Connecting the Monaco Editor with an own Xtext language server

[ghost]

I'm trying to connect the Monaco Editor with a language server where my own Xtext language is loaded. Before I start to build the dsl, I wanted to get a basic communication between the language server and the editor running. So therefore I'm testing with the Hello World basic example model. I was able to get the web socket connection running thanks to following examples:
cdietrich/xtext-languageserver-example
TypeFox/monaco-languageclient

Also I was able to reproduce the JSON example successfully on the fontend side, so frontend wise everything should be fine.

Nethertheless I am failing to connect the Monaco Editor to a language server with a self defined Xtext language. My current state is pushed at nmaoez/composer-language-server where I describe how to get both sides (client/server) running for further investigation. In the Chrome network tab and in my Eclipse console I can see all messages, which are sent between server and client but the editor doesn't show anything regarding i.e. highlighting:

It seems that the client and the server are connected through the web sockets, but the messages are not forwarded to the language server.

I've been analyzing a lot of different projects, like theia-ide/sprotty or the OpenKieler/elkgraph-web project, but unfortunatly I wasn't able to figure it out. Has anyone been able to connect the Monaco Editor with their own language server and/or provide me an example? Is there maybe another approach on the backend side to get the connection running?

I am happy about any help and thanks!

[cdietrich]

i am not sure what you are exactly testing but there is no server side highlighting in this scenario.
thus you would have to provoke a parse error or add a validation to test this.
besides that is the gradle code you checked in inconsistent.
do you start the runserver manually?

[ghost]

My initial goal is to get a complete vertical connection between all components. My expectation was just that I would get to see anything in the frontend like the highlighting (or anything else, just like an indicator for a running connection).

I start the main()-method in the com.novomind.language.server.expression.websockets-subproject manually in Eclipse. For the most part, I focused on the project cdietrich/xtext-languageserver-example. There are 3 RunWebSocketServer.xtend classes in xtext-languageserver-example. Is my assumption correct that it is sufficient to start one of the classes manually in order to establish a complete connection (not only web socket connection) or are these classes not intended for this purpose?

[cdietrich]

no the 3 is correct.
the server runs but it seems it cannot handle your uris.
they are bad / not expected

better

`inmemory:/demo/${guid()}.${LANGUAGE_ID}`

[cdietrich]

you may also have a look at
eclipse-lsp4j/lsp4j#203
eclipse-lsp4j/lsp4j#314
https://github.com/OpenKieler/elkgraph-web/pull/13/files#diff-c6a79430e3155eaa1b62ade47757e09f

(requires lsp 0.8.0 snapshot)

[ghost]

I changed the URI and tried to connect the editor with the web socket server in xtext-languageserver-example (RunWebSocketServer3.xtend). Now I get following error:

Eclipse:

