Flask应用用户注册功能：路由配置与常见404错误排查

# Flask Python code snippet
@app.route("/")
def showForm():
    t_message = "Python and Postgres Registration Application"
    return render_template("register.html", message=t_message)

@app.route("/register", methods=["POST", "GET"])
def register():
    # ... registration logic ...
    pass

<!-- HTML form snippet -->
<form id='frmSignIn' name='frmSignIn' action='/sign_in?stage=login' method='post' onsubmit='return checkform(this);'>
    <!-- ... form fields ... -->
</form>

<form id='frmSignIn' name='frmSignIn' action='/register' method='post' onsubmit='return checkform(this);'>
    <div class="form-row">
      <label for="Email">Email address:</label>
      <input type="text" id="t_email" name="t_email">
    </div>

    <div class="form-row">
      <label for="Email">Password:</label>
      <input type="password" id="t_password" name="t_password"> <!-- Changed type to password for security -->
    </div>

    <div class="form-row">
      <input type="submit" id="btn_submit_sign_in" value='Sign In'>
    </div>
</form>

import hashlib
import psycopg2
from flask import Flask, render_template, request, redirect, url_for
# 推荐使用 werkzeug.security 模块进行密码哈希，因为它提供了更强大的算法和盐值管理
# from werkzeug.security import generate_password_hash, check_password_hash

app = Flask(__name__)

# 数据库配置信息
DB_CONFIG = {
    "host": "localhost",
    "port": "5432",
    "dbname": "register_dc",
    "user": "postgres",
    "password": "=5.k7wT=!D" # 生产环境中请勿硬编码密码，应使用环境变量
}

@app.route("/")
def show_registration_form():
    """显示用户注册表单页面"""
    message = "欢迎注册您的账户"
    return render_template("register.html", message=message)

@app.route("/register", methods=["POST"]) # 注册通常只接受POST请求
def register_user():
    """处理用户注册请求，将新用户数据存储到数据库"""
    # 从表单获取用户输入
    email = request.form.get("t_email", "").strip()
    password = request.form.get("t_password", "").strip()

    # 服务器端输入验证
    if not email:
        message = "请输入您的邮箱地址"
        return render_template("register.html", message=message)
    if not password:
        message = "请输入您的密码"
        return render_template("register.html", message=message)

    # 密码哈希处理
    # 推荐使用 werkzeug.security 中的 generate_password_hash()
    # 例如：hashed_password = generate_password_hash(password, method='pbkdf2:sha256')
    # 这里沿用原代码的 hashlib.sha256，但请注意其安全性不如 bcrypt 或 PBKDF2
    hashed_password = hashlib.sha256(password.encode()).hexdigest()

    conn = None
    cursor = None
    try:
        # 建立数据库连接
        conn = psycopg2.connect(**DB_CONFIG)
        cursor = conn.cursor()

        # 使用参数化查询防止SQL注入
        insert_sql = """
            INSERT INTO public.users (t_email, t_password)
            VALUES (%s, %s);
        """
        cursor.execute(insert_sql, (email, hashed_password))
        conn.commit()

        message = "您的用户账户已成功添加！"
        # 注册成功后可以重定向到登录页面或成功页面
        # return redirect(url_for('login_page')) 
        return render_template("register.html", message=message)

    except psycopg2.Error as e:
        # 数据库操作失败，回滚事务
        if conn:
            conn.rollback()
        message = f"数据库错误：{e}"
        app.logger.error(f"Database error during registration: {e}") # 记录详细错误日志
        return render_template("register.html", message=message)
    except Exception as e:
        message = f"发生未知错误：{e}"
        app.logger.error(f"Unexpected error during registration: {e}")
        return render_template("register.html", message=message)
    finally:
        # 关闭数据库游标和连接
        if cursor:
            cursor.close()
        if conn:
            conn.close()

if __name__ == "__main__":
    app.run(debug=True)

<script language="JavaScript" type="text/javascript">
function checkform (form) {
    function isEmpty (fieldValue, fieldName) {
        if (fieldValue.trim() === "") { // 使用trim()处理空白字符
            alert("请输入" + fieldName);
            return true;
        }
        return false;
    }

    function charCheck(fieldValue) {
        // 允许字母、数字、@、-、_、.
        var validchars = /^[a-zA-Z0-9@\-\._]+$/; 
        if (validchars.test(fieldValue)) {
            return true;
        } else {
            alert("此字段只能包含字母、数字、@、-、_或.");
            return false;
        }
    }

    // 检查空字段
    if (isEmpty(form.t_email.value, "您的邮箱地址")) { 
        form.t_email.focus();  
        return false;
    }
    if (isEmpty(form.t_password.value, "您的密码")) { 
        form.t_password.focus();  
        return false;
    }

    // 检查特殊字符
    if (!charCheck(form.t_email.value)) {
        form.t_email.focus(); 
        return false;
    }
    if (!charCheck(form.t_password.value)) {
        form.t_password.focus(); 
        return false;
    }

    return true ; // 所有验证通过
}
</script>