Initialize request not handled with WebSocket connection

[apupier]

Currently trying to connect a VS Code Client to a Language Server written on LSP4J 0.8.1.

The "connect" method is called and it throws no error (when address is wrong, I have other errors)

The client is sending an initialize request:

[Trace - 5:32:52 PM] Sending request 'initialize - (0)'.
Params: {
    "processId": 74894,
    "clientInfo": {
        "name": "vscode",
        "version": "1.42.0"
    },
    "rootPath": "/home/apupier/git/camel-k-example-basic",
    "rootUri": "file:///home/apupier/git/camel-k-example-basic",
    "capabilities": {
        "workspace": {
            "applyEdit": true,
            "workspaceEdit": {
                "documentChanges": true,
                "resourceOperations": [
                    "create",
                    "rename",
                    "delete"
                ],
                "failureHandling": "textOnlyTransactional"
            },
            "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
            },
            "configuration": true,
            "workspaceFolders": true
        },
        "textDocument": {
            "publishDiagnostics": {
                "relatedInformation": true,
                "versionSupport": false,
                "tagSupport": {
                    "valueSet": [
                        1,
                        2
                    ]
                }
            },
            "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,
                    "tagSupport": {
                        "valueSet": [
                            1
                        ]
                    }
                },
                "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"
                    ],
                    "parameterInformation": {
                        "labelOffsetSupport": true
                    }
                },
                "contextSupport": true
            },
            "definition": {
                "dynamicRegistration": true,
                "linkSupport": 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,
                "isPreferredSupport": 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,
                "prepareSupport": true
            },
            "documentLink": {
                "dynamicRegistration": true,
                "tooltipSupport": true
            },
            "typeDefinition": {
                "dynamicRegistration": true,
                "linkSupport": true
            },
            "implementation": {
                "dynamicRegistration": true,
                "linkSupport": true
            },
            "colorProvider": {
                "dynamicRegistration": true
            },
            "foldingRange": {
                "dynamicRegistration": true,
                "rangeLimit": 5000,
                "lineFoldingOnly": true
            },
            "declaration": {
                "dynamicRegistration": true,
                "linkSupport": true
            },
            "selectionRange": {
                "dynamicRegistration": true
            }
        },
        "window": {
            "workDoneProgress": true
        }
    },
    "trace": "verbose",
    "workspaceFolders": [
        {
            "uri": "file:///home/apupier/git/camel-k-example-basic",
            "name": "camel-k-example-basic"
        }
    ]
}

But the implementation method LanguageServer.initialize(InitializeParams) is not called.
I tried to put breakpoint on org.eclipse.lsp4j.websocket.WebSocketMessageConsumer.consume(Message) and org.eclipse.lsp4j.websocket.WebSocketMessageHandler.onMessage(String) but these methods are not called either.

What is the best place to trace the request on Server side? so that i can see the path that it follows and see where the request is blocked/rejected/lost.

Please note that i was able to make it working with another client, Monaco.

[cdietrich]

does vscode now have websocket support for language servers or did you come up with something custom? (in both cases do both send the same message format at monaco language client / ws jsonrpc does (e.g. regarding headers)
i guess a good starting point might be the jetty code like org.eclipse.jetty.websocket.jsr356.endpoints.JsrEndpointEventDriver

here is a trace when using monaco

LanguageServerImpl.initialize(InitializeParams) line: 205	
NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method]	
NativeMethodAccessorImpl.invoke(Object, Object[]) line: 62	
DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: 43	
Method.invoke(Object, Object...) line: 498	
GenericEndpoint.lambda$null$0(AnnotationUtil$MethodInfo, Object, Object) line: 65	
1918464276.apply(Object) line: not available	
GenericEndpoint.request(String, Object) line: 120	
RemoteEndpoint.handleRequest(RequestMessage) line: 261	
RemoteEndpoint.consume(Message) line: 190	
WebSocketMessageHandler.onMessage(String) line: 40	
WebSocketMessageHandler.onMessage(Object) line: 25	
TextWholeMessage.messageComplete() line: 59	
JsrEndpointEventDriver.onTextFrame(ByteBuffer, boolean) line: 218	
JsrEndpointEventDriver(AbstractEventDriver).incomingFrame(Frame) line: 150	
JsrSession(WebSocketSession).incomingFrame(Frame) line: 319	
PerMessageDeflateExtension(AbstractExtension).nextIncomingFrame(Frame) line: 147	
PerMessageDeflateExtension.nextIncomingFrame(Frame) line: 112	
PerMessageDeflateExtension(CompressExtension).forwardIncoming(Frame, ByteAccumulator) line: 142	
PerMessageDeflateExtension.incomingFrame(Frame) line: 92	
ExtensionStack.incomingFrame(Frame) line: 201	
Parser.notifyFrame(Frame) line: 226	
Parser.parse(ByteBuffer) line: 255	
WebSocketServerConnection(AbstractWebSocketConnection).readParse(ByteBuffer) line: 581	

so any of these might be a good canidate

[apupier]

does vscode now have websocket support for language servers or did you come up with something custom?

