ESP32 HTTPCLIENT get.string() #6391
Description
Board
ESP32 Module
Device Description
Devkit v4
Hardware Configuration
GPIO 5,27 SPI Interface
Version
v2.0.2
IDE Name
ARDUINO IDE
Operating System
W10
Flash frequency
40 MHz
PSRAM enabled
no
Upload speed
115200
Description
Hello ım working on a project rfid mysql and php project, my arduino (esp32) .It connects to a site ( getUID.php) with http.begin and transmits rfid tag information, then php mysql platforms perform operations in the background and show the tag information on a separate php page (readtag2.php). I want to connect with http.begin again for this site and then save the tag information on that page to the payload variable with get.string(), but I see the source string of that site, so actually I can transfer the html codes to my variable. How can I transfer the information from that site to my variable?.
Sketch
My arduino codes :
#include <WebServer.h>
#include <HTTPClient.h>
#include <WiFi.h>
#include <WiFiClient.h>
//------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------//
#include <SPI.h>
#include <MFRC522.h>
//------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------//
#define SS_PIN 5 //–> SDA
#define RST_PIN 27 //–> RST
MFRC522 mfrc522(SS_PIN, RST_PIN);
#define ON_Board_LED 2 //–> On Board LED
//-----------------------------------------SSID and Password of your WiFi router-------------------------------------------------------------------------------------------------------------//
const char* ssid = “”;
const char* password = “”;
//---------------------------------------------------------------------------------------------
WebServer server(80); //–> Server on port 80
int readsuccess;
byte readcard[4];
char str[32] = “”;
String StrUID;
String httpGETRequest(const char* serverName) {
HTTPClient http;
// Your IP address with path or Domain name with URL path
http.begin(serverName);
http.addHeader(“Content-Type”, “application/x-www-form-urlencoded”);
// Send HTTP POST request
int httpResponseCode = http.GET();
String payload = “{}”;
if (httpResponseCode>0) {
Serial.print("HTTP Response code: ");
Serial.println(httpResponseCode);
payload = http.getString();
Serial.println(payload);
}
else {
Serial.print("Error code: ");
Serial.println(httpResponseCode);
}
http.end();
return payload;
}
//-----------------------------------------------------------------------------------------------SETUP--------------------------------------------------------------------------------------//
void setup() {
Serial.begin(115200); //–> Initialize serial communications with the PC
SPI.begin(); //–> Init SPI bus
mfrc522.PCD_Init(); //–> Init MFRC522 card
delay(500);
WiFi.begin(ssid, password); //–> Connect to your WiFi router
Serial.println("");
pinMode(ON_Board_LED,OUTPUT);
digitalWrite(ON_Board_LED, HIGH); //–> Turn off Led On Board
//----------------------------------------Wait for connection
Serial.print(“Connecting”);
while (WiFi.status() != WL_CONNECTED) {
Serial.print(".");
//----------------------------------------Make the On Board Flashing LED on the process of connecting to the wifi router.
digitalWrite(ON_Board_LED, LOW);
delay(250);
digitalWrite(ON_Board_LED, HIGH);
delay(250);
}
digitalWrite(ON_Board_LED, HIGH); //–> Turn off the On Board LED when it is connected to the wifi router.
//----------------------------------------If successfully connected to the wifi router, the IP Address that will be visited is displayed in the serial monitor
Serial.println("");
Serial.print("Successfully connected to : ");
Serial.println(ssid);
Serial.print("IP address: ");
Serial.println(WiFi.localIP());
Serial.println(“Please tag a card or keychain to see the UID !”);
Serial.println("");
}
//------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------//
void loop() {
// put your main code here, to run repeatedly
readsuccess = getid();
if(readsuccess) {
digitalWrite(ON_Board_LED, LOW);
HTTPClient http; //Declare object of class HTTPClient
String UIDresultSend, postData;
UIDresultSend = StrUID;
//Post Data
postData = “UIDresult=” + UIDresultSend;
http.begin(“http://192.168…/…/getUID.php”); //Specify request destination
http.addHeader(“Content-Type”, “application/x-www-form-urlencoded”); //Specify content-type header
int httpCode = http.POST(postData); //Send the request
String payload = http.getString(); //Get the response payload
Serial.println(UIDresultSend);
Serial.println(httpCode); //Print HTTP return code
Serial.println(payload); //Print request response payload
http.end(); //Close connection
delay(1000);
httpGETRequest(“http://192.168…/…/readtag2.php”);
digitalWrite(ON_Board_LED, HIGH);
}
}
//------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------//
//----------------------------------------Procedure for reading and obtaining a UID from a card or keychain---------------------------------------------------------------------------------//
int getid() {
if(!mfrc522.PICC_IsNewCardPresent()) {
return 0;
}
if(!mfrc522.PICC_ReadCardSerial()) {
return 0;
}
Serial.print("THE UID OF THE SCANNED CARD IS : ");
for(int i=0;i<4;i++){
readcard[i]=mfrc522.uid.uidByte[i]; //storing the UID of the tag in readcard
array_to_string(readcard, 4, str);
StrUID = str;
}
mfrc522.PICC_HaltA();
return 1;
}
//------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------//
//----------------------------------------Procedure to change the result of reading an array UID into a string------------------------------------------------------------------------------//
void array_to_string(byte array, unsigned int len, char buffer) {
for (unsigned int i = 0; i < len; i++)
{
byte nib1 = (array[i] >> 4) & 0x0F;
byte nib2 = (array[i] >> 0) & 0x0F;
buffer[i*2+0] = nib1 < 0xA ? ‘0’ + nib1 : ‘A’ + nib1 - 0xA;
buffer[i*2+1] = nib2 < 0xA ? ‘0’ + nib2 : ‘A’ + nib2 - 0xA;
}
buffer[len*2] = ‘\0’;
}
//-------------------------Debug Message
My Serial Monitor
Please tag a card or keychain to see the UID !
23:18:48.137 →
23:18:59.428 → THE UID OF THE SCANNED CARD IS : 421F0DD4
23:19:00.340 → 200
23:19:00.340 →
23:19:01.355 → HTTP Response code: 200
23:19:01.355 → alinan deger
23:19:01.355 → <?php
23:19:01.355 → $Write="<?php $" . "UIDresult=''; " . "echo $" . "UIDresult;" . " ?>";
23:19:01.355 → file_put_contents(‘UIDContainer.php’,$Write);
23:19:01.355 → ?>
23:19:01.355 →
23:19:01.355 →
23:19:01.355 →
23:19:01.355 → Http body script meta etc. all about web site source code, not database
datas. Returns an incorrect String.
23:19:01.355 →
23:19:01.355 →
23:19:01.355 →
23:19:01.355 →
23:19:01.355 →
Other Steps to Reproduce
2 http objects and get.string
I have checked existing issues, online documentation and the Troubleshooting Guide
- I confirm I have checked existing issues, online documentation and Troubleshooting guide.