TypeError: get_bind() got an unexpected keyword argument

问题

I am trying to use a database in flask using

from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker

In it I am created a basic login page and a register page and when I try to use html code:

<form action="/login" method="post">
        <input autocomplete="off" autofocus name="username" placeholder="Username" type="text">
        <input class="form-control" name="password" placeholder="Password" type="password">
    <button class="btn btn-primary" type="submit">Log In</button>
            <li style="list-style-type:none;"><a href="/register">Register</a></li>
</form>

on this python flask code:

# This is the log in page
@app.route("/login", methods=["GET", "POST"])
def login():
    """Log user in"""

    # Forget any user_id
    session.clear()

    # User reached route via POST (as by submitting a form via POST)
    if request.method == "POST":

        # Ensure username was submitted
        if not request.form.get("username"):
            return "must provide username", 403

        # Ensure password was submitted
        elif not request.form.get("password"):
            return "must provide password", 403

        # Query database for username
        rows = db.execute("SELECT * FROM users WHERE username = :username",
                          username=request.form.get("username"))

        # Ensure username exists and password is correct
        if len(rows) != 1 or not check_password_hash(rows[0]["hash"], request.form.get("password")):
            return "invalid username and/or password", 403

        # Remember which user has logged in
        session["user_id"] = rows[0]["id"]

        # Redirect user to home page
        return redirect("/")

    # User reached route via GET (as by clicking a link or via redirect)
    else:
        return render_template("login.html")

I get this error:

TypeError: get_bind() got an unexpected keyword argument 'username'

I connected the database, and set up all other variables including flask_debug. I'm not sure what is wrong or how to test for it. Can anyone help me figure out why im getting this error?

回答1:

There is an error in the syntax of the postgresql query. More specifically in the sanitizing of data to avoid sql injections.

the correct syntax was

db.execute("SELECT * FROM users WHERE username = :username", {"username": request.form.get("username")})

There are also more errors in this code. For example

if len(rows) != 1:

You can not extract the len of the query. However it is possible to check for the amount of rows a query has by using the function .rowcount() which if 0 means the search came back empty.

来源：https://stackoverflow.com/questions/61943673/typeerror-get-bind-got-an-unexpected-keyword-argument

标签

python

postgresql

Flask

flask-sqlalchemy