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-----------------------------------------------------------------------------
-- Little program to download files from URLs
-- LuaSocket sample files
-- Author: Diego Nehab
-- RCS ID: $Id$
-----------------------------------------------------------------------------
-- formats a number of seconds into human readable form
function nicetime(s)
local l = "s"
if s > 60 then
s = s / 60
l = "m"
if s > 60 then
s = s / 60
l = "h"
if s > 24 then
s = s / 24
l = "d" -- hmmm
end
end
end
if l == "s" then return string.format("%2.0f%s", s, l)
else return string.format("%5.2f%s", s, l) end
end
-- formats a number of bytes into human readable form
function nicesize(b)
local l = "B"
if b > 1024 then
b = b / 1024
l = "KB"
if b > 1024 then
b = b / 1024
l = "MB"
if b > 1024 then
b = b / 1024
l = "GB" -- hmmm
end
end
end
return string.format("%7.2f%2s", b, l)
end
-- returns a string with the current state of the download
function gauge(got, delta, size)
local rate = got / delta
if size and size >= 1 then
return string.format("%s received, %s/s throughput, " ..
"%.0f%% done, %s remaining",
nicesize(got),
nicesize(rate),
100*got/size,
nicetime((size-got)/rate))
else
return string.format("%s received, %s/s throughput, %s elapsed",
nicesize(got),
nicesize(rate),
nicetime(delta))
end
end
-- creates a new instance of a receive_cb that saves to disk
-- kind of copied from luasocket's manual callback examples
function stats(size)
local start = socket.time()
local got = 0
return function(chunk)
-- elapsed time since start
local delta = socket.time() - start
if chunk then
-- total bytes received
got = got + string.len(chunk)
-- not enough time for estimate
if delta > 0.1 then
io.stderr:write("\r", gauge(got, delta, size))
io.stderr:flush()
end
return chunk
else
-- close up
io.stderr:write("\n")
return ""
end
end
end
-- downloads a file using the ftp protocol
function getbyftp(url, file)
local save = socket.callback.receive.file(file or io.stdout)
if file then
save = socket.callback.receive.chain(stats(gethttpsize(url)), save)
end
local err = socket.ftp.get_cb {
url = url,
content_cb = save,
type = "i"
}
if err then print(err) end
end
-- downloads a file using the http protocol
function getbyhttp(url, file)
local save = socket.callback.receive.file(file or io.stdout)
if file then
save = socket.callback.receive.chain(stats(gethttpsize(url)), save)
end
local response = socket.http.request_cb({url = url}, {body_cb = save})
if response.code ~= 200 then print(response.status or response.error) end
end
-- determines the size of a http file
function gethttpsize(url)
local response = socket.http.request {
method = "HEAD",
url = url
}
if response.code == 200 then
return tonumber(response.headers["content-length"])
end
end
-- determines the scheme
function getscheme(url)
-- this is an heuristic to solve a common invalid url poblem
if not string.find(url, "//") then url = "//" .. url end
local parsed = socket.url.parse(url, {scheme = "http"})
return parsed.scheme
end
-- gets a file either by http or ftp, saving as <name>
function get(url, name)
local fout = name and io.open(name, "wb")
local scheme = getscheme(url)
if scheme == "ftp" then getbyftp(url, fout)
elseif scheme == "http" then getbyhttp(url, fout)
else print("unknown scheme" .. scheme) end
if name then fout:close() end
end
-- main program
arg = arg or {}
if table.getn(arg) < 1 then
io.write("Usage:\n luasocket get.lua <remote-url> [<local-file>]\n")
os.exit(1)
else get(arg[1], arg[2]) end
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