/**
* @license
* Copyright The Closure Library Authors.
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @fileoverview Utility function for linkifying text.
*/
goog.provide('goog.string.linkify');
goog.require('goog.html.SafeHtml');
goog.require('goog.string');
/**
* Takes a string of plain text and linkifies URLs and email addresses. For a
* URL (unless opt_attributes is specified), the target of the link will be
* _blank and it will have a rel=nofollow attribute applied to it so that links
* created by linkify will not be of interest to search engines.
* @param {string} text Plain text.
* @param {!Object<string, ?goog.html.SafeHtml.AttributeValue>=} opt_attributes
* Attributes to add to all links created. Default are rel=nofollow and
* target=_blank. To clear those default attributes set rel='' and
* target=''.
* @param {boolean=} opt_preserveNewlines Whether to preserve newlines with
* <br>.
* @return {!goog.html.SafeHtml} Linkified HTML. Any text that is not part of a
* link will be HTML-escaped.
*/
goog.string.linkify.linkifyPlainTextAsHtml = function(
text, opt_attributes, opt_preserveNewlines) {
'use strict';
// This shortcut makes linkifyPlainText ~10x faster if text doesn't contain
// URLs or email addresses and adds insignificant performance penalty if it
// does.
if (text.indexOf('@') == -1 && text.indexOf('://') == -1 &&
text.indexOf('www.') == -1 && text.indexOf('Www.') == -1 &&
text.indexOf('WWW.') == -1) {
return opt_preserveNewlines ?
goog.html.SafeHtml.htmlEscapePreservingNewlines(text) :
goog.html.SafeHtml.htmlEscape(text);
}
const attributesMap = {};
for (let key in opt_attributes) {
if (!opt_attributes[key]) {
// Our API allows '' to omit the attribute, SafeHtml requires null.
attributesMap[key] = null;
} else {
attributesMap[key] = opt_attributes[key];
}
}
// Set default options if they haven't been explicitly set.
if (!('rel' in attributesMap)) {
attributesMap['rel'] = 'nofollow';
}
if (!('target' in attributesMap)) {
attributesMap['target'] = '_blank';
}
const output = [];
// Return value is ignored.
text.replace(
goog.string.linkify.FIND_LINKS_RE_,
function(part, before, original, email, protocol) {
'use strict';
output.push(
opt_preserveNewlines ?
goog.html.SafeHtml.htmlEscapePreservingNewlines(before) :
before);
if (!original) {
return '';
}
let href = '';
/** @type {string} */
let linkText;
/** @type {string} */
let afterLink;
if (email) {
href = 'mailto:';
linkText = email;
afterLink = '';
} else {
// This is a full url link.
if (!protocol) {
href = 'http://';
}
const splitEndingPunctuation =
original.match(goog.string.linkify.ENDS_WITH_PUNCTUATION_RE_);
// An open paren in the link will often be matched with a close paren
// at the end, so skip cutting off ending punctuation if
// opening/closing parens are matched in the link. Same for curly
// brackets. For example:
// End symbol is linkified:
// * http://en.wikipedia.org/wiki/Titanic_(1997_film)
// * http://google.com/abc{arg=1}
// e.g. needEndingPunctuationForBalance for split
// 'http://google.com/abc{arg=', and '} is true.
// End symbol is not linkified because there is no open parens to
// close in the link itself, as the open parens occurs before the URL:
// * (http://google.com/)
// e.g. needEndingPunctuationForBalance for split 'http://google.com/
// and ')' is false.
function needEndingPunctuationForBalance(
split, openSymbol, closeSymbol) {
return goog.string.contains(split[2], closeSymbol) &&
goog.string.countOf(split[1], openSymbol) >
goog.string.countOf(split[1], closeSymbol);
}
if (splitEndingPunctuation &&
!needEndingPunctuationForBalance(
splitEndingPunctuation, '(', ')') &&
!needEndingPunctuationForBalance(
splitEndingPunctuation, '{', '}')) {
linkText = splitEndingPunctuation[1];
afterLink = splitEndingPunctuation[2];
} else {
linkText = original;
afterLink = '';
}
}
attributesMap['href'] = href + linkText;
output.push(goog.html.SafeHtml.create('a', attributesMap, linkText));
output.push(
opt_preserveNewlines ?
goog.html.SafeHtml.htmlEscapePreservingNewlines(afterLink) :
afterLink);
return '';
});
return goog.html.SafeHtml.concat(output);
};
/**
* Gets the first URI in text.
* @param {string} text Plain text.
* @return {string} The first URL, or an empty string if not found.
