HTTP POST Error Problem with Parameter json_data

Hello everyone,

I am doing a project with an Arduino UNO and an Ethernet Shield, It consists of doing an HTTP POST from a JSON to a Server, I have reviewed my code many times and I still have the same error, the server receives my POST but it tells me that there is a missing parameter.

However I am sending the parameter I have tried many ways that I have seen all over the internet but I still do not get a solution

My Code :

#include <Ethernet.h>
#include <SPI.h>

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; // MAC CUALQUIERA
byte server[] = {172, 30, 31, 6}; //IP SERVIDOR 
byte ip[] = {172, 30, 36, 32}; // IP ARDUINO 



EthernetClient client; // DEFINIMOS EL CLIENTE


void setup() {
// INICIO DEL SETUP ################################################################
Serial.begin(9600);  // INICIALIZAR MONITOR SERIAL 

while(!Serial){
  ;
}  // ESPERAR POR EL MONITOR SERIAL 
SPI.begin();
Ethernet.begin(mac, ip); //Conexion Por ip Estatica 
Serial.print("My IP : ");
Serial.println(Ethernet.localIP());

delay(500); 

if (client.connect(server, 80)) {   //comprobar si hay conexion con el cliente
  Serial.println("conectado a 172.30.31.6");
}else{
  Serial.println("NO HAY CONEXION");
  }

char PostData[] = "{\"operation\":\"core/create\",\"class\":\"UserRequest\",\"output_fields\":\"id\",\"comment\":\"loquesea\",\"fields\":{\"org_id\":\"1\",\"title\": \"prueba_hospital\",\"description\":\"prueba\"}}";


      if (client) {
          client.println("POST /itop/web/webservices/rest.php?version=1.1&json_data= HTTP/1.1");
          client.println("Host: 172.30.31.6");
          client.println("Authorization: Basic YWRtaW46YWRtaW4="); // User and pass in Base64
          client.println("User-Agent: Arduino/1.8.5");
          client.println("Content-Type: application/json");
          client.print("Content-Lenght: ");
          client.println(strlen(PostData));
          client.println("Connection: close");
          client.println();
          client.print(PostData);
          Serial.println("Post Realizado");
        }else {
          Serial.println("No se ha podido hacer el POST");
        }


} // FINAL DEL SETUP #########################################################



void loop() { // INICIO DEL LOOP ####################################################################

        if(client){
          char c = client.read();
          Serial.print(c);
        }
      
delay(10);

}

In the first line of the post, I am sending the parameters:
version = 1.1 & json_data =
probe send the json_data down along with the json himself, but it has not worked either

client.println(“POST /itop/web/webservices/rest.php?version=1.1&json_data= HTTP/1.1”);

Response :

My IP : 172.30.36.32
conectado a 172.30.31.6
Post Realizado


Date: Wed, 02 May 2018 21:12:56 GMT
Server: Apache/2.4.25 (Debian)
Set-Cookie: itop-cccc625803db2ea97734aa176e552d97=oh2ru9fe93p13jvqes0sfek446; path=/
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-cache
Pragma: no-cache
Access-Control-Allow-Origin: *
Content-Disposition: inline; filename=""
Content-Length: 58
Connection: close
Content-Type: application/json

{"code":3,"message":"Error: Missing parameter 'json_data"}

Thank you all, I hope you can find the error where I can not find it

proved send the json_data down along with the json itself, but it has not worked either *

Sorry spelling mistake.

remove json_data= from the url. you send it in the POST's body

I tried, this way

char PostData = "&json_data={"operation":"core/create","class":"UserRequest","output_fields":"id","comment":"loquesea","fields":{"org_id":"1","title": "prueba_hospital","description":"prueba"}}"

and

char PostData ="json_data={"operation":"core/create","class":"UserRequest","output_fields":"id","comment":"loquesea","fields":{"org_id":"1","title": "prueba_hospital","description":"prueba"}}"

but I still do not get positive results

your Content-Type is application/json, so the body of the request must be json only. if you want to send the data in body in a form of url parameters, use Content-Type application/x-www-form-urlencoded

