Language servers

Contents

• Supported features
• Register custom language servers

Supported features

Check out the official specification at https://microsoft.github.io/language-server-protocol/specification.

• General

  • initialize
  • initalized
  • shutdown
  • exit
  • $/cancelRequest

• Window

  • showMessage
  • showMessageRequest
  • logMessage

• Telemetry

  • event (just log the event)

• Client

  • registerCapability
  • unregisterCapability

• Workspace

  • workspaceFolders
  • didChangeWorkspaceFolders
  • didChangeConfiguration
  • configuration
  • didChangeWatchedFiles
  • symbol
  • executeCommand
  • applyEdit
  • resource operations

• Text Synchronization

  • didOpen
  • didChange
  • willSave
  • willSaveWaitUntil
  • didSave
  • didClose

• Diagnostics

  • publishDiagnostics

• Language Features

  • completion
  • completion resolve
  • hover
  • signatureHelp
  • definition
  • typeDefinition
  • implementation
  • references
  • documentHighlight
  • documentSymbol
  • codeAction
  • codeLens
  • codeLens resolve
  • documentLink
  • documentLink resolve
  • documentColor
  • colorPresentation
  • formatting
  • rangeFormatting
  • onTypeFormatting
  • prepare rename
  • rename
  • foldingRange

Note: different server could have different capabilities.

Register custom language servers

User defined language servers are configured in languageserver field of configuration file.

There're three types of language servers: module,executable and socket.

• module type language server are running by nodejs and using node IPC for connection.
• executable type language server are spawned with executable command while using stdio for connection.
• socket language server are started in separated process, normally used for debugging purpose.

Different language server type have different configuration schema.

An example of module language server:

  "languageserver": {
    "foo": {
      "module": "/usr/local/lib/node_modules/foo/index.js",
      "args": ["--node-ipc"],
      "filetypes": ["foo"],
      "trace.server": "verbose",
      "rootPatterns": ["root.yml"],
      // Used for debugging
      "execArgv": ["--nolazy", "--inspect-brk=6045"],
      "initializationOptions": {
      },
      "settings": {
        "validate": true
      }
    }
  }

module and filetypes are required for module language server.

An example of executable language server:

  "languageserver": {
    "bar": {
      "command": "bar",
      "args": ["--stdio"],
      "filetypes": ["bar"],
      "cwd": "./src",
      "initializationOptions": {
      },
      "settings": {
      }
    }
  }

command and filetypes are required for executable language server.

An example of socket language server:

"languageserver": {
    "socketserver": {
      "host": "127.0.0.1",
      "port": 9527
    }
  }

port is required for socket service and user should start the socket server before coc started.

• initializationOptions is the json object that passed to language server on initialize.
• settings contains specific configuration of language server.
• trace.server controls trace level of communication between server and client, default "off", change to "verbose" if you want to checkout all communication.
• rootPatterns is used for resolve root path which should contain one of patterns as child directory or file, it will use g:rooter_patterns (default to ['.vim/', '.git/', '.hg/', '.projections.json']) when not specified,

Example configuration for custom language servers

Add languageserver section in your coc-settings.json for regist custom language servers.

Dart

Using natebosch/dart_language_server:

  "languageserver": {
    "dart": {
      "command": "dart_language_server",
      "args": [],
      "filetypes": ["dart"],
      "initializationOptions": {},
      "settings": {
        "dart": {
          "validation": {},
          "completion": {}
        }
      }
    }
  }

C/C++/Objective-C

Using ccls

  "ccls": {
    "command": "ccls",
    "filetypes": ["c", "cpp", "objc", "objcpp"],
    "rootPatterns": [".ccls", "compile_commands.json", ".vim/", ".git/", ".hg/"],
    "initializationOptions": {
      "cacheDirectory": "/tmp/ccls"
    }
  }

Using cquery

  "languageserver": {
    "cquery": {
      "command": "cquery",
      "args": ["--log-file=/tmp/cq.log"],
      "filetypes": ["c", "cpp"],
      "rootPatterns": ["compile_flags.txt", "compile_commands.json", ".vim/", ".git/", ".hg/"]，
      "initializationOptions": {
        "cacheDirectory": "/tmp/cquery"
      }
    }
  }

Using clangd

  "languageserver": {
    "clangd": {
      "command": "clangd",
      "rootPatterns": ["compile_flags.txt", "compile_commands.json", ".vim/", ".git/", ".hg/"],
      "filetypes": ["c", "cpp", "objc", "objcpp"]
    }
  }

Like many tools, clangd relies on the presence of a JSON compilation database

Go

Using saibing/bingo

  "languageserver": {
    "golang": {
      "command": "bingo",
      "rootPatterns": ["go.mod", ".vim/", ".git/", ".hg/"],
      "filetypes": ["go"]
    }
  }

Using sourcegraph/go-langserver

  "languageserver": {
    "golang": {
      "command": "go-langserver",
      "filetypes": ["go"],
      "initializationOptions": {
        "gocodeCompletionEnabled": true,
        "diagnosticsEnabled": true,
        "lintTool": "golint"
      }
    }
  }

PHP

Using felixfbecker/php-language-server

  "languageserver": {
    "phplang": {
      "command": "php",
      "args": ["vendor/felixfbecker/language-server/bin/php-language-server.php"],
      "filetypes": ["php"]
    }
  }

Dockerfile

Using rcjsuen/dockerfile-language-server-nodejs

  "languageserver": {
    "dockerfile": {
      "command": "docker-langserver",
      "filetypes": ["dockerfile"],
      "args": ["--stdio"]
    }
  }

Bash

Using mads-hartmann/bash-language-server

  "languageserver": {
    "bash": {
      "command": "bash-language-server",
      "args": ["start"],
      "filetypes": ["sh"],
      "ignoredRootPaths": ["~"]
    }
  }

Lua

Using Alloyed/lua-lsp

  "languageserver": {
    "lua": {
      "command": "lua-lsp",
      "filetypes": ["lua"]
    }
  }

OCaml and ReasonML

Using ocaml-language-server

  "languageserver": {
     "ocaml": {
       "command": "ocaml-language-server",
       "args": ["--stdio"],
       "filetypes": ["ocaml", "reason"]
     }
  }

Using reason-language-server

  "languageserver": {
     "reason": {
      "command": "/absolute/path/to/reason-language-server.exe",
      "filetypes": ["reason"]
     }
  }

Flow

Using flow-language-server

  // disable tsserver for javascript
  "tsserver.enableJavascript": true,
  "languageserver": {
    "flow": {
      "command": "flow-language-server",
      "args": ["--stdio"],
      "filetypes": ["javascript", "javascriptreact"],
      "rootPatterns": [".flowconfig"]
    },
  }