flask template not rendering as expected-CodePudding

Expected output is 'not detected' but I get 'no error' on get and post. Why?

index.html

{% if error %}
    <p>{{ error }}</p>
{% else %}
    <p>no error</p>
{% endif %}

main.py

@app.route('/', methods=['GET', 'POST'])
def index():
    if request.method == 'GET':
        print('get')
        return render_template('index.html')
    elif request.method == 'POST':
        print('post')
        post_data = request.get_json(force=True)
        if post_data['message'] == False:
            print('false')
            print('not detected')
            return render_template('index.html', error='not detected')

edit:

not sure if this is what's causing the errors.

script.js

window.onload = (event) => {
    if (!window.ethereum) {
        console.log('error - not detected');

        fetch(`${window.origin}/`, {
            method: 'POST',
            headers: {'content-type': 'application/json'},
            body: JSON.stringify({
                'message': false
            })
        });
    } else {
        console.log('detected');
    }
};

CodePudding user response：

There's something else wrong. I copied your code exactly and ran

curl.exe --header "Content-Type: application/json" -d '{\"message\":false}' http://localhost:5000

and got

    <p>not detected</p>

CodePudding user response：

The problem is with your js code. As I can see, you make fetch call providing parameters and not providing callback for response processing.

It should be:

fetch(`${window.origin}/`, {
    method: 'POST',
    headers: {'content-type': 'application/json'},
    body: JSON.stringify({
    'message': false
    })
})
.then((response) => response.json())
.then((data) => {
    console.log('Success:', data);
})
.catch((error) => {
    console.error('Error:', error);
});

And in backend it's better to return json response for api calls instead of html. To do it you can change your code:

from flask import jsonify

...
        if post_data['message'] == False:
            print('false')
            print('not detected')
            return jsonify(error='not detected')

Ref: https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch#uploading_json_data