feat(net): vim.net.request(outbuf) writes response to buffer #36164

Problem:
Non-trivial to write output of vim.net.request to buffer. Requires extra
code in plugin/net.lua which can't be reused by other plugin authors.

```
vim.net.request('https://neovim.io', {}, function(err, res)
  if not err then
    local buf = vim.api.nvim_create_buf(true, false)
    if res then
      local lines = vim.split(res.body, '\n', { plain = true })
      vim.api.nvim_buf_set_lines(buf, 0, -1, true, lines)
    end
  end
end)
```

Solution:
Accept an optional `outbuf` argument to indicate the buffer to write output
to, similar to `outpath`.

    vim.net.request('https://neovim.io', { outbuf = buf })

Other fixes / followups:
- Make plugin/net.lua smaller
- Return objection with close() method
- vim.net.request.Opts class
- vim.validate single calls
- Use (''):format(...) instead of `..`

runtime/doc/lua.txt

@@ -4149,29 +4149,62 @@ vim.mpack.encode({obj})                                   *vim.mpack.encode()*
 ==============================================================================
 Lua module: vim.net                                                  *vim.net*
 
+*vim.net.request.Response*
+
+    Fields: ~
+      • {body}  (`string`) The HTTP body of the request
+
+
 vim.net.request({url}, {opts}, {on_response})              *vim.net.request()*
     Makes an HTTP GET request to the given URL (asynchronous).
 
-    This function operates in one mode:
-    • Asynchronous (non-blocking): Returns immediately and passes the response
-      object to the provided `on_response` handler on completion.
+    This function is asynchronous (non-blocking), returning immediately and
+    passing the response object to the optional `on_response` handler on
+    completion.
+
+    Examples: >lua
+        -- Write response body to file
+        vim.net.request('https://neovim.io/charter/', {
+          outpath = 'vision.html',
+        })
+
+        -- Process the response
+        vim.net.request(
+          'https://api.github.com/repos/neovim/neovim',
+          {},
+          function (err, res)
+            if err then return end
+            local stars = vim.json.decode(res.body).stargazers_count
+            vim.print(('Neovim currently has %d stars'):format(stars))
+          end
+        )
+
+        -- Write to both file and current buffer, but cancel it
+        local job = vim.net.request('https://neovim.io/charter/', {
+          outpath = 'vision.html',
+          outbuf = 0,
+        })
+        job:close()
+<
 
     Parameters: ~
       • {url}          (`string`) The URL for the request.
-      • {opts}         (`table?`) Optional parameters:
-                       • `verbose` (boolean|nil): Enables verbose output.
-                       • `retry` (integer|nil): Number of retries on transient
+      • {opts}         (`table?`) A table with the following fields:
+                       • {verbose}? (`boolean`) Enables verbose output.
+                       • {retry}? (`integer`) Number of retries on transient
                          failures (default: 3).
-                       • `outpath` (string|nil): File path to save the
-                         response body to. If set, the `body` value in the
-                         Response Object will be `true` instead of the
-                         response body.
-      • {on_response}  (`fun(err?: string, response?: { body: string|boolean })`)
+                       • {outpath}? (`string`) File path to save the response
+                         body to.
+                       • {outbuf}? (`integer`) Buffer to save the response
+                         body to.
+      • {on_response}  (`fun(err: string?, response: vim.net.request.Response?)?`)
                        Callback invoked on request completion. The `body`
-                       field in the response object contains the raw response
-                       data (text or binary). Called with (err, nil) on
-                       failure, or (nil, { body = string|boolean }) on
-                       success.
+                       field in the response parameter contains the raw
+                       response data (text or binary).
+
+    Return: ~
+        (`{ close: fun() }`) Table with method to cancel, similar to
+        |vim.SystemObj|.
 