*/
goog.string.linkify.findFirstUrl = function(text) {
'use strict';
const link = text.match(goog.string.linkify.URL_RE_);
return link != null ? link[0] : '';
};
/**
* Gets the first email address in text.
* @param {string} text Plain text.
* @return {string} The first email address, or an empty string if not found.
*/
goog.string.linkify.findFirstEmail = function(text) {
'use strict';
const email = text.match(goog.string.linkify.EMAIL_RE_);
return email != null ? email[0] : '';
};
/**
* If a series of these characters is at the end of a url, it will be considered
* punctuation and not part of the url.
* @type {string}
* @const
* @private
*/
goog.string.linkify.ENDING_PUNCTUATION_CHARS_ = '\':;,\\.?}\\]\\)!';
/**
* @type {!RegExp}
* @const
* @private
*/
goog.string.linkify.ENDS_WITH_PUNCTUATION_RE_ = new RegExp(
'^(.*?)([' + goog.string.linkify.ENDING_PUNCTUATION_CHARS_ + ']+)$');
/**
* Set of characters to be put into a regex character set ("[...]"), used to
* match against a url hostname and everything after it. It includes, in order,
* \w which represents [a-zA-Z0-9_], "#-;" which represents the characters
* "#$%&'()*+,-./0123456789:;" and the characters "!=?@[\]`{|}~".
* @type {string}
* @const
* @private
*/
goog.string.linkify.ACCEPTABLE_URL_CHARS_ = '\\w#-;!=?@\\[\\\\\\]_`{|}~';
/**
* List of all protocols patterns recognized in urls (mailto is handled in email
* matching).
* @type {!Array<string>}
* @const
* @private
*/
goog.string.linkify.RECOGNIZED_PROTOCOLS_ = ['https?', 'ftp'];
/**
* Regular expression pattern that matches the beginning of an url.
* Contains a catching group to capture the scheme.
* @type {string}
* @const
* @private
*/
goog.string.linkify.PROTOCOL_START_ =
'(' + goog.string.linkify.RECOGNIZED_PROTOCOLS_.join('|') + ')://';
/**
* Regular expression pattern that matches the beginning of a typical
* http url without the http:// scheme.
* @type {string}
* @const
* @private
*/
goog.string.linkify.WWW_START_ = 'www\\.';
/**
* Regular expression pattern that matches an url.
* @type {string}
* @const
* @private
*/
goog.string.linkify.URL_RE_STRING_ = '(?:' +
goog.string.linkify.PROTOCOL_START_ + '|' + goog.string.linkify.WWW_START_ +
')[' + goog.string.linkify.ACCEPTABLE_URL_CHARS_ + ']+';
/**
* Regular expression that matches an url. Case-insensitive.
* @type {!RegExp}
* @const
* @private
*/
goog.string.linkify.URL_RE_ =
new RegExp(goog.string.linkify.URL_RE_STRING_, 'i');
/**
* Regular expression pattern that matches a top level domain.
* @type {string}
* @const
* @private
*/
goog.string.linkify.TOP_LEVEL_DOMAIN_ = '(?:com|org|net|edu|gov' +
// from http://www.iana.org/gtld/gtld.htm
'|aero|biz|cat|coop|info|int|jobs|mobi|museum|name|pro|travel' +
'|arpa|asia|xxx' +
// a two letter country code
'|[a-z][a-z])\\b';
/**
* Regular expression pattern that matches an email.
* Contains a catching group to capture the email without the optional "mailto:"
* prefix.
* @type {string}
* @const
* @private
*/
goog.string.linkify.EMAIL_RE_STRING_ =
'(?:mailto:)?([\\w.!#$%&\'*+-/=?^_`{|}~]+@[A-Za-z0-9.-]+\\.' +
goog.string.linkify.TOP_LEVEL_DOMAIN_ + ')';
/**
* Regular expression that matches an email. Case-insensitive.
* @type {!RegExp}
* @const
* @private
*/
goog.string.linkify.EMAIL_RE_ =
new RegExp(goog.string.linkify.EMAIL_RE_STRING_, 'i');
/**
* Regular expression to match all the links (url or email) in a string.
* First match is text before first link, might be empty string.
* Second match is the original text that should be replaced by a link.
* Third match is the email address in the case of an email.
* Fourth match is the scheme of the url if specified.
* @type {!RegExp}
* @const
* @private
*/
goog.string.linkify.FIND_LINKS_RE_ = new RegExp(
// Match everything including newlines.
'([\\S\\s]*?)(' +
// Match email after a word break.
'\\b' + goog.string.linkify.EMAIL_RE_STRING_ + '|' +
// Match url after a word break.
'\\b' + goog.string.linkify.URL_RE_STRING_ + '|$)',
'gi');
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