Sending Video URL with http POST to my roku app

I haven't used DIAL, nor the connectSDK, but could it be that you forgot to replace the string literal in this line

        String urlParameters = "videoUrl=" + URLEncoder.encode("video-url", "UTF-8");

... with the actual URL you wish to launch?

Do I even need the parameters? All I want is the video to send and play, could I leave all that out like this?
I'm not sure what way the video url should look like, on roku website they have the url looking like the way I have it but thats through the terminal, Should I be taking out the %2F's?

    public void postVideoURL() throws IOException {
        String appRunLocation = "";
        URL obj = new URL("http://10.50.0.105:8060/dial/dev?url=http%3A%2F%2Fvideo.ted.com%2Ftalks%2Fpodcast%2FDavidBrooks_2011.mp4");
        HttpURLConnection con = (HttpURLConnection) obj.openConnection();

        //add request header
        con.setRequestMethod("POST");

        // Send post request
        con.setDoOutput(true);
        DataOutputStream wr = new DataOutputStream(con.getOutputStream());
     
        try {
            wr.flush();
        } catch (IOException e) {
            e.printStackTrace();
        }
        try {
            wr.close();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

Since you've added the Roku side of your code I can see that it won't work. You should look at the SimpleVideoPlayer sample in the SDK for some working brightscript video playback. You need to be calling Show() before you loop on Wait().

I recommend hard-coding your URL within the Roku channel code until you have it successfully playing. After that you can try adding the DIAL remote launching.

I'm not sure about the Java thing you're using, but here's a working example in C# (error-checking omitted for clarity):

using System.Net;
using System.Web;

class Program
{
    static void Main()
    {
        string rokuIp     = "192.168.0.6";
        string channelId  = "dev";
        string videoUrl   = "http://video.ted.com/talks/podcast/DavidBrooks_2011.mp4";
            
        // Note that the query string parameters should be url-encoded
        string requestUrl = $"http://{rokuIp}:8060/launch/{channelId}?url={HttpUtility.UrlEncode(videoUrl)}";

        using (var wc = new WebClient())
        {
            // POST the query string with no data
            wc.UploadString(requestUrl, "");
        }
    }
}

and the BrightScript code:

Sub Main(params)

    ' Url to play if no launch parameters specified
    urlParam = ""

    ' Check that launch parameters are specified
    If Type(params) = "roAssociativeArray"
        ' Extract the url (if specified) from the launch parameters
        If params.url <> Invalid
            urlParam = params.url
        End If
    End If

    ' Play the video
    port = CreateObject("roMessagePort")
    ui = CreateObject ("roVideoScreen")
    ui.SetMessagePort(port)
    ui.SetContent ({Stream: {Url: urlParam, Bitrate: 0, Quality: False}})
    ui.Show ()
    While True
        msg = Wait (0, port)
        If Type (msg) = "roVideoScreenEvent"
            If msg.IsScreenClosed ()
                Exit While
            End If
        End If
    End While

End Sub

Note that the query string parameters should be url-encoded in the client, but automatically appear in their decoded form when received by your Roku channel.

Here's the Wireshark trace:

POST /launch/dev?url=http%3a%2f%2fvideo.ted.com%2ftalk%2fpodcast%2f2016%2fNone%2fMoranCerf_2016.mp4 HTTP/1.1
Host: 192.168.0.6:8060
Content-Length: 0
Connection: Keep-Alive

HTTP/1.1 200 OK
Server: Roku UPnP/1.0 MiniUPnPd/1.4
Content-Length: 0

Thanks a lot for your BrightScript that i'm now using & the tip about the encoding . I still can't manage to get it to work, I feel like its something simple i'm missing out on but can't figure it out. Googling it looks like i've pretty much what I need for it to work but not sure whats wrong

public void postVideoURL() throws IOException {

    String encodedUrl = URLEncoder.encode("http://video.ted.com/talks/podcast/DavidBrooks_2011.mp4", "UTF-8");
    URL obj = new URL("http://10.50.0.105:8060/launch/dev?url="+encodedUrl);

    HttpURLConnection con = (HttpURLConnection) obj.openConnection();

    //add request header
    con.setRequestMethod("POST");

    // Send post request
    con.setDoOutput(true);
    OutputStreamWriter wr = new OutputStreamWriter(con.getOutputStream());
    System.out.println(con.getResponseCode());
    System.out.println(con.getResponseMessage());
    wr.flush();
    wr.close();

    wr.write("");
 }
        

Make sure you write an empty body before you flush and close the stream.