use this link for more detailed instructions.

Manual Install

1. Navigate to AsyncWebServer_ESP32_W5500 page.
2. Download the latest release AsyncWebServer_ESP32_W5500-main.zip.
3. Extract the zip file to AsyncWebServer_ESP32_W5500-main directory
4. Copy the whole AsyncWebServer_ESP32_W5500-main folder to Arduino libraries' directory such as ~/Arduino/libraries/.

VS Code & PlatformIO:

1. Install VS Code
2. Install PlatformIO
3. Install AsyncWebServer_ESP32_W5500 library by using Library Manager. Search for AsyncWebServer_ESP32_W5500 in Platform.io Author's Libraries
4. Use included platformio.ini file from examples to ensure that all dependent libraries will installed automatically. Please visit documentation for the other options and examples at Project Configuration File

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Important things to remember

• This is fully asynchronous server and as such does not run on the loop() thread.
• You can not use yield() or delay() or any function that uses them inside the callbacks
• The server is smart enough to know when to close the connection and free resources
• You can not send more than one response to a single request

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Principles of operation

The Async Web server

• Listens for connections
• Wraps the new clients into Request
• Keeps track of clients and cleans memory
• Manages Rewrites and apply them on the request url
• Manages Handlers and attaches them to Requests

Request Life Cycle

• TCP connection is received by the server
• The connection is wrapped inside Request object
• When the request head is received (type, url, get params, http version and host), the server goes through all Rewrites (in the order they were added) to rewrite the url and inject query parameters, next, it goes through all attached Handlers (in the order they were added) trying to find one that canHandle the given request. If none are found, the default(catch-all) handler is attached.
• The rest of the request is received, calling the handleUpload or handleBody methods of the Handler if they are needed (POST+File/Body)
• When the whole request is parsed, the result is given to the handleRequest method of the Handler and is ready to be responded to
• In the handleRequest method, to the Request is attached a Response object (see below) that will serve the response data back to the client
• When the Response is sent, the client is closed and freed from the memory

Rewrites and how do they work

• The Rewrites are used to rewrite the request url and/or inject get parameters for a specific request url path.
• All Rewrites are evaluated on the request in the order they have been added to the server.
• The Rewrite will change the request url only if the request url (excluding get parameters) is fully match the rewrite url, and when the optional Filter callback return true.
• Setting a Filter to the Rewrite enables to control when to apply the rewrite, decision can be based on request url, http version, request host/port/target host, get parameters or the request client's localIP or remoteIP.
• The Rewrite can specify a target url with optional get parameters, e.g. /to-url?with=params

Handlers and how do they work

• The Handlers are used for executing specific actions to particular requests
• One Handler instance can be attached to any request and lives together with the server
• Setting a Filter to the Handler enables to control when to apply the handler, decision can be based on request url, http version, request host/port/target host, get parameters or the request client's localIP or remoteIP.
• The canHandle method is used for handler specific control on whether the requests can be handled and for declaring any interesting headers that the Request should parse. Decision can be based on request method, request url, http version, request host/port/target host and get parameters
• Once a Handler is attached to given Request (canHandle returned true) that Handler takes care to receive any file/data upload and attach a Response once the Request has been fully parsed
• Handlers are evaluated in the order they are attached to the server. The canHandle is called only if the Filter that was set to the Handler return true.
• The first Handler that can handle the request is selected, not further Filter and canHandle are called.

Responses and how do they work

• The Response objects are used to send the response data back to the client
• The Response object lives with the Request and is freed on end or disconnect
• Different techniques are used depending on the response type to send the data in packets returning back almost immediately and sending the next packet when this one is received. Any time in between is spent to run the user loop and handle other network packets
• Responding asynchronously is probably the most difficult thing for most to understand
• Many different options exist for the user to make responding a background task

Template processing

• AsyncWebServer_ESP32_W5500 contains simple template processing engine.
• Template processing can be added to most response types.
• Currently it supports only replacing template placeholders with actual values. No conditional processing, cycles, etc.
• Placeholders are delimited with % symbols. Like this: %TEMPLATE_PLACEHOLDER%.
• It works by extracting placeholder name from response text and passing it to user provided function which should return actual value to be used instead of placeholder.
• Since it's user provided function, it is possible for library users to implement conditional processing and cycles themselves.
• Since it's impossible to know the actual response size after template processing step in advance (and, therefore, to include it in response headers), the response becomes chunked.

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Request Variables

Common Variables

request->version();       // uint8_t: 0 = HTTP/1.0, 1 = HTTP/1.1
request->method();        // enum:    HTTP_GET, HTTP_POST, HTTP_DELETE, HTTP_PUT, HTTP_PATCH, HTTP_HEAD, HTTP_OPTIONS
request->url();           // String:  URL of the request (not including host, port or GET parameters)
request->host();          // String:  The requested host (can be used for virtual hosting)
request->contentType();   // String:  ContentType of the request (not available in Handler::canHandle)
request->contentLength(); // size_t:  ContentLength of the request (not available in Handler::canHandle)
request->multipart();     // bool:    True if the request has content type "multipart"

Headers

//List all collected headers
int headers = request->headers();
int i;

for (i=0;i<headers;i++)
{
  AsyncWebHeader* h = request->getHeader(i);
  Serial.printf("HEADER[%s]: %s\n", h->name().c_str(), h->value().c_str());
}

//get specific header by name
if (request->hasHeader("MyHeader"))
{
  AsyncWebHeader* h = request->getHeader("MyHeader");
  Serial.printf("MyHeader: %s\n", h->value().c_str());
}

//List all collected headers (Compatibility)
int headers = request->headers();
int i;

for (i=0;i<headers;i++)
{
  Serial.printf("HEADER[%s]: %s\n", request->headerName(i).c_str(), request->header(i).c_str());
}

//get specific header by name (Compatibility)
if (request->hasHeader("MyHeader"))
{
  Serial.printf("MyHeader: %s\n", request->header("MyHeader").c_str());
}

GET, POST and FILE parameters

//List all parameters
int params = request->params();

for (int i=0;i<params;i++)
{
  AsyncWebParameter* p = request->getParam(i);
  
  if (p->isFile())
  { 
    //p->isPost() is also true
    Serial.printf("FILE[%s]: %s, size: %u\n", p->name().c_str(), p->value().c_str(), p->size());
  } 
  else if (p->isPost())
  {
    Serial.printf("POST[%s]: %s\n", p->name().c_str(), p->value().c_str());
  } 
  else 
  {
    Serial.printf("GET[%s]: %s\n", p->name().c_str(), p->value().c_str());
  }
}

//Check if GET parameter exists
if (request->hasParam("download"))
  AsyncWebParameter* p = request->getParam("download");

//Check if POST (but not File) parameter exists
if (request->hasParam("download", true))
  AsyncWebParameter* p = request->getParam("download", true);

//Check if FILE was uploaded
if (request->hasParam("download", true, true))
  AsyncWebParameter* p = request->getParam("download", true, true);

