UnityからスクショをSlackに投げる

CaptureSendSlack.cs

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using MiniJSON;
using KeyValue = System.Collections.Generic.Dictionary<string, string>;

public class CaptureSendSlack : MonoBehaviour {
  private static string CAPTURE_DIRECTORY;
  private static string CAPTURE_FILENAME = "slack_share.png";
  private static string CAPTURE_PATH;
  private bool _isCapturing = false;
  private string _message;
  private KeyValue _channels = new KeyValue();
  public string _channel;
  public string _apiToken;
  //
  public string apiToken {
    get { return _apiToken; }
    set { _apiToken = value; }
  }
  //
  void Start() {
    StartCoroutine(get_channel_list());
  }
  // Update is called once per frame
  void Update() {
    if (_isCapturing) {
      if (System.IO.File.Exists(CAPTURE_PATH)) {
        _isCapturing = false;
        StartCoroutine(file_upload());
      }
    }
  }
  void OnGUI() {
    if (GUILayout.Button("SHOT")) Capture("hogehoge");
  }
  //
  public void Capture(string m) {
    if (!_isCapturing) {
#if UNITY_EDITOR
      if (CAPTURE_PATH == null) {
        CAPTURE_PATH = CAPTURE_FILENAME;
      }
#else
      if (CAPTURE_DIRECTORY == null) {
        CAPTURE_DIRECTORY = Application.persistentDataPath;
        CAPTURE_PATH = System.IO.Path.Combine(CAPTURE_DIRECTORY, CAPTURE_FILENAME);
        System.IO.Directory.CreateDirectory(CAPTURE_DIRECTORY);
      }
#endif
      if (System.IO.File.Exists(CAPTURE_PATH)) {
        System.IO.File.Delete(CAPTURE_PATH);
      }
      _isCapturing = true;
      _message = m;
      Application.CaptureScreenshot(CAPTURE_FILENAME);
    }
  }
  string escape(string txt) {
    return System.Uri.EscapeUriString(txt);
  }
  string make_url(string action) {
    return string.Format("https://slack.com/api/{0}?token={1}", action, _apiToken);
  }
  string channel_id(string cname) {
    return _channels[cname];
  }
  IEnumerator get_channel_list() {
    WWW www = new WWW(make_url("channels.list"));
    yield return www;
    _channels.Clear();
    if (string.IsNullOrEmpty(www.error)) {
      var json = Json.Deserialize(www.text) as Dictionary<string, object>;
      var channels = json["channels"] as List<object>;
      foreach (Dictionary<string, object> o in channels) {
        string cname = o["name"] as string;
        string cid = o["id"] as string;
        _channels[cname] = cid;
      }
    }
  }
  IEnumerator post_message() {
    WWW www = new WWW(make_url("chat.postMessage") + string.Format("&channel={0}&text=HogeFromUnity", channel_id(_channel)));
    yield return www;
  }
  IEnumerator file_upload() {
    while (_channels.Count == 0) yield return new WaitForSeconds(0.5f);
    if (System.IO.File.Exists(CAPTURE_PATH) && channel_id(_channel) != null) {
      byte[] data = System.IO.File.ReadAllBytes(CAPTURE_PATH);
      WWWForm form = new WWWForm();
      form.AddBinaryData("file", data, CAPTURE_FILENAME, "image/png");
      WWW www = new WWW(make_url("files.upload") + string.Format("&channels={0}&initial_comment={1}", channel_id(_channel), escape(_message)), form);
      yield return www;
    }
  }
}