Java library to extract links such as URLs and email addresses from plain text. Fast, small and smart about recognizing where links end.
Inspired by Rinku. Similar to it, regular expressions are not used. Instead, the input text is parsed in one pass with limited backtracking.
This library requires Java 7. It works on Android (minimum API level 15). It has no external dependencies.
Maven coordinates (see here for other build systems):
<dependency>
<groupId>org.nibor.autolink</groupId>
<artifactId>autolink</artifactId>
<version>0.7.0</version>
</dependency>
Extract links:
import org.nibor.autolink.*;
String input = "wow, so example: http://test.com";
LinkExtractor linkExtractor = LinkExtractor.builder()
.linkTypes(EnumSet.of(LinkType.URL, LinkType.WWW, LinkType.EMAIL))
.build();
Iterable<LinkSpan> links = linkExtractor.extractLinks(input);
LinkSpan link = links.iterator().next();
link.getType(); // LinkType.URL
link.getBeginIndex(); // 17
link.getEndIndex(); // 32
input.substring(link.getBeginIndex(), link.getEndIndex()); // "http://test.com"
Note that by default all supported types of links are extracted. If
you're only interested in specific types, narrow it down using the
linkTypes
method.
There's also a static method to replace links found in the text. Here's
an example of using that for wrapping URLs in an <a>
tag. Note that it
doesn't handle escaping at all:
import org.nibor.autolink.*;
String input = "wow http://test.com such linked";
LinkExtractor linkExtractor = LinkExtractor.builder()
.linkTypes(EnumSet.of(LinkType.URL)) // limit to URLs
.build();
Iterable<LinkSpan> links = linkExtractor.extractLinks(input);
String result = Autolink.renderLinks(input, links, (link, text, sb) -> {
sb.append("<a href=\"");
sb.append(text, link.getBeginIndex(), link.getEndIndex());
sb.append("\">");
sb.append(text, link.getBeginIndex(), link.getEndIndex());
sb.append("</a>");
});
result; // "wow <a href=\"http://test.com\">http://test.com</a> such linked"
Extracts URLs of the form scheme://example
with any scheme. URIs such
as example:test
are not matched (may be added as an option in the future).
If only certain schemes should be allowed, the result can be filtered.
Includes heuristics for not including trailing delimiters such as punctuation and unbalanced parentheses, see examples below.
Supports internationalized domain names (IDN). Note that they are not validated and as a result, invalid URLs may be matched.
Example input and linked result:
http://example.com.
→ http://example.com.http://example.com,
→ http://example.com,(http://example.com)
→ (http://example.com)(... (see http://example.com))
→ (... (see http://example.com))https://en.wikipedia.org/wiki/Link_(The_Legend_of_Zelda)
→ https://en.wikipedia.org/wiki/Link_(The_Legend_of_Zelda)http://üñîçøðé.com/
→ http://üñîçøðé.com/
Use LinkType.URL
for this, and see test
cases here.
Extract links like www.example.com
. They need to start with www.
but
don't need a scheme://
. For detecting the end of the link, the same
heuristics apply as for URLs.
Examples:
www.example.com.
→ www.example.com.(www.example.com)
→ (www.example.com)[..] link:www.example.com [..]
→ [..] link:www.example.com [..]
Not supported:
- Uppercase
www
's, e.g.WWW.example.com
andwWw.example.com
- Too many or too few
w
's, e.g.wwww.example.com
The domain must have at least 3 parts, so www.com
is not valid, but www.something.co.uk
is.
Use LinkType.WWW
for this, and see test
cases here.
Extracts emails such as [email protected]
. Matches international email
addresses, but doesn't verify the domain name (may match too much).
Examples:
[email protected]
→ [email protected][email protected].
→ [email protected].[email protected],
→ [email protected],üñîçøðé@üñîçøðé.com
→ üñîçøðé@üñîçøðé.com
Not supported:
- Quoted local parts, e.g.
"this is sparta"@example.com
- Address literals, e.g.
foo@[127.0.0.1]
Note that the domain must have at least one dot (e.g. foo@com
isn't
matched), unless the emailDomainMustHaveDot
option is disabled.
Use LinkType.EMAIL
for this, and see test cases
here.
Pull requests, issues and comments welcome ☺. For pull requests:
- Add tests for new features and bug fixes
- Follow the existing style (always use braces, 4 space indent)
- Separate unrelated changes into multiple pull requests
Copyright (c) 2015-2017 Robin Stocker and others, see Git history
MIT licensed, see LICENSE file.