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LuaSocket 2.0.2 + CMake build description.
author Eric Wing <ewing . public |-at-| gmail . com>
date Tue, 26 Aug 2008 18:40:01 -0700
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-1:000000000000 0:4b915342e2a8
1 -----------------------------------------------------------------------------
2 -- Little program to download files from URLs
3 -- LuaSocket sample files
4 -- Author: Diego Nehab
5 -- RCS ID: $Id: get.lua,v 1.25 2007/03/12 04:08:40 diego Exp $
6 -----------------------------------------------------------------------------
7 local socket = require("socket")
8 local http = require("socket.http")
9 local ftp = require("socket.ftp")
10 local url = require("socket.url")
11 local ltn12 = require("ltn12")
12
13 -- formats a number of seconds into human readable form
14 function nicetime(s)
15 local l = "s"
16 if s > 60 then
17 s = s / 60
18 l = "m"
19 if s > 60 then
20 s = s / 60
21 l = "h"
22 if s > 24 then
23 s = s / 24
24 l = "d" -- hmmm
25 end
26 end
27 end
28 if l == "s" then return string.format("%5.0f%s", s, l)
29 else return string.format("%5.2f%s", s, l) end
30 end
31
32 -- formats a number of bytes into human readable form
33 function nicesize(b)
34 local l = "B"
35 if b > 1024 then
36 b = b / 1024
37 l = "KB"
38 if b > 1024 then
39 b = b / 1024
40 l = "MB"
41 if b > 1024 then
42 b = b / 1024
43 l = "GB" -- hmmm
44 end
45 end
46 end
47 return string.format("%7.2f%2s", b, l)
48 end
49
50 -- returns a string with the current state of the download
51 local remaining_s = "%s received, %s/s throughput, %2.0f%% done, %s remaining"
52 local elapsed_s = "%s received, %s/s throughput, %s elapsed "
53 function gauge(got, delta, size)
54 local rate = got / delta
55 if size and size >= 1 then
56 return string.format(remaining_s, nicesize(got), nicesize(rate),
57 100*got/size, nicetime((size-got)/rate))
58 else
59 return string.format(elapsed_s, nicesize(got),
60 nicesize(rate), nicetime(delta))
61 end
62 end
63
64 -- creates a new instance of a receive_cb that saves to disk
65 -- kind of copied from luasocket's manual callback examples
66 function stats(size)
67 local start = socket.gettime()
68 local last = start
69 local got = 0
70 return function(chunk)
71 -- elapsed time since start
72 local current = socket.gettime()
73 if chunk then
74 -- total bytes received
75 got = got + string.len(chunk)
76 -- not enough time for estimate
77 if current - last > 1 then
78 io.stderr:write("\r", gauge(got, current - start, size))
79 io.stderr:flush()
80 last = current
81 end
82 else
83 -- close up
84 io.stderr:write("\r", gauge(got, current - start), "\n")
85 end
86 return chunk
87 end
88 end
89
90 -- determines the size of a http file
91 function gethttpsize(u)
92 local r, c, h = http.request {method = "HEAD", url = u}
93 if c == 200 then
94 return tonumber(h["content-length"])
95 end
96 end
97
98 -- downloads a file using the http protocol
99 function getbyhttp(u, file)
100 local save = ltn12.sink.file(file or io.stdout)
101 -- only print feedback if output is not stdout
102 if file then save = ltn12.sink.chain(stats(gethttpsize(u)), save) end
103 local r, c, h, s = http.request {url = u, sink = save }
104 if c ~= 200 then io.stderr:write(s or c, "\n") end
105 end
106
107 -- downloads a file using the ftp protocol
108 function getbyftp(u, file)
109 local save = ltn12.sink.file(file or io.stdout)
110 -- only print feedback if output is not stdout
111 -- and we don't know how big the file is
112 if file then save = ltn12.sink.chain(stats(), save) end
113 local gett = url.parse(u)
114 gett.sink = save
115 gett.type = "i"
116 local ret, err = ftp.get(gett)
117 if err then print(err) end
118 end
119
120 -- determines the scheme
121 function getscheme(u)
122 -- this is an heuristic to solve a common invalid url poblem
123 if not string.find(u, "//") then u = "//" .. u end
124 local parsed = url.parse(u, {scheme = "http"})
125 return parsed.scheme
126 end
127
128 -- gets a file either by http or ftp, saving as <name>
129 function get(u, name)
130 local fout = name and io.open(name, "wb")
131 local scheme = getscheme(u)
132 if scheme == "ftp" then getbyftp(u, fout)
133 elseif scheme == "http" then getbyhttp(u, fout)
134 else print("unknown scheme" .. scheme) end
135 end
136
137 -- main program
138 arg = arg or {}
139 if table.getn(arg) < 1 then
140 io.write("Usage:\n lua get.lua <remote-url> [<local-file>]\n")
141 os.exit(1)
142 else get(arg[1], arg[2]) end