Feature request: mechanism for intercepting progress reports

[hyangah]

I want to intercept the progress messages sent from the server, but don't see how yet.
Other LSP messages, Middleware in LanguageClientOptions provides the functionality.

vscode-languageserver-node/client/src/common/client.ts

Lines 456 to 488 in f9c16a9

	export interface _Middleware {
	didOpen?: NextSignature<TextDocument, void>;
	didChange?: NextSignature<TextDocumentChangeEvent, void>;
	willSave?: NextSignature<TextDocumentWillSaveEvent, void>;
	willSaveWaitUntil?: NextSignature<TextDocumentWillSaveEvent, Thenable<VTextEdit[]>>;
	didSave?: NextSignature<TextDocument, void>;
	didClose?: NextSignature<TextDocument, void>;
	handleDiagnostics?: (this: void, uri: Uri, diagnostics: VDiagnostic[], next: HandleDiagnosticsSignature) => void;
	provideCompletionItem?: (this: void, document: TextDocument, position: VPosition, context: VCompletionContext, token: CancellationToken, next: ProvideCompletionItemsSignature) => ProviderResult<VCompletionItem[] | VCompletionList>;
	resolveCompletionItem?: (this: void, item: VCompletionItem, token: CancellationToken, next: ResolveCompletionItemSignature) => ProviderResult<VCompletionItem>;
	provideHover?: (this: void, document: TextDocument, position: VPosition, token: CancellationToken, next: ProvideHoverSignature) => ProviderResult<VHover>;
	provideSignatureHelp?: (this: void, document: TextDocument, position: VPosition, context: VSignatureHelpContext, token: CancellationToken, next: ProvideSignatureHelpSignature) => ProviderResult<VSignatureHelp>;
	provideDefinition?: (this: void, document: TextDocument, position: VPosition, token: CancellationToken, next: ProvideDefinitionSignature) => ProviderResult<VDefinition | VDefinitionLink[]>;
	provideReferences?: (this: void, document: TextDocument, position: VPosition, options: { includeDeclaration: boolean; }, token: CancellationToken, next: ProvideReferencesSignature) => ProviderResult<VLocation[]>;
	provideDocumentHighlights?: (this: void, document: TextDocument, position: VPosition, token: CancellationToken, next: ProvideDocumentHighlightsSignature) => ProviderResult<VDocumentHighlight[]>;
	provideDocumentSymbols?: (this: void, document: TextDocument, token: CancellationToken, next: ProvideDocumentSymbolsSignature) => ProviderResult<VSymbolInformation[] | VDocumentSymbol[]>;
	provideWorkspaceSymbols?: (this: void, query: string, token: CancellationToken, next: ProvideWorkspaceSymbolsSignature) => ProviderResult<VSymbolInformation[]>;
	provideCodeActions?: (this: void, document: TextDocument, range: VRange, context: VCodeActionContext, token: CancellationToken, next: ProvideCodeActionsSignature) => ProviderResult<(VCommand | VCodeAction)[]>;
	provideCodeLenses?: (this: void, document: TextDocument, token: CancellationToken, next: ProvideCodeLensesSignature) => ProviderResult<VCodeLens[]>;
	resolveCodeLens?: (this: void, codeLens: VCodeLens, token: CancellationToken, next: ResolveCodeLensSignature) => ProviderResult<VCodeLens>;
	provideDocumentFormattingEdits?: (this: void, document: TextDocument, options: VFormattingOptions, token: CancellationToken, next: ProvideDocumentFormattingEditsSignature) => ProviderResult<VTextEdit[]>;
	provideDocumentRangeFormattingEdits?: (this: void, document: TextDocument, range: VRange, options: VFormattingOptions, token: CancellationToken, next: ProvideDocumentRangeFormattingEditsSignature) => ProviderResult<VTextEdit[]>;
	provideOnTypeFormattingEdits?: (this: void, document: TextDocument, position: VPosition, ch: string, options: VFormattingOptions, token: CancellationToken, next: ProvideOnTypeFormattingEditsSignature) => ProviderResult<VTextEdit[]>;
	provideRenameEdits?: (this: void, document: TextDocument, position: VPosition, newName: string, token: CancellationToken, next: ProvideRenameEditsSignature) => ProviderResult<VWorkspaceEdit>;
	prepareRename?: (this: void, document: TextDocument, position: VPosition, token: CancellationToken, next: PrepareRenameSignature) => ProviderResult<VRange | { range: VRange, placeholder: string }>;
	provideDocumentLinks?: (this: void, document: TextDocument, token: CancellationToken, next: ProvideDocumentLinksSignature) => ProviderResult<VDocumentLink[]>;
	resolveDocumentLink?: (this: void, link: VDocumentLink, token: CancellationToken, next: ResolveDocumentLinkSignature) => ProviderResult<VDocumentLink>;
	executeCommand?: (this: void, command: string, args: any[], next: ExecuteCommandSignature) => ProviderResult<any>;
	workspace?: WorkspaceMiddleware;
	}
	export type Middleware = _Middleware & TypeDefinitionMiddleware & ImplementationMiddleware & ColorProviderMiddleware &

Background: we want to enhance our integration tests by monitoring the progress reports from the language server, and ensuring the language server's internal state to be ready for probing/testing. If there is other way to achieve this, that's also appreciated.

[dbaeumer]

@hyangah this is currently not possible. Two ideas:

• we allow to access a set handler so that you can chain them
• we add middleware support for this

A PR would be welcome.

[DanTup]

@dbaeumer which option do you prefer, and can you give me some pointers? I'm trying to port some of my tests to LSP, and discovered that I can't get at the progress events (if I use this.client.onProgress, it complains that they're already being handled - I presume by the code that reports the progress to VS Code).

[dbaeumer]

@DanTup thanks for offering help. The right approach is a middle ware handler along the lines of the handleDiagnostics middleware since progress flows from the server to the client as well.

[DanTup]

@dbaeumer does this seem like the right idea?

DanTup@5812e67

I'm not sure how to simulate the progress from the server in the test though - I couldn't find a similar test to copy (I couldn't find any diagnostic one, for example).

[dbaeumer]

Added a comment here: DanTup@5812e67#commitcomment-43610915

[DanTup]

@dbaeumer in case you didn't see it, I responded here with a question or two:

DanTup@5812e67#commitcomment-43611962

[dbaeumer]

Sorry, too many things on my plate. I commented in the PR.

[ericdallo]

@dbaeumer @DanTup I just realized that for some reason handleWorkDoneProgress is not called if server sends a $/progress notification during server intialize request, do you know why?
I tried using client.onProgress(...) as well but I get a error that the client is not ready yet, but AFAIK it's possible to server send $/progress notifications during initialize.

[dbaeumer]

@ericdallo this is currently not possible due to the limitation how the language client handles progress on initialize. You can open a issue to request that support.