Johny19 Johny19 - 3 months ago 52
HTTP Question

UnityWebRequest how to print all Request headers

Is there a way to print all the request headers from the UnityWebRequest API?
(I'm especially interested in the one automatically added "x-unity-version" and "user-agent")

Also, where are these headers are stored in the code?

Answer Source

where are these headers are stored in the code?

They are automatically added to a variable on the native side (C++). As of Unity 5.6.03f release, you cannot access these headers that are automatically added to the UnityWebRequest API with the official API. You can't even use reflection to do this since it only has a write but no read function.

Is there a way to print all the request headers from the UnityWebRequest API?

Yes, but that's tricky since you can't do this with the official API or with reflection.

You have to create a local server with HttpListener in another Thread, connect to it with UnityWebRequest then retrieve all the headers from the HttpListenerRequest of the HttpListener API and store them in a List.You can then close the HttpListener server.

volatile bool serverIsReady = false;
//Holds List of all the headers from received from UnityWebRequest request
List<HeaderInfo> headers = new List<HeaderInfo>();

void Start()

IEnumerator getUnityWebRequestHeaders()
    //Start Http Server
    ThreadPool.QueueUserWorkItem(new WaitCallback(RunInNewThread), new string[] { "http://*:8080/" });

    //Wait for server to actually start
    while (!serverIsReady)
        yield return null;

    Debug.LogWarning("Server is ready");

    yield return new WaitForSeconds(0.2f);

    UnityWebRequest www = UnityWebRequest.Post("http://localhost:8080", "");
    yield return www.Send();

    //Check if connections was successfull
    if (!www.isError && www.downloadHandler.text.Contains("SUCCESS"))
        Debug.LogWarning("Connection was successfull");

    //Show all the headers from UnityWebRequest
    for (int i = 0; i < headers.Count; i++)
        Debug.Log("KEY: " + headers[i].header + "    -    VALUE: " + headers[i].value);

private void RunInNewThread(object a)
    //Cast parameter back to string array
    string[] serverPrefix = (string[])a;
    //Start server with the provided parameter

//Creates a http server
public void SimpleListenerExample(string[] prefixes)
    serverIsReady = false;

    if (!HttpListener.IsSupported)
        Debug.LogWarning("Windows XP SP2 or Server 2003 is required to use the HttpListener class.");
    //URI prefixes are required,
    //for example "".
    if (prefixes == null || prefixes.Length == 0)
        throw new ArgumentException("prefixes");

    //Create a listener.
    HttpListener listener = new HttpListener();
    //Add the prefixes.
    foreach (string s in prefixes)

    serverIsReady = true;

    //Note: The GetContext method blocks while waiting for a request. 
    HttpListenerContext context = listener.GetContext();
    HttpListenerRequest request = context.Request;
    //Obtain a response object.
    HttpListenerResponse response = context.Response;
    //Construct a response.
    string responseString = "<HTML><BODY>SUCCESS</BODY></HTML>";
    byte[] buffer = System.Text.Encoding.UTF8.GetBytes(responseString);
    //Get a response stream and write the response to it.
    response.ContentLength64 = buffer.Length;
    System.IO.Stream output = response.OutputStream;
    output.Write(buffer, 0, buffer.Length);

    //Get all the headers sent from UnityWebRequest and add them to the List

    //You must close the output stream.

//Get all the headers sent from UnityWebRequest
void addHeaders(HttpListenerRequest request)
    System.Collections.Specialized.NameValueCollection receivedHeaders = request.Headers;
    for (int i = 0; i < receivedHeaders.Count; i++)
        string key = receivedHeaders.GetKey(i);
        string value = receivedHeaders.Get(i);
        headers.Add(new HeaderInfo(key, value));

//Hold header and value
public class HeaderInfo
    public string header;
    public string value;

    public HeaderInfo(string header, string value)
        this.header = header;
        this.value = value;

Output with Unity 5.6.03f:

KEY: Host - VALUE: localhost:8080

KEY: User-Agent - VALUE: UnityPlayer/5.6.0f3 (UnityWebRequest/1.0, libcurl/7.51.0-DEV)

KEY: Accept - VALUE: */*

KEY: Accept-Encoding - VALUE: identity

KEY: Content-Type - VALUE: application/x-www-form-urlencoded

KEY: X-Unity-Version - VALUE: 5.6.0f3

KEY: Content-Length - VALUE: 0