CODEWITHSUNDEEP
pythonflaskjinja2
Rachel Barcklay
Rachel Barcklay

Reputation: 11

Access values from a dict in a function called in a Jinja expression

I'm passing a dict from a Flask view to a Jinja template. I can render the values in the dict, but if I try to pass them to url_for I get UndefinedError: 'dict object' has no attribute 'eId'. Why did the second access fail when the first succeeded?

@app.route('/')
def show_entries():
    if session.get('logged_in'):
        cur = g.db.execute('select title, text, id from entries1 WHERE userid = ? OR public = 1 order by id desc', [userInfo['userid']])
    else:
        cur = g.db.execute('select title, text, id from entries1 WHERE public = 1 order by id desc')
    entries = [dict(title=row[0], text=row[1], eId=row[2]) for row in cur.fetchall()]
    return render_template('show_entries.html', entries=entries)

{% for entry in entries %}
    This works: {{ entry.eId }}
    This errors: {{ url_for('delete_entry', btnId=entry.eId) }}
{% endfor %}

Upvotes: 1

Views: 1858

Answers (2)

djc
djc

Reputation: 11711

Your entry is a dictionary. While Jinja's expression syntax allows you to use attribute syntax (dict.attr) for dictionaries, as soon as you're passing an argument to a function with Python syntax you need to use Python's normal dictionary access syntax, dict['attr'].

Upvotes: 2

Jules
Jules

Reputation: 973

Instead of "{{ url_for('delete_entry', btnId= entry.eId) }}" you should have "{{ url_for('delete_entry', btnId= entry['eId']) }}" because elements in a dictionary should be accessed by their get method. The only reason that {{ entry.title }} works is because of jinja2.

Essenially {{ entry.title }} gets evaluated by jinja whereas "{{ url_for('delete_entry', btnId= entry.eId) }}" gets evaluated by python and breaks.

Upvotes: 2

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