 
 ==============================================================================

runtime/doc/news.txt

@@ -26,6 +26,11 @@ EXPERIMENTS
 
 • todo
 
+LUA
+
+• |vim.net.request()| does not set the response body to `true` if an output
+  buffer is supplied.
+
 LSP
 
 • |vim.lsp.buf.selection_range()| now accepts an integer which specifies its

runtime/lua/vim/net.lua

@@ -1,23 +1,67 @@
 local M = {}
 
+---@class vim.net.request.Opts
+---@inlinedoc
+---
+---Enables verbose output.
+---@field verbose? boolean
+---
+---Number of retries on transient failures (default: 3).
+---@field retry? integer
+---
+---File path to save the response body to.
+---@field outpath? string
+---
+---Buffer to save the response body to.
+---@field outbuf? integer
+
+---@class vim.net.request.Response
+---
+---The HTTP body of the request
+---@field body string
+
 --- Makes an HTTP GET request to the given URL (asynchronous).
 ---
---- This function operates in one mode:
----   - Asynchronous (non-blocking): Returns immediately and passes the response object to the
----   provided `on_response` handler on completion.
+--- This function is asynchronous (non-blocking), returning immediately and
+--- passing the response object to the optional `on_response` handler on
+--- completion.
+---
+--- Examples:
+--- ```lua
+--- -- Write response body to file
+--- vim.net.request('https://neovim.io/charter/', {
+---   outpath = 'vision.html',
+--- })
+---
+--- -- Process the response
+--- vim.net.request(
+---   'https://api.github.com/repos/neovim/neovim',
+---   {},
+---   function (err, res)
+---     if err then return end
+---     local stars = vim.json.decode(res.body).stargazers_count
+---     vim.print(('Neovim currently has %d stars'):format(stars))
+---   end
+--- )
+---
+--- -- Write to both file and current buffer, but cancel it
+--- local job = vim.net.request('https://neovim.io/charter/', {
+---   outpath = 'vision.html',
+---   outbuf = 0,
+--- })
+--- job:close()
+--- ```
 ---
 --- @param url string The URL for the request.
---- @param opts? table Optional parameters:
----   - `verbose` (boolean|nil): Enables verbose output.
----   - `retry`   (integer|nil): Number of retries on transient failures (default: 3).
----   - `outpath`  (string|nil): File path to save the response body to. If set, the `body` value in the Response Object will be `true` instead of the response body.
---- @param on_response fun(err?: string, response?: { body: string|boolean }) Callback invoked on request
---- completion. The `body` field in the response object contains the raw response data (text or binary).
---- Called with (err, nil) on failure, or (nil, { body = string|boolean }) on success.
+--- @param opts? vim.net.request.Opts
+--- @param on_response? fun(err: string?, response: vim.net.request.Response?)
+--- Callback invoked on request completion. The `body` field in the response
+--- parameter contains the raw response data (text or binary).
+--- @return { close: fun() } # Table with method to cancel, similar to [vim.SystemObj].
 function M.request(url, opts, on_response)
   vim.validate('url', url, 'string')
   vim.validate('opts', opts, 'table', true)
-  vim.validate('on_response', on_response, 'function')
+  vim.validate('on_response', on_response, 'function', true)
 
   opts = opts or {}
   local retry = opts.retry or 3
@@ -37,19 +81,39 @@ function M.request(url, opts, on_response)
 
   table.insert(args, url)
 
-  local function on_exit(res)
-    local s = 'Request failed with exit code %d'
-    local err_msg = res.code ~= 0
-        and ((res.stderr ~= '' and res.stderr) or string.format(s, res.code))
-      or nil
-    local response = res.code == 0 and { body = opts.outpath and true or res.stdout } or nil
+  local job = vim.system(args, {}, function(res)
+    ---@type string?, vim.net.request.Response?
+    local err, response = nil, nil
+    if res.signal ~= 0 then
+      err = ('Request killed with signal %d'):format(res.signal)
+    elseif res.code ~= 0 then
+      err = res.stderr ~= '' and res.stderr or ('Request failed with exit code %d'):format(res.code)
+    else
+      if not (opts.outpath or opts.outbuf) then
+        response = {
+          body = res.stdout --[[@as string]],
+        }
+      end
+    end
+
+    -- nvim_buf_is_loaded and nvim_buf_set_lines are not allowed in fast context
+    vim.schedule(function()
+      if res.code == 0 and opts.outbuf and vim.api.nvim_buf_is_loaded(opts.outbuf) then
+        local lines = vim.split(res.stdout, '\n', { plain = true })
+        vim.api.nvim_buf_set_lines(opts.outbuf, 0, -1, true, lines)
+      end
+    end)
 
     if on_response then
-      on_response(err_msg, response)
+      on_response(err, response)
     end
-  end
+  end)
 
