Validate MaxBodyCaptureSizeKb Configuration

[georgidhristov]

Description

DebugProbe currently allows MaxBodyCaptureSizeKb to be configured with negative values.

Negative values can break request and response body capture calculations, leading to unexpected behavior during body truncation and size validation.

Current Behavior

MaxBodyCaptureSizeKb can currently be configured with invalid values such as:

builder.Services.AddDebugProbe(options =>
{
    options.MaxBodyCaptureSizeKb = -1;
});

This may cause incorrect body size calculations and unexpected capture behavior.

Expected Behavior

DebugProbe should validate MaxBodyCaptureSizeKb and reject invalid values during application startup.

Suggested Fix

Validate MaxBodyCaptureSizeKb during options configuration or initialization.

Recommended validation:

MaxBodyCaptureSizeKb >= 0

A value of:

• 0 disables body capture
• Positive values enable body capture up to the configured limit

If an invalid value is provided, throw a clear configuration exception explaining the allowed range.

Result

After this change:

• Invalid configuration is detected early.
• Body capture calculations remain predictable.
• Unexpected truncation or capture behavior is prevented.
• Users receive clear feedback when configuration values are invalid.