gogogo
start
open
message: {"jsonrpc":"2.0","id":0,"method":"initialize","params":{"rootPath":null,"rootUri":null,"capabilities":{"workspace":{"applyEdit":true,"workspaceEdit":{"documentChanges":true},"didChangeConfiguration":{"dynamicRegistration":true},"didChangeWatchedFiles":{"dynamicRegistration":true},"symbol":{"dynamicRegistration":true,"symbolKind":{"valueSet":[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26]}},"executeCommand":{"dynamicRegistration":true},"workspaceFolders":true},"textDocument":{"publishDiagnostics":{"relatedInformation":true},"synchronization":{"dynamicRegistration":true,"willSave":true,"willSaveWaitUntil":true,"didSave":true},"completion":{"dynamicRegistration":true,"contextSupport":true,"completionItem":{"snippetSupport":true,"commitCharactersSupport":true,"documentationFormat":["markdown","plaintext"],"deprecatedSupport":true,"preselectSupport":true},"completionItemKind":{"valueSet":[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25]}},"hover":{"dynamicRegistration":true,"contentFormat":["markdown","plaintext"]},"signatureHelp":{"dynamicRegistration":true,"signatureInformation":{"documentationFormat":["markdown","plaintext"]}},"definition":{"dynamicRegistration":true},"references":{"dynamicRegistration":true},"documentHighlight":{"dynamicRegistration":true},"documentSymbol":{"dynamicRegistration":true,"symbolKind":{"valueSet":[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26]},"hierarchicalDocumentSymbolSupport":true},"codeAction":{"dynamicRegistration":true,"codeActionLiteralSupport":{"codeActionKind":{"valueSet":["","quickfix","refactor","refactor.extract","refactor.inline","refactor.rewrite","source","source.organizeImports"]}}},"codeLens":{"dynamicRegistration":true},"formatting":{"dynamicRegistration":true},"rangeFormatting":{"dynamicRegistration":true},"onTypeFormatting":{"dynamicRegistration":true},"rename":{"dynamicRegistration":true},"documentLink":{"dynamicRegistration":true},"typeDefinition":{"dynamicRegistration":true},"implementation":{"dynamicRegistration":true},"colorProvider":{"dynamicRegistration":true},"foldingRange":{"dynamicRegistration":true,"rangeLimit":5000,"lineFoldingOnly":true}}},"trace":"off","workspaceFolders":null}}
{"jsonrpc":"2.0","id":0,"result":{"capabilities":{"textDocumentSync":2,"hoverProvider":true,"completionProvider":{"resolveProvider":false,"triggerCharacters":["."]},"signatureHelpProvider":{"triggerCharacters":["(",","]},"definitionProvider":true,"referencesProvider":true,"documentHighlightProvider":true,"documentSymbolProvider":true,"workspaceSymbolProvider":true,"codeActionProvider":true,"documentFormattingProvider":true,"documentRangeFormattingProvider":true,"renameProvider":true,"executeCommandProvider":{"commands":["mydsl.a","mydsl.b","mydsl.c"]},"semanticHighlighting":{"scopes":[]}}}}
message: {"jsonrpc":"2.0","method":"initialized","params":{}}
message: {"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{"uri":"inmemory:/demo/e3c2a3c8-3590-a4ff-cf30-b7f604e9a6f6.mydsl","languageId":"mydsl","version":1,"text":"Hello Xtext!"}}}
message: {"jsonrpc":"2.0","id":1,"method":"textDocument/codeAction","params":{"textDocument":{"uri":"inmemory:/demo/e3c2a3c8-3590-a4ff-cf30-b7f604e9a6f6.mydsl"},"range":{"start":{"line":0,"character":0},"end":{"line":0,"character":0}},"context":{"diagnostics":[]}}}
message: {"jsonrpc":"2.0","method":"$/cancelRequest","params":{"id":1}}
message: {"jsonrpc":"2.0","id":2,"method":"shutdown","params":null}
{"jsonrpc":"2.0","id":1,"error":{"code":-32800,"message":"The request (id: 1, method: \u0027textDocument/codeAction\u0027) has been cancelled"}}
{"jsonrpc":"2.0","id":2,"result":{}}
message: {"jsonrpc":"2.0","method":"exit","params":null}

Browser console:

Cannot read property 'addCommand' of undefined
Composer Expressions Language Client: [Error - 16:51:07] Server initialization failed.
Composer Expressions Language Client: TypeError: Cannot read property 'addCommand' of undefined
    at MonacoCommands.registerCommand (webpack-internal:///./node_modules/monaco-languageclient/lib/monaco-commands.js:8:44)
    at Object.registerCommand (webpack-internal:///./node_modules/monaco-languageclient/lib/vscode-api.js:663:29)
    at _loop_2 (webpack-internal:///./node_modules/vscode-base-languageclient/lib/client.js:1747:53)
    at ExecuteCommandFeature.register (webpack-internal:///./node_modules/vscode-base-languageclient/lib/client.js:1764:21)
    at ExecuteCommandFeature.initialize (webpack-internal:///./node_modules/vscode-base-languageclient/lib/client.js:1736:14)
    at MonacoLanguageClient.BaseLanguageClient.initializeFeatures (webpack-internal:///./node_modules/vscode-base-languageclient/lib/client.js:2548:25)
    at eval (webpack-internal:///./node_modules/vscode-base-languageclient/lib/client.js:2201:19)
Uncaught (in promise) TypeError: Cannot read property 'addCommand' of undefined
    at MonacoCommands.registerCommand (monaco-commands.js?53e5:8)
    at Object.registerCommand (vscode-api.js?0c54:663)
    at _loop_2 (client.js?a91b:1747)
    at ExecuteCommandFeature.register (client.js?a91b:1764)
    at ExecuteCommandFeature.initialize (client.js?a91b:1736)
    at MonacoLanguageClient.BaseLanguageClient.initializeFeatures (client.js?a91b:2548)
    at eval (client.js?a91b:2201)

Okay I will have a look at your suggested links. Thank you very much for your help so far.

[cdietrich]

Please debug your server

[cdietrich]

BTW this seems as you explicitly call the stuff so you may restart everything / close the editors. This code is not working with more than one client

also make sure that all the versions of monaco, languageclient, vscode etc match

[cdietrich]

you use "monaco-editor": "^0.17.1",
but #163 is not done yet.
=> you should use monaco 14 (or 15 - have not tested that)

[ghost]

Sorry for the late reply. I was on vacation last week.

After some local testing and debugging I managed to get the smallest example running. The current state is pushed into my personal project. The main issues were firstly the wrong URI and lastly I had a typo in the language id...

Nethertheless thank you very much for your help. Now I can continue on my main task.