app.py

# app.py

import os
import re
from flask import Flask, render_template_string, abort, request, session
from werkzeug.utils import safe_join
import traceback

# --- 初始化和配置 ---
app = Flask(__name__)
app.secret_key = 'a-very-secret-and-complex-key-for-pyecho'
PYECHO_DIR = 'pyecho_pages'
DEFAULT_PAGE = 'index.pyecho'

# --- Pyecho 解析器 ---
def parse_pyecho_to_python(content):
    parts = re.split(r'(<\?py.*?\?>)', content, flags=re.DOTALL)
    py_script_lines = []
    for part in parts:
        if not part:
            continue
        if part.startswith('<?py') and part.endswith('?>'):
            code = part[4:-2].strip()
            py_script_lines.append(code)
        else:
            escaped_html = f"echo(r'''{part}''')"
            py_script_lines.append(escaped_html)
    return "\n".join(py_script_lines)

# --- 核心路由 ---
@app.route('/', defaults={'page': ''}, methods=['GET', 'POST'])
@app.route('/<path:page>', methods=['GET', 'POST'])
def pyecho_executor(page):
    file_name = DEFAULT_PAGE if not page else f"{page}.pyecho"
    try:
        file_path = safe_join(os.path.abspath(PYECHO_DIR), file_name)
    except Exception:
        abort(404)

    if not os.path.exists(file_path):
        abort(404)

    output_buffer = []
    template_context = {}

    def echo(*args):
        if len(args) == 1:
            output_buffer.append(str(args[0]))
        elif len(args) == 2 and isinstance(args[0], str):
            template_context[args[0]] = args[1]
        else:
            raise TypeError(f"echo() takes 1 or 2 arguments, but {len(args)} were given.")
    
    exec_globals = {
        'echo': echo,
        'request': request,
        'session': session,
        'include': None
    }

    # 定义 include 函数以支持文件包含
    def include(include_file_name):
        # 安全地拼接路径
        include_path = safe_join(os.path.abspath(PYECHO_DIR), include_file_name)
        
        if not os.path.exists(include_path):
            # 如果文件不存在，直接抛出异常，这样错误页面就会显示出来
            raise FileNotFoundError(f"Pyecho include error: File '{include_file_name}' not found at path '{include_path}'.")

        with open(include_path, 'r', encoding='utf-8') as f:
            include_content = f.read()
        
        # 解析被包含的文件
        include_script = parse_pyecho_to_python(include_content)
        
        # 在当前的执行上下文中执行该脚本。
        # 异常会向上传递，并被下面的主 try...except 块捕获。
        exec(include_script, exec_globals)

    exec_globals['include'] = include

    py_script = "" # 预定义，以防解析失败
    try:
        with open(file_path, 'r', encoding='utf-8') as f:
            pyecho_content = f.read()
        
        py_script = parse_pyecho_to_python(pyecho_content)
        
        exec(py_script, exec_globals)

    except Exception as e:
        # 使用 traceback 来获取发生错误的具体位置
        error_trace = traceback.format_exc()
        error_message = f"""
        <h1>Pyecho Execution Error</h1>
        <p>An error occurred while executing <strong>{file_name}</strong>.</p>
        
        <h2>Error Details:</h2>
        <pre style="background-color: #f8d7da; color: #721c24; padding: 1em; border-radius: 5px; white-space: pre-wrap; word-wrap: break-word;">{error_trace}</pre>
        
        <h2>Generated Python Script (for debugging):</h2>
        <pre style="background-color: #eee; border: 1px solid #ccc; padding: 1em; border-radius: 5px; white-space: pre-wrap; word-wrap: break-word;">{py_script if py_script else 'Parsing failed before script generation.'}</pre>
        """
        return error_message, 500

    template_string = "".join(output_buffer)
    return render_template_string(template_string, **template_context)


# --- 运行应用 ---
if __name__ == '__main__':
    if not os.path.exists(PYECHO_DIR):
        os.makedirs(PYECHO_DIR)
        print(f"Created directory: {PYECHO_DIR}")
    
    if not os.path.exists('blog_posts.json'):
        with open('blog_posts.json', 'w') as f:
            f.write('[]')
        print("Created empty blog_posts.json")

    app.run(debug=True, port=5000)