//List all parameters (Compatibility)
int args = request->args();

for (int i=0;i<args;i++)
{
  Serial.printf("ARG[%s]: %s\n", request->argName(i).c_str(), request->arg(i).c_str());
}

//Check if parameter exists (Compatibility)
if (request->hasArg("download"))
  String arg = request->arg("download");

JSON body handling with ArduinoJson

Endpoints which consume JSON can use a special handler to get ready to use JSON data in the request callback:

#include "AsyncJson.h"
#include "ArduinoJson.h"

AsyncCallbackJsonWebHandler* handler = new AsyncCallbackJsonWebHandler("/rest/endpoint", [](AsyncWebServerRequest *request, JsonVariant &json) 
{
  JsonObject& jsonObj = json.as<JsonObject>();
  // ...
});

server.addHandler(handler);

---

Responses

Redirect to another URL

//to local url
request->redirect("/login");

//to external url
request->redirect("http://esp8266.com");

Basic response with HTTP Code

request->send(404); //Sends 404 File Not Found

Basic response with HTTP Code and extra headers

AsyncWebServerResponse *response = request->beginResponse(404); //Sends 404 File Not Found
response->addHeader("Server","AsyncWebServer_ESP32_W5500");
request->send(response);

Basic response with string content

request->send(200, "text/plain", "Hello World!");

Basic response with string content and extra headers

AsyncWebServerResponse *response = request->beginResponse(200, "text/plain", "Hello World!");
response->addHeader("Server","AsyncWebServer");
request->send(response);

Respond with content coming from a Stream

//read 12 bytes from Serial and send them as Content Type text/plain
request->send(Serial, "text/plain", 12);

Respond with content coming from a Stream and extra headers

//read 12 bytes from Serial and send them as Content Type text/plain
AsyncWebServerResponse *response = request->beginResponse(Serial, "text/plain", 12);
response->addHeader("Server","AsyncWebServer_ESP32_W5500");
request->send(response);

Respond with content coming from a Stream containing templates

String processor(const String& var)
{
  if (var == "HELLO_FROM_TEMPLATE")
    return F("Hello world!");
    
  return String();
}

// ...

//read 12 bytes from Serial and send them as Content Type text/plain
request->send(Serial, "text/plain", 12, processor);

Respond with content coming from a Stream containing templates and extra headers

String processor(const String& var)
{
  if (var == "HELLO_FROM_TEMPLATE")
    return F("Hello world!");
  return String();
}

// ...

//read 12 bytes from Serial and send them as Content Type text/plain
AsyncWebServerResponse *response = request->beginResponse(Serial, "text/plain", 12, processor);
response->addHeader("Server","AsyncWebServer_ESP32_W5500");
request->send(response);

Respond with content using a callback

//send 128 bytes as plain text
request->send("text/plain", 128, [](uint8_t *buffer, size_t maxLen, size_t index) -> size_t 
{
  //Write up to "maxLen" bytes into "buffer" and return the amount written.
  //index equals the amount of bytes that have been already sent
  //You will not be asked for more bytes once the content length has been reached.
  //Keep in mind that you can not delay or yield waiting for more data!
  //Send what you currently have and you will be asked for more again
  return mySource.read(buffer, maxLen);
});

Respond with content using a callback and extra headers

//send 128 bytes as plain text
AsyncWebServerResponse *response = request->beginResponse("text/plain", 128, [](uint8_t *buffer, size_t maxLen, size_t index) -> size_t 
{
  //Write up to "maxLen" bytes into "buffer" and return the amount written.
  //index equals the amount of bytes that have been already sent
  //You will not be asked for more bytes once the content length has been reached.
  //Keep in mind that you can not delay or yield waiting for more data!
  //Send what you currently have and you will be asked for more again
  return mySource.read(buffer, maxLen);
});

response->addHeader("Server","AsyncWebServer_ESP32_W5500");
request->send(response);

Respond with content using a callback containing templates

String processor(const String& var)
{
  if (var == "HELLO_FROM_TEMPLATE")
    return F("Hello world!");
    
  return String();
}

// ...

//send 128 bytes as plain text
request->send("text/plain", 128, [](uint8_t *buffer, size_t maxLen, size_t index) -> size_t 
{
  //Write up to "maxLen" bytes into "buffer" and return the amount written.
  //index equals the amount of bytes that have been already sent
  //You will not be asked for more bytes once the content length has been reached.
  //Keep in mind that you can not delay or yield waiting for more data!
  //Send what you currently have and you will be asked for more again
  return mySource.read(buffer, maxLen);
}, processor);

Respond with content using a callback containing templates and extra headers

String processor(const String& var)
{
  if (var == "HELLO_FROM_TEMPLATE")
    return F("Hello world!");
  return String();
}

// ...

//send 128 bytes as plain text
AsyncWebServerResponse *response = request->beginResponse("text/plain", 128, [](uint8_t *buffer, size_t maxLen, size_t index) -> size_t 
{
  //Write up to "maxLen" bytes into "buffer" and return the amount written.
  //index equals the amount of bytes that have been already sent
  //You will not be asked for more bytes once the content length has been reached.
  //Keep in mind that you can not delay or yield waiting for more data!
  //Send what you currently have and you will be asked for more again
  return mySource.read(buffer, maxLen);
}, processor);

response->addHeader("Server","AsyncWebServer_ESP32_W5500");
request->send(response);

Chunked Response

Used when content length is unknown. Works best if the client supports HTTP/1.1

AsyncWebServerResponse *response = request->beginChunkedResponse("text/plain", [](uint8_t *buffer, size_t maxLen, size_t index) -> size_t 
{
  //Write up to "maxLen" bytes into "buffer" and return the amount written.
  //index equals the amount of bytes that have been already sent
  //You will be asked for more data until 0 is returned
  //Keep in mind that you can not delay or yield waiting for more data!
  return mySource.read(buffer, maxLen);
});

response->addHeader("Server","AsyncWebServer_ESP32_W5500");
request->send(response);

Chunked Response containing templates

Used when content length is unknown. Works best if the client supports HTTP/1.1

String processor(const String& var)
{
  if (var == "HELLO_FROM_TEMPLATE")
    return F("Hello world!");
    
  return String();
}

// ...

