How to pass a list in flask flash in jinja template

Question

I build a social media website here I am making a signup form with some errors flashing on unsuccessful signup. Python :

@app.route("/signup-request", methods=['POST'])
def signupRequest():
    errors = ["","",""]
    # Error 0 => username taken
    # Error 1 => email used
    # Error 2 => password mismatch

    name = request.form["name"]
    usrnm = request.form["username"]
    email = request.form["email"]
    paswd = request.form["password"]
    cpswd = request.form["confirm password"]

    RacF = open(".\\database\\accounts.csv","rt")
    read = csv.reader(RacF)
    for rows in read:
        if rows[1] == usrnm:
            errors[0] = "Username has already been taken"
        if rows[2] == email:
            errors[1] = "Email has already been registered"
        if paswd != cpswd:
            error[2] = "Password and confirm password doesn't match"
    RacF.close()

    if errors != ["","",""]:
        flash(errors)
        print("signup failed")
        print(errors)
        return redirect(request.referrer)
    else:
        WacF = open(".\\database\\accounts.csv","at")
        WacF.write(f'{name},{usrnm},{email},{paswd}\n')
        WacF.close()
        session["user"] = usrnm
        return "<h1>You're registered</h1>"

HTML:

<form action="/signup-request" method="POST" class="form shadow">
                {% with message = get_flashed_messages() %}
                <p>
                    <label for="nm">Name :</label><br/>
                    <input type="text" name="name" id="nm" placeholder="Full Name..." class="wd-lg" required/><br/>
                    
                    <label for="usrnm">Username :</label><br/>
                    <input type="text" name="username" id="usrnm" placeholder="Username..." class="wd-lg" required/><br/>
                    {% if message[0] != "" %}
                        {{ message[0] }}<br/>
                    {% endif %}

                    <label for="email">Email Address :</label><br/>
                    <input type="email" name="email" id="email" placeholder="E-Mail Address" class="wd-lg" required/><br/>
                    {% if message[1] != "" %}
                        {{ message[1] }}<br/>
                    {% endif %}

                    Password :<br/>
                    <input type="password" name="password" id="paswd" placeholder="Password" class="wd-lg" required/><br/>
                    <input type="password" id="cpaswd" name="confirm password" placeholder="Confirm Password" class="wd-lg" required/>
                    {% if message[2] != "" %}
                        {{ message[2] }}<br/>
                    {% endif %}
                </p>
                <p>
                    <input type="checkbox" id="chk" onclick="showPassword()"/>
                    <label for="chk" style="cursor: pointer;">Show Password</label>
                </p>
                <p>
                    <input type="submit" value="Signup" class="btn wd-lg btn-primary"/>
                </p>
                {% endwith %}
            </form>

But I am facing an error:

File "D:\My Coding\Websites\Cloud Town\signup.py", line 31, in signupRequest error[2] = "Password and confirm password doesn't match" TypeError: 'type' object does not support item assignment.

Please let me know hot to solve this. I will be thankful to you.

Answer 1

You misspelled errors as error:

Change the line error[2] = "Password and confirm password doesn't match" to errors[2] = "Password and confirm password doesn't match"

@app.route("/signup-request", methods=['POST'])
def signupRequest():
    errors = ["","",""]
    # Error 0 => username taken
    # Error 1 => email used
    # Error 2 => password mismatch

    name = request.form["name"]
    usrnm = request.form["username"]
    email = request.form["email"]
    paswd = request.form["password"]
    cpswd = request.form["confirm password"]

    RacF = open(".\\database\\accounts.csv","rt")
    read = csv.reader(RacF)
    for rows in read:
        if rows[1] == usrnm:
            errors[0] = "Username has already been taken"
        if rows[2] == email:
            errors[1] = "Email has already been registered"
        if paswd != cpswd:
            errors[2] = "Password and confirm password doesn't match" # Added the 's' in errors
    RacF.close()

    if errors != ["","",""]:
        flash(errors)
        print("signup failed")
        print(errors)
        return redirect(request.referrer)
    else:
        WacF = open(".\\database\\accounts.csv","at")
        WacF.write(f'{name},{usrnm},{email},{paswd}\n')
        WacF.close()
        session["user"] = usrnm
        return "<h1>You're registered</h1>"