ionic - wait for return from http get

Question

ionic - wait for return from http get

Navigation

#1 by (0 votes)
#2 by (0 votes)

2

Edit: solution in the third answer.

I'm trying to do a login function for a project in Ionic 2. This function checks if the user is registered in the database through the php server and returns the id of the user if he / she has a registration. My problem is that since the http.get() method works asynchronously, I can not check if the function return was empty, since the return result is set to undefined. I tried two ways, using observable and promise:

With Observable: function that calls the service:

    login() 
  {
    this.usuario = this.loginservice.get_usuario(this.loginusuario).subscribe(response =>this.usuario = response);
    console.log(this.usuario);
  }

Service encoding:

public get_usuario(usuario):Observable<any>
  {
      return this.http.get(this.urlusuario +"/"+ usuario.usuario +"/"+ 
   usuario.senha); 
  }

That way, the first time I click the button that triggers the login () function, I get the undefined value as a response. The second time I click, it returns the value of the previous request.

Using promise: Function calling the service:

login() 
  {
    this.usuario = this.loginservice.get_usuario(this.loginusuario);
    console.log(this.usuario);
  }

encoding service:

public get_usuario(usuario):Promise<any>
  {
    var resultado;
      return this.http.get(this.urlusuario +"/"+ usuario.usuario +"/"+ usuario.senha).toPromise().then(function(data){
         return  data; 
      });
  }

Using promise I get the id return on the first execution of the login function, however I could not find any way to access the __zone_symbol__value which is where the object is stored according to console.log() .

I want to know if there is a way to wait for the response of http.get() to the program to continue execution (in case of using observable) or how do I access the object that is returned from the promise

.

promises ionic get angular

asked by anonymous 23.05.2018 / 16:57

2 answers

0

I want to thank you for your help, Lucas, and tell you how I got the final solution to my problem. I used the code you gave in response to get the value of a promise. To wait for the return of the request, I added async in the name of the login () function and await in the service call. The code looks like this:

login ()

async login() {
   await this.loginservice.get_usuario(this.loginusuario).
  then(response => this.usuario = response);
   console.log(this.usuario);
}

get_user ()

public get_usuario(usuario):Promise<any>
  {
      return this.http.get(this.urlusuario +"/"+ usuario.usuario +"/"+ usuario.senha).toPromise().then(function(data){
         return  data; 
      });
  }

24.05.2018 / 22:47

Doubt of how to increase input size according to div size using bootstrap Framework for documentation for java REST API

score 0 · Accepted Answer

To access the result of a promise you can do the service request as follows:

public get_usuario(usuario):Promise<any> {
var resultado;
  return new Promise(resolve => { 
  this.http.get(this.urlusuario +"/"+ usuario.usuario +"/"+ usuario.senha)
  .subscribe( res => resolve(res));
 });

}

In the login method, capture the data with:

 login() {
       this.loginservice.get_usuario(this.loginusuario).
       then(response => this.usuario = response);
        console.log(this.usuario);
  }

I have an example working with promises in github. link