I think they have but I'm connecting to Language Server which is not managed by VS Code. So the Language Server is launched outside of VS Code. The client part of VS Code is just connecting to this Language Server implementation.
It is using Tyrus

Thanks for the trace!

[cdietrich]

so how does the client in your vscode plugin look like?

[apupier]

the important part is:

const host = 'localhost';
	const socketPort = 8077;
	const serverOptions: ServerOptions = function () {
		return new Promise((resolve) => {
			let socket = new WebSocket(`ws://${host}:${socketPort}/teiid-ddl-language-server`);
			const messageStream = WebSocket.createWebSocketStream(socket, {});
			const result: StreamInfo = {
				writer: messageStream,
				reader: messageStream
			};
			return resolve(result);
		});
	};

EDIT: here is full branch of the client https://github.com/apupier/vscode-datavirt/tree/testLSPWebsocket-githubreference

[cdietrich]

i am not sure if this will send the messages the websocket on server expects or if it will sent the header as well which then will break the json parsing see e.g. #189

[apupier]

interesting link.

By following linke dissues, i came on one of your comment

you use the upcoming lsp 0.8.0-SNAPSHOT which has support for websockets directly by avoiding using StreamMessageProducer/Consumer

My Language Server is using LSP4J 0.8.1 so I would expect that it is not hitting the issue. Or I misunderstood a part? And I still need to provide a specific implementation for MessageProducer/Consumer either on VS Code side or on Server side?

[cdietrich]

no. the monaco language client does not send json rpc with header but the payload json only.
i assume that is you just give vscode a stream it will send the headers
(maybe you can wrap the streams in the client and have a look what it actually sends on the pipe)

[apupier]

I think that th eproblem is that VS COde is sending in Binary format although LSP4J does not provide a BinaryHandler:

here is the stack that let me think that:

Daemon Thread [Grizzly-worker(2)] (Suspended (breakpoint at line 804 in TyrusEndpointWrapper))	
	TyrusEndpointWrapper.onMessage(TyrusWebSocket, ByteBuffer) line: 804	
	TyrusWebSocket.onMessage(BinaryFrame) line: 179	
	BinaryFrame.respond(TyrusWebSocket) line: 70	
	ProtocolHandler.process(Frame, TyrusWebSocket) line: 783	
	TyrusWebSocketEngine$TyrusReadHandler.handle(ByteBuffer) line: 538	
	GrizzlyServerFilter$ProcessTask.execute() line: 355	
	TaskProcessor.processTask() line: 91	
	TaskProcessor.processTask(TaskProcessor$Task) line: 68	
	GrizzlyServerFilter.handleRead(FilterChainContext) line: 191	
	ExecutorResolver$9.execute(Filter, FilterChainContext) line: 95	
	DefaultFilterChain.executeFilter(FilterExecutor, Filter, FilterChainContext) line: 260	
	DefaultFilterChain.executeChainPart(FilterChainContext, FilterExecutor, int, int, DefaultFilterChain$FiltersState) line: 177	
	DefaultFilterChain.execute(FilterChainContext) line: 109	
	DefaultFilterChain.process(Context) line: 88	
	ProcessorExecutor.execute(Context) line: 53	
	TCPNIOTransport.fireIOEvent(IOEvent, Connection, IOEventLifeCycleListener) line: 515	
	AbstractIOStrategy.fireIOEvent(Connection, IOEvent, IOEventLifeCycleListener, Logger) line: 89	
	WorkerThreadIOStrategy.run0(Connection, IOEvent, IOEventLifeCycleListener) line: 94	
	WorkerThreadIOStrategy.access$100(Connection, IOEvent, IOEventLifeCycleListener) line: 33	
	WorkerThreadIOStrategy$WorkerThreadRunnable.run() line: 114	
	FixedThreadPool$BasicWorker(AbstractThreadPool$Worker).doWork() line: 569	
	FixedThreadPool$BasicWorker(AbstractThreadPool$Worker).run() line: 549	
	DefaultWorkerThread(Thread).run() line: 834	

