为什么我的路线没有以正确的参数将我带到我想在 Flask 中去的地方？

Question

所以在我的路线 displayinfo 上我正在显示信息，所以我提出了请求方法 GET，另外在我的 html 页面上，我有一个要求用户审查的表单，所以我提出了请求方法 post。但是，当我单击按钮提交表单信息时，它需要我到 displayinfo/，但我希望它带我到 displayinfo/（isbn 编号）

这是我的python代码

@app.route("/displayinfo/<book_isbn>", methods=["POST", "GET"])

def displayinfo(book_isbn):
    #global Book_isbn
    #Book_isbn = book_isbn
    if request.method == "POST":

        if not session.get("USERNAME") is None:
            username = session.get("USERNAME")

            review = request.form.get("review")

            user_id = db.execute("SELECT user_id FROM users WHERE username=:username", {"username": username}).fetchone()
            book_id = db.execute("SELECT book_id FROM books WHERE isbn=:isbn)", {"isbn": book_isbn}).fetchone()

            db.execute("INSERT INTO reviews (comment, user_id, book_id) VALUES (:comment, :user_id, :book_id)",{"comment": review, "user_id": user_id, "book_id":book_id})


            db.commit()

        else:
            return render_template("error.html", printthis="Not signed in.")

    else:

        if not session.get("USERNAME") is None:

            booktitle = db.execute("SELECT title FROM BOOKS WHERE isbn = :isbn", {"isbn": book_isbn}).fetchone()
            bookauthor = db.execute("SELECT author FROM BOOKS WHERE isbn = :isbn", {"isbn": book_isbn}).fetchone()
            bookyear = db.execute("SELECT year FROM BOOKS WHERE isbn = :isbn", {"isbn": book_isbn}).fetchone()
            bookisbn = db.execute("SELECT isbn FROM BOOKS WHERE isbn = :isbn", {"isbn": book_isbn}).fetchone()

            #res = requests.get("https://www.goodreads.com/book/review_counts.json", params={"key": KqqGbJlg2XMOyLiYRAnhvQ, "isbns": bookisbn})

            return render_template("displayinfo.html", printtitle=booktitle, printauthor=bookauthor,printyear=bookyear, printisbn=bookisbn, book=booktitle)

            db.commit()
        else:
            return render_template("error.html", printthis="Not signed in.")

这是我的html代码

{% extends "template.html" %}
{% block title %}Bookstore{% endblock %}

{% block head %}{{ printtitle }}{% endblock %}

{% block body %}
{{ printtitle }}
{{ printauthor }}
{{ printyear }}
{{ printisbn }}





<p>Write a review: </p>

<form action="{{ url_for('displayinfo',  book_isbn=book.isbn)}}" method="post">

<!--, book_isbn=book.isbn-->

    <li><input type="text" name="review" placeholder="Write a review for {{ book }}"></li>
    <div class="btn">
    <button>Submit</button>
    </div>


</form>




{% block text %}{{ review }}{% endblock %}

{% endblock %}

Answer 1

之后

db.commit()

粘贴下面的行

return redirect(url_for('displayinfo', book_isbn=book_isbn))

相关的进口是：

from flask import redirect, url_for

Answer 2

从 Flask 传递给模板的 book 变量似乎不是 book 对象，而是一个以书名作为内容的字符串。

return render_template("displayinfo.html", printtitle=booktitle, printauthor=bookauthor,printyear=bookyear, printisbn=bookisbn, book=booktitle)

也许您可以尝试通过传递 book 对象或将 book.isbn 替换为您传递的 isbn 字符串来修复它 - bookisbn

另外，我建议在@app.route 中的URL 末尾使用尾随slask。更好，根据 Flask 快速入门 - https://flask.palletsprojects.com/en/1.1.x/quickstart/#unique-urls-redirection-behaviorhttps://flask.palletsprojects.com/en/1.1.x/quickstart/#unique-urls-redirection-behavior