I am using this =

char PostData = “{“operation”:“core/create”,“class”:“UserRequest”,“output_fields”:“id”,“comment”:“loquesea”,“fields”:{“org_id”:“1”,“title”: “prueba_hospital”,“description”:“prueba”}}”;

if (client) {
client.println(“POST /itop/web/webservices/rest.php?version=1.1 HTTP/1.1”);
client.println(“Host: 172.30.31.6”);
client.println(“Authorization: Basic YWRtaW46YWRtaW4=”); // USUARIO Y CONTRASEÑA EN BASE 64
client.println(“User-Agent: Arduino/1.8.5”);
client.println(“Content-Type: application/json”);
client.print("Content-Lenght: ");
client.println(strlen(PostData));
client.println(“Connection: close”);
client.println();
client.print(PostData);
Serial.println(“Post Realizado”);
}else {
Serial.println(“No se ha podido hacer el POST”);
}

Sending =

POST /itop/web/webservices/rest.php?version=1.1 HTTP/1.1
Host: 172.30.31.6
Authorization: Basic YWRtaW46YWRtaW4=
User-Agent: Arduino/1.8.5
Content-Type: application/json
Content-Lenght: 165
Connection: close

{“operation”:“core/create”,“class”:“UserRequest”,“output_fields”:“id”,“comment”:“loquesea”,“fields”:{“org_id”:“1”,“title”: “prueba_hospital”,“description”:“prueba”}}

Response =

HTTP/1.1 200 OK
Date: Thu, 03 May 2018 15:32:31 GMT
Server: Apache/2.4.25 (Debian)
Set-Cookie: itop-cccc625803db2ea97734aa176e552d97=7qgb59ot28bol9tmp4u29h5825; path=/
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-cache
Pragma: no-cache
Access-Control-Allow-Origin: *
Content-Disposition: inline; filename=""
Content-Length: 58
Connection: close
Content-Type: application/json

{“code”:3,“message”:“Error: Missing parameter 'json_data”}

it is something that the web service expects and we don't know about it. what service is it?

a web service is iTop,

if i copy and paste this in the url

http://172.30.31.6/itop/web/webservices/rest.php?version=1.1&auth_user=admin&auth_pwd=admin&json_data={"operation":"core/create","class":"UserRequest","output_fields":"id","comment":"loquesea","fields":{"org_id":"1","title":"prueba_hospital",
"description":"prueba"}}

the server accept the request.

i need replicate that same in the POST of the arduino

again, if you want to send the data in body in a form of url parameters, use Content-Type application/x-www-form-urlencoded

He did catch traffic with wireshark, and analyzed the packages that they send with the mailman, to see the http headers that he uses.

Guiding me a little there, my code goes like that, but it still does not work, I do not like it and I like the goal or going away

char PostData = “{“operation”:“core/create”,“class”:“UserRequest”,“output_fields”:“id”,“comment”:“loquesea”,“fields”:{“org_id”:“1”,“title”: “prueba_hospital”,“description”:“prueba”}}\r\n”;

if (client) {

client.println(“POST /itop/web/webservices/rest.php? HTTP/1.1”);

client.print(“Host: 172.30.31.6\r\n”);

client.print(“Authorization: Basic YWRtaW46YWRtaW4=\r\n”); // USUARIO Y CONTRASEÑA EN BASE 64

client.print(“User-Agent: Arduino/1.8.5\r\n”);

client.print("Content-Lenght: ");

client.print(strlen(PostData));

client.print("\r\n");

client.print(“Content-Type: application/json\r\n”);

client.print(“Accept: /\r\n”);

client.print(“Connection: keep-alive\r\n”);

client.print(“Content-Disposition: form-data; name=“version”\r\n”);

client.print("\r\n");

client.print(“1.1\r\n”);

client.print("\r\n");

client.print(“Content-Disposition: form-data; name=“json_data”\r\n”);

client.print("\r\n");

client.print(PostData);

client.print("\r\n");

Serial.println(“Post Realizado”);

}else {
Serial.println(“No se ha podido hacer el POST”);
}

i try with
client.print(“Content-Type: application/json\r\n”);

and

client.print(“Content-Type: application/x-www-form-urlencoded\r\n”);

But i have not got possitive results

show the complete url-encoded vetsion of code. was the version parameter in the body too?

version 1.1 is a necessary parameter for the web service, independent of HTTP 1.1 are different things, so I pass it as a parameter like the json, and certainly not taking it.

POST with all url parameters in the body and x-www-form-urlencoded is equivalent to GET with the same url parameters

try to pass version = 1.1 as a parameter like json_data, but the server does not receive it either and it gives me another similar error:

{"code": 2, "message": "Error: Missing parameter 'version}

that is, you are not receiving that parameter either

show the version of your code with x-www-form-urlencoded