backend/pdf_component.py

from __future__ import annotations
from typing import Any, Callable, Dict, List, Optional, TYPE_CHECKING
from gradio.components.base import Component
from gradio.data_classes import FileData
from gradio.events import Events, EventListener

if TYPE_CHECKING:
    from gradio.components import Timer

class PDF(Component):
    """
    PDF component for displaying PDF files and enabling citation analysis.
    
    This component renders PDF documents with page navigation controls and
    supports integration with Anthropic's Citations API. It allows users 
    to view PDFs, navigate through pages, and interact with citations.
    """
    EVENTS = [
        Events.change,
        Events.upload,
        EventListener("cite", doc="Triggered when a citation is selected or interacted with.")
    ]
    data_model = FileData
    
    def __init__(
        self, 
        value: Optional[str | FileData] = None, 
        *,
        height: Optional[int] = None,
        label: Optional[str] = None, 
        info: Optional[str] = None,
        show_label: Optional[bool] = None,
        container: bool = True,
        scale: Optional[int] = None,
        min_width: Optional[int] = None,
        interactive: Optional[bool] = None,
        visible: bool = True,
        elem_id: Optional[str] = None,
        elem_classes: Optional[List[str] | str] = None,
        render: bool = True,
        load_fn: Optional[Callable[..., Any]] = None,
        every: Optional[Timer | float] = None
    ):
        """
        Parameters:
            value: Initial path to PDF file or FileData object
            height: Height of the PDF viewer in pixels
            label: Component label displayed to user
            info: Additional information about the component
            show_label: Whether to display the label
            container: Whether to display the component in a container
            scale: Relative width compared to adjacent Components
            min_width: Minimum width in pixels
            interactive: Whether the Component is interactive
            visible: Whether the Component is visible
            elem_id: HTML id for the Component
            elem_classes: CSS classes for the Component
            render: Whether to render the Component
            load_fn: Function to call when Component loads
            every: How frequently to call load_fn
        """
        super().__init__(
            value, 
            label=label, 
            info=info,
            show_label=show_label, 
            container=container,
            scale=scale, 
            min_width=min_width,
            interactive=interactive, 
            visible=visible,
            elem_id=elem_id, 
            elem_classes=elem_classes,
            render=render, 
            load_fn=load_fn, 
            every=every
        )
        self.height = height
    
    def preprocess(self, payload: Optional[FileData]) -> Optional[str]:
        """
        Process the uploaded PDF file data.
        
        Returns:
            Path to the uploaded PDF file or None if no file was uploaded
        """
        return payload.path if payload else None
    
    def postprocess(self, value: Optional[str]) -> Optional[FileData]:
        """
        Process the PDF file path into a FileData object.
        
        Parameters:
            value: Path to the PDF file or None
        
        Returns:
            FileData object containing the path to the PDF file or None if path is None
        """
        if not value:
            return None
        return FileData(path=value)
    
    def example_inputs(self) -> Any:
        """
        Provides example inputs for documentation and testing.
        
        Returns:
            Example FileData for documentation
        """
        return FileData(path="example.pdf")
    
    def example_payload(self) -> str:
        """Example payload for documentation.
        
        Returns:
            URL to an example PDF file
        """
        return "https://cdn.anthropic.com/claude/example.pdf"
    
    def example_value(self) -> str:
        """Example value for documentation.
        
        Returns:
            URL to an example PDF file
        """
        return "https://cdn.anthropic.com/claude/example.pdf"