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-----------------------------------------------------------------------------
-- HTTP/1.1 client support for the Lua language.
-- LuaSocket toolkit.
-- Author: Diego Nehab
-- RCS ID: $Id: http.lua,v 1.71 2007/10/13 23:55:20 diego Exp $
-----------------------------------------------------------------------------
-----------------------------------------------------------------------------
-- Declare module and import dependencies
-------------------------------------------------------------------------------
local socket = require("socket")
local url = require("socket.url")
local ltn12 = require("ltn12")
local mime = require("mime")
local string = require("string")
local base = _G
local table = require("table")
module("socket.http")
-----------------------------------------------------------------------------
-- Program constants
-----------------------------------------------------------------------------
-- connection timeout in seconds
TIMEOUT = 60
-- default port for document retrieval
PORT = 80
-- user agent field sent in request
USERAGENT = socket._VERSION
-----------------------------------------------------------------------------
-- Reads MIME headers from a connection, unfolding where needed
-----------------------------------------------------------------------------
local function receiveheaders(sock, headers)
local line, name, value, err
headers = headers or {}
-- get first line
line, err = sock:receive()
if err then return nil, err end
-- headers go until a blank line is found
while line ~= "" do
-- get field-name and value
name, value = socket.skip(2, string.find(line, "^(.-):%s*(.*)"))
if not (name and value) then return nil, "malformed reponse headers" end
name = string.lower(name)
-- get next line (value might be folded)
line, err = sock:receive()
if err then return nil, err end
-- unfold any folded values
while string.find(line, "^%s") do
value = value .. line
line = sock:receive()
if err then return nil, err end
end
-- save pair in table
if headers[name] then headers[name] = headers[name] .. ", " .. value
else headers[name] = value end
end
return headers
end
-----------------------------------------------------------------------------
-- Extra sources and sinks
-----------------------------------------------------------------------------
socket.sourcet["http-chunked"] = function(sock, headers)
return base.setmetatable({
getfd = function() return sock:getfd() end,
dirty = function() return sock:dirty() end
}, {
__call = function()
-- get chunk size, skip extention
local line, err = sock:receive()
if err then return nil, err end
local size = base.tonumber(string.gsub(line, ";.*", ""), 16)
if not size then return nil, "invalid chunk size" end
-- was it the last chunk?
if size > 0 then
-- if not, get chunk and skip terminating CRLF
local chunk, err, part = sock:receive(size)
if chunk then sock:receive() end
return chunk, err
else
-- if it was, read trailers into headers table
headers, err = receiveheaders(sock, headers)
if not headers then return nil, err end
end
end
})
end
socket.sinkt["http-chunked"] = function(sock)
return base.setmetatable({
getfd = function() return sock:getfd() end,
dirty = function() return sock:dirty() end
}, {
__call = function(self, chunk, err)
if not chunk then return sock:send("0\r\n\r\n") end
local size = string.format("%X\r\n", string.len(chunk))
return sock:send(size .. chunk .. "\r\n")
end
})
end
-----------------------------------------------------------------------------
-- Low level HTTP API
-----------------------------------------------------------------------------
local metat = { __index = {} }
function open(host, port, create)
-- create socket with user connect function, or with default
local c = socket.try((create or socket.tcp)())
local h = base.setmetatable({ c = c }, metat)
-- create finalized try
h.try = socket.newtry(function() h:close() end)
-- set timeout before connecting
h.try(c:settimeout(TIMEOUT))
h.try(c:connect(host, port or PORT))
-- here everything worked
return h
end
function metat.__index:sendrequestline(method, uri)
local reqline = string.format("%s %s HTTP/1.1\r\n", method or "GET", uri)
return self.try(self.c:send(reqline))
end
function metat.__index:sendheaders(headers)
local h = "\r\n"
for i, v in base.pairs(headers) do
h = i .. ": " .. v .. "\r\n" .. h
end
self.try(self.c:send(h))
return 1
end
function metat.__index:sendbody(headers, source, step)
source = source or ltn12.source.empty()
step = step or ltn12.pump.step
-- if we don't know the size in advance, send chunked and hope for the best
local mode = "http-chunked"
if headers["content-length"] then mode = "keep-open" end
return self.try(ltn12.pump.all(source, socket.sink(mode, self.c), step))
end
function metat.__index:receivestatusline()
local status = self.try(self.c:receive(5))
-- identify HTTP/0.9 responses, which do not contain a status line
-- this is just a heuristic, but is what the RFC recommends
if status ~= "HTTP/" then return nil, status end
-- otherwise proceed reading a status line
status = self.try(self.c:receive("*l", status))
local code = socket.skip(2, string.find(status, "HTTP/%d*%.%d* (%d%d%d)"))
return self.try(base.tonumber(code), status)
end
function metat.__index:receiveheaders()
return self.try(receiveheaders(self.c))
end
function metat.__index:receivebody(headers, sink, step)
sink = sink or ltn12.sink.null()
step = step or ltn12.pump.step
local length = base.tonumber(headers["content-length"])
local t = headers["transfer-encoding"] -- shortcut
local mode = "default" -- connection close
if t and t ~= "identity" then mode = "http-chunked"
elseif base.tonumber(headers["content-length"]) then mode = "by-length" end
return self.try(ltn12.pump.all(socket.source(mode, self.c, length),
sink, step))
end
function metat.__index:receive09body(status, sink, step)
local source = ltn12.source.rewind(socket.source("until-closed", self.c))
source(status)
return self.try(ltn12.pump.all(source, sink, step))
end
function metat.__index:close()
return self.c:close()
end
-----------------------------------------------------------------------------
-- High level HTTP API
-----------------------------------------------------------------------------
local function adjusturi(reqt)
local u = reqt
-- if there is a proxy, we need the full url. otherwise, just a part.
