Enhance LSP client to support configuring language ID and add support for Typescript React

ide/lsp.client/apichanges.xml

@@ -25,6 +25,34 @@
     <apidef name="lsp_client">LSP Client API</apidef>
 </apidefs>
 <changes>
+    <change id="LanguageIdProvider">
+        <api name="lsp_client" />
+        <summary>Adding LanguageIdProvider</summary>
+        <version major="0" minor="1.34" />
+        <date day="27" month="2" year="2026" />
+        <author login="mmatblsi" />
+        <compatibility addition="yes" binary="compatible" source="compatible" />
+        <description>
+            <p>
+                While NetBeans uses mimetypes as primary identifier for source types,
+                LSP uses languageId as a carrier to inform what language/type of file
+                is being edited. Even a single language server can provide support
+                for multiple languages. One such example is the typescript language
+                server, which defaults to typescript, but also supports the
+                typescript variant that embeds react templates (TSX).
+            </p>
+            <p>
+                To support this an implementation can provide a resolver. The
+                resolver has to implement the interface
+                <code>org.netbeans.modules.lsp.client.spi.LanguageIdResolver</code>
+                and will be provided by a lookup provided to the
+                <code>LanguageServerDescription</code>. For each opened file
+                the resolver will be called with the file object and will return
+                the language id if it can resolve it for the given file.
+            </p>
+        </description>
+        <class name="LanguageIdResolver" package="org.netbeans.modules.lsp.client.spi"/>
+    </change>
     <change id="MultiMimeLanguageServerProvider">
         <api name="lsp_client" />
         <summary>Adding MultiMimeLanguageServerProvider</summary>

ide/lsp.client/src/org/netbeans/modules/lsp/client/LSPBindings.java

@@ -92,6 +92,7 @@
 import org.netbeans.modules.lsp.client.bindings.LanguageClientImpl;
 import org.netbeans.modules.lsp.client.bindings.TextDocumentSyncServerCapabilityHandler;
 import org.netbeans.modules.lsp.client.options.MimeTypeInfo;
+import org.netbeans.modules.lsp.client.spi.LanguageIdResolver;
 import org.netbeans.modules.lsp.client.spi.ServerRestarter;
 import org.netbeans.modules.lsp.client.spi.LanguageServerProvider;
 import org.netbeans.modules.lsp.client.spi.LanguageServerProvider.LanguageServerDescription;
@@ -372,7 +373,9 @@ public void close() throws IOException {
                     }
                     InitializeResult result = initServer(process, server, dir); //XXX: what if a different root is expected????
                     server.initialized(new InitializedParams());
-                    b = new LSPBindings(server, result, LanguageServerProviderAccessor.getINSTANCE().getProcess(desc));
+                    process = LanguageServerProviderAccessor.getINSTANCE().getProcess(desc);
+                    Lookup serverLookup = LanguageServerProviderAccessor.getINSTANCE().getLookup(desc);
+                    b = new LSPBindings(server, result, process, serverLookup.lookup(LanguageIdResolver.class));
                     // Register cleanup via LSPReference#run
                     new LSPReference(b, Utilities.activeReferenceQueue());
                     lci.setBindings(b);
@@ -426,7 +429,7 @@ public void write(int w) throws IOException {
                 LanguageServer server = launcher.getRemoteProxy();
                 InitializeResult result = initServer(null, server, root);
                 server.initialized(new InitializedParams());
-                LSPBindings bindings = new LSPBindings(server, result, null);
+                LSPBindings bindings = new LSPBindings(server, result, null, null);
 
                 lc.setBindings(bindings);
 
@@ -521,11 +524,13 @@ public static synchronized Set<LSPBindings> getAllBindings() {
     private final LanguageServer server;
     private final InitializeResult initResult;
     private final Process process;
+    private final LanguageIdResolver languageIdResolver;
 
-    private LSPBindings(LanguageServer server, InitializeResult initResult, Process process) {
+    private LSPBindings(LanguageServer server, InitializeResult initResult, Process process, LanguageIdResolver languageIdResolver) {
         this.server = server;
         this.initResult = initResult;
         this.process = process;
+        this.languageIdResolver = languageIdResolver;
     }
 
     public TextDocumentService getTextDocumentService() {
@@ -541,6 +546,16 @@ public InitializeResult getInitResult() {
         return initResult;
     }
 
