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1-----------------------------------------------------------------------------
2-- Simple FTP support for the Lua language using the LuaSocket toolkit.
3-- Author: Diego Nehab
4-- Date: 26/12/2000
5-- Conforming to: RFC 959
6-----------------------------------------------------------------------------
7
8-----------------------------------------------------------------------------
9-- Program constants
10-----------------------------------------------------------------------------
11-- timeout in seconds before the program gives up on a connection
12local TIMEOUT = 60
13-- default port for ftp service
14local PORT = 21
15-- this is the default anonymous password. used when no password is
16-- provided in url. should be changed for your e-mail.
17local EMAIL = "anonymous@anonymous.org"
18
19-----------------------------------------------------------------------------
20-- Parses a url and returns its scheme, user, password, host, port
21-- and path components, according to RFC 1738, Uniform Resource Locators (URL),
22-- of December 1994
23-- Input
24-- url: unique resource locator desired
25-- default: table containing default values to be returned
26-- Returns
27-- table with the following fields:
28-- host: host to connect
29-- path: url path
30-- port: host port to connect
31-- user: user name
32-- pass: password
33-- scheme: protocol
34-----------------------------------------------------------------------------
35local split_url = function(url, default)
36 -- initialize default parameters
37 local parsed = default or {}
38 -- get scheme
39 url = gsub(url, "^(.+)://", function (s) %parsed.scheme = s end)
40 -- get user name and password. both can be empty!
41 -- moreover, password can be ommited
42 url = gsub(url, "^([^@:/]*)(:?)([^:@/]-)@", function (u, c, p)
43 %parsed.user = u
44 -- there can be an empty password, but the ':' has to be there
45 -- or else there is no password
46 %parsed.pass = nil -- kill default password
47 if c == ":" then %parsed.pass = p end
48 end)
49 -- get host
50 url = gsub(url, "^([%w%.%-]+)", function (h) %parsed.host = h end)
51 -- get port if any
52 url = gsub(url, "^:(%d+)", function (p) %parsed.port = p end)
53 -- whatever is left is the path
54 if url ~= "" then parsed.path = url end
55 return parsed
56end
57
58-----------------------------------------------------------------------------
59-- Gets ip and port for data connection from PASV answer
60-- Input
61-- pasv: PASV command answer
62-- Returns
63-- ip: string containing ip for data connection
64-- port: port for data connection
65-----------------------------------------------------------------------------
66local get_pasv = function(pasv)
67 local a,b,c,d,p1,p2
68 local ip, port
69 _,_, a, b, c, d, p1, p2 =
70 strfind(pasv, "(%d*),(%d*),(%d*),(%d*),(%d*),(%d*)")
71 if not a or not b or not c or not d or not p1 or not p2 then
72 return nil, nil
73 end
74 ip = format("%d.%d.%d.%d", a, b, c, d)
75 port = tonumber(p1)*256 + tonumber(p2)
76 return ip, port
77end
78
79-----------------------------------------------------------------------------
80-- Sends a FTP command through socket
81-- Input
82-- control: control connection socket
83-- cmd: command
84-- arg: command argument if any
85-----------------------------------------------------------------------------
86local send_command = function(control, cmd, arg)
87 local line, err
88 if arg then line = cmd .. " " .. arg .. "\r\n"
89 else line = cmd .. "\r\n" end
90 err = control:send(line)
91 return err
92end
93
94-----------------------------------------------------------------------------
95-- Gets FTP command answer, unfolding if neccessary
96-- Input
97-- control: control connection socket
98-- Returns
99-- answer: whole server reply, nil if error
100-- code: answer status code or error message
101-----------------------------------------------------------------------------
102local get_answer = function(control)
103 local code, lastcode, sep
104 local line, err = control:receive()
105 local answer = line
106 if err then return nil, err end
107 _,_, code, sep = strfind(line, "^(%d%d%d)(.)")
108 if not code or not sep then return nil, answer end
109 if sep == "-" then -- answer is multiline
110 repeat
111 line, err = control:receive()
112 if err then return nil, err end
113 _,_, lastcode, sep = strfind(line, "^(%d%d%d)(.)")
114 answer = answer .. "\n" .. line
115 until code == lastcode and sep == " " -- answer ends with same code
116 end
117 return answer, tonumber(code)
118end
119
120-----------------------------------------------------------------------------
121-- Checks if a message return is correct. Closes control connection if not.
