The best way to make a GET request to a server in Unity

Question

So right now I am making HTTP requests to a server, but I need to send a GET request with some JSON data as well. What I am doing right now "works", but is terrible because it drops down to nearly 15 FPS each request. Here is my code.

Here is my GET Query:

{
"query": {
    "match_all": {}
},
"size": 1,
"sort": [{
    "@timestamp": {
        "order": "desc"
    }
}]
}

Here is my start method:

void Start()
{
        queryString = File.ReadAllText(Application.streamingAssetsPath +"/gimmeData.json");

        StartCoroutine(SetJsonData()); 
}

Here is the co-coutine I have set up to actually do the requests:

private IEnumerator SetJsonData()
{
    // Make a new web request with the .net WebRequest
    request = WebRequest.Create(elk_url);
    yield return null;

    request.ContentType = "application/json";
    request.Method = "POST";
    buffer = Encoding.GetEncoding("UTF-8").GetBytes(queryString);

    // Put this yield here so that I get higher FPS
    yield return null;

    requestStream = request.GetRequestStream();
    requestStream.Write(buffer, 0, buffer.Length);
    requestStream.Close();
    // Again this is about getting higher FPS
    yield return null;

    response = (HttpWebResponse)request.GetResponse();
    // Wait until we have all of the data we need from the response to continue
    yield return requestStream = response.GetResponseStream();

    // Open the stream using a StreamReader for easy access.
    reader = new StreamReader(requestStream);
    // Set my string to the response from the website
    JSON_String = reader.ReadToEnd();

    yield return null;

    // Cleanup the streams and the response.
    reader.Close();
    requestStream.Close();
    response.Close();
    yield return null;

    // As long as we are not null, put this in as real C# data
    if (JSON_String != null)
    {
        // Wait until we finish converting the string to JSON data to continue
        yield return StartCoroutine(StringToJson());  
    }

    if(dataObject != null)
    {
        // Send the data to the game controller for all of our hits
        for(int i = 0; i < dataObject.hits.hits.Length; i++)
        {
            StartCoroutine(
                gameControllerObj.CheckIpEnum(dataObject.hits.hits[i]._source));
        }
    }

    // As long as we didn't say to stop yet
    if (keepGoing)
    {
        yield return null;

        // Start this again
        StartCoroutine(SetJsonData());
    }
}

I have all those "yield return null"s in there because it improved the FPS from what it already was.

How can I optimize this? Is there a better way to make a web request that can also send GET data with it? I know that UnityWebRequest is a thing, but that does not allow me to send the JSON data that I have.

Answer 1

Note: The code in your question is performing a POST, not a GET. There's no such thing as 'get data'.

The following suggestion is equivalent from the server's point of view.

If you actually want a GET request - i.e. something totally different to what your code does - see the end of this answer.

Coroutines aren't threads

Wait until we have all of the data - This is where your framerate comes to die. This is because the Unity main thread - essentially your entire game - will wait for the server to respond with all of the data.

In short, that's just because of how coroutines work - they're very different from threads.

The general approach in Unity is to use WWW in a coroutine instead. Internally Unity runs the actual request on a separate thread and that coroutine just checks in on the progress every so often:

POST, matching your question's code:

// Build up the headers:
Dictionary<string,string> headers = new Dictionary<string,string>();

// Add in content type:
headers["Content-Type"] = "application/json";

// Get the post data:
byte[] postData = Encoding.GetEncoding("UTF-8").GetBytes(queryString);

// Start up the reqest:
WWW myRequest = new WWW(elk_url, postData, headers);

// Yield until it's done:
yield return myRequest;

// Get the response (into your JSON_String field like above)
// Don't forget to also check myRequest.error too.
JSON_String = myRequest.text;

// Load the JSON as an object and do magical things next.
// There's no need to add extra yields because
// your JSON parser probably doesn't support chunked json anyway.        
// They can cover a few hundred kb of JSON in an unnoticeable amount of time.
....

GET, matching your question:

// Start up the reqest (Total guess based on your variable names):
// E.g. mysite.com/hello?id=2&test=hi
WWW myRequest = new WWW(elk_url + "?"+queryString);

// Yield until it's done:
yield return myRequest;

// Get the response
JSON_String = myRequest.text;
....