app.py

import subprocess
import json
import os
import gradio as gr
import tempfile

# Set JAVA_HOME environment variable
# os.environ['JAVA_HOME'] = '/usr/lib/jvm/java-11-openjdk-amd64'

def grade_pdf(input_pdf, pdffigures2_jar):
    """
    Process a PDF file using pdffigures2 and return the extracted JSON output.

    Args:
        input_pdf (str): Path to the input PDF file.
        output_dir (str): Path to the directory where JSON output will be saved.
        pdffigures2_jar (str): Path to the pdffigures2 JAR file.

    Returns:
        dict: Parsed JSON data extracted by pdffigures2.

    Raises:
        FileNotFoundError: If the input PDF or JAR file does not exist.
        Exception: If the command fails or the JSON output is not generated.
    """
    # Check if input file and JAR file exist
    if not os.path.exists(input_pdf):
        raise FileNotFoundError(f"Input PDF file not found: {input_pdf}")
    if not os.path.exists(pdffigures2_jar):
        raise FileNotFoundError(f"pdffigures2 JAR file not found: {pdffigures2_jar}")


    # Command to execute pdffigures2
    command = [
        "java", "-jar", pdffigures2_jar,
        input_pdf,
        "-d", '_'
    ]
    print(input_pdf)

    try:
        # Run the command
        subprocess.run(command, capture_output=True, text=True, check=True)

        # Construct the output JSON file path
        # print()
        output_json_file = "_"+os.path.splitext(os.path.basename(input_pdf))[0] +".json"
        print("output_json_file: ", output_json_file)

        # Read and return the JSON data
        if os.path.exists(output_json_file):
            with open(output_json_file, "r") as f:
                regions = json.load(f)

            issueList = list()

            for region in regions:
                issues = dict()
                if(region["captionBoundary"]["y1"]>region["regionBoundary"]["y1"]):
                    region["captionLocation"]="Below"
                else:
                    region["captionLocation"]="Above"

                if(region["captionLocation"]=="Below" and region["figType"] == "Table"):
                    issues["page_number"]=region["page"]+1
                    issues["caption_coordinate"]=region["captionBoundary"]
                    issues["fig_type"] = region["figType"]
                    issues["caption_location"] = region["captionLocation"]
                    issues["description"]="Location of the caption for tables must be above the table."
                    issueList.append(issues)
                    
                if(region["captionLocation"]=="Above" and region["figType"] == "Figure"):
                    issues["page_number"]=region["page"]+1
                    issues["caption_coordinate"]=region["captionBoundary"]
                    issues["fig_type"] = region["figType"]
                    issues["description"]="Location of the caption for figures must be below the table."
                    issueList.append(issues)
                    
            return issueList

        else:
            raise Exception(f"JSON output file not found: {output_json_file}")

    except subprocess.CalledProcessError as e:
        raise Exception(f"Error while running pdffigures2: {e.stderr}")

def process_file(file):
    """
    Wrapper to process a file via grade_pdf and return JSON data.

    Args:
        file (str): Path to the uploaded PDF file.

    Returns:
        str: JSON string of extracted data.
    """
    # Define paths
    pdffigures2_jar_path = "pdffigures2.jar"  # Path to pdffigures2 JAR file
    
    temp_input = tempfile.NamedTemporaryFile(delete=False, suffix='.pdf')
    temp_input.write(file)
    temp_input_path = temp_input.name
    print("Path of the input file: ",temp_input_path)

    try:
        # Process the PDF and get JSON data
        # print(file.name)
        extracted_data = grade_pdf(temp_input_path, pdffigures2_jar_path)
        # Clean up the temporary input file
        os.unlink(temp_input_path)
        

        # Return JSON as a formatted string
        return json.dumps(extracted_data, indent=4)
    except Exception as e:
        return f"An error occurred: {e}"

# Gradio Interface
def gradio_interface():
    interface = gr.Interface(
        fn=process_file,
        
        inputs=gr.File(label="Upload PDF File", file_types=[".pdf"], type="binary"),
        
        outputs=gr.Textbox(label="Extracted JSON Data", lines=20),
        
        title="PDF Grading Interface",
        
        description="Upload a PDF file, and this tool will extract figures and captions as JSON."
    )
    return interface

if __name__ == "__main__":
    # Launch the Gradio app
    gradio_interface().launch()