it is throwing the IllegalStateException in this piece of code:

            if (session.isWholeBinaryHandlerPresent()) {
                session.notifyMessageHandlers(messageBytes, findApplicableDecoders(session, messageBytes, false));
            } else if (session.isPartialBinaryHandlerPresent()) {
                session.notifyMessageHandlers(messageBytes, true);
            } else {
                throw new IllegalStateException(LocalizationMessages.BINARY_MESSAGE_HANDLER_NOT_FOUND(session));
            }

[apupier]

so, this can be workarounded on client side by configuring it to use text format, for TypeScript, when using ws library, this can be done using decodeStrings:false options when creating WebSocketStream, so something like:

			let socket = new WebSocket(`ws://${host}:${socketPort}/teiid-ddl-language-server`);
			const messageStream = WebSocket.createWebSocketStream(socket, {decodeStrings:false});
			const result: StreamInfo = {
				writer: messageStream,
				reader: messageStream
			};

unfortunately it is still not working.

The lsp4j MessageJSOnHandler is unable to read the incoming content:

com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 1 path $

[cdietrich]

and what is in the message?

[apupier]

the content of the message is:

Content-Length: 3111\r\n\r\n

strange

[cdietrich]

as i have said and is mentioned in that other issue:
VSCode sends the content header length
but the websocket impl here cannot deal with it.
(as https://github.com/TypeFox/monaco-languageclient does not send it)
(for the responses there will be the same problem)

am not sure how https://github.com/TypeFox/vscode-ws-jsonrpc will behave

[apupier]

asked on StaskOverflow how to avoid "CONTENT-LENGTH" with a Websocket connection: https://stackoverflow.com/questions/60372566/how-to-configure-websocket-to-not-send-content-length-in-javascript-typescript

[tivervac]

Just to chime in, we've been having the same issue once in a while as well. In our case, it happens in plain java JUnit tests so VS Code is not even in the loop. What we've seen is that the jsonRPC message is sometimes jumbled up for unknown reasons. This message can then of course not be interpreted by LSP4J. An example is shown below. As you can see somehow the Content-Length is sent separately as well as at the end of the initialize message ( }Content-Length: 53) instead of being a header of the initialize message.

Do note that this is for LSP4J <= 0.12.0

Started language server listening on port 34679
Oct 19, 2022 9:52:39 AM org.eclipse.lsp4j.jsonrpc.json.StreamMessageProducer fireError
SEVERE: Missing header Content-Length in input "Content-Length: 5530

"
java.lang.IllegalStateException: Missing header Content-Length in input "Content-Length: 5530

"
	at org.eclipse.lsp4j.jsonrpc.json.StreamMessageProducer.listen(StreamMessageProducer.java:91)
	at org.eclipse.lsp4j.jsonrpc.json.ConcurrentMessageProcessor.run(ConcurrentMessageProcessor.java:113)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
	at java.base/java.lang.Thread.run(Thread.java:833)

