This codebase is an open source C# port of the Java code in https://github.com/URL-Detector/URL-Detector, which in turn was a fork of the LinkedIn Engineering team's open sourced https://github.com/linkedin/URL-Detector, which seems to be abandoned. This port was originally based the Java code as at July 20, 2019, and was created to allow continued maintenance by the OS C# community.

For any and all future updates, the code releases will utilizing SemVer semantic versioning style.

Conveniently, eladaus.urldetector is available on NuGet as eladaus.urldetector. Install it from NuGet Package Manager Console with:

Install-Package eladaus.urldetector

Currently, 3 test cases fail out of the original suite of over 350. This appears to be a difference between how Java and C# represent signed ints/bytes, however fixing this is currently low priority/backlogged.

That said, anyone who needs this fixed will be able to compare the C# port with the Java original to debug, and we welcome any contributions and pull-requests.

The url detector is a library originally created by the Linkedin Security Team to detect and extract urls in a body of text.

It is able to find and detect any urls such as:

• HTML 5 Scheme - //www.linkedin.com
• Usernames - user:pass@linkedin.com
• Email - fred@linkedin.com
• IPv4 Address - 192.168.1.1/hello.html
• IPv4 Octets - 0x00.0x00.0x00.0x00
• IPv4 Decimal - http://123123123123/
• IPv6 Address - ftp://[::]/hello
• IPv4-mapped IPv6 Address - http://[fe30:4:3:0:192.3.2.1]/

Note: Keep in mind that for security purposes, its better to overdetect urls and check more against blacklists than to not detect a url that was submitted. As such, some things that we detect might not be urls but somewhat look like urls. Also, instead of complying with RFC 3986 (http://www.ietf.org/rfc/rfc3986.txt), we try to detect based on browser behavior, optimizing detection for urls that are visitable through the address bar of Chrome, Firefox, Internet Explorer, and Safari.

It is also able to identify the parts of the identified urls. For example, for the url: http://user@linkedin.com:39000/hello?boo=ff#frag

• Scheme - "http"
• Username - "user"
• Password - null
• Host - "linkedin.com"
• Port - 39000
• Path - "/hello"
• Query - "?boo=ff"
• Fragment - "#frag"

Using the URL detector library is simple. Simply import the UrlDetector object and give it some options. In response, you will get a list of urls which were detected.

For example, the following code will find the url linkedin.com

    UrlDetector parser = new UrlDetector("hello this is a url Linkedin.com", UrlDetectorOptions.Default);
    List<Url> found = parser.Detect();

    foreach(Url url in found) {
        Console.WriteLine("Scheme: " + url.getScheme());
        Console.WriteLine("Host: " + url.getHost());
        Console.WriteLine("Path: " + url.getPath());
    }

Depending on your input string, you may want to handle certain characters in a special way. For example if you are parsing HTML, you probably want to break out of things like quotes and brackets. For example, if your input looks like

<a href="http://linkedin.com/abc"&gt;linkedin.com&lt;/a>

You probably want to make sure that the quotes and brackets are extracted. For that reason, using UrlDetectorOptions will allow you to change the sensitivity level of detection based on your expected input type. This way you can detect linkedin.com instead of linkedin.com</a>.

In code this looks like:

    UrlDetector parser = new UrlDetector("<a href="linkedin.com/abc">linkedin.com</a>", UrlDetectorOptions.HTML);
    List<Url> found = parser.Detect();

This C# port was originally created by Dale Holborow of eladaus oy. Future contributions are welcome.

The original Java library was written by the security team and Linkedin when other options did not exist. Some of the primary authors are:

• Vlad Shlosberg (vshlosbe@linkedin.com)
• Tzu-Han Jan (tjan@linkedin.com)
• Yulia Astakhova (jastakho@linkedin.com)

The C# port provided by eladaus is released under Apache License Version 2.0, as per the original LinkedIn java library.

Original Java code is Copyright 2015 LinkedIn Corp. All rights reserved.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the license at http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.