public FileTailerViewModel(ILogger logger,ISchedulerProvider schedulerProvider, FileInfo fileInfo)
{
if (logger == null) throw new ArgumentNullException(nameof(logger));
if (schedulerProvider == null) throw new ArgumentNullException(nameof(schedulerProvider));
if (fileInfo == null) throw new ArgumentNullException(nameof(fileInfo));
var filterRequest = this.WhenValueChanged(vm => vm.SearchText).Throttle(TimeSpan.FromMilliseconds(125));
var autoChanged = this.WhenValueChanged(vm => vm.AutoTail);
var scroller = _userScrollRequested
.CombineLatest(autoChanged, (user, auto) =>
{
var mode = AutoTail ? ScrollingMode.Tail : ScrollingMode.User;
return new ScrollRequest(mode, user.PageSize, user.FirstIndex);
})
.Sample(TimeSpan.FromMilliseconds(150))
.DistinctUntilChanged();
var tailer = new FileTailer(fileInfo, filterRequest, scroller);
//create user display for count line count
var lineCounter = tailer.TotalLines.CombineLatest(tailer.MatchedLines,(total,matched)=>
{
return total == matched
? $"File has {total.ToString("#,###")} lines"
: $"Showing {matched.ToString("#,###")} of {total.ToString("#,###")} lines";
})
.Subscribe(text => LineCountText=text);
//load lines into observable collection
var loader = tailer.Lines.Connect()
.Transform(line => new LineProxy(line))
.Sort(SortExpressionComparer<LineProxy>.Ascending(proxy => proxy.Number))
.ObserveOn(schedulerProvider.MainThread)
.Bind(out _data)
.Subscribe(changes => logger.Info($"Rows changed {changes.Adds} adds, {changes.Removes} removed"),
ex => logger.Error(ex, "There is a problem with bind data"));
//monitor matching lines and start index,
var matchedLinesMonitor = tailer.MatchedLines
.Subscribe(matched => MatchedLineCount = matched);
//track first visible index
var firstIndexMonitor = tailer.Lines.Connect()
.QueryWhenChanged(lines =>lines.Count == 0 ? 0 : lines.Select(l => l.Index).Min())
.Subscribe(first=> FirstIndex= first);
_cleanUp = new CompositeDisposable(tailer,
lineCounter,
loader,
firstIndexMonitor,
matchedLinesMonitor,
Disposable.Create(() =>
{
_userScrollRequested.OnCompleted();
}));
}
public void AutoTailWithFilter()
{
var file = Path.GetTempFileName();
var info = new FileInfo(file);
var scheduler = new TestScheduler();
var textMatch = Observable.Return("odd");
var autoTailer = Observable.Return(new ScrollRequest(10));
File.AppendAllLines(file, Enumerable.Range(1, 100)
.Select(i => i%2 == 1 ? $"{i} is an odd number" : $"{i} is an even number").ToArray());
using (var tailer = new FileTailer(info, textMatch, autoTailer, scheduler))
{
//lines which contain "1"
var expectedLines = Enumerable.Range(1, 100)
.Select(i => i % 2 == 1 ? $"{i} is an odd number" : $"{i} is an even number")
.Where(s => s.Contains("odd"))
.Reverse()
.Take(10)
.Reverse()
.ToArray();
scheduler.AdvanceBySeconds(1);
tailer.Lines.Items.Select(l => l.Text).ShouldAllBeEquivalentTo(expectedLines);
File.AppendAllLines(file, Enumerable.Range(101, 10)
.Select(i => i % 2 == 1 ? $"{i} is an odd number" : $"{i} is an even number").ToArray());
scheduler.AdvanceBySeconds(1);
expectedLines = Enumerable.Range(1, 110)
.Select(i => i % 2 == 1 ? $"{i} is an odd number" : $"{i} is an even number")
.Where(s => s.Contains("odd"))
.Reverse()
.Take(10)
.Reverse()
.ToArray();
scheduler.AdvanceBySeconds(1);
File.Delete(file);
tailer.Lines.Items.Select(l => l.Text).ShouldAllBeEquivalentTo(expectedLines);
}
}
public void AutoTailWithFilter()
{
var scheduler = new TestScheduler();
