How to send JSON GET data with an HTTP request in C#

Question

So I am having a lot of trouble with how to send the below JSON data in C# format. I know exactly how to do it in cURL, but I can't figure this out for the life of me. This request is essential to what I am doing and I really need to get it done. Here is the curl statement:

   curl <ip of server>/<index>/_search?pretty=true -d '
 {
"query": {
    "match_all": {}
},
"size": 1,
"sort": [{
    "_timestamp": {
        "order": "desc"
    }
}]
}

If it helps at all I am making a request to an Elasticsearch server, and I am grabbing the JSON data. This cURL request gives me EXACTLY what I need. Here is the C# code that I have now, but I am not sure how to add this JSON data to the GET request. This is also gonna be running in the Unity game engine.

        // Create a request for the URL.        
        request = WebRequest.Create(elk_url);
        // If required by the server, set the credentials.
        request.Credentials = CredentialCache.DefaultCredentials;
        // Get the response.

        response = (HttpWebResponse)request.GetResponse();
        // Display the status.
        Debug.Log(response.StatusDescription);
        // Get the stream containing content returned by the server.
        dataStream = response.GetResponseStream();
        // Open the stream using a StreamReader for easy access.
        reader = new StreamReader(dataStream);
        // Read the content.
        string responseFromServer = reader.ReadToEnd();
        // Display the content.
        Debug.Log(responseFromServer);
        // Cleanup the streams and the response.
        reader.Close();
        dataStream.Close();
        response.Close();

The above is just from the documentation page, and I am pretty new to HTTP requests in code, so any help would be greatly appreciated.

BenjaFriend · Accepted Answer · 2017-01-27 15:14:48Z

2

I figured it out!

    WebRequest request = WebRequest.Create(elk_url);

    request.ContentType = "application/json";
    request.Method = "POST";
    byte[] buffer = Encoding.GetEncoding("UTF-8").GetBytes(queryString);
    string result = System.Convert.ToBase64String(buffer);
    Stream reqstr = request.GetRequestStream();
    reqstr.Write(buffer, 0, buffer.Length);
    reqstr.Close();

    HttpWebResponse response = (HttpWebResponse)request.GetResponse();
    Debug.Log(response.StatusDescription);
    dataStream = response.GetResponseStream();
    // Open the stream using a StreamReader for easy access.
    reader = new StreamReader(dataStream);
    // Read the content.
    string responseFromServer = reader.ReadToEnd();
    // Display the content.
    Debug.Log(responseFromServer);
    // Cleanup the streams and the response.
    reader.Close();
    dataStream.Close();
    response.Close();

The Query string is the JSON data in the original post. For those who want to know for the ELK stack, this will give you the JSON data(in string format) from the most recent event. Depending on what beat you use, this could be pretty cool for data visualization.

answered Jan 27, 2017 at 15:14

BenjaFriend

6643 gold badges15 silver badges31 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Duan Walker Over a year ago

how are you passing the "result" from the queryString byte buffer to the request object?

Fredrik · Accepted Answer · 2017-01-27 15:14:01Z

0

Here's how I'd send a Unity WWW-request with POST:

    public IEnumerator SendSomething()
    {
        WWWForm wwwForm = new WWWForm();
        wwwForm.AddField("Parameter_Name", jsonString);

        WWW www = new WWW(url, wwwForm);
        yield return www;

        if (www.error == null)
        {
             Debug.Log("Everything worked!");
        }
        else
        {
             Debug.Log("Something went wrong: " + www.error);
        }
    }

The WWW-class defaults to GET if you don't supply the postData parameter (my wwwForm), so if you want to use GET you could just supply the WWW-class with:

WWW www = new WWW(url + "?" + jsonString);

and skipping the first 2 rows of my method.

Here we're utilizing the IEnumerator to yield return www: which waits for the request to complete until continuing. To utilize the IEnumerator method you invoke it with StartCoroutine(SendSomething()); which will run asyncronized.

answered Jan 27, 2017 at 15:14

Fredrik

5,0971 gold badge24 silver badges33 bronze badges

1 Comment

BenjaFriend Over a year ago

I get a "400 Bad Request" when I run that

Collectives™ on Stack Overflow

How to send JSON GET data with an HTTP request in C#

2 Answers 2

1 Comment

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related