-  vim.system(args, {}, on_exit)
+  return {
+    close = function()
+      job:kill('sigint')
+    end,
+  }
 end
 
 return M

runtime/pack/dist/opt/netrw/plugin/netrwPlugin.vim

@@ -39,7 +39,7 @@ augroup Network
     au!
     au BufReadCmd file://* call netrw#FileUrlEdit(expand("<amatch>"))
     au BufReadCmd ftp://*,rcp://*,scp://*,dav://*,davs://*,rsync://*,sftp://* exe "sil doau BufReadPre ".fnameescape(expand("<amatch>"))|call netrw#Nread(2,expand("<amatch>"))|exe "sil doau BufReadPost ".fnameescape(expand("<amatch>"))
-    au FileReadCmd ftp://*,rcp://*,scp://*,http://*,file://*,https://*,dav://*,davs://*,rsync://*,sftp://* exe "sil doau FileReadPre ".fnameescape(expand("<amatch>"))|call netrw#Nread(1,expand("<amatch>"))|exe "sil doau FileReadPost ".fnameescape(expand("<amatch>"))
+    au FileReadCmd ftp://*,rcp://*,scp://*,file://*,dav://*,davs://*,rsync://*,sftp://* exe "sil doau FileReadPre ".fnameescape(expand("<amatch>"))|call netrw#Nread(1,expand("<amatch>"))|exe "sil doau FileReadPost ".fnameescape(expand("<amatch>"))
     au BufWriteCmd ftp://*,rcp://*,scp://*,http://*,file://*,dav://*,davs://*,rsync://*,sftp://* exe "sil doau BufWritePre ".fnameescape(expand("<amatch>"))|exe 'Nwrite '.fnameescape(expand("<amatch>"))|exe "sil doau BufWritePost ".fnameescape(expand("<amatch>"))
     au FileWriteCmd ftp://*,rcp://*,scp://*,http://*,file://*,dav://*,davs://*,rsync://*,sftp://* exe "sil doau FileWritePre ".fnameescape(expand("<amatch>"))|exe "'[,']".'Nwrite '.fnameescape(expand("<amatch>"))|exe "sil doau FileWritePost ".fnameescape(expand("<amatch>"))
     try

runtime/plugin/net.lua

@@ -1,45 +1,70 @@
-vim.g.loaded_remote_file_loader = true
-
---- Callback for BufReadCmd on remote URLs.
---- @param ev { buf: integer }
-local function on_remote_read(ev)
-  if vim.fn.executable('curl') ~= 1 then
-    vim.api.nvim_echo({
-      { 'Warning: `curl` not found; remote URL loading disabled.', 'WarningMsg' },
-    }, true, {})
-    return true
-  end
-
-  local bufnr = ev.buf
-  local url = vim.api.nvim_buf_get_name(bufnr)
-  local view = vim.fn.winsaveview()
-
-  vim.api.nvim_echo({ { 'Fetching ' .. url .. ' …', 'MoreMsg' } }, true, {})
-
-  vim.net.request(
-    url,
-    { retry = 3 },
-    vim.schedule_wrap(function(err, content)
-      if err then
-        vim.notify('Failed to fetch ' .. url .. ': ' .. tostring(err), vim.log.levels.ERROR)
-        vim.fn.winrestview(view)
-        return
-      end
-
-      local lines = vim.split(content.body, '\n', { plain = true })
-      vim.api.nvim_buf_set_lines(bufnr, 0, -1, true, lines)
-      vim.api.nvim_exec_autocmds('BufRead', { group = 'filetypedetect', buffer = bufnr })
-      vim.bo[bufnr].modified = false
-
-      vim.fn.winrestview(view)
-      vim.api.nvim_echo({ { 'Loaded ' .. url, 'Normal' } }, true, {})
-    end)
-  )
+if vim.g.loaded_nvim_net_plugin ~= nil then
+  return
 end
+vim.g.loaded_nvim_net_plugin = true
+
+local augroup = vim.api.nvim_create_augroup('nvim.net.remotefile', {})
+local url_patterns = { 'http://*', 'https://*' }
 
