Hooking up our LSP to Neovim

Its time to talk to hook up our editor! For this rather than use something like lsp-config, I’m just going to call vim.lsp.start_client directly.

vim.api.nvim_create_autocmd("FileType", {
  pattern = "markdown",
  callback = function()
    local bufnr = vim.api.nvim_get_current_buf()

    -- Check if the LSP client is already attached to the buffer
    if vim.b[bufnr].markdown_lsp_attached then
      return
    end

    -- Start the LSP client
    local client_id = vim.lsp.start({
      name = "markdown-awesome-server",
      cmd = { "/Users/michaelduren/Code/learning/go-meetups/demo-proj/demo_lsp" },
    })

    -- Mark the buffer as having the LSP client attached
    if client_id then
      vim.b[bufnr].markdown_lsp_attached = true
    end
  end,
})

We can give it any name we like, we just need to assign the absolute path of where our binary is located, and we can start the server. Typically we would have a /bin/ folder nested perhaps somewhere in our home directory where we would store our binaries, but for development it’s nice to have it in the project directory.

Note

Although this neovim configuration will work for development, it will create a new server instance for every markdown file we open. This is because we are starting the server on the FileType event, which is triggered everytime we open a new file. Once we would finish our plugin we would want to configure it for actual use.

Startup

Next, simply exit vim.

Create a markdown file (I have neovim aliased to vim)

touch test.md && vim test.md

You can add some contents if you would like, but that’s it lets go check our logs in our project!

About four lines in after “initialize” we should see a huge json blob. In here we have a lot of information about the capabilities of our server, and the client. Towards the bottom we have information about our client specifically we should see our old friend neovim!

    "clientInfo": {
      "version": "0.10.0-dev",
      "name": "Neovim"
    },

🎉 Congratulations! You have successfully hooked up your LSP server to your editor! Moving forward everytime we open a markdown file with our editor, our LSP server will start up and we can start sending requests to it!