Error while using thing HTTP

While i have written a code and transmitted the values to thing speak and now iam trying to use message alerts with twilio and included HTTP and while using it iam getting an error.

the code is as follows and iam highlighting the error and the error [ is exit status 1

'HTTPClient' was not declared in this scope]

/*
WriteMultipleFields

Description: Writes values to fields 1,2,3,4 and status in a single ThingSpeak update every 20 seconds.

Hardware: Arduino Uno WiFi Rev2

!!! IMPORTANT - Modify the secrets.h file for this project with your network connection and ThingSpeak channel details. !!!

Note:
- Requires WiFiNINA library.
- This example is written for a network using WPA encryption. For WEP or WPA, change the WiFi.begin() call accordingly.
 ThingSpeak ( https://www.thingspeak.com ) is an analytic IoT platform service that allows you to aggregate, visualize, and 
  analyze live data streams in the cloud. Visit https://www.thingspeak.com to sign up for a free account and create a channel.  
  
  Documentation for the ThingSpeak Communication Library for Arduino is in the README.md folder where the library was installed.
  See https://www.mathworks.com/help/thingspeak/index.html for the full ThingSpeak documentation.
  
  For licensing information, see the accompanying license file.
  
  Copyright 2020, The MathWorks, Inc.
*/

#include <WiFiNINA.h>
#include "secrets.h"
#include "ThingSpeak.h" // always include thingspeak header file after other header files and custom macros
#include <ArduinoHttpClient.h>


// the libraries of the ph sensor and varibles defined
#include <Wire.h>
float calibration_value = 21.34-5.5;
int phval = 0; 
unsigned long int avgval; 
int buffer_arr[10],temp;

// the libraries of tds sensor and varibles are declared here

#include <EEPROM.h>
#include "GravityTDS.h"
#define TdsSensorPin A1
GravityTDS gravityTds;
float temperature = 25,tdsValue = 0;

//the libraries of dissolved oxygen meter are declared here
#include <Arduino.h>

#define DO_PIN A2

#define VREF 5000    //VREF (mv)
#define ADC_RES 1024 //ADC Resolution

//Single-point calibration Mode=0
//Two-point calibration Mode=1
#define TWO_POINT_CALIBRATION 0

#define READ_TEMP (25) //Current water temperature ℃, Or temperature sensor function

//Single point calibration needs to be filled CAL1_V and CAL1_T
#define CAL1_V (1831) //mv
#define CAL1_T (25)   //℃
//Two-point calibration needs to be filled CAL2_V and CAL2_T
//CAL1 High temperature point, CAL2 Low temperature point
#define CAL2_V (1300) //mv
#define CAL2_T (15)   //℃

const uint16_t DO_Table[41] = {
14460, 14220, 13820, 13440, 13090, 12740, 12420, 12110, 11810, 11530,
11260, 11010, 10770, 10530, 10300, 10080, 9860, 9660, 9460, 9270,
9080, 8900, 8730, 8570, 8410, 8250, 8110, 7960, 7820, 7690,
7560, 7430, 7300, 7180, 7070, 6950, 6840, 6730, 6630, 6530, 6410};

uint8_t Temperaturet;
uint16_t ADC_Raw;
uint16_t ADC_Voltage;
uint16_t DO;
uint16_t dissolved;

int16_t readDO(uint32_t voltage_mv, uint8_t temperature_c)
{
    #if TWO_POINT_CALIBRATION == 0
    uint16_t V_saturation = (uint32_t)CAL1_V + (uint32_t)35 * temperature_c - (uint32_t)CAL1_T * 35;
    return (voltage_mv * DO_Table[temperature_c] / V_saturation);
    #else
    uint16_t V_saturation = (int16_t)((int8_t)temperature_c - CAL2_T) * ((uint16_t)CAL1_V - CAL2_V) / ((uint8_t)CAL1_T - CAL2_T) + CAL2_V;
    return (voltage_mv * DO_Table[temperature_c] / V_saturation);
    #endif
    }
    
    //wifi and api keys  are declared here
    char ssid[] = SECRET_SSID;   // your network SSID (name) 
    char pass[] = SECRET_PASS;   // your network password
    int keyIndex = 0;            // your network key Index number (needed only for WEP)
    WiFiClient  client;
    boolean checkpoint= true;
    boolean checkpoint1= true;
    
    unsigned long myChannelNumber = SECRET_CH_ID;
    const char * myWriteAPIKey = SECRET_WRITE_APIKEY;
    
