如何读取Jinja2模板并获取需要变量的列表以进行渲染？

Question

I need to get the list of variable needed in the context of a template to be able to give some feedback to the programmer that will use my service .

How can I do that ?

I was thinking on giving a context object that will create the variable when the template try to access it and then give me the list of variable in the context object after rendering.

Is that possible?

Answer 1

解析模板，您可以找到所有变量： http : //jinja.pocoo.org/docs/api/#the-meta-api包括示例。

Answer 2

Use jinja2 meta api

from jinja2 import Environment, FileSystemLoader,meta

PATH = os.path.dirname(os.path.abspath(__file__)) #get the path of current file
TEMPLATE_ENVIRONMENT = Environment(
                autoescape=False,
                loader=FileSystemLoader(os.path.join(PATH)),
                trim_blocks=False)
template_source =TEMPLATE_ENVIRONMENT.loader.get_source(TEMPLATE_ENVIRONMENT,   template_filename)[0] #replace template_filename with your template file relative to current file
parsed_content = TEMPLATE_ENVIRONMENT.parse(template_source)
variables= meta.find_undeclared_variables(parsed_content)
print variables

output : Set of used variables

set(['CONFIG_PARAM_HTTPS_PROXY_PORT', 'CONFIG_PARAM_HTTP_PROXY_PORT'])