greenshot/Greenshot/Help/HelpFileLoader.cs

83 lines
2.8 KiB
C#

/*
* Created by SharpDevelop.
* User: jens
* Date: 09.04.2012
* Time: 19:24
*
* To change this template use Tools | Options | Coding | Edit Standard Headers.
*/
using Greenshot.Configuration;
using GreenshotPlugin.Core;
using System;
using System.Diagnostics;
using System.Net;
using System.Windows.Forms;
namespace Greenshot.Help
{
/// <summary>
/// Description of HelpFileLoader.
/// </summary>
public sealed class HelpFileLoader
{
private static readonly log4net.ILog LOG = log4net.LogManager.GetLogger(typeof(HelpFileLoader));
private const string EXT_HELP_URL = @"http://getgreenshot.org/help/";
private HelpFileLoader() {
}
public static void LoadHelp() {
string uri = findOnlineHelpUrl(Language.CurrentLanguage);
if(uri == null) {
uri = Language.HelpFilePath;
}
Process.Start(uri);
}
/// <returns>URL of help file in selected ietf, or (if not present) default ietf, or null (if not present, too. probably indicating that there is no internet connection)</returns>
private static string findOnlineHelpUrl(string currentIETF) {
string ret = null;
string extHelpUrlForCurrrentIETF = EXT_HELP_URL;
if(!currentIETF.Equals("en-US")) {
extHelpUrlForCurrrentIETF += currentIETF.ToLower() + "/";
}
HttpStatusCode? httpStatusCode = getHttpStatus(extHelpUrlForCurrrentIETF);
if(httpStatusCode == HttpStatusCode.OK) {
ret = extHelpUrlForCurrrentIETF;
} else if(httpStatusCode != null && !extHelpUrlForCurrrentIETF.Equals(EXT_HELP_URL)) {
LOG.DebugFormat("Localized online help not found at {0}, will try {1} as fallback", extHelpUrlForCurrrentIETF, EXT_HELP_URL);
httpStatusCode = getHttpStatus(EXT_HELP_URL);
if(httpStatusCode == HttpStatusCode.OK) {
ret = EXT_HELP_URL;
} else {
LOG.WarnFormat("{0} returned status {1}", EXT_HELP_URL, httpStatusCode);
}
} else if(httpStatusCode == null){
LOG.Info("Internet connection does not seem to be available, will load help from file system.");
}
return ret;
}
/// <summary>
/// Retrieves HTTP status for a given url.
/// </summary>
/// <param name="url">URL for which the HTTP status is to be checked</param>
/// <returns>An HTTP status code, or null if there is none (probably indicating that there is no internet connection available</returns>
private static HttpStatusCode? getHttpStatus(string url) {
try {
HttpWebRequest req = (HttpWebRequest)NetworkHelper.CreateWebRequest(url);
HttpWebResponse res = (HttpWebResponse)req.GetResponse();
return res.StatusCode;
} catch(WebException e) {
if(e.Response != null) return ((HttpWebResponse)e.Response).StatusCode;
else return null;
}
}
}
}