122-- Input
123-- control: control connection socket
124-- success: table with successfull reply status code
125-- Returns
126-- code: reply code or nil in case of error
127-- answer: server complete answer or system error message
128-----------------------------------------------------------------------------
129local check_answer = function(control, success)
130 local answer, code = %get_answer(control)
131 if not answer then
132 control:close()
133 return nil, code
134 end
135 if type(success) ~= "table" then success = {success} end
136 for i = 1, getn(success) do
137 if code == success[i] then
138 return code, answer
139 end
140 end
141 control:close()
142 return nil, answer
143end
144
145-----------------------------------------------------------------------------
146-- Trys a command on control socked, in case of error, the control connection
147-- is closed.
148-- Input
149-- control: control connection socket
150-- cmd: command
151-- arg: command argument or nil if no argument
152-- success: table with successfull reply status code
153-- Returns
154-- code: reply code or nil in case of error
155-- answer: server complete answer or system error message
156-----------------------------------------------------------------------------
157local try_command = function(control, cmd, arg, success)
158 local err = %send_command(control, cmd, arg)
159 if err then
160 control:close()
161 return nil, err
162 end
163 local code, answer = %check_answer(control, success)
164 if not code then return nil, answer end
165 return code, answer
166end
167
168-----------------------------------------------------------------------------
169-- Creates a table with all directories in path
170-- Input
171-- file: abolute path to file
172-- Returns
173-- file: filename
174-- path: table with directories to reach filename
175-- isdir: is it a directory or a file
176-----------------------------------------------------------------------------
177local split_path = function(file)
178 local path = {}
179 local isdir
180 file = file or "/"
181 -- directory ends with a '/'
182 _,_, isdir = strfind(file, "([/])$")
183 gsub(file, "([^/]+)", function (dir) tinsert(%path, dir) end)
184 if not isdir then file = tremove(path)
185 else file = nil end
186 return file, path, isdir
187end
188
189-----------------------------------------------------------------------------
190-- Check server greeting
191-- Input
192-- control: control connection with server
193-- Returns
194-- code: nil if error
195-- answer: server answer or error message
196-----------------------------------------------------------------------------
197local check_greeting = function(control)
198 local code, answer = %check_answer(control, {120, 220})
199 if not code then return nil, answer end
200 if code == 120 then -- please try again, somewhat busy now...
201 code, answer = %check_answer(control, {220})
202 end
203 return code, answer
204end
205
206-----------------------------------------------------------------------------
207-- Log in on server
208-- Input
209-- control: control connection with server
210-- user: user name
211-- pass: user password if any
212-- Returns
213-- code: nil if error
214-- answer: server answer or error message
215-----------------------------------------------------------------------------
216local login = function(control, user, pass)
217 local code, answer = %try_command(control, "user", parsed.user, {230, 331})
218 if not code then return nil, answer end
219 if code == 331 and parsed.pass then -- need pass and we have pass
220 code, answer = %try_command(control, "pass", parsed.pass, {230, 202})
221 end
222 return code, answer
223end
224
225-----------------------------------------------------------------------------
226-- Change to target directory
227-- Input
228-- control: socket for control connection with server
229-- path: array with directories in order
230-- Returns
231-- code: nil if error
232-- answer: server answer or error message
233-----------------------------------------------------------------------------
234local cwd = function(control, path)
235 local code, answer = 250, "Home directory used"
236 for i = 1, getn(path) do
237 code, answer = %try_command(control, "cwd", path[i], {250})
238 if not code then return nil, answer end
239 end
240 return code, answer
241end
242
243-----------------------------------------------------------------------------
244-- Start data connection with server
245-- Input
246-- control: control connection with server
247-- Returns
248-- data: socket for data connection with server, nil if error
249-- answer: server answer or error message
250-----------------------------------------------------------------------------
251local start_dataconnection = function(control)
252 -- ask for passive data connection
253 local code, answer = %try_command(control, "pasv", nil, {227})
254 if not code then return nil, answer end
255 -- get data connection parameters from server reply
256 local host, port = %get_pasv(answer)
257 if not host or not port then return nil, answer end
258 -- start data connection with given parameters
259 local data, err = connect(host, port)
260 if not data then return nil, err end
261 data:timeout(%TIMEOUT)
262 return data
263end
264
265-----------------------------------------------------------------------------
266-- Closes control connection with server
267-- Input
268-- control: control connection with server
269-- Returns
270-- code: nil if error
271-- answer: server answer or error message
272-----------------------------------------------------------------------------
273local logout = function(control)
274 local code, answer = %try_command(control, "quit", nil, {221})
275 if not code then return nil, answer end
276 control:close()
277 return code, answer
278end
279
280-----------------------------------------------------------------------------
281-- Retrieves file or directory listing
282-- Input
283-- control: control connection with server
284-- data: data connection with server
285-- file: file name under current directory
286-- isdir: is file a directory name?
