Examples of POST request with ESP8266WiFi.h

[jim-at-jibba]

Hey,

I have been trawling the web looking for an example of a POST request using the ESP8266WiFi.h library. Please can you help.

Thanks
James

[andig]

You can read up on HTTP. A POST request sends its payload in the body- encoding varies on what youre trying to do (file upload). Typcial case is form encoding the data. Dont have an example thought, sorry.

[mrbubble62]

Example POST to Azure

void senddata(JsonObject& json)
{
// POST URI
client.print("POST /tables/"); client.print(table_name); client.println(" HTTP/1.1");
// Host header
client.print("Host:"); client.println(mserver);
// Azure Mobile Services application key
client.print("X-ZUMO-APPLICATION:"); client.println(ams_key);
// JSON content type
client.println("Content-Type: application/json");
// Content length
int length = json.measureLength();
client.print("Content-Length:"); client.println(length);
// End of headers
client.println();
// POST message body
//json.printTo(client); // very slow ??
String out;
json.printTo(out);
client.println(out);
}

[Links2004]

easy way:
#1159 (comment)

[sukhmeet032795]

Hi,

I worked on it for days to find the perfect example for the library you want to use. Let me give you an example:

Serial.begin(115200);
while(!Serial){}
WiFiClient client;
const char* host="http://jsonplaceholder.typicode.com/";
String PostData = "title=foo&body=bar&userId=1";

if (client.connect(host, 80)) {

client.println("POST /posts HTTP/1.1");
client.println("Host: jsonplaceholder.typicode.com");
client.println("Cache-Control: no-cache");
client.println("Content-Type: application/x-www-form-urlencoded");
client.print("Content-Length: ");
client.println(PostData.length());
client.println();
client.println(PostData);

long interval = 2000;
unsigned long currentMillis = millis(), previousMillis = millis();

while(!client.available()){

  if( (currentMillis - previousMillis) > interval ){

    Serial.println("Timeout");
    blinkLed.detach();
    digitalWrite(2, LOW);
    client.stop();     
    return;
  }
  currentMillis = millis();
}

while (client.connected())
{
  if ( client.available() )
  {
    char str=client.read();
   Serial.println(str);
  }      
}

}

This is a proper working example for POST request using the library you mentioned and you can verify the the particular example using chrome extension POSTMAN.Let me show you the preview of the POST request i just created:

POST /posts HTTP/1.1
Host: jsonplaceholder.typicode.com
Cache-Control: no-cache
Content-Type: application/x-www-form-urlencoded

title=foo&body=bar&userId=1

This is the post request i just created.

Happy Coding :)

[Links2004]

any reason not to use the HTTP client ?

HTTPClient http;
http.begin("http://jsonplaceholder.typicode.com/posts");
http.addHeader("Content-Type", "application/x-www-form-urlencoded");
http.POST("title=foo&body=bar&userId=1");
http.writeToStream(&Serial);
http.end();

https://github.com/esp8266/Arduino/tree/master/libraries/ESP8266HTTPClient

[hallard]

Yeah HTTP client is fine I'm using something like this (not sure it's the best way but rocks) with prepared URL for emoncms

/* ======================================================================
Function: httpPost
Purpose : Do a http post
Input   : hostname
          port
          url
Output  : true if received 200 OK
Comments: -
====================================================================== */
boolean httpPost(char * host, uint16_t port, char * url)
{
  HTTPClient http;
  bool ret = false;

  unsigned long start = millis();

  // configure target server and url
  http.begin(host, port, url, port==443 ? true : false); 
  //http.begin("http://emoncms.org/input/post.json?node=20&apikey=apikey&json={PAPP:100}");

  Debugf("http%s://%s:%d%s => ", port==443?"s":"", host, port, url);

