source/texk/web2c/luatexdir/luasocket/etc/get.lua

   1 -----------------------------------------------------------------------------
   2 -- Little program to download files from URLs
   3 -- LuaSocket sample files
   4 -- Author: Diego Nehab
   5 -----------------------------------------------------------------------------
   6 local socket = require("socket")
   7 local http = require("socket.http")
   8 local ftp = require("socket.ftp")
   9 local url = require("socket.url")
  10 local ltn12 = require("ltn12")
  11
  12 -- formats a number of seconds into human readable form
  13 function nicetime(s)
  14     local l = "s"
  15     if s > 60 then
  16         s = s / 60
  17         l = "m"
  18         if s > 60 then
  19             s = s / 60
  20             l = "h"
  21             if s > 24 then
  22                 s = s / 24
  23                 l = "d" -- hmmm
  24             end
  25         end
  26     end
  27     if l == "s" then return string.format("%5.0f%s", s, l)
  28     else return string.format("%5.2f%s", s, l) end
  29 end
  30
  31 -- formats a number of bytes into human readable form
  32 function nicesize(b)
  33     local l = "B"
  34     if b > 1024 then
  35         b = b / 1024
  36         l = "KB"
  37         if b > 1024 then
  38             b = b / 1024
  39             l = "MB"
  40             if b > 1024 then
  41                 b = b / 1024
  42                 l = "GB" -- hmmm
  43             end
  44         end
  45     end
  46     return string.format("%7.2f%2s", b, l)
  47 end
  48
  49 -- returns a string with the current state of the download
  50 local remaining_s = "%s received, %s/s throughput, %2.0f%% done, %s remaining"
  51 local elapsed_s =   "%s received, %s/s throughput, %s elapsed                "
  52 function gauge(got, delta, size)
  53     local rate = got / delta
  54     if size and size >= 1 then
  55         return string.format(remaining_s, nicesize(got),  nicesize(rate),
  56             100*got/size, nicetime((size-got)/rate))
  57     else
  58         return string.format(elapsed_s, nicesize(got),
  59             nicesize(rate), nicetime(delta))
  60     end
  61 end
  62
  63 -- creates a new instance of a receive_cb that saves to disk
  64 -- kind of copied from luasocket's manual callback examples
  65 function stats(size)
  66     local start = socket.gettime()
  67     local last = start
  68     local got = 0
  69     return function(chunk)
  70         -- elapsed time since start
  71         local current = socket.gettime()
  72         if chunk then
  73             -- total bytes received
  74             got = got + string.len(chunk)
  75             -- not enough time for estimate
  76             if current - last > 1 then
  77                 io.stderr:write("\r", gauge(got, current - start, size))
  78                 io.stderr:flush()
  79                 last = current
  80             end
  81         else
  82             -- close up
  83             io.stderr:write("\r", gauge(got, current - start), "\n")
  84         end
  85         return chunk
  86     end
  87 end
  88
  89 -- determines the size of a http file
  90 function gethttpsize(u)
  91     local r, c, h = http.request {method = "HEAD", url = u}
  92     if c == 200 then
  93         return tonumber(h["content-length"])
  94     end
  95 end
  96
  97 -- downloads a file using the http protocol
  98 function getbyhttp(u, file)
  99     local save = ltn12.sink.file(file or io.stdout)
 100     -- only print feedback if output is not stdout
 101     if file then save = ltn12.sink.chain(stats(gethttpsize(u)), save) end
 102     local r, c, h, s = http.request {url = u, sink = save }
 103     if c ~= 200 then io.stderr:write(s or c, "\n") end
 104 end
 105
 106 -- downloads a file using the ftp protocol
 107 function getbyftp(u, file)
 108     local save = ltn12.sink.file(file or io.stdout)
 109     -- only print feedback if output is not stdout
 110     -- and we don't know how big the file is
 111     if file then save = ltn12.sink.chain(stats(), save) end
 112     local gett = url.parse(u)
 113     gett.sink = save
 114     gett.type = "i"
 115     local ret, err = ftp.get(gett)
 116     if err then print(err) end
 117 end
 118
 119 -- determines the scheme
 120 function getscheme(u)
 121     -- this is an heuristic to solve a common invalid url poblem
 122     if not string.find(u, "//") then u = "//" .. u end
 123     local parsed = url.parse(u, {scheme = "http"})
 124     return parsed.scheme
 125 end
 126
 127 -- gets a file either by http or ftp, saving as <name>
 128 function get(u, name)
 129     local fout = name and io.open(name, "wb")
 130     local scheme = getscheme(u)
 131     if scheme == "ftp" then getbyftp(u, fout)
 132     elseif scheme == "http" then getbyhttp(u, fout)
 133     else print("unknown scheme" .. scheme) end
 134 end
 135
 136 -- main program
 137 arg = arg or {}
 138 if table.getn(arg) < 1 then
 139     io.write("Usage:\n  lua get.lua <remote-url> [<local-file>]\n")
 140     os.exit(1)
 141 else get(arg[1], arg[2]) end