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How to PERMANENTLY escape curly braces in Python format string?
Related: How can I print literal curly-brace characters in python string and also use .format on it?
You need to put double braces ({{, }}) to put literal curly brace characters in a string and use .format() on it.
{{
}}
.format()
Problem is, I have JavaScript in my strings which contain nested curly braces. I use .format() on these strings an undefined number of times in a chain. Like, if some condition is true, format this. If some other condition is true, format this too.
.format()
I can't do this:
'''
<script type="application/javascript" src="//code.jquery.com/jquery-3.3.1.min.js" integrity="sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8=" crossorigin="anonymous"></script>
<script type="application/javascript">
$(document).ready(() => {{{{{
window.top.location.replace('https://www.youtube.com/watch?v=hSlb1ezRqfA');
}}}}});
</script>
'''
Because I don't know how many curly braces I need. The number of .formats() in the chain depends on several conditions that depend on stuff outputed by an external source.
.formats()
I want a way to PERMANENTLY escape curly braces in a Python string. No matter how many times I use .format() on it, the literal braces should never be formatted.
.format()
How to PERMANENTLY escape curly braces in Python format string?
Simplified example (still quite long):
Simple example of problems with complex formatting chains
footerHTML = '''
<footer>
<p>
<strong>©</strong> Copyright 2018, powered by the Stack Exchange API v2.2
</p>
</footer>
'''
def format1(string):
scriptInjection = '''
<script type="application/javascript" src="//code.jquery.com/jquery-3.3.1.min.js" integrity="sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8=" crossorigin="anonymous"></script>
<script type="application/javascript">
$(document).ready(() => {{{
window.top.location.replace('https://www.youtube.com/watch?v=hSlb1ezRqfA');
}}});
</script>
''' if random.randint(0, 10) == random.randint(0, 10) else "{{CONTENT}}"
return content.format(PRANK=scriptInjection)
def format2(string):
# Do something complicated here
# Irrelavent to the question
# Now I have some extra variables now
HTMLcontent = '''
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>StackPromo Q&A Stack Exchange Community Content Showcase</title>
<link rel="stylesheet" type="text/css" href="assets/style.css">
<style type="text/css">
* {{
cursor: pointer !important;
}}
#click-overlay {{
position: fixed;
top: 0;
left: 0;
right: 0;
bottom: 0;
z-index: 999;
}}
</style>
</head>
<body>
<div id="click-overlay" onclick="window.parent.location.assign('{{postURL}}');"></div>
<h1>{{postTitle}}</h1>
</body>
</html>
'''.format(postURL=post, postTitle=title)
return string.format(CONTENT=HTMLcontent)
class Submit(webapp2.RequestHandler):
def get(self):
self.response.write(format1('''
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Enter a post into the StackPromo advertisement service database</title>
<link rel="stylesheet" type="text/css" href="assets/style.css">
{PRANK}
<script type="application/javascript">
$(document).ready(() => {{{
if (window.location.search.includes("error=YES")) {{{
$("body").prepend("<p class='error'><strong>AN ERROR OCCURED!</strong></p><div class='spacer'></div>");
}}}
}}});
</script>
</head>
<body>
<header>
<h1>StackPromo™</h1>
<div class="spacer"></div>
<p>
<em>StackPromo™</em> is a free-to-use advertising platform for Stack Exchange posts!
</p>
</header>
<div class="spacer"></div>
<main>
<form action="/submit" method="POST">
<strong>Post ID:</strong>
<input type="number" name="id">
<div class="spacer"></div>
<strong>Site:</strong>
<select name="site">
<option value="stackoverflow">Stack Overflow</option>
<option value="superuser">Super User</option>
<option value="serverfault">Server Fault</option>
<option value="stackapps">Stack Apps</option>
<option value="ux">User Experience</option>
</select>
<div class="spacer"></div>
<input type="submit" value="Advertise">
</form>
</main>
<div class="spacer"></div>
{{FOOTER}}
</body>
</html>
''').format(FOOTER=footerHTML).format(CONTENT=""))
def post(self):
ID = self.request.get('id', 'garbage')
site = self.request.get('site', 'garbage')
SE_API_AJAX = urlfetch.fetch('https://api.stackexchange.com/2.2/{}?site={}'.format(ID, site), validate_certificate=True)
if SE_API_AJAX.status_code == 200:
newPost = Post()
newPost.postID = ID
newPost.site = site
newPost.initialJSON = SE_API_AJAX.content
newPost.put()
self.response.write(format1('''
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Success!</title>
<link rel="stylesheet" type="text/css" href="assets/style.css">
{PRANK}
</head>
<body>
<header>
<h1>Post Successfully Submitted into the StackPromo System</h1>
</header>
<div class="spacer"></div>
<main>
<a href="https://www.youtube.com/watch?v=hSlb1ezRqfA">Click here to go to Stack Apps Post</a>
</main>
<div class="spacer"></div>
{{FOOTER}}
</body>
</html>
''').format(FOOTER=footerHTML).format(CONTENT=""))
else:
self.redirect("/submit?error=YES", code=303)
class Advert(webapp2.RequestHandler):
def get(self):
self.response.write(format2(format1('''
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>StackPromo Q&A Stack Exchange Community Content Showcase</title>
<link rel="stylesheet" type="text/css" href="assets/style.css">
{PRANK}
<style type="text/css">
* {{{
cursor: pointer !important;
}}}
#click-overlay {{{
position: fixed;
top: 0;
left: 0;
right: 0;
bottom: 0;
z-index: 999;
}}}
</style>
</head>
<body>
<div id="click-overlay" onclick="window.parent.location.assign('{{postURL}}');"></div>
<h1>{{postTitle}}</h1>
</body>
</html>
''')))
What I want is that the curly braces in JavaScript and CSS stay as curly braces and never get formatted no matter how many times I format the string. My current method of using a ton of braces is bad code, non-scalable, and very error-prone (I have errors now).
.format()
format
format()
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How does this
.format()chain work exactly?– Ry-♦
28 mins ago