    // Initialize our values
    int number1 = 0;
    int number2 = random(0,100);
    int number3 = random(0,100);
    int number4 = random(0,100);
    String myStatus = "";
    
    
    void setup() {
    Serial.begin(9600);  // Initialize serial
    gravityTds.setPin(TdsSensorPin);
    gravityTds.setAref(5.0);  //reference voltage on ADC, default 5.0V on Arduino UNO
    gravityTds.setAdcRange(1024);  //1024 for 10bit ADC;4096 for 12bit ADC
            gravityTds.begin();  //initialization
            while (!Serial) {
                ; // wait for serial port to connect. Needed for Leonardo native USB port only
                    }
                    
                    // check for the WiFi module:
                        if (WiFi.status() == WL_NO_MODULE) {
                            Serial.println("Communication with WiFi module failed!");
                            // don't continue
                            while (true);
                                }
                                
                                String fv = WiFi.firmwareVersion();
                                if (fv != "1.0.0") {
                                    Serial.println("Please upgrade the firmware");
                                    }
                                    
                                    ThingSpeak.begin(client);  //Initialize ThingSpeak
                                    }
                                    
                                    void loop() {
                                    
                                    // Connect or reconnect to WiFi
                                    if(WiFi.status() != WL_CONNECTED){
                                        Serial.print("Attempting to connect to SSID: ");
                                        Serial.println(SECRET_SSID);
                                        while(WiFi.status() != WL_CONNECTED){
                                            WiFi.begin(ssid, pass); // Connect to WPA/WPA2 network. Change this line if using open or WEP network
                                            Serial.print(".");
                                            delay(5000);     
                                            } 
                                            Serial.println("\nConnected.");
                                            }
                                            // TDS sensor values starts from here
                                            gravityTds.setTemperature(temperature);  // set the temperature and execute temperature compensation
                                            gravityTds.update();  //sample and calculate
                                            tdsValue = gravityTds.getTdsValue();  // then get the value
                                            Serial.print(tdsValue,0);
                                            Serial.println("ppm");
                                            delay(1000);
                                            
                                            
                                            // ph meter values and code here
                                            for(int i=0;i<10;i++) 
                                                {  
buffer_arr[i]=analogRead(A0);
 delay(30);
 }
 for(int i=0;i<9;i++)
 {
 for(int j=i+1;j<10;j++)
 {
 if(buffer_arr[i]>buffer_arr[j])
 {
 temp=buffer_arr[i];
 buffer_arr[i]=buffer_arr[j];
 buffer_arr[j]=temp;
 }
 }
 }
 avgval=0;
 for(int i=2;i<8;i++)
 avgval+=buffer_arr[i];
 float volt=(float)avgval*5.0/1024/6;
 float ph_act = -5.70 * volt + calibration_value;
 Serial.println(ph_act);
 
 delay(1000);
 
 // dissolved oxygen meter starts from here
 
 
 Temperaturet = (uint8_t)READ_TEMP;
 ADC_Raw = analogRead(DO_PIN);
 ADC_Voltage = uint32_t(VREF) * ADC_Raw / ADC_RES;
 
 Serial.print("Temperaturet:\t" + String(Temperaturet) + "\t");
 Serial.print("ADC RAW:\t" + String(ADC_Raw) + "\t");
 Serial.print("ADC Voltage:\t" + String(ADC_Voltage) + "\t");
 Serial.println("DO:\t" + String(readDO(ADC_Voltage, Temperaturet)) + "\t");
 delay(1000);
 
 if (ph_act < 4)
     {
         if(checkpoint)
         {
             HTTPClient http;            [errror]
             
             Serial.println("[HTTP] begin...\n");
             String str= String(h)+"pH has reached ";
             http.begin("https://api.thingspeak.com/apps/thinghttp/send_request?api_key=GCA8S03FIUORHJJM0&message="+str);
             Serial.print("[HTTP] begin...\n");
             
             
             int httpcode= http.GET();
             
             if(httpcode >0)
             {
                 Serial.printf("[HTTP] GET...code :%d\n",httpcode);
                 
                 if(httpcode=HTTP_CODE_OK)
                 {
                     String payload=http.GETString();
                     Serial.println(payload);
                     checkpoint= false;
                     }
                 }
                 }
                 }
                 else {
                         checkpoint=true;
                         }
                     }
                     
                     
                     // set the fields with the values
                     ThingSpeak.setField(1, ph_act);
                     ThingSpeak.setField(2, tdsValue);
                     ThingSpeak.setField(3, float(ADC_Voltage));
                     ThingSpeak.setField(4, Temperaturet);
                     
                     // figure out the status message
                     if(number1 > number2){
                         myStatus = String("field1 is greater than field2"); 
                         }
                     else if(number1 < number2){
                             myStatus = String("field1 is less than field2");
                             }
                     else{
                             myStatus = String("field1 equals field2");
                             }
                         
                         // set the status
                         ThingSpeak.setStatus(myStatus);
                         
                         // write to the ThingSpeak channel
                         int x = ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey);
                         if(x == 200){
                             Serial.println("Channel update successful.");
                             }
                         else{
                                 Serial.println("Problem updating channel. HTTP error code " + String(x));
                                 }
                             
                             // change the values
                             number1++;
                             if(number1 > 99){
                                 number1 = 0;
                                 }
                                 number2 = random(0,100);
                                 number3 = random(0,100);
                                 number4 = random(0,100);
                                 
                                 delay(15000); // Wait 20 seconds to update the channel again
                                 }

[Christopher Stapels]

Can you define the http client as a global (at the top) or at the beginnning of the loop function?

