internal OutputWriter(SearchCommand command, string originalCommand)
{
regularForeGround = Console.ForegroundColor; //using current
hasOutputPath = !string.IsNullOrEmpty(command.FileOutputPath);
writeOutputFile = command.OutputHtml || hasOutputPath;
this.command = command;
if (!writeOutputFile)
{
return;
}
terms = command.Terms;
if (command.OutputHtml)
{
var context = BrowsingContext.New(Configuration.Default);
document = context.OpenNewAsync().Result;
var style = document.CreateElement("style");
style.TextContent = "pre > em { background-color: yellow }";
document.Head.Append(style);
output = document.CreateElement("pre");
document.Body.Append(output);
}
else
{
textOut = new StringWriter();
}
WriteLine(originalCommand);
WriteLine();
}
private static async Task Search(SearchCommand command, string originalCommand,
Func <Youtube, IAsyncEnumerable <VideoSearchResult> > getResultsAsync)
{
var terms = command.Terms;
if (!terms.Any())
{
Console.WriteLine("None of the terms contain anything but whitespace. I refuse to work like this!");
return;
}
//inspired by https://johnthiriet.com/cancel-asynchronous-operation-in-csharp/
using (var search = new CancellationTokenSource())
{
var searching = true;
var cancel = Task.Run(async() => //start in background, don't wait for completion
{
Console.WriteLine("Press any key to cancel");
Console.WriteLine();
/* wait for key or search to finish, non-blockingly; but only as long as to not cause perceivable lag
* inspired by https://stackoverflow.com/a/5620647 and https://stackoverflow.com/a/23628232 */
while (searching && !Console.KeyAvailable)
{
await Task.Delay(200, search.Token);
}
if (Console.KeyAvailable)
{
Console.ReadKey(true); //consume cancel key without displaying it
}
if (searching)
{
search.Cancel();
}
});
var youtube = new Youtube(new JsonFileDataStore(GetCachePath()));
var output = new OutputWriter(command, originalCommand);
try
{
/* passing token into search implementations for them to react to cancellation,
* see https://docs.microsoft.com/en-us/archive/msdn-magazine/2019/november/csharp-iterating-with-async-enumerables-in-csharp-8#a-tour-through-async-enumerables*/
await foreach (var result in getResultsAsync(youtube).WithCancellation(search.Token))
{
output.DisplayVideoResult(result);
}
}
catch (OperationCanceledException) { Console.WriteLine("The search was cancelled."); }
output.WriteOutputFile(() => GetFileStoragePath("out"));
searching = false; //to complete the cancel task
await cancel; //just to rethrow possible exceptions
}
}