Oct 19, 2022 9:52:39 AM org.eclipse.lsp4j.jsonrpc.json.StreamMessageProducer fireError
SEVERE: Missing header Content-Length in input "{
  "jsonrpc": "2.0",
  "id": "1",
  "method": "initialize",
  "params": {
    "processId": null,
    "rootUri": null,
    "initializationOptions": {
    },
    "capabilities": {
      "workspace": {
        "applyEdit": false,
        "workspaceEdit": {
          "documentChanges": false,
          "resourceOperations": [
            "create",
            "delete",
            "rename"
          ],
          "failureHandling": "abort"
        },
        "didChangeConfiguration": {
          "dynamicRegistration": false
        },
        "didChangeWatchedFiles": {
          "dynamicRegistration": false
        },
        "symbol": {
          "symbolKind": {
            "valueSet": []
          },
          "dynamicRegistration": false
        },
        "executeCommand": {
          "dynamicRegistration": false
        },
        "workspaceFolders": true,
        "configuration": false
      },
      "textDocument": {
        "synchronization": {
          "willSave": false,
          "willSaveWaitUntil": false,
          "didSave": false,
          "dynamicRegistration": false
        },
        "completion": {
          "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
            ]
          },
          "contextSupport": true,
          "dynamicRegistration": false
        },
        "hover": {
          "contentFormat": [
            "markdown",
            "plaintext"
          ],
          "dynamicRegistration": false
        },
        "signatureHelp": {
          "signatureInformation": {
            "documentationFormat": [
              "markdown",
              "plaintext"
            ]
          },
          "dynamicRegistration": false
        },
        "references": {
          "dynamicRegistration": false
        },
        "documentHighlight": {
          "dynamicRegistration": false
        },
        "documentSymbol": {
          "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,
          "dynamicRegistration": false
        },
        "formatting": {
          "dynamicRegistration": false
        },
        "rangeFormatting": {
          "dynamicRegistration": false
        },
        "onTypeFormatting": {
          "dynamicRegistration": false
        },
        "definition": {
          "dynamicRegistration": false
        },
        "typeDefinition": {
          "dynamicRegistration": false
        },
        "implementation": {
          "dynamicRegistration": false
        },
        "codeAction": {
          "codeActionLiteralSupport": {}
        },
        "codeLens": {
          "dynamicRegistration": false
        },
        "documentLink": {
          "dynamicRegistration": false
        },
        "colorProvider": {
          "dynamicRegistration": false
        },
        "rename": {
          "prepareSupport": false,
          "dynamicRegistration": false
        },
        "publishDiagnostics": {
          "relatedInformation": true
        },
        "foldingRange": {
          "rangeLimit": 1000,
          "lineFoldingOnly": false,
          "dynamicRegistration": false
        },
        "semanticTokens": {
          "requests": {
            "full": true
          },
          "tokenTypes": [
            "namespace",
            "type",
            "class",
            "enum",
            "interface",
            "struct",
            "typeparameter",
            "parameter",
            "variable",
            "property",
            "enummember",
            "event",
            "function",
            "method",
            "macro",
            "keyword",
            "modifier",
            "comment",
            "string",
            "number",
            "regexp",
            "operator"
          ],
          "tokenModifiers": [
            "declaration",
            "definition",
            "readonly",
            "static",
            "deprecated",
            "abstract",
            "async",
            "modification",
            "documentation",
            "defaultlibrary"
          ],
          "formats": [
            "relative"
          ]
        }
      }
    },
    "trace": "false",
    "workspaceFolders": [
      {
        "uri": "file:///tmp/workspace_folder4001760077488830224/"
      }
    ]
  }
}Content-Length: 53

"
java.lang.IllegalStateException: Missing header Content-Length in input "{
  "jsonrpc": "2.0",
  "id": "1",
  "method": "initialize",
  "params": {
    "processId": null,
    "rootUri": null,
    "initializationOptions": {
      "useUPD": true
    },
    "capabilities": {
      "workspace": {
        "applyEdit": false,
        "workspaceEdit": {
          "documentChanges": false,
          "resourceOperations": [
            "create",
            "delete",
            "rename"
          ],
          "failureHandling": "abort"
        },
        "didChangeConfiguration": {
          "dynamicRegistration": false
        },
        "didChangeWatchedFiles": {
          "dynamicRegistration": false
        },
        "symbol": {
          "symbolKind": {
            "valueSet": []
          },
          "dynamicRegistration": false
        },
        "executeCommand": {
          "dynamicRegistration": false
        },
        "workspaceFolders": true,
        "configuration": false
      },
      "textDocument": {
        "synchronization": {
          "willSave": false,
          "willSaveWaitUntil": false,
          "didSave": false,
          "dynamicRegistration": false
        },
        "completion": {
          "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
            ]
          },
          "contextSupport": true,
          "dynamicRegistration": false
        },
        "hover": {
          "contentFormat": [
            "markdown",
            "plaintext"
          ],
          "dynamicRegistration": false
        },
        "signatureHelp": {
          "signatureInformation": {
            "documentationFormat": [
              "markdown",
              "plaintext"
            ]
          },
          "dynamicRegistration": false
        },
        "references": {
          "dynamicRegistration": false
        },
        "documentHighlight": {
          "dynamicRegistration": false
        },
        "documentSymbol": {
          "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,
          "dynamicRegistration": false
        },
        "formatting": {
          "dynamicRegistration": false
        },
        "rangeFormatting": {
          "dynamicRegistration": false
        },
        "onTypeFormatting": {
          "dynamicRegistration": false
        },
        "definition": {
          "dynamicRegistration": false
        },
        "typeDefinition": {
          "dynamicRegistration": false
        },
        "implementation": {
          "dynamicRegistration": false
        },
        "codeAction": {
          "codeActionLiteralSupport": {}
        },
        "codeLens": {
          "dynamicRegistration": false
        },
        "documentLink": {
          "dynamicRegistration": false
        },
        "colorProvider": {
          "dynamicRegistration": false
        },
        "rename": {
          "prepareSupport": false,
          "dynamicRegistration": false
        },
        "publishDiagnostics": {
          "relatedInformation": true
        },
        "foldingRange": {
          "rangeLimit": 1000,
          "lineFoldingOnly": false,
          "dynamicRegistration": false
        },
        "semanticTokens": {
          "requests": {
            "full": true
          },
          "tokenTypes": [
            "namespace",
            "type",
            "class",
            "enum",
            "interface",
            "struct",
            "typeparameter",
            "parameter",
            "variable",
            "property",
            "enummember",
            "event",
            "function",
            "method",
            "macro",
            "keyword",
            "modifier",
            "comment",
            "string",
            "number",
            "regexp",
            "operator"
          ],
          "tokenModifiers": [
            "declaration",
            "definition",
            "readonly",
            "static",
            "deprecated",
            "abstract",
            "async",
            "modification",
            "documentation",
            "defaultlibrary"
          ],
          "formats": [
            "relative"
          ]
        }
      }
    },
    "trace": "false",
    "workspaceFolders": [
      {
        "uri": "file:///tmp/workspace_folder4001760077488830224/"
      }
    ]
  }
}Content-Length: 53