 vim.api.nvim_create_autocmd('BufReadCmd', {
-  group = vim.api.nvim_create_augroup('nvim.net.remotefile', {}),
-  pattern = { 'http://*', 'https://*' },
+  group = augroup,
+  pattern = url_patterns,
   desc = 'Edit remote files (:edit https://example.com)',
-  callback = on_remote_read,
+  callback = function(ev)
+    if vim.fn.executable('curl') ~= 1 then
+      vim.notify('vim.net.request: curl not found', vim.log.levels.WARN)
+      return
+    end
+
+    local url = ev.file
+    vim.notify(('Fetching %s …'):format(url), vim.log.levels.INFO)
+
+    vim.net.request(
+      url,
+      { outbuf = ev.buf },
+      vim.schedule_wrap(function(err, _)
+        if err then
+          vim.notify(('Failed to fetch %s: %s'):format(url, err), vim.log.levels.ERROR)
+          return
+        end
+
+        vim.api.nvim_exec_autocmds('BufRead', { group = 'filetypedetect', buffer = ev.buf })
+        vim.bo[ev.buf].modified = false
+        vim.notify(('Loaded %s'):format(url), vim.log.levels.INFO)
+      end)
+    )
+  end,
+})
+
+vim.api.nvim_create_autocmd('FileReadCmd', {
+  group = augroup,
+  pattern = url_patterns,
+  desc = 'Read remote files (:read https://example.com)',
+  callback = function(ev)
+    if vim.fn.executable('curl') ~= 1 then
+      vim.notify('vim.net.request: curl not found', vim.log.levels.WARN)
+      return
+    end
+
+    local url = ev.file
+    vim.notify(('Fetching %s …'):format(url), vim.log.levels.INFO)
+
+    vim.net.request(
+      url,
+      {},
+      vim.schedule_wrap(function(err, response)
+        if err or not response then
+          vim.notify(('Failed to fetch %s: %s'):format(url, err), vim.log.levels.ERROR)
+          return
+        end
+
+        -- Start inserting the response at the line number given by read (e.g. :10read).
+        -- FIXME: Doesn't work for :0read as '[ is set to 1. See #7177 for possible solutions.
+        local start = vim.fn.line("'[")
+        local lines = vim.split(response.body or '', '\n', { plain = true })
+        vim.api.nvim_buf_set_lines(ev.buf, start, start, true, lines)
+        vim.notify(('Loaded %s'):format(url), vim.log.levels.INFO)
+      end)
+    )
+  end,
 })

test/functional/lua/net_spec.lua

@@ -21,9 +21,8 @@ describe('vim.net.request', function()
     local content = exec_lua([[
       local done = false
       local result
-      local M = require('vim.net')
 
-      M.request("https://httpbingo.org/anything", { retry = 3 }, function(err, body)
+      vim.net.request("https://httpbingo.org/anything", { retry = 3 }, function(err, body)
         assert(not err, err)
         result = body.body
         done = true
@@ -63,9 +62,8 @@ describe('vim.net.request', function()
     local err = exec_lua([[
       local done = false
       local result
-      local M = require('vim.net')
 
-      M.request("https://httpbingo.org/status/404", {}, function(e, _)
+      vim.net.request("https://httpbingo.org/status/404", {}, function(e, _)
         result = e
         done = true
       end)
@@ -76,4 +74,43 @@ describe('vim.net.request', function()
 
     assert_404_error(err)
   end)
+
+  it('plugin writes output to buffer', function()
+    t.skip(skip_integ, 'NVIM_TEST_INTEG not set: skipping network integration test')
+    local content = exec_lua([[
+      local lines
+
+      local buf = vim.api.nvim_create_buf(false, true)
+      vim.net.request("https://httpbingo.org", { outbuf = buf })
+
+      vim.wait(2000, function()
+        lines = vim.api.nvim_buf_get_lines(buf, 0, -1, false)
+        return lines[1] ~= ""
+      end)
+
+      return lines
+    ]])
+    assert(content and content[1]:find('html'))
+  end)
+
+  it('works with :read', function()
+    t.skip(skip_integ, 'NVIM_TEST_INTEG not set: skipping network integration test')
+    local content = exec_lua([[
+      vim.cmd('runtime plugin/net.lua')
+      local lines
+
+      vim.api.nvim_buf_set_lines(0, 0, -1, false, { 'Here is some text' })
+      vim.cmd(':read https://example.com')
+
+      vim.wait(2000, function()
+        lines = vim.api.nvim_buf_get_lines(0, 0, -1, false)
+        return #lines > 1
+      end)
+
+      return lines
+    ]])
+    t.eq(true, content ~= nil)
+    t.eq(true, content[1]:find('Here') ~= nil)
+    t.eq(true, content[2]:find('html') ~= nil)
+  end)
 end)