AsyncWebServerResponse *response = request->beginChunkedResponse("text/plain", [](uint8_t *buffer, size_t maxLen, size_t index) -> size_t 
{
  //Write up to "maxLen" bytes into "buffer" and return the amount written.
  //index equals the amount of bytes that have been already sent
  //You will be asked for more data until 0 is returned
  //Keep in mind that you can not delay or yield waiting for more data!
  return mySource.read(buffer, maxLen);
}, processor);

response->addHeader("Server","AsyncWebServer_ESP32_W5500");
request->send(response);

Print to response

AsyncResponseStream *response = request->beginResponseStream("text/html");
response->addHeader("Server","AsyncWebServer_ESP32_W5500");
response->printf("<!DOCTYPE html><html><head><title>Webpage at %s</title></head><body>", request->url().c_str());

response->print("<h2>Hello ");
response->print(request->client()->remoteIP());
response->print("</h2>");

response->print("<h3>General</h3>");
response->print("<ul>");
response->printf("<li>Version: HTTP/1.%u</li>", request->version());
response->printf("<li>Method: %s</li>", request->methodToString());
response->printf("<li>URL: %s</li>", request->url().c_str());
response->printf("<li>Host: %s</li>", request->host().c_str());
response->printf("<li>ContentType: %s</li>", request->contentType().c_str());
response->printf("<li>ContentLength: %u</li>", request->contentLength());
response->printf("<li>Multipart: %s</li>", request->multipart()?"true":"false");
response->print("</ul>");

response->print("<h3>Headers</h3>");
response->print("<ul>");
int headers = request->headers();

for (int i=0;i<headers;i++)
{
  AsyncWebHeader* h = request->getHeader(i);
  response->printf("<li>%s: %s</li>", h->name().c_str(), h->value().c_str());
}

response->print("</ul>");

response->print("<h3>Parameters</h3>");
response->print("<ul>");

int params = request->params();

for (int i=0;i<params;i++)
{
  AsyncWebParameter* p = request->getParam(i);
  
  if (p->isFile())
  {
    response->printf("<li>FILE[%s]: %s, size: %u</li>", p->name().c_str(), p->value().c_str(), p->size());
  } 
  else if (p->isPost())
  {
    response->printf("<li>POST[%s]: %s</li>", p->name().c_str(), p->value().c_str());
  } 
  else 
  {
    response->printf("<li>GET[%s]: %s</li>", p->name().c_str(), p->value().c_str());
  }
}

response->print("</ul>");

response->print("</body></html>");
//send the response last
request->send(response);

ArduinoJson Basic Response

This way of sending Json is great for when the result is below 4KB

#include "AsyncJson.h"
#include "ArduinoJson.h"


AsyncResponseStream *response = request->beginResponseStream("application/json");
DynamicJsonBuffer jsonBuffer;
JsonObject &root = jsonBuffer.createObject();
root["heap"] = ESP.getFreeHeap();
root["ssid"] = WiFi.SSID();
root.printTo(*response);

request->send(response);

ArduinoJson Advanced Response

This response can handle really large Json objects (tested to 40KB)

There isn't any noticeable speed decrease for small results with the method above

Since ArduinoJson does not allow reading parts of the string, the whole Json has to be passed every time a chunks needs to be sent, which shows speed decrease proportional to the resulting json packets

#include "AsyncJson.h"
#include "ArduinoJson.h"

AsyncJsonResponse * response = new AsyncJsonResponse();
response->addHeader("Server","AsyncWebServer");
JsonObject& root = response->getRoot();
root["IP"] = Ethernet.localIP();
response->setLength();

request->send(response);

---

Param Rewrite With Matching

It is possible to rewrite the request url with parameter matchg. Here is an example with one parameter: Rewrite for example "/radio/{frequence}" -> "/radio?f={frequence}"

class OneParamRewrite : public AsyncWebRewrite
{
  protected:
    String _urlPrefix;
    int _paramIndex;
    String _paramsBackup;

  public:
  OneParamRewrite(const char* from, const char* to)
    : AsyncWebRewrite(from, to) 
    {

      _paramIndex = _from.indexOf('{');

      if ( _paramIndex >=0 && _from.endsWith("}")) 
      {
        _urlPrefix = _from.substring(0, _paramIndex);
        int index = _params.indexOf('{');
        
        if (index >= 0) 
        {
          _params = _params.substring(0, index);
        }
      } 
      else 
      {
        _urlPrefix = _from;
      }
      
      _paramsBackup = _params;
  }

  bool match(AsyncWebServerRequest *request) override 
  {
    if (request->url().startsWith(_urlPrefix)) 
    {
      if (_paramIndex >= 0) 
      {
        _params = _paramsBackup + request->url().substring(_paramIndex);
      } 
      else 
      {
        _params = _paramsBackup;
      }
      
      return true;

    } 
    else 
    {
      return false;
    }
  }
};

Usage:

  server.addRewrite( new OneParamRewrite("/radio/{frequence}", "/radio?f={frequence}") );

---

Using filters

Filters can be set to Rewrite or Handler in order to control when to apply the rewrite and consider the handler. A filter is a callback function that evaluates the request and return a boolean true to include the item or false to exclude it.

---

Bad Responses

Some responses are implemented, but you should not use them, because they do not conform to HTTP. The following example will lead to unclean close of the connection and more time wasted than providing the length of the content

Respond with content using a callback without content length to HTTP/1.0 clients

//This is used as fallback for chunked responses to HTTP/1.0 Clients
request->send("text/plain", 0, [](uint8_t *buffer, size_t maxLen, size_t index) -> size_t 
{
  //Write up to "maxLen" bytes into "buffer" and return the amount written.
  //You will be asked for more data until 0 is returned
  //Keep in mind that you can not delay or yield waiting for more data!
  return mySource.read(buffer, maxLen);
});

---

Async WebSocket Plugin

The server includes a web socket plugin which lets you define different WebSocket locations to connect to without starting another listening service or using different port

Async WebSocket Event

void onEvent(AsyncWebSocket * server, AsyncWebSocketClient * client, AwsEventType type, void * arg, uint8_t *data, size_t len)
{
  if (type == WS_EVT_CONNECT)
  {
    //client connected
    Serial.printf("ws[%s][%u] connect\n", server->url(), client->id());
    client->printf("Hello Client %u :)", client->id());
    client->ping();
  } 
  else if (type == WS_EVT_DISCONNECT)
  {
    //client disconnected
    Serial.printf("ws[%s][%u] disconnect: %u\n", server->url(), client->id());
  } 
  else if (type == WS_EVT_ERROR)
  {
    //error was received from the other end
    Serial.printf("ws[%s][%u] error(%u): %s\n", server->url(), client->id(), *((uint16_t*)arg), (char*)data);
  } 
  else if (type == WS_EVT_PONG)
  {
    //pong message was received (in response to a ping request maybe)
    Serial.printf("ws[%s][%u] pong[%u]: %s\n", server->url(), client->id(), len, (len)?(char*)data:"");
  } 
  else if (type == WS_EVT_DATA)
  {
    //data packet
    AwsFrameInfo * info = (AwsFrameInfo*)arg;
    
    if (info->final && info->index == 0 && info->len == len)
    {
      //the whole message is in a single frame and we got all of it's data
      Serial.printf("ws[%s][%u] %s-message[%llu]: ", server->url(), client->id(), (info->opcode == WS_TEXT)?"text":"binary", info->len);
      
      if (info->opcode == WS_TEXT)
      {
        data[len] = 0;
        Serial.printf("%s\n", (char*)data);
      } 
      else 
      {
        for (size_t i=0; i < info->len; i++)
        {
          Serial.printf("%02x ", data[i]);
        }
        
