private async Task <GetFileResult> ReadFileFromLocalAsync()
{
return(await Task.Run(delegate
{
GetFileResult getFileResult = new GetFileResult
{
Code = HttpStatusCode.Unused
};
try
{
getFileResult.RespStream = fileReader.ReadFile();
getFileResult.Code = HttpStatusCode.OK;
return getFileResult;
}
catch (ArgumentException)
{
getFileResult.ErrorMessage = "File path contains invalid characters";
return getFileResult;
}
catch (IOException)
{
getFileResult.ErrorMessage = "IO exception reading file";
return getFileResult;
}
catch (UnauthorizedAccessException)
{
getFileResult.ErrorMessage = "Could not access file for reading";
return getFileResult;
}
}).ConfigureAwait(false));
}
private bool IsStale(GetFileResult fileResult)
{
if (fileResult.IsFromCache && fileResult.AgeSeconds.HasValue)
{
return(fileResult.AgeSeconds <= PollingIntervalMins * 60);
}
return(false);
}
/// <summary>
/// Get a file and send telemetry events.
/// </summary>
/// <param name="fromServer"></param>
/// <returns></returns>
private async Task <GetFileResult> GetFileAndInstrumentAsync(bool fromServer = false)
{
GetFileResult getFileResult = await(fromServer ? requestor.GetFileFromServerAsync() : requestor.GetFileFromCacheAsync()).ConfigureAwait(false);
if (fromServer && (!getFileResult.IsFromCache || !getFileResult.IsSuccessStatusCode))
{
InstrumentGetFile(getFileResult);
}
return(getFileResult);
}
/// <summary>
/// Gets the elapsed time (in seconds) since the last error in downloading / revalidating the file from the
/// server.
/// </summary>
/// <returns>Time in seconds since last error or Int.MaxValue if no error has ever occured.</returns>
async Task <int> IRemoteControlHTTPRequestor.LastServerRequestErrorSecondsAgoAsync()
{
using (GetFileResult getFileResult = await GetFile(errorMarkerFileUrl, httpRequestTimeoutMillis, CacheOnlyPolicy).ConfigureAwait(false))
{
if (getFileResult.IsFromCache)
{
return(getFileResult.AgeSeconds.Value);
}
return(int.MaxValue);
}
}
/// <summary>
/// Reads the file from the server url.
/// In case of errors reading the file from the server, returned <see cref="T:Coding4Fun.VisualStudio.RemoteControl.GetFileResult" /> object's
/// IsSuccessStatusCode value will be false.
/// </summary>
/// <returns>Information about the file obtained from the server</returns>
async Task <GetFileResult> IRemoteControlHTTPRequestor.GetFileFromServerAsync()
{
GetFileResult result = new GetFileResult
{
Code = HttpStatusCode.Unused
};
try
{
int i = 0;
while (true)
{
if (i >= 2)
{
return(result);
}
if (i > 0)
{
int num = Math.Min(32, (int)Math.Pow(2.0, i));
try
{
await Task.Delay(num * 1000, cancellationTokenSource.Token).ConfigureAwait(false);
}
catch (OperationCanceledException)
{
return(result);
}
catch (ObjectDisposedException)
{
return(result);
}
result.Dispose();
}
result = await GetFile(url, httpRequestTimeoutMillis, ServerRevalidatePolicy).ConfigureAwait(false);
if (result.IsSuccessStatusCode)
{
break;
}
i++;
}
return(result);
}
finally
{
if (!result.IsSuccessStatusCode && Platform.IsWindows)
{
WinINetHelper.WriteErrorResponseToCache(errorMarkerFileUrl, result.Code);
}
}
}
/// <summary>
/// Instruments the usage of GetFileFromCache and GetFileFromServer.
