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-- 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 format("%2.0f%s", s, l)
else return 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 format("%7.2f%2s", b, l)
end
-- returns a string with the current state of the download
function gauge(got, dt, size)
local rate = got / dt
if size and size >= 1 then
return format("%s received, %s/s throughput, " ..
"%.0f%% done, %s remaining",
nicesize(got),
nicesize(rate),
100*got/size,
nicetime((size-got)/rate))
else
return format("%s received, %s/s throughput, %s elapsed",
nicesize(got),
nicesize(rate),
nicetime(dt))
end
end
-- creates a new instance of a receive_cb that saves to disk
-- kind of copied from luasocket's manual callback examples
function receive2disk(file, size)
local aux = {
start = _time(),
got = 0,
file = openfile(file, "wb"),
size = size
}
local receive_cb = function(chunk, err)
local dt = _time() - %aux.start -- elapsed time since start
if not chunk or chunk == "" then
write("\n")
closefile(%aux.file)
return
end
write(%aux.file, chunk)
%aux.got = %aux.got + strlen(chunk) -- total bytes received
if dt < 0.1 then return 1 end -- not enough time for estimate
write("\r", gauge(%aux.got, dt, %aux.size))
return 1
end
return receive_cb
end
-- downloads a file using the ftp protocol
function getbyftp(url, file)
local err = FTP.get_cb {
url = url,
content_cb = receive2disk(file),
type = "i"
}
print()
if err then print(err) end
end
-- downloads a file using the http protocol
function getbyhttp(url, file, size)
local response = HTTP.request_cb(
{url = url},
{body_cb = receive2disk(file, size)}
)
print()
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 = HTTP.request {
method = "HEAD",
url = url
}
if response.code == 200 then
return tonumber(response.headers["content-length"])
end
end
-- determines the scheme and the file name of a given url
function getschemeandname(url, name)
-- this is an heuristic to solve a common invalid url poblem
if not strfind(url, "//") then url = "//" .. url end
local parsed = URL.parse_url(url, {scheme = "http"})
if name then return parsed.scheme, name end
local segment = URL.parse_path(parsed.path)
name = segment[getn(segment)]
if segment.is_directory then name = nil end
return parsed.scheme, name
end
-- gets a file either by http or url, saving as name
function get(url, name)
local scheme
scheme, name = getschemeandname(url, name)
if not name then print("unknown file name")
elseif scheme == "ftp" then getbyftp(url, name)
elseif scheme == "http" then getbyhttp(url, name, gethttpsize(url))
else print("unknown scheme" .. scheme) end
end
-- main program
arg = arg or {}
if getn(arg) < 1 then
write("Usage:\n luasocket -f get.lua <remote-url> [<local-file>]\n")
exit(1)
else get(arg[1], arg[2]) end
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