feat: add verbose command to preview cURL requests

Author: NTBBloodbath

doc/rest-nvim.txt

@@ -87,7 +87,12 @@ Notes:
 ===============================================================================
 COMMANDS                                             *rest-nvim-usage-commands*
 
-| `<Plug>RestNvim` | Run `rest.nvim` in the current cursor position.
+- `<Plug>RestNvim`
+  Run `rest.nvim` in the current cursor position.
+
+- `<Plug>RestNvimPreview`
+  Same as `RestNvim` but it returns the cURL command without executing the
+  request. Intended for debugging purposes.
 
 
 ===============================================================================

lua/rest-nvim/init.lua

@@ -232,6 +232,15 @@ end
 -- @param opts curl arguments
 local function curl_cmd(opts)
 	local res = curl[opts.method](opts)
+	if opts.dry_run then
+		print(
+			'[rest.nvim] Request preview:\n'
+				.. 'curl '
+				.. table.concat(res, ' ')
+		)
+		return
+	end
+
 	local res_bufnr = get_or_create_buf()
 	local parsed_url = parse_url(fn.getline('.'))
 	local json_body = false
@@ -301,7 +310,7 @@ end
 
 -- run will retrieve the required request information from the current buffer
 -- and then execute curl
-local function run()
+local function run(verbose)
 	local bufnr = api.nvim_win_get_buf(0)
 	local parsed_url = parse_url(fn.getline('.'))
 	local last_query_line_number = fn.line('.')
@@ -331,18 +340,20 @@ local function run()
 	local auth = get_auth(bufnr, last_query_line_number)
 	local accept = get_accept(bufnr, last_query_line_number)
 
-	local success_req = pcall(curl_cmd, {
+	local success_req, req_err = pcall(curl_cmd, {
 		method = parsed_url.method:lower(),
 		url = parsed_url.url,
 		headers = headers,
 		accept = accept,
 		body = body,
 		auth = auth,
+		dry_run = verbose and verbose or false,
 	})
 
 	if not success_req then
 		error(
-			'[rest.nvim] Failed to perform the request.\nMake sure that you have entered the proper URL and the server is running.',
+			'[rest.nvim] Failed to perform the request.\nMake sure that you have entered the proper URL and the server is running.\n\nTraceback: '
+				.. req_err,
 			2
 		)
 	end

plugin/rest-nvim.vim

@@ -6,6 +6,7 @@ endif
 if exists('g:loaded_rest_nvim') | finish | endif
 
 nnoremap <Plug>RestNvim :lua require('rest-nvim').run()<CR>
+nnoremap <Plug>RestNvimPreview :lua require('rest-nvim').run(true)<CR>
 
 let s:save_cpo = &cpo
 set cpo&vim