287-- Returns
288-- file: string with file contents, nil if error
289-- answer: server answer or error message
290-----------------------------------------------------------------------------
291local retrieve_file = function(control, data, file, isdir)
292 -- ask server for file or directory listing accordingly
293 if isdir then code, answer = %try_command(control, "nlst", file, {150, 125})
294 else code, answer = %try_command(control, "retr", file, {150, 125}) end
295 if not code then
296 control:close()
297 data:close()
298 return nil, answer
299 end
300 -- download whole file
301 file, err = data:receive("*a")
302 data:close()
303 if err then
304 control:close()
305 return nil, err
306 end
307 -- make sure file transfered ok
308 code, answer = %check_answer(control, {226, 250})
309 if not code then return nil, answer
310 else return file, answer end
311end
312
313-----------------------------------------------------------------------------
314-- Stores a file
315-- Input
316-- control: control connection with server
317-- data: data connection with server
318-- file: file name under current directory
319-- bytes: file contents in string
320-- Returns
321-- file: string with file contents, nil if error
322-- answer: server answer or error message
323-----------------------------------------------------------------------------
324local store_file = function (control, data, file, bytes)
325 local code, answer = %try_command(control, "stor", file, {150, 125})
326 if not code then
327 data:close()
328 return nil, answer
329 end
330 -- send whole file and close connection to mark file end
331 answer = data:send(bytes)
332 data:close()
333 if answer then
334 control:close()
335 return nil, answer
336 end
337 -- check if file was received right
338 return %check_answer(control, {226, 250})
339end
340
341-----------------------------------------------------------------------------
342-- Change transfer type
343-- Input
344-- control: control connection with server
345-- type: new transfer type
346-- Returns
347-- code: nil if error
348-- answer: server answer or error message
349-----------------------------------------------------------------------------
350local change_type = function(control, type)
351 if type == "b" then type = "i" else type = "a" end
352 return %try_command(control, "type", type, {200})
353end
354
355-----------------------------------------------------------------------------
356-- Retrieve a file from a ftp server
357-- Input
358-- url: file location
359-- type: "binary" or "ascii"
360-- Returns
361-- file: downloaded file or nil in case of error
362-- err: error message if any
363-----------------------------------------------------------------------------
364function ftp_get(url, type)
365 local control, data, err
366 local answer, code, server, file, path
367 parsed = %split_url(url, {user = "anonymous", port = 21, pass = %EMAIL})
368 -- start control connection
369 control, err = connect(parsed.host, parsed.port)
370 if not control then return nil, err end
371 control:timeout(%TIMEOUT)
372 -- get and check greeting
373 code, answer = %check_greeting(control)
374 if not code then return nil, answer end
375 -- try to log in
376 code, answer = %login(control, parsed.user, parsed.pass)
377 if not code then return nil, answer end
378 -- go to directory
379 file, path, isdir = %split_path(parsed.path)
380 code, answer = %cwd(control, path)
381 if not code then return nil, answer end
382 -- change to binary type?
383 code, answer = %change_type(control, type)
384 if not code then return nil, answer end
385 -- start data connection
386 data, answer = %start_dataconnection(control)
387 if not data then return nil, answer end
388 -- ask server to send file or directory listing
389 file, answer = %retrieve_file(control, data, file, isdir)
390 if not file then return nil, answer end
391 -- disconnect
392 %logout(control)
393 -- return whatever file we received plus a possible error
394 return file, answer
395end
396
397-----------------------------------------------------------------------------
398-- Uploads a file to a FTP server
399-- Input
400-- url: file location
401-- bytes: file contents
402-- type: "binary" or "ascii"
403-- Returns
404-- err: error message if any
405-----------------------------------------------------------------------------
406function ftp_put(url, bytes, type)
407 local control, data
408 local answer, code, server, file, path
409 parsed = %split_url(url, {user = "anonymous", port = 21, pass = %EMAIL})
410 -- start control connection
411 control, answer = connect(parsed.host, parsed.port)
412 if not control then return answer end
413 control:timeout(%TIMEOUT)
414 -- get and check greeting
415 code, answer = %check_greeting(control)
416 if not code then return answer end
417 -- try to log in
418 code, answer = %login(control, parsed.user, parsed.pass)
419 if not code then return answer end
420 -- go to directory
421 file, path, isdir = %split_path(parsed.path)
422 code, answer = %cwd(control, path)
423 if not code then return answer end
424 -- change to binary type?
425 code, answer = %change_type(control, type)
426 if not code then return answer end
427 -- start data connection
428 data, answer = %start_dataconnection(control)
429 if not data then return answer end
430 -- ask server to send file or directory listing
431 code, answer = %store_file(control, data, file, bytes)
432 if not code then return answer end
433 -- disconnect
434 %logout(control)
435 -- return whatever file we received plus a possible error
436 return nil
437end