/// <summary>
/// <para>
/// Maps an <see cref="UpdateInfo"/> to a
/// <see cref="Tuple{T1, T2, T3}"/>.
/// </para>
/// </summary>
/// <param name="info">
/// The <see cref="UpdateInfo"/> to map to a tuple.
/// </param>
/// <returns>
/// A three-tuple of <see cref="Uri"/>s, with the first item
/// being the archive location, the second the installer location,
/// and the third the release notes location.
/// </returns>
/// <exception cref="ArgumentException">
/// Thrown if the <see cref="IsAvailable"/> property of
/// <paramref name="info"/> is false.
/// </exception>
public static Tuple<Uri, Uri, Uri> Unmap(UpdateInfo info)
{
if (!info.IsAvailable)
{
throw new ArgumentException(
paramName: nameof(info),
message: "The provided UpdateInfo did not contain " +
"information to map to a Tuple<Uri, Uri, Uri>."
);
}
return Tuple.Create(
item1: info.ArchiveLocation,
item2: info.InstallerLocation,
item3: info.ReleaseNotesLocation
);
}
/// <summary>
/// <para>
/// Checks whether an update is available for this version, and
/// provides access information if one is available.
/// </para>
/// </summary>
/// <param name="info">
/// <para>
/// The variable to which information about any available update
/// is to be assigned.
/// </para>
/// </param>
public static void CheckNewVersion(out UpdateInfo info)
{
// If there's no internet connection, we obviously can't check
// for an update using the internet.
if (!Interop.InternetCheckConnection())
{
info = new UpdateInfo();
return;
}
var uri = String.Join(
String.Empty, UPDATE_CHECK_URI, "?hash=", VersionHash);
var req = WebRequest.CreateHttp(uri);
// Get the response, catching any exceptions if the request fails.
var res = req.GetResponseSafe() as HttpWebResponse;
// If the request fails, indicate that no update is available.
if (res.StatusCode != HttpStatusCode.OK)
{
info = new UpdateInfo();
return;
}
// The response we get should be some XML.
var xpd = new XPathDocument(res.GetResponseStream());
var update = xpd.CreateNavigator().SelectSingleNode("/data/update");
// Is there an update available? If not, we return.
bool isAvail;
if (!bool.TryParse(update.GetAttribute("available", ""), out isAvail) ||
!isAvail)
{
info = new UpdateInfo();
return;
}
// Try and parse the URIs
Uri archive, installer, notes;
if (!Uri.TryCreate(update.GetAttribute("archive", ""),
UriKind.Absolute,
out archive) ||
!Uri.TryCreate(update.GetAttribute("install", ""),
UriKind.Absolute,
out installer) ||
!Uri.TryCreate(update.GetAttribute("notes", ""),
UriKind.Absolute,
out notes))
{
info = new UpdateInfo();
return;
}
// Return the retrieved URIs
info = new UpdateInfo(archive, installer, notes);
}