For my first and ongoing project as an intern at Red Hat, I’ve been working alongside Angelo Zerr and Fred Bricon to develop an implementation of the Language Server Protocol (LSP) for XML. Through the XML language server, developer tools like VSCode and Eclipse receive XML syntax highlighting and checking, code completion, document folding, etc. At the moment we appear to have the most feature rich XML language server implementation, including our Schema-based support which is an essential XML feature that we are most proud of. Combined, all these features make it much easier for developers to work on any type of project involving XML, from the comfort of their favorite editor or IDE.
Watch a demo of the XML VS Code Extension
https://www.youtube.com/watch?v=2T4g9R56Cc0
The XML language server is currently available in VSCode (via Red Hat’s XML extension), Eclipse LSP4E, and soon in Eclipse Che, which should be available in early 2019.
Supported features:
- Syntax error reporting
- General code completion
- Auto-close tags
- Automatic node indentation
- Symbol highlighting
- Document folding
- Document links
- Document symbols and outline
- Renaming support
- Document Formatting
- DTD validation
- XSD validation
- XSD based hover
- XSD based code completion
- XSL support
- XML catalogs
- File associations
- Code actions
- Schema Caching
The amount of features will only keep growing, with our second version having recently been released with great improvements, such as local schema caching for faster load times. Some upcoming additions will include major improvements and fixes to DTD and XSD support, which will complement the entire XML suite.
Initiated by Angelo, this language server is a port of Microsoft’s fault-tolerant HTML language server, that we have developed in Java. Since XML is a subset of HTML we were able to build upon the underlying structure of the HTML language server, which in return enabled us to quickly start work on XML specific features.
If you’d like to contribute to the language server, the repository can be found here.
It has been a great experience working on this project with Red Hat and the open source community, especially on a tool that has so much potential. And with the growth of lightweight and cloud based IDE’s like VSCode or Eclipse Che, language servers will be essential to the success of these editors. It's exciting to know that even as an intern, my work will be a part of a very important movement in the developer space.
I hope you'll try the XML language server in VSCode, or your favorite editor that supports the language server protocol, and feel free to leave feedback or report any bugs here.
Additional Resources
- A common interface for developer tools—an introduction to the Language Server Protocol by Gorkem Ercan
- Language support for Java for Visual Studio Cod by Red Hat—This Java LSP implementation is one of the most popular extensions in the Visual Studio Code Marketplace. It has been downloaded 10 million times so far.
- Announcing Red Hat OpenShift extension for Visual Studio Code—Control your OpenShift/Kubernetes development environment from within your IDE.
- Extensions by Red Hat on the Visual Studio Marketplace covering
- Java Language Support—Java Linting, Intellisense, formatting, refactoring, Maven/Gradle support and more
- YAML Support—YAML Support with built-in Kubernetes and Kedge syntax support
- OpenShift Connector—A streamlined experience for interacting with Red Hat OpenShift clusters using Visual Studio Code
- Dependency analytics—Insights about your application dependencies: Security, License compatibility and AI based guidance to choose appropriate dependencies for your application.
Last updated: December 11, 2018