var autoTailer = Observable.Return(new ScrollRequest(10));
Func<string, bool> predicate = s => s.Contains("odd");
using (var file = new TestFile())
{
file.Append(Enumerable.Range(1, 100).Select(i => i%2 == 1 ? $"{i} is an odd number" : $"{i} is an even number").ToArray());
var search = file.Info.Search(predicate, scheduler);
using (var tailer = new FileTailer(file.Info, search, autoTailer, new NullLogger(), scheduler))
{
//lines which contain "1"
var expectedLines = Enumerable.Range(1, 100)
.Select(i => i%2 == 1 ? $"{i} is an odd number" : $"{i} is an even number")
.Where(s => s.Contains("odd"))
.Reverse()
.Take(10)
.Reverse()
.ToArray();
scheduler.AdvanceBySeconds(1);
tailer.Lines.Items.Select(l => l.Text).ShouldAllBeEquivalentTo(expectedLines);
file.Append( Enumerable.Range(101, 10).Select(i => i%2 == 1 ? $"{i} is an odd number" : $"{i} is an even number").ToArray());
scheduler.AdvanceBySeconds(1);
expectedLines = Enumerable.Range(1, 110)
.Select(i => i%2 == 1 ? $"{i} is an odd number" : $"{i} is an even number")
.Where(s => s.Contains("odd"))
.Reverse()
.Take(10)
.Reverse()
.ToArray();
scheduler.AdvanceBySeconds(1);
tailer.Lines.Items.Select(l => l.Text).ShouldAllBeEquivalentTo(expectedLines);
}
}
}
public void AutoTail()
{
var file = Path.GetTempFileName();
var info = new FileInfo(file);
var scheduler = new TestScheduler();
var textMatch = Observable.Return((string)null);
var autoTailer = Observable.Return(new ScrollRequest(10));
File.AppendAllLines(file, Enumerable.Range(1, 100).Select(i =>i.ToString()).ToArray());
using (var tailer = new FileTailer(info, textMatch, autoTailer,scheduler))
{
tailer.Lines.Items.Select(l => l.Number).ShouldAllBeEquivalentTo(Enumerable.Range(91, 10));
File.AppendAllLines(file, Enumerable.Range(101, 10).Select(i => i.ToString()));
scheduler.AdvanceByMilliSeconds(250);
File.Delete(file);
tailer.Lines.Items.Select(l => l.Number).ShouldAllBeEquivalentTo(Enumerable.Range(101, 10));
}
}
public void AutoTail()
{
var scheduler = new TestScheduler();
var textMatch = Observable.Return(FileSearchResult.None);
var autoTailer = Observable.Return(new ScrollRequest(10));
using (var file = new TestFile())
{
file.Append( Enumerable.Range(1, 100).Select(i => i.ToString()).ToArray());
using (var tailer = new FileTailer(file.Info, textMatch, autoTailer, new NullLogger(), scheduler))
{
scheduler.AdvanceByMilliSeconds(250);
tailer.Lines.Items.Select(l => l.Number).ShouldAllBeEquivalentTo(Enumerable.Range(91, 10));
file.Append( Enumerable.Range(101, 10).Select(i => i.ToString()));
scheduler.AdvanceByMilliSeconds(250);
tailer.Lines.Items.Select(l => l.Number).ShouldAllBeEquivalentTo(Enumerable.Range(101, 10));
}
}
}
public void WillNotApplyFilterWhenTextIsLessThan3Character()
{
var file = Path.GetTempFileName();
var info = new FileInfo(file);
var scheduler = new TestScheduler();
var textMatch = Observable.Return((string)"1");
var autoTailer = Observable.Return(new ScrollRequest(10));
File.AppendAllLines(file, Enumerable.Range(1, 100).Select(i => i.ToString()).ToArray());
using (var tailer = new FileTailer(info, textMatch, autoTailer, scheduler))
{
//lines which contain "1"
int[] expectedLines = Enumerable.Range(91, 10)
.Select(i => i.ToString())
.Select(int.Parse)
.ToArray();
scheduler.AdvanceBySeconds(1);
tailer.Lines.Items.Select(l => l.Number).ShouldAllBeEquivalentTo(expectedLines);
File.Delete(file);
tailer.Lines.Items.Select(l => l.Number).ShouldAllBeEquivalentTo(expectedLines);
}
}