v1.5.0 to save heap when sending large data

#### Releases v1.5.0

1. 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](khoih-prog/Portenta_H7_AsyncWebServer#8) and [All memmove() removed - string no longer destroyed #11](khoih-prog/Portenta_H7_AsyncWebServer#11)
2. Add multiple examples to demo the new feature

Author: khoih-prog

CONTRIBUTING.md

@@ -30,10 +30,10 @@ Arduino IDE version: 1.8.19
 ESP8266_NODEMCU_ESP12E using ESP8266_W5500 Ethernet
 ESP8266 core v3.0.2
 OS: Ubuntu 20.04 LTS
-Linux xy-Inspiron-3593 5.13.0-39-generic #44~20.04.1-Ubuntu SMP Thu Mar 24 16:43:35 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
+Linux xy-Inspiron-3593 5.15.0-48-generic #54~20.04.1-Ubuntu SMP Thu Sep 1 16:17:26 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
 
 Context:
-I encountered a crash while trying to use the Timer Interrupt.
+I encountered a crash while using this library
 
 Steps to reproduce:
 1. ...

changelog.md

@@ -11,13 +11,19 @@
 ## Table of contents
 
 * [Changelog](#changelog)
+  * [Releases v1.5.0](#releases-v150)
   * [Releases v1.4.1](#releases-v141)
 
 ---
 ---
 
 ## Changelog
 
+#### Releases v1.5.0
+
+1. 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](https://github.com/khoih-prog/Portenta_H7_AsyncWebServer/pull/8) and [All memmove() removed - string no longer destroyed #11](https://github.com/khoih-prog/Portenta_H7_AsyncWebServer/pull/11)
+2. Add multiple examples to demo the new feature
+
 #### Releases v1.4.1
 
 1. Initial coding to port [ESPAsyncWebServer](https://github.com/me-no-dev/ESPAsyncWebServer) to ESP8266 boards using W5x00 / ENC28J60 Ethernet.

examples/Async_AdvancedWebServer/defines.h

@@ -30,7 +30,8 @@
 
 #include <SPI.h>
 
-#define CSPIN       16      // 5
+// Using GPIO4, GPIO16, or GPIO5
+#define CSPIN       4   //16      // 5
 
 #if USING_W5500
   #include "W5500lwIP.h"

examples/Async_AdvancedWebServer_MemoryIssues_SendArduinoString/Async_AdvancedWebServer_MemoryIssues_SendArduinoString.ino

