_posts/2019-08-17-netbeans1594.markdown

---
layout: post
title: LSP Client demo - (ba)sh language server
date: '2019-08-17T15:25:14+00:00'
categories: netbeans
---
<p>Below is a scenario by Jan Lahoda, the creator of LSP integration for Apache NetBeans, for how to integrate the bash language server with Apache NetBeans, including syntax highlighting.</p>

<h3>Setting Up</h3>

<ol>

<li><p>Install npm (and node.js). On Ubuntu, e.g., do "apt install npm", though something different will be needed on Mac OS X.</p></li>

<li><p>Create a directory in which we are going to work, have a terminal opened in that directory.</p></li>

<li><p>Install the bash-language-server:</p>

<pre>npm install bash-language-server</pre>

<p>On Mac OSX:</p>

<pre>npm install bash-language-server --unsafe-perm</pre>

<p>This will install the server into the current directory.</p>

</li>

<li><p>Try the bash server:</p>

<pre>./node_modules/bash-language-server/bin/main.js --help</pre>

<p>You should see something like this:</p>

<pre>Usage:
  bash-language-server start
  bash-language-server -h | --help
  bash-language-server -v | --version</pre>

</li>

<li>

<p>Create a NetBeans module. Create a File Type (Module Development/File Type), mime type: text/sh, file extension: sh</p>

</li>

</ol>

<h3>Syntax Coloring via TextMate</h3>

<ol>

<li>

<p>Download the TextMate grammar file here, and put it alongside the newly created DataObject:</p>

<p><a href="https://raw.githubusercontent.com/microsoft/vscode/master/extensions/shellscript/syntaxes/shell-unix-bash.tmLanguage.json">https://raw.githubusercontent.com/microsoft/vscode/master/extensions/shellscript/syntaxes/shell-unix-bash.tmLanguage.json</a></p>

</li>

<li>

<p>
Add "TextMate Lexer" as a dependency of the module.
</p>

</li>

<li><p>Into the DataObject add this annotation:</p>

<pre>@GrammarRegistration(grammar="shell-unix-bash.tmLanguage.json", mimeType="text/sh")</pre>

<p>GrammarRegistration is:</p>

<pre>import org.netbeans.modules.textmate.lexer.api.GrammarRegistration;</pre>

</li>

</ol>

<p>This should lead to syntax highlighted source for .sh bash files taken from the TextMate grammar file.</p>


<h3>Language Support via the Language Server</h3>

<p>Next, we need to add language support using the language server.</p>

<ol>

<li>

<p>Add "LSP Client" and "MIME Lookup API" as dependencies of the module.</p>

</li>

<li>

<p>Create a new class, ShellClient, in the module, put this into it, (replacing "&lt;path-to-bash-language-server&gt;" with the absolute path to "node_modules/bash-language-server"):</p>

<pre>import java.io.IOException;
import org.netbeans.api.editor.mimelookup.MimeRegistration;
import org.netbeans.modules.lsp.client.spi.LanguageServerProvider;
import org.openide.util.Exceptions;
import org.openide.util.Lookup;

@MimeRegistration(mimeType="text/sh", service=LanguageServerProvider.class)
public class ShellClient implements LanguageServerProvider {

   @Override
   public LanguageServerDescription startServer(Lookup lkp) {
       try {
           Process p = new ProcessBuilder("&lt;path-to-bash-language-server&gt;/bin/main.js", "start").start();
           return LanguageServerDescription.create(p.getInputStream(), p.getOutputStream(), p);
       } catch (IOException ex) {
           Exceptions.printStackTrace(ex);
           return null;
       }
   }

}</pre>

<p>You may need to explicitly call node in the above code, i.e., as follows:</p>

<pre>Process p = new ProcessBuilder(
        "/usr/local/bin/node", 
        "&lt;path-to-bash-language-server&gt;/bin/main.js", 
        "start").start();</pre>

</li>

<li>

<p>Build and start the module.</p>

</li>

</ol>

<p>Caveat: the language server is started only for files that are inside a project, so create (any) new project, and inside the project, put a shell file. E.g. copy "bin/netbeans" as "test.sh" into the project. Open it in the editor - there should be syntax highlighting, Navigator, and code completion should show something, etc.</p>