Debugging Tools

FlexQuery.NET provides a dedicated debug mode to help you understand how your string-based queries are transformed into executable code.

ToFlexQueryDebug()

The ToFlexQueryDebug extension method allows you to inspect the internal state of a query before it is executed.

var options = QueryOptionsParser.Parse(Request.Query);
var debug = _context.Customers.ToFlexQueryDebug(options);

// Inspect results
Console.WriteLine(debug.LinqLambda);      // The C#-like LINQ syntax
Console.WriteLine(debug.ExpressionTree);  // The structural expression node tree
Console.WriteLine(debug.Ast);             // The raw parsed Abstract Syntax Tree

Example Analysis

For a query like ?query=orders.any(status = Cancelled AND total > 500):

1. LINQ Lambda

Shows you exactly what the generated C# code looks like. This is the most helpful for verifying logic.

query.Where(x => x.Orders.Any(sc => (sc.Status == "Cancelled") && (sc.Total > 500)))

2. AST (Abstract Syntax Tree)

Shows how the parser interpreted the input string before it was converted to an expression tree.

orders.any(AND(status eq [Cancelled], total gt [500]))

3. Expression Tree

A detailed breakdown of the System.Linq.Expressions.Expression tree, useful for deep debugging of custom operator handlers or provider-specific translation issues.

Debugging Tips

• Check Types: If a filter isn't working as expected, use debug mode to ensure the value was parsed as the correct type (e.g., ensuring a string "123" was converted to a numeric constant).
• Verify Logic: Nesting parentheses in DSL can be tricky. Use the LinqLambda output to ensure the logic groups are prioritized correctly.
• Log in Development: Consider logging the LinqLambda for all dynamic queries during development to build confidence in the system.