[NAGUBATHULA SATYA SRIRAM]

Tried it. But, still getting the same error.

[Christopher Stapels]

I would suggest using the examples in the ThingSpeak library. You wont need the arduino HTTP library.

In the examples for that library, they seem to call the clinet function in this way

HttpClient client = HttpClient(wifi, serverAddress, port);

But im pretty sure you dont need that client. You can make the thingHTTP requests with the wifi client you already have.

   WiFiClient  client;

you can do something like this example: (its for talkback, but you can use something similar for thingHTTP)

     postMessage += "&headers=false";
  
  String Headers =  String("POST ") + uri + String(" HTTP/1.1\r\n") +
                    String("Host: api.thingspeak.com\r\n") +
                    String("Content-Type: application/x-www-form-urlencoded\r\n") +
                    String("Connection: close\r\n") +
                    String("Content-Length: ") + String(postMessage.length()) +
                    String("\r\n\r\n");

  client.print(Headers);
  client.print(postMessage);

[NAGUBATHULA SATYA SRIRAM]

Tried , those examples first got a lot of errors. So, I changed the code to this .

[Christopher Stapels]

Using the code patterns I suggested above, Ive definitely succeeded in creating working code that accesses ThingSpeak channels and ThingHTTP in the same code. I suggest you simplify and try to do one task at a time. Then you can make functions in your code that do those tasks.

[NAGUBATHULA SATYA SRIRAM]

/*
Simple GET client for ArduinoHttpClient library
Connects to server once every five seconds, sends a GET request

created 14 Feb 2016
modified 22 Jan 2019
by Tom Igoe

this example is in the public domain
*/
#include <ArduinoHttpClient.h>
#include <WiFiNINA.h>
#include <Wire.h>
float calibration_value = 21.34-5.5;
int phval = 0; 
unsigned long int avgval; 
int buffer_arr[10],temp;

#include "arduino_secrets.h"

///////please enter your sensitive data in the Secret tab/arduino_secrets.h
/////// Wifi Settings ///////
char ssid[] = SECRET_SSID;
char pass[] = SECRET_PASS;

char serverAddress[] = "https://api.thingspeak.com/apps/thinghttp/send_request?api_key=xxxxxxxxxxxxxxxx";  // server address
int port = 8080;

WiFiClient wifi;
HttpClient client = HttpClient(wifi, serverAddress, port);
int status = WL_IDLE_STATUS;

void setup() {
Serial.begin(9600);
while ( status != WL_CONNECTED) {
    Serial.print("Attempting to connect to Network named: ");
    Serial.println(ssid);                   // print the network name (SSID);
    
    // Connect to WPA/WPA2 network:
    status = WiFi.begin(ssid, pass);
    }
    
    // print the SSID of the network you're attached to:
    Serial.print("SSID: ");
    Serial.println(WiFi.SSID());
    
    // print your WiFi shield's IP address:
    IPAddress ip = WiFi.localIP();
    Serial.print("IP Address: ");
    Serial.println(ip);
    }
    
    void loop() {
    
    for(int i=0;i<10;i++) 
        { 
            buffer_arr[i]=analogRead(A0);
            delay(30);
            }
        for(int i=0;i<9;i++)
            {
                for(int j=i+1;j<10;j++)
                {
                    if(buffer_arr[i]>buffer_arr[j])
                    {
                        temp=buffer_arr[i];
                        buffer_arr[i]=buffer_arr[j];
                        buffer_arr[j]=temp;
                        }
                    }
                    }
                    avgval=0;
                    for(int i=2;i<8;i++)
                        avgval+=buffer_arr[i];
                        float volt=(float)avgval*5.0/1024/6;
                        float ph_act = -5.70 * volt + calibration_value;
                        Serial.println(ph_act);
                        
                        delay(1000);
                        
                        if(ph_act<7){
                            Serial.println("making GET request");
                            client.get("/");
                            
                            // read the status code and body of the response
                            int statusCode = client.responseStatusCode();
                            String response = client.responseBody();
                            
                            Serial.print("Status code: ");
                            Serial.println(statusCode);
                            Serial.print("Response: ");
                            Serial.println(response);
                            Serial.println("Wait five seconds");
                            delay(5000);
                            }
                            }

I have tried this code and getting HTTP error code = -2. Can you please help me clearing this issue?