"
	at org.eclipse.lsp4j.jsonrpc.json.StreamMessageProducer.listen(StreamMessageProducer.java:91)
	at org.eclipse.lsp4j.jsonrpc.json.ConcurrentMessageProcessor.run(ConcurrentMessageProcessor.java:113)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
	at java.base/java.lang.Thread.run(Thread.java:833)

[javaduke]

Sorry to resurrect this old issue but I have exact same problem. My LSP4J version is 0.21.0 and I cannot get it to work with VSCode LSP client. Wondering if anyone can give me any pointers on how to troubleshoot.

Many thanks!

E.

[cdietrich]

i assume you have to copy & paste subclass the class that calls the constructor.
my test unfortunately arrives in

org.eclipse.lsp4j.websocket.WebSocketMessageHandler.WebSocketMessageHandler(MessageConsumer, MessageJsonHandler, MessageIssueHandler)

but no more.
but that might be me using jetty.
(am getting binary frame, what did you change)
what do you server side to serve the websocket

[javaduke]

See my sample code above, it's Jetty.
One issue I noticed is that the VSCode sends message in chunks rather than the entire message, so this may be an issue too.

[cdietrich]

i am still see
org.eclipse.jetty.websocket.jsr356.endpoints.JsrEndpointEventDriver.onBinaryFrame(ByteBuffer, boolean)
called which has no wrapper
and thus message is ignored.
wonder why this works for you

[javaduke]

Well, I tried to set decodeStrings to true in the client: return WebSocket.createWebSocketStream(ws, {decodeStrings: true});
Without it, it doesn't reach the Json handler.

[cdietrich]

which jsonHandler?

[javaduke]

MessageJsonHandler class.

[cdietrich]

i dont see this called at all. wonder how you setup jetty

[javaduke]

Nothing special about my jetty setup, I posted the code above: #406 (comment)
The jetty version is 11.0.15

[javaduke]

Well, I tried everything I could and now I'm kinda stuck. I was able to successfully connect Monaco client to my LSP4J implementation, but not VSCode extension.

[cdietrich]

Is there a reason / usecase you need to connect via web socket / process io or normal socket not an option

[javaduke]

Actually, no, normal socket would also be an option, but I'm not sure I know how to implement this in VSCode.
Ideally I would like to keep websocket option because it would allow me to use web-based clients as well as other clients too.

[cdietrich]

https://github.com/xtext/xtext-languageserver-example/blob/master/vscode-extension/src/extension.ts

[javaduke]

Yep, thanks, with plain socket it works now. I will still need to solve the websocket problem though, but I can save this for later.

[cdietrich]

Maybe also talk to vscode language client Team to introduce an option to configure if array is sent or plain text

[xyangwu]

i assume you have to copy & paste subclass the class that calls the constructor.

This subclass solution fixed the JSON-RPC header issue for me, but the backend LS I was using is implemented with pygls.
(I don't know wether the issue should be solved on vscode client or on server side. Just post it here for someone has encountered similar problem)