  // start connection and send HTTP header
  int httpCode = http.GET();
  if(httpCode) {
      // HTTP header has been send and Server response header has been handled
      Debug(httpCode);
      Debug(" ");
      // file found at server
      if(httpCode == 200) {
        String payload = http.getString();
        Debug(payload);
        ret = true;
      }
  } else {
      DebugF("failed!");
  }
  Debugf(" in %d ms\r\n",millis()-start);
  return ret;
}

[mrbubble62]

Should accept more than just 200 OK as a valid response code. Most common code used to indicate success with REST is 201 Created.
https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html

[hallard]

@mrbubble62
Thanks for this useful information, I never saw this code, good to know!
Anyway, it was just an example for Emoncms, so this one should be better ;-)

if( httpCode => 200 && httpCode < 300 ) {

[igrr]

@thorburn1 This is not about library for Arduino UNO. This is an HTTPClient library which runs on the ESP8266 itself, no external Arduino attached.

[sopan-sarkar]

How do I write the url for http.GET() that have a space in between letters such as example.com/default/datetime=2016-10-23 12:03:33

[rohit-rcrohit7]

try adding a + sign between the two instead of the space

[rohit-rcrohit7]

Try using + where space would be. It might work.

On Oct 23, 2016 11:56 AM, "sopan-sarkar" notifications@github.com wrote:

How do I write the url for http.GET() that have a space in between letters
such as example.com/default/datetime=2016-10-23 12:03:33

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[rezamar555]

Hello, can someone help me with this...

`
#include <DallasTemperature.h>
#include <OneWire.h>
#include <SoftwareSerial.h>

const int tmpPin = 9;
OneWire one(tmpPin);
DallasTemperature sensor(&one);
SoftwareSerial wifi(4, 2);

String red = "clave";
String pass = "pass";

String serv = "maleconjuarez.com.es";
String url = "/temperita";

void setup()
{
Serial.begin(115200);
wifi.begin(115200);
sensor.begin();
resetear();

}

void resetear()
{
wifi.println("AT+RST");
delay(1000);
if(wifi.find("OK")) Serial.println("Modulo reiniciado");

}

void loop()
{
ConnectWifi();
VincularTCP();
Temp();
resetear();

}

void ConnectWifi()
{
String conectar = "AT+CWJAP="" + red +"","" + pass+ """;
wifi.println(conectar);
delay(4000);
if(wifi.find("OK"))
{
Serial.println("Conectado!");
}
else
Serial.println("Paso 1 no completado");

}

void VincularTCP()
{
wifi.println( "AT+CIPSTART="TCP",""); //Crear el comando para comenzar una conexion TCP
delay(2000); //Darle 2 segundos para responder

if(Serial.find("ERROR")){
return; //No se pudo conectar
}

}

void Temp()
{
sensor.requestTemperatures(); //Escaneo de temperatura
float tmp = sensor.getTempCByIndex(0);

//URL Temperatura
//URL: maleconjuaresz.com.es:8901/temperita?Id_temp=0&Id_Device=1&Valor=00.00&Temperatura_Action=Insert
String urluno = String("Id_temp=0&Id_Device=2&Valor=");
String temp = String(tmp);
String urldos = String("&Temperatura_Action=Insert");
String urlfinal = String(String(urluno) + String(tmp) + String(urldos));

wifi.println("AT+CIPSTART=\"TCP\",\"" + serv + "\",8901");//Inicia la conexión TCP
if(wifi.find("OK"))
{
  Serial.println("Conectado al servidor");
}

wifi.println("POST /temperita HTTP/1.0");                   //Petición de HTTP POST Temperatura
wifi.println("Host: maleconjuarez.com.es:8901");
wifi.println("Content-Type: application/x-www-form-urlencoded");
//wifi.print("Content-Length: ");
wifi.println("AT+CIPSEND=");//determine the number of caracters to be sent.
wifi.println(urlfinal.length());
wifi.println();
wifi.println(urlfinal);

}
`
Doesn't send anything!

[rohit-rcrohit7]

First, Use the Postman Google Chrome extension app and check wether it sends the data or not.