        Serial.printf("\n");
      }
      
      if (info->opcode == WS_TEXT)
        client->text("I got your text message");
      else
        client->binary("I got your binary message");
    } 
    else 
    {
      //message is comprised of multiple frames or the frame is split into multiple packets
      if (info->index == 0)
      {
        if (info->num == 0)
          Serial.printf("ws[%s][%u] %s-message start\n", server->url(), client->id(), (info->message_opcode == WS_TEXT)?"text":"binary");
          
        Serial.printf("ws[%s][%u] frame[%u] start[%llu]\n", server->url(), client->id(), info->num, info->len);
      }

      Serial.printf("ws[%s][%u] frame[%u] %s[%llu - %llu]: ", server->url(), client->id(), info->num, (info->message_opcode == WS_TEXT)?"text":"binary", info->index, info->index + len);
      
      if (info->message_opcode == WS_TEXT)
      {
        data[len] = 0;
        Serial.printf("%s\n", (char*)data);
      } 
      else 
      {
        for (size_t i=0; i < len; i++){
          Serial.printf("%02x ", data[i]);
        }
        Serial.printf("\n");
      }

      if ((info->index + len) == info->len)
      {
        Serial.printf("ws[%s][%u] frame[%u] end[%llu]\n", server->url(), client->id(), info->num, info->len);
        
        if (info->final)
        {
          Serial.printf("ws[%s][%u] %s-message end\n", server->url(), client->id(), (info->message_opcode == WS_TEXT)?"text":"binary");
          
          if (info->message_opcode == WS_TEXT)
            client->text("I got your text message");
          else
            client->binary("I got your binary message");
        }
      }
    }
  }
}

Methods for sending data to a socket client

//Server methods
AsyncWebSocket ws("/ws");
//printf to a client
ws.printf((uint32_t)client_id, arguments...);
//printf to all clients
ws.printfAll(arguments...);
//send text to a client
ws.text((uint32_t)client_id, (char*)text);
ws.text((uint32_t)client_id, (uint8_t*)text, (size_t)len);
//send text to all clients
ws.textAll((char*)text);
ws.textAll((uint8_t*)text, (size_t)len);
//send binary to a client
ws.binary((uint32_t)client_id, (char*)binary);
ws.binary((uint32_t)client_id, (uint8_t*)binary, (size_t)len);
ws.binary((uint32_t)client_id, flash_binary, 4);
//send binary to all clients
ws.binaryAll((char*)binary);
ws.binaryAll((uint8_t*)binary, (size_t)len);
//HTTP Authenticate before switch to Websocket protocol
ws.setAuthentication("user", "pass");

//client methods
AsyncWebSocketClient * client;
//printf
client->printf(arguments...);
//send text
client->text((char*)text);
client->text((uint8_t*)text, (size_t)len);
//send binary
client->binary((char*)binary);
client->binary((uint8_t*)binary, (size_t)len);

Direct access to web socket message buffer

When sending a web socket message using the above methods a buffer is created. Under certain circumstances you might want to manipulate or populate this buffer directly from your application, for example to prevent unnecessary duplications of the data. This example below shows how to create a buffer and print data to it from an ArduinoJson object then send it.

void sendDataWs(AsyncWebSocketClient * client)
{
  DynamicJsonBuffer jsonBuffer;
  JsonObject& root = jsonBuffer.createObject();
  root["a"] = "abc";
  root["b"] = "abcd";
  root["c"] = "abcde";
  root["d"] = "abcdef";
  root["e"] = "abcdefg";
  size_t len = root.measureLength();
  AsyncWebSocketMessageBuffer * buffer = ws.makeBuffer(len); //  creates a buffer (len + 1) for you.
  
  if (buffer) 
  {
    root.printTo((char *)buffer->get(), len + 1);
    
    if (client) 
    {
        client->text(buffer);
    } 
    else 
    {
        ws.textAll(buffer);
    }
  }
}

Limiting the number of web socket clients

Browsers sometimes do not correctly close the websocket connection, even when the close() function is called in javascript. This will eventually exhaust the web server's resources and will cause the server to crash. Periodically calling the cleanClients() function from the main loop() function limits the number of clients by closing the oldest client when the maximum number of clients has been exceeded. This can called be every cycle, however, if you wish to use less power, then calling as infrequently as once per second is sufficient.

void loop()
{
  ws.cleanupClients();
}

---

Async Event Source Plugin

The server includes EventSource (Server-Sent Events) plugin which can be used to send short text events to the browser. Difference between EventSource and WebSockets is that EventSource is single direction, text-only protocol.

Setup Event Source on the server

AsyncWebServer server(80);
AsyncEventSource events("/events");

void setup()
{
  // setup ......
  events.onConnect([](AsyncEventSourceClient *client)
  {
    if (client->lastId())
    {
      Serial.printf("Client reconnected! Last message ID that it got is: %u\n", client->lastId());
    }
    
    //send event with message "hello!", id current millis
    // and set reconnect delay to 1 second
    client->send("hello!",NULL,millis(),1000);
  });
  
  //HTTP Basic authentication
  events.setAuthentication("user", "pass");
  server.addHandler(&events);
  // setup ......
}

void loop()
{
  if (eventTriggered)
  { 
    // your logic here
    //send event "myevent"
    events.send("my event content","myevent",millis());
  }
}

Setup Event Source in the browser

if (!!window.EventSource) 
{
  var source = new EventSource('/events');

  source.addEventListener('open', function(e) 
  {
    console.log("Events Connected");
  }, false);

  source.addEventListener('error', function(e) 
  {
    if (e.target.readyState != EventSource.OPEN) 
    {
      console.log("Events Disconnected");
    }
  }, false);

  source.addEventListener('message', function(e) 
  {
    console.log("message", e.data);
  }, false);

  source.addEventListener('myevent', function(e) 
  {
    console.log("myevent", e.data);
  }, false);
}

---

Remove handlers and rewrites

Server goes through handlers in same order as they were added. You can't simple add handler with same path to override them. To remove handler:

// save callback for particular URL path
auto handler = server.on("/some/path", [](AsyncWebServerRequest *request)
{
  //do something useful
});

// when you don't need handler anymore remove it
server.removeHandler(&handler);

// same with rewrites
server.removeRewrite(&someRewrite);

server.onNotFound([](AsyncWebServerRequest *request)
{
  request->send(404);
});

// remove server.onNotFound handler
server.onNotFound(NULL);

// remove all rewrites, handlers and onNotFound/onFileUpload/onRequestBody callbacks
server.reset();

---

Setting up the server

#if !( defined(ESP32) )
  #error This code is designed for (ESP32 + W5500) to run on ESP32 platform! Please check your Tools->Board setting.
#endif

#include <Arduino.h>

#define _ASYNC_WEBSERVER_LOGLEVEL_       2

// Enter a MAC address and IP address for your controller below.
#define NUMBER_OF_MAC      20

byte mac[][NUMBER_OF_MAC] =
{
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x01 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x02 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x03 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x04 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x05 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x06 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x07 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x08 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x09 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x0A },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x0B },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x0C },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x0D },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x0E },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x0F },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x10 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x11 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x12 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x13 },
  { 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x14 },
};

