/*
Copyright (C) 2016 maik.jablonski@jease.org
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package jfix.util;
import java.util.ArrayList;
import java.util.List;
import java.util.function.Function;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Common utilitites based on regular expressions.
*
* Regular expressions for URLs copied from:
* https://github.com/mzsanford/twitter-text-java License:
* http://www.apache.org/licenses/LICENSE-2.0
*/
public class Regexps {
private static final Pattern EXPRESSION_PATTERN = Pattern.compile(
"\\$\\{(.*?)\\}", Pattern.DOTALL | Pattern.MULTILINE);
private static final Pattern HTML_URLS = Pattern.compile(
"(action|cite|href|src)=\"(.*?)\"", Pattern.DOTALL
| Pattern.MULTILINE);
/* URL related hash regex collection */
private static final String URL_VALID_PRECEEDING_CHARS = "(?:[^\\-/\"':!=A-Z0-9_@＠]+|^|\\:)";
private static final String URL_VALID_DOMAIN = "(?:[^\\p{Punct}\\s][\\.-](?=[^\\p{Punct}\\s])|[^\\p{Punct}\\s]){1,}\\.[a-z]{2,}(?::[0-9]+)?";
private static final String URL_VALID_GENERAL_PATH_CHARS = "[a-z0-9!\\*';:=\\+\\$/%#\\[\\]\\-_,~]";
private static final String URL_VALID_PATH_CHARS_WITHOUT_SLASH = "["
+ URL_VALID_GENERAL_PATH_CHARS + "&&[^/]]";
private static final String URL_VALID_PATH_CHARS_WITHOUT_COMMA = "["
+ URL_VALID_GENERAL_PATH_CHARS + "&&[^,]]";
/**
* Allow URL paths to contain balanced parens 1. Used in Wikipedia URLs like
* /Primer_(film) 2. Used in IIS sessions like /S(dfd346)/
**/
private static final String URL_BALANCE_PARENS = "(?:\\("
+ URL_VALID_GENERAL_PATH_CHARS + "+\\))";
private static final String URL_VALID_URL_PATH_CHARS = "(?:"
+ URL_BALANCE_PARENS + "|@" + URL_VALID_PATH_CHARS_WITHOUT_SLASH
+ "++/" + "|(?:[.,]*+" + URL_VALID_PATH_CHARS_WITHOUT_COMMA + ")++"
+ ")";
/**
* Valid end-of-path chracters (so /foo. does not gobble the period). 2.
* Allow =&# for empty URL parameters and other URL-join artifacts
**/
private static final String URL_VALID_URL_PATH_ENDING_CHARS = "(?:[a-z0-9=_#/\\-\\+]+|"
+ URL_BALANCE_PARENS + ")";
private static final String URL_VALID_URL_QUERY_CHARS = "[a-z0-9!\\*'\\(\\);:&=\\+\\$/%#\\[\\]\\-_\\.,~]";
private static final String URL_VALID_URL_QUERY_ENDING_CHARS = "[a-z0-9_&=#/]";
private static final String VALID_URL_PATTERN_STRING = "(" + // $1 total
// match
"(" + URL_VALID_PRECEEDING_CHARS + ")" + // $2 Preceeding chracter
"(" + // $3 URL
"(https?://)" + // $4 Protocol
"(" + URL_VALID_DOMAIN + ")" + // $5 Domain(s) and optional port
// number
"(/" + "(?:" + URL_VALID_URL_PATH_CHARS + "+|" + // 1+ path chars
// and a valid
// last char
URL_VALID_URL_PATH_ENDING_CHARS + // Just a # case
")?" + ")?" + // $6 URL Path and anchor
"(\\?" + URL_VALID_URL_QUERY_CHARS + "*" + // $7 Query String
URL_VALID_URL_QUERY_ENDING_CHARS + ")?" + ")" + ")";
public static final Pattern VALID_URL = Pattern.compile(
VALID_URL_PATTERN_STRING, Pattern.CASE_INSENSITIVE);
public static final int VALID_URL_GROUP_ALL = 1;
public static final int VALID_URL_GROUP_BEFORE = 2;
public static final int VALID_URL_GROUP_URL = 3;
public static final int VALID_URL_GROUP_PROTOCOL = 4;
public static final int VALID_URL_GROUP_DOMAIN = 5;
public static final int VALID_URL_GROUP_PATH = 6;
public static final int VALID_URL_GROUP_QUERY_STRING = 7;
/**
* Parses given template for expressions (${...}) and applies given
* transform-function on all expressions.
*/
public static String parseExpressions(String template,
Function<String, String> transform) {
Matcher matcher = EXPRESSION_PATTERN.matcher(template);
while (matcher.find()) {
template = template.replace(matcher.group(),
transform.apply(matcher.group(1)));
}
return template;
}
/**
* Converts given plain text into HTML by replacing newlines with paragraphs
* and urls with links.
*/
public static String convertTextToHtml(String text) {
StringBuilder sb = new StringBuilder();
text = text.replaceAll("\r", "").replaceAll("\n\n\n*", "\n\n");
for (int index = 0; index < text.length(); index += 2) {
int start = index;
index = text.indexOf("\n\n", start);
if (index < 0) {
index = text.length();
}
String para = text.substring(start, index);
if (para.length() > 0) {
sb.append("<p>");
sb.append(convertUrlsToLinks(para.replace("\n", "<br />\n")));
sb.append("</p>\n");
}
}
return sb.toString();
}
/**
* Converts all urls in given text into links.
*/
public static String convertUrlsToLinks(String text) {
Matcher matcher = VALID_URL.matcher(text);
StringBuffer sb = new StringBuffer(text.length());
while (matcher.find()) {
String protocol = matcher.group(VALID_URL_GROUP_PROTOCOL);
if (!protocol.isEmpty()) {
String url = matcher.group(VALID_URL_GROUP_URL);
matcher.appendReplacement(sb, String.format(
"$%s<a href=\"%s\">%s</a>", VALID_URL_GROUP_BEFORE,
url, url));
continue;
}
matcher.appendReplacement(sb,
String.format("$%s", VALID_URL_GROUP_ALL));
}
matcher.appendTail(sb);
return sb.toString();
}
/**
* Returns list of http(s)-urls contained in given text.
*/
public static List<String> extractUrls(String text) {
if (text == null) {
return null;
}
List<String> urls = new ArrayList<String>();
Matcher matcher = VALID_URL.matcher(text.replace("\"", " "));
while (matcher.find()) {
if (!matcher.group(VALID_URL_GROUP_PROTOCOL).isEmpty()) {
urls.add(matcher.group(VALID_URL_GROUP_URL));
}
}
return urls;
}
/**
* Returns true if given url is a full qualified valid http(s)-url.
*/
public static boolean isValidUrl(String url) {
if (url == null) {
return false;
}
return VALID_URL.matcher(url).matches();
}
/**
* Returns all urls contained in attributes in given html.
*/
public static List<String> extractUrlsFromHtml(String html) {
List<String> result = new ArrayList<String>();
Matcher matcher = HTML_URLS.matcher(html);
while (matcher.find()) {
result.add(matcher.group(2));
}
return result;
}
}