/// </summary>
/// <param name="fileResult"></param>
private void InstrumentGetFile(GetFileResult fileResult)
{
Dictionary <string, object> dictionary = new Dictionary <string, object>
{
{
"VS.RemoteControl.DownloadFile.FullUrl",
FullUrl
},
{
"VS.RemoteControl.DownloadFile.IsSuccess",
fileResult.IsSuccessStatusCode
},
{
"VS.RemoteControl.DownloadFile.HttpRequestTimeoutInSecs",
httpRequestTimeoutSeconds
},
{
"VS.RemoteControl.DownloadFile.IsFromCache",
fileResult.IsFromCache
},
{
"VS.RemoteControl.DownloadFile.PollingIntervalInMins",
PollingIntervalMins
}
};
Dictionary <string, object> dictionary2 = new Dictionary <string, object>();
if (fileResult.IsSuccessStatusCode)
{
dictionary.Add("VS.RemoteControl.DownloadFile.IsNotFound", fileResult.Code == HttpStatusCode.NotFound);
if (fileResult.RespStream != null)
{
dictionary.Add("VS.RemoteControl.DownloadFile.StreamSize", fileResult.RespStream.Length);
}
if (fileResult.AgeSeconds.HasValue)
{
dictionary.Add("VS.RemoteControl.DownloadFile.AgeInSecs", fileResult.AgeSeconds.Value);
}
}
else
{
if (fileResult.Code != HttpStatusCode.Unused)
{
dictionary.Add("VS.RemoteControl.DownloadFile.ErrorCode", Enum.GetName(typeof(HttpStatusCode), fileResult.Code));
}
dictionary2.Add("VS.RemoteControl.DownloadFile.ErrorMessage", fileResult.ErrorMessage);
}
TelemetryLogger2("VS/RemoteControl/DownloadFile", dictionary, dictionary2);
}
/// <summary>
/// Determines if a local IE cache copy of the file is up-to-date. If no cached copy is available or the
/// cached copy is not up-to-date, a request is made to the server to download or revalidate the file. The
/// result of the server request is cached.
/// </summary>
/// <param name="cancellationToken">Cancellation token to cancel waiting of operation</param>
/// <returns>Returns True if the copy in the IE cache is up-to-date by the end of the method. False in case of
/// failures that prevent updating file.</returns>
private async Task <bool> EnsureFileIsUpToDateAsync(CancellationToken cancellationToken)
{
if (isDisabled)
{
return(false);
}
try
{
await updateMutex.WaitAsync(cancellationToken).ConfigureAwait(false);
for (int i = 1; i <= 2; i++)
{
using (GetFileResult getFileResult = await GetFileAndInstrumentAsync().ConfigureAwait(false))
{
if (IsStale(getFileResult))
{
return(getFileResult.IsSuccessStatusCode);
}
}
if (await requestor.LastServerRequestErrorSecondsAgoAsync().ConfigureAwait(false) < PollingIntervalMins * 60)
{
return(false);
}
if (i < 2)
{
await Task.Delay(rand.Next(0, maxRandomDownloadDelaySeconds), cancellationToken).ConfigureAwait(false);
}
}
using (GetFileResult getFileResult2 = await GetFileAndInstrumentAsync(true).ConfigureAwait(false))
{
return(getFileResult2.IsSuccessStatusCode);
}
}
finally
{
try
{
updateMutex.Release();
}
catch (SemaphoreFullException)
{
}
}
}
/// <summary>
/// Reads the settings file based on the <paramref name="staleBehavior" /> specified. This is the Async version
/// of ReadFile method.
/// </summary>
/// <param name="staleBehavior">See <see cref="T:Coding4Fun.VisualStudio.RemoteControl.BehaviorOnStale" /> for details about each possible setting.
/// In most cases use the BehaviorOnStale.ReturnStale setting.</param>
/// <returns>A Stream that can be used to read the setting file. !Callers must call Dispose on this stream
/// object returned. Or Null is returned in case of failure to get the file (or if server returned
/// NotFound).</returns>
public async Task <Stream> ReadFileAsync(BehaviorOnStale staleBehavior)
{
if (isDisabled)
{
return(null);
}
if (isDisposed)
{
throw new ObjectDisposedException("RemoteControlClient");
}
if (Uri.IsLocalFile)
{
return((await ReadFileFromLocalAsync().ConfigureAwait(false)).RespStream);
}
switch (staleBehavior)
{
case BehaviorOnStale.ReturnStale:
return((await GetFileAndInstrumentAsync().ConfigureAwait(false)).RespStream);
case BehaviorOnStale.ReturnNull:
{
GetFileResult getFileResult = await GetFileAndInstrumentAsync().ConfigureAwait(false);
if (IsStale(getFileResult))
{
return(getFileResult.RespStream);
}
getFileResult.Dispose();
return(null);
}
case BehaviorOnStale.ForceDownload:
return((await GetFileAndInstrumentAsync(true).ConfigureAwait(false)).RespStream);
default:
return(null);
}
}