// Select the IP address according to your local network
IPAddress myIP(192, 168, 2, 232);
IPAddress myGW(192, 168, 2, 1);
IPAddress mySN(255, 255, 255, 0);

// Google DNS Server IP
IPAddress myDNS(8, 8, 8, 8);

//////////////////////////////////////////////////////////

// Optional values to override default settings
// Don't change unless you know what you're doing
//#define ETH_SPI_HOST        SPI3_HOST
//#define SPI_CLOCK_MHZ       25

// Must connect INT to GPIOxx or not working
//#define INT_GPIO            4

//#define MISO_GPIO           19
//#define MOSI_GPIO           23
//#define SCK_GPIO            18
//#define CS_GPIO             5

//////////////////////////////////////////////////////////

#include <AsyncTCP.h>

#include <AsyncWebServer_ESP32_W5500.h>

AsyncWebServer    server(80);

void handleRoot(AsyncWebServerRequest *request)
{
  request->send(200, "text/plain", String("Hello from Async_HelloServer on ") + ARDUINO_BOARD );
}

void handleNotFound(AsyncWebServerRequest *request)
{
  String message = "File Not Found\n\n";

  message += "URI: ";
  //message += server.uri();
  message += request->url();
  message += "\nMethod: ";
  message += (request->method() == HTTP_GET) ? "GET" : "POST";
  message += "\nArguments: ";
  message += request->args();
  message += "\n";

  for (uint8_t i = 0; i < request->args(); i++)
  {
    message += " " + request->argName(i) + ": " + request->arg(i) + "\n";
  }

  request->send(404, "text/plain", message);
}

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

  while (!Serial && millis() < 5000);

  delay(200);

  Serial.print(F("\nStart Async_HelloServer on "));
  Serial.print(ARDUINO_BOARD);
  Serial.print(F(" with "));
  Serial.println(SHIELD_TYPE);
  Serial.println(ASYNC_WEBSERVER_ESP32_W5500_VERSION);

  AWS_LOGWARN(F("Default SPI pinout:"));
  AWS_LOGWARN1(F("SPI_HOST:"), ETH_SPI_HOST);
  AWS_LOGWARN1(F("MOSI:"), MOSI_GPIO);
  AWS_LOGWARN1(F("MISO:"), MISO_GPIO);
  AWS_LOGWARN1(F("SCK:"),  SCK_GPIO);
  AWS_LOGWARN1(F("CS:"),   CS_GPIO);
  AWS_LOGWARN1(F("INT:"),  INT_GPIO);
  AWS_LOGWARN1(F("SPI Clock (MHz):"), SPI_CLOCK_MHZ);
  AWS_LOGWARN(F("========================="));

  ///////////////////////////////////

  // To be called before ETH.begin()
  ESP32_W5500_onEvent();

  // start the ethernet connection and the server:
  // Use DHCP dynamic IP and random mac
  uint16_t index = millis() % NUMBER_OF_MAC;

  //bool begin(int MISO_GPIO, int MOSI_GPIO, int SCLK_GPIO, int CS_GPIO, int INT_GPIO, int SPI_CLOCK_MHZ,
  //           int SPI_HOST, uint8_t *W5500_Mac = W5500_Default_Mac);
  //ETH.begin( MISO_GPIO, MOSI_GPIO, SCK_GPIO, CS_GPIO, INT_GPIO, SPI_CLOCK_MHZ, ETH_SPI_HOST );
  ETH.begin( MISO_GPIO, MOSI_GPIO, SCK_GPIO, CS_GPIO, INT_GPIO, SPI_CLOCK_MHZ, ETH_SPI_HOST, mac[index] );

  // Static IP, leave without this line to get IP via DHCP
  //bool config(IPAddress local_ip, IPAddress gateway, IPAddress subnet, IPAddress dns1 = 0, IPAddress dns2 = 0);
  //ETH.config(myIP, myGW, mySN, myDNS);

  ESP32_W5500_waitForConnect();

  ///////////////////////////////////


  server.on("/", HTTP_GET, [](AsyncWebServerRequest * request)
  {
    handleRoot(request);
  });

  server.on("/inline", [](AsyncWebServerRequest * request)
  {
    request->send(200, "text/plain", "This works as well");
  });

  server.onNotFound(handleNotFound);

  server.begin();

  Serial.print(F("HTTP EthernetWebServer is @ IP : "));
  Serial.println(ETH.localIP());
}

void loop()
{
}

---

Setup global and class functions as request handlers

#include <Arduino.h>

#include <AsyncWebServer_ESP32_W5500.h>

...

void handleRequest(AsyncWebServerRequest *request){}

class WebClass 
{
public :
  AsyncWebServer classWebServer = AsyncWebServer(81);

  WebClass(){};

  void classRequest (AsyncWebServerRequest *request){}

  void begin()
  {
    // attach global request handler
    classWebServer.on("/example", HTTP_ANY, handleRequest);

    // attach class request handler
    classWebServer.on("/example", HTTP_ANY, std::bind(&WebClass::classRequest, this, std::placeholders::_1));
  }
};

AsyncWebServer globalWebServer(80);
WebClass webClassInstance;

void setup() 
{
  // attach global request handler
  globalWebServer.on("/example", HTTP_ANY, handleRequest);

  // attach class request handler
  globalWebServer.on("/example", HTTP_ANY, std::bind(&WebClass::classRequest, webClassInstance, std::placeholders::_1));
}

void loop() 
{
}

Methods for controlling websocket connections

// Disable client connections if it was activated
if ( ws.enabled() )
  ws.enable(false);

// enable client connections if it was disabled
if ( !ws.enabled() )
  ws.enable(true);

Adding Default Headers

In some cases, such as when working with CORS, or with some sort of custom authentication system, you might need to define a header that should get added to all responses (including static, websocket and EventSource). The DefaultHeaders singleton allows you to do this.

Example:

DefaultHeaders::Instance().addHeader("Access-Control-Allow-Origin", "*");
webServer.begin();

NOTE: You will still need to respond to the OPTIONS method for CORS pre-flight in most cases. (unless you are only using GET)

This is one option:

webServer.onNotFound([](AsyncWebServerRequest *request) 
{
  if (request->method() == HTTP_OPTIONS) 
  {
    request->send(200);
  } 
  else 
  {
    request->send(404);
  }
});

---

Path variable

With path variable you can create a custom regex rule for a specific parameter in a route. For example we want a sensorId parameter in a route rule to match only a integer.

server.on("^\\/sensor\\/([0-9]+)$", HTTP_GET, [] (AsyncWebServerRequest *request) 
{
    String sensorId = request->pathArg(0);
});

NOTE: All regex patterns starts with ^ and ends with $

To enable the Path variable support, you have to define the buildflag -DASYNCWEBSERVER_REGEX.

