# safe-template-rendering

## Purpose

Defines the pattern for safe template rendering in HTMX partial handlers to prevent truncated HTML from reaching clients.

## Requirements

### Requirement: Buffered template execution for HTMX partials
All HTMX partial handlers SHALL render templates into a buffer before writing to the HTTP response. If template execution fails, the handler SHALL return an error response (HTML error fragment) instead of partial/truncated HTML.

#### Scenario: Template executes successfully
- **WHEN** an HTMX partial handler renders a template with valid data
- **THEN** the full HTML output is written to the ResponseWriter with status 200

#### Scenario: Template execution fails due to missing field
- **WHEN** a template references a field that does not exist on the data struct
- **THEN** no partial HTML is written to the ResponseWriter
- **AND** an error HTML fragment is returned to the client
- **AND** the error is logged with template name and error details

#### Scenario: Template execution fails due to nil data
- **WHEN** a template is executed with nil or invalid data
- **THEN** no partial HTML is written to the ResponseWriter
- **AND** an error HTML fragment is returned to the client

### Requirement: Centralized template execution helper
The server package SHALL provide a shared helper function for buffered template execution. All HTMX partial handlers (operator, fedwiki, dashboard) SHALL use this helper instead of calling `ExecuteTemplate` directly on `http.ResponseWriter`.

#### Scenario: Helper function signature
- **WHEN** a handler needs to render a template
- **THEN** it calls the shared helper with the ResponseWriter, template set, template name, and data
- **AND** the helper handles buffering, error detection, and error response rendering internally