### Navigation - [index](# "General Index") - [modules](# "Python Module Index") | - [next](# "tornado.locale — Internationalization support") | - [previous](# "tornado.template — Flexible output generation") | - [Tornado 4.4.dev1 documentation](#) » - [Web framework](#) » # `tornado.escape` — Escaping and string manipulation Escaping/unescaping methods for HTML, JSON, URLs, and others. Also includes a few other miscellaneous string manipulation functions thathave crept in over time. ### Escaping functions `tornado.escape.``xhtml_escape`(*value*)[[source]](#) Escapes a string so it is valid within HTML or XML. Escapes the characters `<`, `>`, `"`, `'`, and `&`.When used in attribute values the escaped strings must be enclosedin quotes. Changed in version 3.2: Added the single quote to the list of escaped characters. `tornado.escape.``xhtml_unescape`(*value*)[[source]](#) Un-escapes an XML-escaped string. `tornado.escape.``url_escape`(*value*, *plus=True*)[[source]](#) Returns a URL-encoded version of the given value. If `plus` is true (the default), spaces will be representedas “+” instead of “%20”. This is appropriate for query stringsbut not for the path component of a URL. Note that this defaultis the reverse of Python's urllib module. New in version 3.1: The `plus` argument `tornado.escape.``url_unescape`(*value*, *encoding='utf-8'*, *plus=True*)[[source]](#) Decodes the given value from a URL. The argument may be either a byte or unicode string. If encoding is None, the result will be a byte string. Otherwise,the result is a unicode string in the specified encoding. If `plus` is true (the default), plus signs will be interpretedas spaces (literal plus signs must be represented as “%2B”). Thisis appropriate for query strings and form-encoded values but notfor the path component of a URL. Note that this default is thereverse of Python's urllib module. New in version 3.1: The `plus` argument `tornado.escape.``json_encode`(*value*)[[source]](#) JSON-encodes the given Python object. `tornado.escape.``json_decode`(*value*)[[source]](#) Returns Python objects for the given JSON string. ### Byte/unicode conversions These functions are used extensively within Tornado itself,but should not be directly needed by most applications. Note thatmuch of the complexity of these functions comes from the fact thatTornado supports both Python 2 and Python 3. `tornado.escape.``utf8`(*value*)[[source]](#) Converts a string argument to a byte string. If the argument is already a byte string or None, it is returned unchanged.Otherwise it must be a unicode string and is encoded as utf8. `tornado.escape.``to_unicode`(*value*)[[source]](#) Converts a string argument to a unicode string. If the argument is already a unicode string or None, it is returnedunchanged. Otherwise it must be a byte string and is decoded as utf8. `tornado.escape.``native_str`() Converts a byte or unicode string into type [`str`](https://docs.python.org/3.4/library/stdtypes.html#str "(in Python v3.4)") [https://docs.python.org/3.4/library/stdtypes.html#str]. Equivalent to[`utf8`](# "tornado.escape.utf8") on Python 2 and [`to_unicode`](# "tornado.escape.to_unicode") on Python 3. `tornado.escape.``to_basestring`(*value*)[[source]](#) Converts a string argument to a subclass of basestring. In python2, byte and unicode strings are mostly interchangeable,so functions that deal with a user-supplied argument in combinationwith ascii string constants can use either and should return the typethe user supplied. In python3, the two types are not interchangeable,so this method is needed to convert byte strings to unicode. `tornado.escape.``recursive_unicode`(*obj*)[[source]](#) Walks a simple data structure, converting byte strings to unicode. Supports lists, tuples, and dictionaries. ### Miscellaneous functions `tornado.escape.``linkify`(*text, shorten=False, extra_params='', require_protocol=False, permitted_protocols=['http', 'https']*)[[source]](#) Converts plain text into HTML with links. For example: `linkify("Hello http://tornadoweb.org!")` would return`Hello <a href="http://tornadoweb.org">http://tornadoweb.org</a>!` Parameters: - `shorten`: Long urls will be shortened for display. - `extra_params`: Extra text to include in the link tag, or a callable taking the link as an argument and returning the extra texte.g. `linkify(text, extra_params='rel="nofollow" class="external"')`,or: ~~~ def extra_params_cb(url): if url.startswith("http://example.com"): return 'class="internal"' else: return 'class="external" rel="nofollow"' linkify(text, extra_params=extra_params_cb) ~~~ - `require_protocol`: Only linkify urls which include a protocol. If this is False, urls such as www.facebook.com will also be linkified. - `permitted_protocols`: List (or set) of protocols which should be linkified, e.g. `linkify(text, permitted_protocols=["http", "ftp","mailto"])`. It is very unsafe to include protocols such as`javascript`. `tornado.escape.``squeeze`(*value*)[[source]](#) Replace all sequences of whitespace chars with a single space. © Copyright 2009-2016, The Tornado Authors. Created using [Sphinx](http://sphinx-doc.org/) 1.3.5.