For Arduino IDE create/update platform.local.txt:

Windows: C:\Users(username)\AppData\Local\Arduino15\packages\{espxxxx}\hardware\espxxxx\{version}\platform.local.txt

Linux: ~/.arduino15/packages/{espxxxx}/hardware/{espxxxx}/{version}/platform.local.txt

Add/Update the following line:

compiler.cpp.extra_flags=-DDASYNCWEBSERVER_REGEX

For platformio modify platformio.ini:

[env:myboard]
build_flags = 
  -DASYNCWEBSERVER_REGEX

NOTE: By enabling ASYNCWEBSERVER_REGEX, <regex> will be included. This will add an 100k to your binary.

---

---

How to connect W5500 to ESP32

You can change the INT pin to another one. Default is GPIO4

// Must connect INT to GPIOxx or not working
#define INT_GPIO            4

---

W5500

---

W5500	<--->	ESP32
MOSI	<--->	GPIO23
MISO	<--->	GPIO19
SCK	<--->	GPIO18
SS	<--->	GPIO5
INT	<--->	GPIO4
RST	<--->	RST
GND	<--->	GND
3.3V	<--->	3.3V

---

---

Examples

1. Async_AdvancedWebServer
2. Async_AdvancedWebServer_MemoryIssues_SendArduinoString
3. Async_AdvancedWebServer_MemoryIssues_Send_CString
4. Async_AdvancedWebServer_SendChunked
5. Async_HelloServer
6. Async_HelloServer2
7. Async_HttpBasicAuth
8. AsyncMultiWebServer_ESP32_W5500
9. Async_PostServer
10. Async_RegexPatterns_ESP32_W5500
11. AsyncSimpleServer_ESP32_W5500
12. AsyncWebServer_SendChunked
13. Async_WebSocketsServer
14. MQTTClient_Auth
15. MQTTClient_Basic
16. MQTT_ThingStream

---

---

Example Async_AdvancedWebServer

AsyncWebServer_ESP32_W5500/examples/Async_AdvancedWebServer/Async_AdvancedWebServer.ino

Lines 41 to 256 in 80ac7ee

	#if !( defined(ESP32) )
	#error This code is designed for (ESP32 + W5500) to run on ESP32 platform! Please check your Tools->Board setting.
	#endif
	#include <Arduino.h>
	#define _ASYNC_WEBSERVER_LOGLEVEL_ 2
	// Enter a MAC address and IP address for your controller below.
	#define NUMBER_OF_MAC 20
	byte mac[][NUMBER_OF_MAC] =
	{
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x01 },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x02 },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x03 },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x04 },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x05 },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x06 },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x07 },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x08 },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x09 },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x0A },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x0B },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x0C },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x0D },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x0E },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x0F },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x10 },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x11 },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x12 },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x13 },
	{ 0xDE, 0xAD, 0xBE, 0xEF, 0xBE, 0x14 },
	};
	// Select the IP address according to your local network
	IPAddress myIP(192, 168, 2, 232);
	IPAddress myGW(192, 168, 2, 1);
	IPAddress mySN(255, 255, 255, 0);
	// Google DNS Server IP
	IPAddress myDNS(8, 8, 8, 8);
	//////////////////////////////////////////////////////////
	// Optional values to override default settings
	// Don't change unless you know what you're doing
	//#define ETH_SPI_HOST SPI3_HOST
	//#define SPI_CLOCK_MHZ 25
	// Must connect INT to GPIOxx or not working
	//#define INT_GPIO 4
	//#define MISO_GPIO 19
	//#define MOSI_GPIO 23
	//#define SCK_GPIO 18
	//#define CS_GPIO 5
	//////////////////////////////////////////////////////////
	#include <AsyncTCP.h>
	#include <AsyncWebServer_ESP32_W5500.h>
	AsyncWebServer server(80);
	int reqCount = 0; // number of requests received
	void handleRoot(AsyncWebServerRequest *request)
	{
	#define BUFFER_SIZE 400
	char temp[BUFFER_SIZE];
	int sec = millis() / 1000;
	int min = sec / 60;
	int hr = min / 60;
	int day = hr / 24;
	snprintf(temp, BUFFER_SIZE - 1,
	"<html>\
	<head>\
	<meta http-equiv='refresh' content='5'/>\
	<title>AsyncWebServer-%s</title>\
	<style>\
	body { background-color: #cccccc; font-family: Arial, Helvetica, Sans-Serif; Color: #000088; }\
	</style>\
	</head>\
	<body>\
	<h2>AsyncWebServer_ESP32_W5500!</h2>\
	<h3>running on %s</h3>\
	<p>Uptime: %d d %02d:%02d:%02d</p>\
	<img src=\"/test.svg\" />\
	</body>\
	</html>", ARDUINO_BOARD, ARDUINO_BOARD, day, hr % 24, min % 60, sec % 60);
	request->send(200, "text/html", temp);
	}
	void handleNotFound(AsyncWebServerRequest *request)
	{
	String message = "File Not Found\n\n";
	message += "URI: ";
	message += request->url();
	message += "\nMethod: ";
	message += (request->method() == HTTP_GET) ? "GET" : "POST";
	message += "\nArguments: ";
	message += request->args();
	message += "\n";
	for (uint8_t i = 0; i < request->args(); i++)
	{
	message += " " + request->argName(i) + ": " + request->arg(i) + "\n";
	}
	request->send(404, "text/plain", message);
	}
	void drawGraph(AsyncWebServerRequest *request)
	{
	String out;
	out.reserve(3000);
	char temp[70];
	out += "<svg xmlns=\"http://www.w3.org/2000/svg\" version=\"1.1\" width=\"310\" height=\"150\">\n";
	out += "<rect width=\"310\" height=\"150\" fill=\"rgb(250, 230, 210)\" stroke-width=\"2\" stroke=\"rgb(0, 0, 0)\" />\n";
	out += "<g stroke=\"blue\">\n";
	int y = rand() % 130;
	for (int x = 10; x < 300; x += 10)
	{
	int y2 = rand() % 130;
	sprintf(temp, "<line x1=\"%d\" y1=\"%d\" x2=\"%d\" y2=\"%d\" stroke-width=\"2\" />\n", x, 140 - y, x + 10, 140 - y2);
	out += temp;
	y = y2;
	}
	out += "</g>\n</svg>\n";
	request->send(200, "image/svg+xml", out);
	}
	void setup()
	{
	Serial.begin(115200);
	while (!Serial && millis() < 5000);
	delay(200);
	Serial.print(F("\nStart AAsync_AdvancedWebServer on "));
	Serial.print(ARDUINO_BOARD);
	Serial.print(F(" with "));
	Serial.println(SHIELD_TYPE);
	Serial.println(ASYNC_WEBSERVER_ESP32_W5500_VERSION);
	AWS_LOGWARN(F("Default SPI pinout:"));
	AWS_LOGWARN1(F("SPI_HOST:"), ETH_SPI_HOST);
	AWS_LOGWARN1(F("MOSI:"), MOSI_GPIO);
	AWS_LOGWARN1(F("MISO:"), MISO_GPIO);
	AWS_LOGWARN1(F("SCK:"), SCK_GPIO);
	AWS_LOGWARN1(F("CS:"), CS_GPIO);
	AWS_LOGWARN1(F("INT:"), INT_GPIO);
	AWS_LOGWARN1(F("SPI Clock (MHz):"), SPI_CLOCK_MHZ);
	AWS_LOGWARN(F("========================="));
	///////////////////////////////////
	// To be called before ETH.begin()
	ESP32_W5500_onEvent();
	// start the ethernet connection and the server:
	// Use DHCP dynamic IP and random mac
	uint16_t index = millis() % NUMBER_OF_MAC;
	//bool begin(int MISO_GPIO, int MOSI_GPIO, int SCLK_GPIO, int CS_GPIO, int INT_GPIO, int SPI_CLOCK_MHZ,
	// int SPI_HOST, uint8_t *W5500_Mac = W5500_Default_Mac);
	//ETH.begin( MISO_GPIO, MOSI_GPIO, SCK_GPIO, CS_GPIO, INT_GPIO, SPI_CLOCK_MHZ, ETH_SPI_HOST );
	ETH.begin( MISO_GPIO, MOSI_GPIO, SCK_GPIO, CS_GPIO, INT_GPIO, SPI_CLOCK_MHZ, ETH_SPI_HOST, mac[index] );
	// Static IP, leave without this line to get IP via DHCP
	//bool config(IPAddress local_ip, IPAddress gateway, IPAddress subnet, IPAddress dns1 = 0, IPAddress dns2 = 0);
	//ETH.config(myIP, myGW, mySN, myDNS);
	ESP32_W5500_waitForConnect();
	///////////////////////////////////
	server.on("/", HTTP_GET, [](AsyncWebServerRequest * request)
	{
	handleRoot(request);
	});
	server.on("/test.svg", HTTP_GET, [](AsyncWebServerRequest * request)
	{
	drawGraph(request);
	});
	server.on("/inline", [](AsyncWebServerRequest * request)
	{
	request->send(200, "text/plain", "This works as well");
	});
	server.onNotFound(handleNotFound);
	server.begin();
	Serial.print(F("HTTP EthernetWebServer is @ IP : "));
	Serial.println(ETH.localIP());
	}
	void loop()
	{
	}