+    public String resolveLanguageId(FileObject fileObject) {
+        if(languageIdResolver != null) {
+            String languageId = languageIdResolver.resolveLanguageId(fileObject);
+            if (languageId != null) {
+                return languageId;
+            }
+        }
+        return FileUtil.getMIMEType(fileObject);
+    }
+
     @SuppressWarnings("AccessingNonPublicFieldOfAnotherObject")
     public static synchronized void addBackgroundTask(FileObject file, BackgroundTask task) {
         RequestProcessor.Task req = WORKER.create(() -> {

ide/lsp.client/src/org/netbeans/modules/lsp/client/LanguageServerProviderAccessor.java

@@ -24,6 +24,7 @@
 import org.netbeans.api.annotations.common.NonNull;
 import org.netbeans.modules.lsp.client.spi.LanguageServerProvider.LanguageServerDescription;
 import org.openide.util.Exceptions;
+import org.openide.util.Lookup;
 
 /**
  *
@@ -57,4 +58,5 @@ public static void setINSTANCE (LanguageServerProviderAccessor instance) {
     public abstract LSPBindings getBindings(LanguageServerDescription desc);
     public abstract void setBindings(LanguageServerDescription desc, LSPBindings bindings);
     public abstract LanguageServerDescription createLanguageServerDescription(@NonNull LanguageServer server);
+    public abstract Lookup getLookup(LanguageServerDescription desc);
 }

ide/lsp.client/src/org/netbeans/modules/lsp/client/bindings/TextDocumentSyncServerCapabilityHandler.java

@@ -315,14 +315,13 @@ private void ensureDidOpenSent(Document doc, boolean sync) {
                 }
             });
 
-            // @todo: the mimetype is not the language ID
-            TextDocumentItem textDocumentItem = new TextDocumentItem(uri,
-                                                                     FileUtil.getMIMEType(file),
-                                                                     0,
-                                                                     text[0]);
 
             for (LSPBindings server : servers) {
                 if (server.getOpenedFiles().add(file)) {
+                    TextDocumentItem textDocumentItem = new TextDocumentItem(uri,
+                                                                             server.resolveLanguageId(file),
+                                                                             0,
+                                                                             text[0]);
                     server.getTextDocumentService().didOpen(new DidOpenTextDocumentParams(textDocumentItem));
                 }
             }

ide/lsp.client/src/org/netbeans/modules/lsp/client/options/Bundle.properties

@@ -41,3 +41,5 @@ ACSD_Marks_CB=Keep Marks Checkbox
 
 text/x-generic-lsp=Language Server Protocol Client (generic)
 LanguageDescriptionPanel.debugger.text=Enable &Breakpoints
+LanguageDescriptionPanel.languageIdLabel.text=Language Identifier:
+LanguageDescriptionPanel.languageId.text=

ide/lsp.client/src/org/netbeans/modules/lsp/client/options/GenericLanguageServer.java

@@ -25,6 +25,7 @@
 import org.netbeans.api.io.InputOutput;
 import org.netbeans.api.project.Project;
 import org.netbeans.api.project.ProjectUtils;
+import org.netbeans.modules.lsp.client.spi.LanguageIdResolver;
 import org.netbeans.modules.lsp.client.spi.LanguageServerProvider;
 import org.openide.filesystems.FileAttributeEvent;
 import org.openide.filesystems.FileChangeListener;
@@ -35,6 +36,7 @@
 import org.openide.util.Exceptions;
 import org.openide.util.Lookup;
 import org.openide.util.RequestProcessor;
+import org.openide.util.lookup.Lookups;
 
 /**
  *
@@ -57,6 +59,7 @@ public LanguageServerDescription startServer(Lookup lookup) {
         FileObject server = FileUtil.getConfigFile("Editors/" + mti.mimeType + "/org-netbeans-modules-lsp-client-options-GenericLanguageServer.instance");
         String[] command = (String[]) server.getAttribute("command");
         String name = (String) server.getAttribute("name");
+        String languageId = (String) server.getAttribute("languageId");
 
         if (name == null) {
             name = command[0];
@@ -130,7 +133,16 @@ private void update() {
                     io.show();
                 }
             });
-            return LanguageServerDescription.create(process.getInputStream(), process.getOutputStream(), process);
+            Lookup serverLookup = null;
+            if(languageId != null && ! languageId.isBlank()) {
+                serverLookup = Lookups.fixed(new LanguageIdResolver() {
+                    @Override
+                    public String resolveLanguageId(FileObject fileObject) {
+                        return languageId;
+                    }
+                });
+            }
+            return LanguageServerDescription.create(process.getInputStream(), process.getOutputStream(), process, serverLookup);
         } catch (Throwable t) {
             t.printStackTrace(); //TODO
             return null;