jinja2模板中未定义变量时如何删除行

How to remove line when variable is not defined in jinja2 template

我有一个简单的 jinja2 模板:

{% for test in tests %}
{{test.status}} {{test.description}}:
    {{test.message}}
    Details:
        {% for detail in test.details %}
        {{detail}}
        {% endfor %}
{% endfor %}

当 'test' 对象的所有变量都像这里这样定义时,效果非常好:

from jinja2 import Environment, PackageLoader
env = Environment(loader=PackageLoader('my_package', 'templates'), trim_blocks=True, lstrip_blocks=True, keep_trailing_newline=True)
template = env.get_template('template.hbs')
test_results = {
    'tests': [
        {
            'status': 'ERROR',
            'description': 'Description of test',
            'message': 'Some test message what went wrong and something',
            'details': [
                'First error',
                'Second error'
            ]
        }
    ]
}

output = template.render(title=test_results['title'], tests=test_results['tests'])

然后输出如下所示:

ERROR Description of test:
    Some test message what went wrong and something
    Details:
        First error
        Second error

但有时 'test' 对象可能没有 'message' 属性 并且在这种情况下有一个空行:

ERROR Description of test:

    Details:
        First error
        Second error

是否可以让这个变量粘在整行?当变量未定义时让它消失?

您可以在for循环中加入一个if条件,以避免在没有消息时出现空行。

{% for test in tests %}
{{test.status}} {{test.description}}:
    {% if test.message %}
        {{test.message}}
    {% endif %}
    Details:
        {% for detail in test.details %}
        {{detail}}
        {% endfor %}
{% endfor %}