You can access the Async Advanced WebServer @ the server IP

---

---

Debug Terminal Output Samples

1. AsyncMultiWebServer_ESP32_W5500 on ESP32_DEV with ESP32_W5500

Following are debug terminal output and screen shots when running example AsyncMultiWebServer_ESP32_W5500 on ESP32_DEV with LwIP W5500, using ESP32 core v2.0.0+, to demonstrate the operation of 3 independent AsyncWebServers on 3 different ports and how to handle the complicated AsyncMultiWebServers.

Start AsyncMultiWebServer_ESP32_W5500 on ESP32_DEV with ESP32_W5500
AsyncWebServer_ESP32_W5500 v1.6.4 for core v2.0.0+
[AWS] Default SPI pinout:
[AWS] SPI_HOST: 2
[AWS] MOSI: 23
[AWS] MISO: 19
[AWS] SCK: 18
[AWS] CS: 5
[AWS] INT: 4
[AWS] SPI Clock (MHz): 25
[AWS] =========================

ETH Started
ETH Connected
ETH MAC: DE:AD:BE:EF:BE:08, IPv4: 192.168.2.88
FULL_DUPLEX, 100Mbps

Connected to network. IP = 192.168.2.88
Initialize multiServer OK, serverIndex = 0, port = 8080
HTTP server started at ports 8080
Initialize multiServer OK, serverIndex = 1, port = 8081
HTTP server started at ports 8081
Initialize multiServer OK, serverIndex = 2, port = 8082
HTTP server started at ports 8082

You can access the Async Advanced WebServers @ the server IP and corresponding ports (8080, 8081 and 8082)

---

2. Async_AdvancedWebServer_MemoryIssues_Send_CString on ESP32_DEV with ESP32_W5500

Following is the debug terminal and screen shot when running example Async_AdvancedWebServer_MemoryIssues_Send_CString, on ESP32_DEV with LwIP W5500, to demonstrate the new and powerful HEAP-saving feature

Using CString ===> smaller heap (111,828 bytes)

Start Async_AdvancedWebServer_MemoryIssues_Send_CString on ESP32_DEV with ESP32_W5500
AsyncWebServer_ESP32_W5500 v1.6.4 for core v2.0.0+
[AWS] Default SPI pinout:
[AWS] SPI_HOST: 2
[AWS] MOSI: 23
[AWS] MISO: 19
[AWS] SCK: 18
[AWS] CS: 5
[AWS] INT: 4
[AWS] SPI Clock (MHz): 25
[AWS] =========================

ETH Started
ETH Connected
ETH MAC: DE:AD:BE:EF:BE:08, IPv4: 192.168.2.88
FULL_DUPLEX, 100Mbps
HTTP EthernetWebServer is @ IP : 192.168.2.88

HEAP DATA - Pre Create Arduino String  Max heap: 323016  Free heap: 222076  Used heap: 100940
.
HEAP DATA - Pre Send  Max heap: 323016  Free heap: 217656  Used heap: 105360

HEAP DATA - Post Send  Max heap: 323016  Free heap: 209648  Used heap: 111828
.

While using Arduino String, the HEAP usage is very large

Async_AdvancedWebServer_MemoryIssues_SendArduinoString ===> very large heap (144,124 bytes)

Start Async_AdvancedWebServer_MemoryIssues_SendArduinoString on ESP32_DEV with ESP32_W5500
AsyncWebServer_ESP32_W5500 v1.6.4 for core v2.0.0+
[AWS] Default SPI pinout:
[AWS] SPI_HOST: 2
[AWS] MOSI: 23
[AWS] MISO: 19
[AWS] SCK: 18
[AWS] CS: 5
[AWS] INT: 4
[AWS] SPI Clock (MHz): 25
[AWS] =========================

ETH Started
ETH Connected
ETH MAC: DE:AD:BE:EF:BE:08, IPv4: 192.168.2.88
FULL_DUPLEX, 100Mbps
HTTP EthernetWebServer is @ IP : 192.168.2.88

HEAP DATA - Pre Create Arduino String  Max heap: 323288  Free heap: 262348  Used heap: 60940
.
HEAP DATA - Pre Send  Max heap: 323288  Free heap: 218444  Used heap: 104844

HEAP DATA - Post Send  Max heap: 323288  Free heap: 180644  Used heap: 144124
.

