public ExpressionFilter(string filterExpression)
{
Func <LogEvent, bool> filter;
// Our custom Serilog Functions to extend Serilog.Expressions
// In this case we are plugging the gap for the missing Has()
// function from porting away from Serilog.Filters.Expressions to Serilog.Expressions
// Along with patching support for the more verbose built in property names
var customSerilogFunctions = new SerilogLegacyNameResolver(typeof(SerilogExpressionsFunctions));
if (string.IsNullOrEmpty(filterExpression))
{
return;
}
// If the expression is one word and doesn't contain a serilog operator then we can perform a like search
if (!filterExpression.Contains(" ") && !filterExpression.ContainsAny(s_expressionOperators.Select(c => c)))
{
filter = PerformMessageLikeFilter(filterExpression);
}
else // check if it's a valid expression
{
// If the expression evaluates then make it into a filter
if (SerilogExpression.TryCompile(filterExpression, null, customSerilogFunctions, out CompiledExpression compiled, out var error))
{
filter = evt =>
{
LogEventPropertyValue result = compiled(evt);
return(ExpressionResult.IsTrue(result));
};
}
private Func <LogEvent, bool>?PerformMessageLikeFilter(string filterExpression)
{
var filterSearch = $"@Message like '%{SerilogExpression.EscapeLikeExpressionContent(filterExpression)}%'";
if (SerilogExpression.TryCompile(filterSearch, out CompiledExpression? compiled, out var error))
{
// `compiled` is a function that can be executed against `LogEvent`s:
return(evt =>
{
LogEventPropertyValue?result = compiled(evt);
return ExpressionResult.IsTrue(result);
});
}
return(null);
}
public LogResults Search(int pageNumber = 1, int pageSize = 100, string?filterExpression = null, SortOrder sort = SortOrder.Descending)
{
//If filter null - return a simple page of results
if (filterExpression == null)
{
var totalRecords = _logItems.Count;
var logMessages = _logItems
.OrderBy(x => x.Timestamp, sort)
.Skip(pageSize * (pageNumber - 1))
.Take(pageSize)
.Select(x => new LogMessage
{
Timestamp = x.Timestamp,
Level = x.Level,
MessageTemplateText = x.MessageTemplate.Text,
Exception = x.Exception?.ToString(),
Properties = x.Properties,
RenderedMessage = x.RenderMessage()
});
return(new LogResults()
{
Logs = new PagedResult <LogMessage>(totalRecords, pageNumber, pageSize)
{
Items = logMessages
},
MessageTemplates = GetMessageTemplates(_logItems)
});
}
Func <LogEvent, bool>?filter;
// Our custom Serilog Functions in this case plugging the gap for missing Has() function
var customSerilogFunctions = new LegacyNameResolver(typeof(SerilogExtensions));
// With an empty expression - ensure all logs are sent back
if (filterExpression == string.Empty)
{
filter = evt =>
{
// Return true/matches
return(true);
};
}
// If the expression is one word and doesn't contain a serilog operator then we can perform a like search
else if (!filterExpression.Contains(" ") && !filterExpression.ContainsAny(ExpressionOperators))
{
filter = PerformMessageLikeFilter(filterExpression);
}
else
{
// Check if it's a valid expression
// If the expression evaluates then make it into a filter
if (SerilogExpression.TryCompile(filterExpression, null, customSerilogFunctions, out var compiled, out var error))
{
// `compiled` is a function that can be executed against `LogEvent`s:
filter = evt =>
{
var result = compiled(evt);
return(ExpressionResult.IsTrue(result));
};
}