UnityWebRequest never returns on script attached to a prefab

Question

I have a IEnumerator function that download a image from a server, on script not attached to prefabs, it works, but on script attached to prefabs, it doesnt work.

By doesnt work i want to say that the www.SendWebRequest() never returns, i've waited for almost 10 minutes and its doesnt returns, the image has about 200kb, so the problem isn't the image size.

I already checked if the url is correct, tried to change the image, tried to re-write the function but nothing works, this is my function:

public void Set(string NomeIcone, string NomeAnalise, string idzinho, string descricaozinha, string NomeCapa)
{
    Name.text = NomeAnalise;
    ID = idzinho;
    Descricao = descricaozinha;
    Capa = NomeCapa;
    StartCoroutine(LoadLogo(NomeIcone));
}

public IEnumerator LoadLogo(string nomeArquivo)
{
    string url = PathIcone + nomeArquivo;
    print(url);

    using (UnityWebRequest www = UnityWebRequestTexture.GetTexture(url))
    {
        yield return www.SendWebRequest();

        if (www.error == null)
        {
            Texture2D tex = new Texture2D(1, 1);
            tex = DownloadHandlerTexture.GetContent(www);
            Icon.texture = tex;
            RawImage Foto = Icon.GetComponentInChildren<RawImage>();
            Foto.SetNativeSize();
            float altura = 100 * Foto.rectTransform.rect.height / Foto.rectTransform.rect.width;
            Foto.rectTransform.sizeDelta = new Vector2(100, altura);
        }
    }
}

My prefab setup in the inspector

As you can see, my "IconeSimbolo" is a RawImage in the prefab which this script is attached

I expect to my "IconeSimbolo" texture change to the image on the server, but it never changes.

I have this same code on another script with the same setup on the inspector, on this another prefab everything works fine, but in this one it doesnt

Answer 1

Well it is quite simple: The Update method is not executed on assets but only on GameObject/MonoBehaviour that are active and enabled in the Scene hierachy

→ Prefabs don't get Update calls.

Started Coroutines in Unity are executed (MoveNext) together with the Update call (or better said after it - see the Order of Execution for Event Functions)

→ So your IEnumerator begins and actually should send and return the request ... but you never call MoveNext on it so it never realizes that the request already finished.

---

Somewhere you are calling the method Set. So as a workaround you could let some GameObject/MonoBehaviour execute the IEnumerator for you like e.g.

public void Set(string NomeIcone, string NomeAnalise, string idzinho, string descricaozinha, string NomeCapa, MonoBehaviour responsibleBehaviour)
{
    Name.text = NomeAnalise;
    ID = idzinho;
    Descricao = descricaozinha;
    Capa = NomeCapa;

    // This now starts the coroutine instead on the passed 
    // responsibleBehaviour and uses that ones Update calls in order to
    // move on with the IEnumerator
    responsibleBehaviour.StartCoroutine(LoadLogo(NomeIcone));
}

and in the calling script simply add this to the end of the parameters (assuming ofcourse the calling script is a MonoBehaviour)

prefab.Set(someNomeIcone, someNomeAnalise, someIdzinho, someDescricaozinha, someNomeCapa, this);

---

Alternatively since you made LoadLogo public anyway you can also directly use another IEnumerator in order to execute it like:

public IEnumerator LoadLogo(string NomeIcone, string NomeAnalise, string idzinho, string descricaozinha, string NomeCapa)
{
    Name.text = NomeAnalise;
    ID = idzinho;
    Descricao = descricaozinha;
    Capa = NomeCapa;

    string url = PathIcone + NomeIcone;
    print(url);

    using (UnityWebRequest www = UnityWebRequestTexture.GetTexture(url))
    {
        yield return www.SendWebRequest();

        if (www.error == null)
        {
            Texture2D tex = new Texture2D(1, 1);
            tex = DownloadHandlerTexture.GetContent(www);
            Icon.texture = tex;
            RawImage Foto = Icon.GetComponentInChildren<RawImage>();
            Foto.SetNativeSize();
            float altura = 100 * Foto.rectTransform.rect.height / Foto.rectTransform.rect.width;
            Foto.rectTransform.sizeDelta = new Vector2(100, altura);
        }
    }
}

and then run it on a GameObject in the Scene e.g. like

public class SomeBehaviourInScene : MonoBehaviour
{
    // reference the Prefab here
    public YourPrefabScript prefab;

    // wherever you want to call this
    public void LoadPrefabLogo()
    {
        StartCoroutine(LoadPrefabLogoRoutine());
    }

    // If you want this to be called automatically
    // on app start this could also be a 
    //private IEnumerator Start()
    private IEnumerator LoadPrefabLogoRoutine()
    {
        // this also executes the LoadLogo and at 
        // the same time waits until it is finished
        yield return prefab.LoadLogo(/* Your parameters here */);

        Debug.Log("Finished");
    }
}

---

Or if this is about an EditorScript you could register to EditorApplication.update in order to call MoveNext on your IEnumerator.

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A general sidenote: For convenience and reasons of cooperation (e.g. see here) you should get used to use English names for all methods, variables and also in your comments.