Another yield and www question

Questions & Answers
1

Hi there!

I’m kind of noob with unity, but I manage to make already a couple of good stuff with it.

Nowadays, and after reading tons of questions about yield, I couldn’t get the right answers for my problem.

I want to make a query to a web server from my code. To be able to do that, I’m creating the WWW object with the url that I want to use, and wait for it with yield. When I do that in the Start function, everything goes cool and smooth, but here comes the problem. I don’t want to call it from the start function.

I want to have a class called serverConnection, and into there retrieving the data form the webpage. At the moment I reached this stage, but I no longer know what to do.

using UnityEngine;
using System.Collections;

public class serverConnection
{
     public string query()
     {
          string url = "http://www.google.com";
          StartCoroutine(queryServer(url));
     }

     IEnumerator queryServer(string url)
     {
          WWW server = new WWW(url);
          yield return www;
          Debug.Log(www.text);
     }
}

As you can see, I try to manage to split the code because I read that I should use the StartCoroutine call.

My original idea was to create something like this:

public class serverConnection
{
    public string query(string url)
    {
         WWW www = new WWW(url);
         return www.text;
    }
}

I don’t know if I explain myself there… I was trying to create an “envelope” around the interaction with the server, and to retrieve only the “web content” inside the string return value.

The main problem of that, is that I’m forced to wait for the WWW object to be completely downloaded, and I found no other solution than yield (or busy waiting, but I really don’t want to go through that ugly way :S)

Does somebody have some ideas?

2

You can’t return it, but you can pass an action to be executed when the code is ready.

  public void RunQuery(string url, System.Action<string> onComplete)
  {
         StartCoroutine(DoQuery(url, onComplete));
  }

  IEnumerator DoQuery(string url, System.Action<string>onComplete)
  {
         var www = new WWW(url);
         yield return www;
         if(string.IsNullOrEmpty(www.error)) onComplete(www.text);
  }

Then you can call it like this:

    var query = "search?q=whydoidoit";
    RunQuery("http://www.google.com/" + query, result=>{
          Debug.Log(query + ": " + result);
          //Actually do something useful
          
    });
3

I was just asking if someone knew another solution.
Yours is really cool one, and I learned about the System.Action. But for the case that I need, I require that all those operations to be synchronized with the “main” couroutine.
I have done a solution that I’m not proud of, but it works, and it fits with the requirements of my programm. It’s:

string queryServer(string url){
     WWW www = new WWW(url);
     while(!www.isDone){
          //This line is for not having the processor always checking, so we give a bit time to the internet
          Thread.sleep(100); 
     }
     return www.text;
}

Thanks a lot for your suggestions and help :), and again really cool the System.Action. I’ll keep that on mind.