@@ -0,0 +1,303 @@
+/****************************************************************************************************************************
+  Async_AdvancedWebServer_MemoryIssues_SendArduinoString.ino
+
+  For ESP8266 using W5x00/ENC8266 Ethernet
+   
+  AsyncWebServer_Ethernet is a library for the Ethernet with lwIP_5100, lwIP_5500 or lwIP_enc28j60 library
+  
+  Based on and modified from ESPAsyncWebServer (https://github.com/me-no-dev/ESPAsyncWebServer)
+  Built by Khoi Hoang https://github.com/khoih-prog/AsyncWebServer_Ethernet
+  Licensed under GPLv3 license
+  
+  Copyright (c) 2015, Majenko Technologies
+  All rights reserved.
+  
+  Redistribution and use in source and binary forms, with or without modification,
+  are permitted provided that the following conditions are met:
+  
+  Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+  
+  Redistributions in binary form must reproduce the above copyright notice, this
+  list of conditions and the following disclaimer in the documentation and/or
+  other materials provided with the distribution.
+  
+  Neither the name of Majenko Technologies nor the names of its
+  contributors may be used to endorse or promote products derived from
+  this software without specific prior written permission.
+  
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+  ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *****************************************************************************************************************************/
+
+#include "defines.h"
+
+#include <AsyncWebServer_Ethernet.h>
+
+// In bytes
+//#define STRING_SIZE                    40000
+#define STRING_SIZE                    12000
+
+AsyncWebServer    server(80);
+
+int reqCount = 0;                // number of requests received
+
+#define BUFFER_SIZE         512
+char temp[BUFFER_SIZE];
+
+void handleRoot(AsyncWebServerRequest *request)
+{
+  digitalWrite(LED_BUILTIN, LED_ON);
+
+  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_Ethernet!</h2>\
+<h3>running on %s</h3>\
+<p>Uptime: %d d %02d:%02d:%02d</p>\
+<img src=\"/test.svg\" />\
+</body>\
+</html>", BOARD_NAME, SHIELD_TYPE, day, hr % 24, min % 60, sec % 60);
+
+  request->send(200, "text/html", temp);
+
+  digitalWrite(LED_BUILTIN, LED_OFF);
+}
+
+void handleNotFound(AsyncWebServerRequest *request)
+{
+  digitalWrite(LED_BUILTIN, LED_ON);
+  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);
+  digitalWrite(LED_BUILTIN, LED_OFF);
+}
+
+void PrintHeapData(String hIn)
+{
+  // cores/esp8266/Esp.cpp
+  static uint32_t maxFreeHeap = 0xFFFFFFFF;
+
+  // Get once at the beginning for comparison only
+  static uint32_t totalHeap = ESP.getFreeHeap();
+
+  uint32_t freeHeap  = ESP.getFreeHeap();
+  
+  // Print and update only when larger heap
+  if (maxFreeHeap > freeHeap)
+  {
+    maxFreeHeap = freeHeap;
+  
+    Serial.print("\nHEAP DATA - ");
+    Serial.print(hIn);
+    
+    Serial.print("  Free heap: ");
+    Serial.print(freeHeap);
+    Serial.print("  Used heap: ");
+    Serial.println(totalHeap - freeHeap);
+  }
+}
+
+void PrintStringSize(String & out)
+{ 
+  static uint32_t count = 0;
+
+  // Print only when cStr length too large and corrupting memory or every (20 * 5) s
+  if ( (out.length() >= STRING_SIZE) || (++count > 20) )
+  {
+    Serial.print("\nOut String Length=");
+    Serial.println(out.length());
+
+    count = 0;
+  }
+}
+
+void drawGraph(AsyncWebServerRequest *request)
+{
+  String out;
+
+  out.reserve(STRING_SIZE);
+  char temp[70];
+
+  out += "<svg xmlns=\"http://www.w3.org/2000/svg\" version=\"1.1\" width=\"1810\" height=\"150\">\n";
+  out += "<rect width=\"1510\" 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 < 1500; 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";
+
+  PrintHeapData("Pre Send");
+
+  PrintStringSize(out);
+
+  request->send(200, "image/svg+xml", out);
+
+  PrintHeapData("Post Send");
+}
+
+void initEthernet()
+{
+  SPI.begin();
+  SPI.setClockDivider(SPI_CLOCK_DIV4);
+  SPI.setBitOrder(MSBFIRST);
+  SPI.setDataMode(SPI_MODE0);
+
+#if !USING_DHCP
+  eth.config(localIP, gateway, netMask, gateway);
+#endif
+  
+  eth.setDefault();
+  
+  if (!eth.begin()) 
+  {
+    Serial.println("No Ethernet hardware ... Stop here");
+    
+    while (true) 
+    {
+      delay(1000);
+    }
+  } 
+  else 
+  {
+    Serial.print("Connecting to network : ");
+    
+    while (!eth.connected()) 
+    {
+      Serial.print(".");
+      delay(1000);
+    }
+  }
+ 
+  Serial.println();
+
+#if USING_DHCP  
+  Serial.print("Ethernet DHCP IP address: ");
+#else
+  Serial.print("Ethernet Static IP address: ");
+#endif
+  
+  Serial.println(eth.localIP());
+}
+
+void setup()
+{ 
+  pinMode(LED_BUILTIN, OUTPUT);
+  digitalWrite(LED_BUILTIN, LED_OFF);
+
+  Serial.begin(115200);
+  while (!Serial && millis() < 5000);
+
+  delay(200);
+
+  Serial.print("\nStart Async_AdvancedWebServer_MemoryIssues_SendArduinoString on "); Serial.print(BOARD_NAME);
+  Serial.print(" with "); Serial.println(SHIELD_TYPE);
+  Serial.println(ASYNC_WEBSERVER_ETHERNET_VERSION);
+
+  PrintHeapData("Start =>");
+
+  initEthernet();
+
+  ///////////////////////////////////
+ 
+  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());
+
+  PrintHeapData("Pre Create Arduino String");
+
+}
+
+void heartBeatPrint()
+{
+  static int num = 1;
+
+  Serial.print(F("."));
+
+  if (num == 80)
+  {
+    Serial.println();
+    num = 1;
+  }
+  else if (num++ % 10 == 0)
+  {
+    Serial.print(F(" "));
+  }
+}
+
+void check_status()
+{
+  static unsigned long checkstatus_timeout = 0;
+
+#define STATUS_CHECK_INTERVAL     10000L
+
+  // Send status report every STATUS_REPORT_INTERVAL (60) seconds: we don't need to send updates frequently if there is no status change.
+  if ((millis() > checkstatus_timeout) || (checkstatus_timeout == 0))
+  {
+    heartBeatPrint();
+    checkstatus_timeout = millis() + STATUS_CHECK_INTERVAL;
+  }
+}
+
+void loop()
+{
+  check_status();
+}