How can I check if static file exists or not from url_for() in Flask?

user_1349726 0
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Is there is way I can check the static file from url_for() is really exist or not? Because I would like to check that if the first file does not exists, I would like to replace it with another file just like this in my html file:

{% set IconPng = url_for('static', filename="images/favo.png") %}
{% set IconIco = url_for('static', filename="images/favo.ico") %}
{% set Default = url_for('static', filename="images/default.ico") %}

{% if IconPng %}
    <img src="{{IconPng}}" />
{% elif IconIco %}
    <img src="{{IconIco}}" />
{% else %}
    <img src="{{Default}}" />
{% endif %}

I have tried with above and also with or operator like:

<img src="{{IconPng or IconIco or Default}}" />

However, it does not work. Any tip how can I do this check for url_for() in Flask?

Thanks

flask jinja2 python
1 Answers

In my opinion it is rather task for javascript than your backend. You can check if image exist using function like this one, and then change image src accordingly:

function file_exists(url){
    var http = new XMLHttpRequest();

    http.open('HEAD', url, false);
    http.send();

    return http.status != 404;
}
user_122196980
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