You can access the Async Advanced WebServers at the displayed server IP, e.g. 192.168.2.88

---

3. Async_AdvancedWebServer_SendChunked on ESP32_DEV with ESP32_W5500

Following is debug terminal output when running example Async_AdvancedWebServer_SendChunked on ESP32_DEV with LwIP W5500, using ESP32 core v2.0.0+, to demo how to use beginChunkedResponse() to send large html in chunks

Start Async_AdvancedWebServer_SendChunked on ESP32_DEV with ESP32_W5500
AsyncWebServer_ESP32_W5500 v1.6.4 for core v2.0.0+
[AWS] Default SPI pinout:
[AWS] SPI_HOST: 2
[AWS] MOSI: 23
[AWS] MISO: 19
[AWS] SCK: 18
[AWS] CS: 5
[AWS] INT: 4
[AWS] SPI Clock (MHz): 25
[AWS] =========================

ETH Started
ETH Connected
ETH MAC: DE:AD:BE:EF:BE:08, IPv4: 192.168.2.88
FULL_DUPLEX, 100Mbps
AsyncWebServer is @ IP : 192.168.2.88
.[AWS] Total length to send in chunks = 31259
[AWS] Bytes sent in chunk = 5620
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 4300
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 4203
[AWS] Bytes sent in chunk = 0
.[AWS] Total length to send in chunks = 31279
[AWS] Bytes sent in chunk = 5620
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 2864
[AWS] Bytes sent in chunk = 2864
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 2864
[AWS] Bytes sent in chunk = 2787
[AWS] Bytes sent in chunk = 0

You can access the Async Advanced WebServers @ the server IP

---

4. AsyncWebServer_SendChunked on ESP32_DEV with ESP32_W5500

Following is debug terminal output when running example AsyncWebServer_SendChunked on ESP32_DEV with LwIP W5500, using ESP32 core v2.0.0+, to demo how to use beginChunkedResponse() to send large html in chunks

Start AsyncWebServer_SendChunked on ESP32_DEV with ESP32_W5500
AsyncWebServer_ESP32_W5500 v1.6.4 for core v2.0.0+
[AWS] Default SPI pinout:
[AWS] SPI_HOST: 2
[AWS] MOSI: 23
[AWS] MISO: 19
[AWS] SCK: 18
[AWS] CS: 5
[AWS] INT: 4
[AWS] SPI Clock (MHz): 25
[AWS] =========================

ETH Started
ETH Connected
ETH MAC: DE:AD:BE:EF:BE:08, IPv4: 192.168.2.88
FULL_DUPLEX, 100Mbps
AsyncWebServer is @ IP : 192.168.2.88
.[AWS] Total length to send in chunks = 47802
[AWS] Bytes sent in chunk = 5624
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 4300
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 1428
[AWS] Bytes sent in chunk = 4300
[AWS] Bytes sent in chunk = 2864
[AWS] Bytes sent in chunk = 2864
[AWS] Bytes sent in chunk = 2864
[AWS] Bytes sent in chunk = 2864
[AWS] Bytes sent in chunk = 2864
[AWS] Bytes sent in chunk = 2122
[AWS] Bytes sent in chunk = 0

---

5. Async_WebSocketsServer on ESP32_DEV with ESP32_W5500

Following is debug terminal output when running example Async_WebSocketsServer on ESP32_DEV with LwIP W5500, using ESP32 core v2.0.0+, to demo how to use Async_WebSocketsServer feature

Starting Async_WebSocketsServer on ESP32_DEV with ESP32_W5500
AsyncWebServer_ESP32_W5500 v1.6.4 for core v2.0.0+
[AWS] Default SPI pinout:
[AWS] SPI_HOST: 2
[AWS] MOSI: 23
[AWS] MISO: 19
[AWS] SCK: 18
[AWS] CS: 5
[AWS] INT: 4
[AWS] SPI Clock (MHz): 25
[AWS] =========================

ETH Started
ETH Connected
ETH MAC: DE:AD:BE:EF:BE:08, IPv4: 192.168.2.88
FULL_DUPLEX, 100Mbps
ws[Server: /ws][ClientID: 1] WSClient connected
ws[Server: /ws][ClientID: 1] WSClient disconnected
ws[Server: /ws][ClientID: 2] WSClient connected
ws[Server: /ws][ClientID: 3] WSClient connected

---

6. Async_HTTPBasicAuth on ESP32_DEV with ESP32_W5500

Following is debug terminal output when running example Async_HTTPBasicAuth on ESP32_DEV with LwIP W5500, using ESP32 core v2.0.0+, to demo how to use Async_Auth feature

Start Async_HTTPBasicAuth on ESP32_DEV with ESP32_W5500
AsyncWebServer_ESP32_W5500 v1.6.4 for core v2.0.0+
[AWS] Default SPI pinout:
[AWS] SPI_HOST: 2
[AWS] MOSI: 23
[AWS] MISO: 19
[AWS] SCK: 18
[AWS] CS: 5
[AWS] INT: 4
[AWS] SPI Clock (MHz): 25
[AWS] =========================

ETH Started
ETH Connected
ETH MAC: DE:AD:BE:EF:BE:08, IPv4: 192.168.2.88
FULL_DUPLEX, 100Mbps
Async_HttpBasicAuth started @ IP : 192.168.2.88
Open http://192.168.2.88/ in your browser to see it working
Login using username = admin and password = esp32_w5500

---

---

Debug

Debug is enabled by default on Serial. Debug Level from 0 to 4. To disable, change the ETHERNET_WEBSERVER_LOGLEVEL to 0

// Use this to output debug msgs to Serial
#define DEBUG_ASYNC_WEBSERVER_PORT       Serial
// Use this to disable all output debug msgs
// Debug Level from 0 to 4
#define _ASYNC_WEBSERVER_LOGLEVEL_       0

---

Troubleshooting

If you get compilation errors, more often than not, you may need to install a newer version of Arduino IDE, the Arduino ESP32 core or depending libraries.

Sometimes, the library will only work if you update the ESP32 core to the latest version because I'm always using the latest cores /libraries.

---

Issues

Submit issues to: AsyncWebServer_ESP32_W5500 issues

---

---

TO DO

1. Fix bug. Add enhancement
2. Add support to more Ethernet shields, such as DP83848, TLK110, IP101, RTL8201, DM9051, KSZ8041, KSZ8081, W6100, etc.
3. Add LittleFS support to use with new cores

---

DONE

1. Initial port to ESP32 boards using LwIP W5500 Ethernet.
2. Add more examples.
3. Add debugging features.
4. Add Table-of-Contents and Version String
5. Display compiler #warning only when DEBUG_LEVEL is 3+
6. Fix AsyncWebSocket bug
7. Support using CString to save heap to send very large data. Check request->send(200, textPlainStr, jsonChartDataCharStr); - Without using String Class - to save heap #8
8. Add examples Async_AdvancedWebServer_SendChunked and AsyncWebServer_SendChunked to demo how to use beginChunkedResponse() to send large html in chunks
9. Use allman astyle and add utils
10. Add Async_WebSocketsServer, Async_HttpBasicAuth and MQTT examples

---

---

Contributions and Thanks

1. Based on and modified from Hristo Gochkov's ESPAsyncWebServer. Many thanks to Hristo Gochkov for great ESPAsyncWebServer Library

⭐️⭐️ Hristo Gochkov

---

Contributing

If you want to contribute to this project:

• Report bugs and errors
• Ask for enhancements
• Create issues and pull requests
• Tell other people about this library

---

License

• The library is licensed under GPLv3

---

Copyright

• Copyright (c) 2016- Hristo Gochkov

• Copyright (c) 2022- Khoi Hoang