CLI Transform Authoring

CLI Transform Authoring

This skill covers creating new transforms for the webforms-to-blazor CLI migration pipeline.

Architecture Overview

The migration CLI uses two transform interfaces that run in sequence during file conversion:

1. Markup transforms (IMarkupTransform) — Convert .aspx/.ascx/.master markup to .razor syntax
2. Code-behind transforms (ICodeBehindTransform) — Convert .aspx.cs code-behind to .razor.cs

Both interfaces share the same contract:

public interface IMarkupTransform  // (or ICodeBehindTransform)
{
    string Name { get; }
    int Order { get; }
    string Apply(string content, FileMetadata metadata);
}

• Name — Human-readable identifier (used in logs and diagnostics)
• Order — Execution sequence (ascending). Lower numbers run first.
• Apply — Takes current content + file metadata, returns transformed content

Pipeline Execution Order

MigrationPipeline runs transforms in this order:

1. Markup transforms (sorted by Order ascending) — all run on .razor content
2. Code-behind transforms (sorted by Order ascending) — all run on .razor.cs content
3. Semantic patterns (SemanticPatternCatalog) — page-level rewrites after all transforms

FileMetadata

Every transform receives FileMetadata which carries context about the file being processed:

• OriginalPath — Source .aspx path
• OutputPath — Target .razor path