有没有更好的方法在Jinja/Flask中应用nl2br过滤器?

问题描述

我正在使用带有Flask的Jinja(已启用自动转义)，并且尝试应用此过滤器

I'm using Jinja with Flask (autoescape enabled) and I'm attempting to apply this filter

import re

from jinja2 import evalcontextfilter, Markup, escape

_paragraph_re = re.compile(r'(?:\r\n|\r|\n){2,}')

app = Flask(__name__)

@app.template_filter()
@evalcontextfilter
def nl2br(eval_ctx, value):
    result = u'\n\n'.join(u'<p>%s</p>' % p.replace('\n', '<br>\n') \
        for p in _paragraph_re.split(escape(value)))
    if eval_ctx.autoescape:
        result = Markup(result)
    return result

问题在于它从不应用<br>，而总是在每行周围应用<p>.

The problem with it is that it never applies <br>s and always applies <p>s around each line.

如果我输入:

1
2

3
4

在textarea中，它以"u'1 \ r \ n2 \ r \ n \ r \ n3 \ r \ n4'"的形式保存到数据库中，并在使用|nl2br过滤器放入Jinja时进行过滤出现为

in a textarea, it gets saved to the DB as "u'1\r\n2\r\n\r\n3\r\n4'" and when put in Jinja with the |nl2br filter it comes out as

<p>1</p>

<p>2</p>

<p>3</p>

<p>4</p>

我正在寻找它

<p>1<br>2</p>
<p>3<br>4</p>

这种正则表达式方法似乎对我追求的目标来说是过大的.

this regular expression method seems like overkill for what I'm after.

请告诉我，有一种更简单的方法可以完成此操作，因为我整天都在梳理头发，试图找出答案...

Please tell me there is a simpler way to accomplish this as I've been pulling my hair out all day trying to figure it out...

推荐答案

简单，但是稍微复杂些呢?尝试使用此正则表达式:

Simpler no, but how about only slightly more complicated? Try it with this regex:

(?:\r\n|\r(?!\n)|\n){2,}

最初的正则表达式首先将\r\n作为单行分隔符进行匹配，但是需要匹配其中的两个，因此它将回溯并将其匹配为\r，然后是\n.如果下一个字符为\n，则负前瞻(?!\n)阻止它单独匹配\r.

The original regex matches \r\n as a single line separator at first, but it's required to match two of them, so it backtracks and matches it as \r followed by \n. The negative lookahead, (?!\n), prevents it from matching \r alone if the next character is \n.

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