Custom Vim function to open hyperlinks

.vimrc

" Easily open hyperlinks in any Vim buffer:
" Place cursor before or at the beginning of a URL that
" begins with http: or https: and press <leader>o

let s:http_link_pattern = 'https\?:[^ >)\]]\+'
let g:browser_command = 'open '
func! s:find_href()
  let res = search(s:http_link_pattern, 'cw')
  if res != 0
    let href = matchstr(expand("<cWORD>") , s:http_link_pattern)
    return href
  end
endfunc
func! s:open_href_under_cursor()
  let command = g:browser_command . " '" . shellescape(s:find_href()) . "' "
  call system(command)
endfunc
nnoremap <leader>o :call <SID>open_href_under_cursor()<CR>