if not reqt.proxy and not PROXY then
u = {
path = socket.try(reqt.path, "invalid path 'nil'"),
params = reqt.params,
query = reqt.query,
fragment = reqt.fragment
}
end
return url.build(u)
end
local function adjustproxy(reqt)
local proxy = reqt.proxy or PROXY
if proxy then
proxy = url.parse(proxy)
return proxy.host, proxy.port or 3128
else
return reqt.host, reqt.port
end
end
local function adjustheaders(reqt)
-- default headers
local lower = {
["user-agent"] = USERAGENT,
["host"] = reqt.host,
["connection"] = "close, TE",
["te"] = "trailers"
}
-- if we have authentication information, pass it along
if reqt.user and reqt.password then
lower["authorization"] =
"Basic " .. (mime.b64(reqt.user .. ":" .. reqt.password))
end
-- override with user headers
for i,v in base.pairs(reqt.headers or lower) do
lower[string.lower(i)] = v
end
return lower
end
-- default url parts
local default = {
host = "",
port = PORT,
path ="/",
scheme = "http"
}
local function adjustrequest(reqt)
-- parse url if provided
local nreqt = reqt.url and url.parse(reqt.url, default) or {}
-- explicit components override url
for i,v in base.pairs(reqt) do nreqt[i] = v end
if nreqt.port == "" then nreqt.port = 80 end
socket.try(nreqt.host and nreqt.host ~= "",
"invalid host '" .. base.tostring(nreqt.host) .. "'")
-- compute uri if user hasn't overriden
nreqt.uri = reqt.uri or adjusturi(nreqt)
-- ajust host and port if there is a proxy
nreqt.host, nreqt.port = adjustproxy(nreqt)
-- adjust headers in request
nreqt.headers = adjustheaders(nreqt)
return nreqt
end
local function shouldredirect(reqt, code, headers)
return headers.location and
string.gsub(headers.location, "%s", "") ~= "" and
(reqt.redirect ~= false) and
(code == 301 or code == 302) and
(not reqt.method or reqt.method == "GET" or reqt.method == "HEAD")
and (not reqt.nredirects or reqt.nredirects < 5)
end
local function shouldreceivebody(reqt, code)
if reqt.method == "HEAD" then return nil end
if code == 204 or code == 304 then return nil end
if code >= 100 and code < 200 then return nil end
return 1
end
-- forward declarations
local trequest, tredirect
function tredirect(reqt, location)
local result, code, headers, status = trequest {
-- the RFC says the redirect URL has to be absolute, but some
-- servers do not respect that
url = url.absolute(reqt.url, location),
source = reqt.source,
sink = reqt.sink,
headers = reqt.headers,
proxy = reqt.proxy,
nredirects = (reqt.nredirects or 0) + 1,
create = reqt.create
}
-- pass location header back as a hint we redirected
headers = headers or {}
headers.location = headers.location or location
return result, code, headers, status
end
function trequest(reqt)
-- we loop until we get what we want, or
-- until we are sure there is no way to get it
local nreqt = adjustrequest(reqt)
local h = open(nreqt.host, nreqt.port, nreqt.create)
-- send request line and headers
h:sendrequestline(nreqt.method, nreqt.uri)
h:sendheaders(nreqt.headers)
-- if there is a body, send it
if nreqt.source then
h:sendbody(nreqt.headers, nreqt.source, nreqt.step)
end
local code, status = h:receivestatusline()
-- if it is an HTTP/0.9 server, simply get the body and we are done
if not code then
h:receive09body(status, nreqt.sink, nreqt.step)
return 1, 200
end
local headers
-- ignore any 100-continue messages
while code == 100 do
headers = h:receiveheaders()
code, status = h:receivestatusline()
end
headers = h:receiveheaders()
-- at this point we should have a honest reply from the server
-- we can't redirect if we already used the source, so we report the error
if shouldredirect(nreqt, code, headers) and not nreqt.source then
h:close()
return tredirect(reqt, headers.location)
end
-- here we are finally done
if shouldreceivebody(nreqt, code) then
h:receivebody(headers, nreqt.sink, nreqt.step)
end
h:close()
return 1, code, headers, status
end
local function srequest(u, b)
local t = {}
local reqt = {
url = u,
sink = ltn12.sink.table(t)
}
if b then
reqt.source = ltn12.source.string(b)
reqt.headers = {
["content-length"] = string.len(b),
["content-type"] = "application/x-www-form-urlencoded"
}
reqt.method = "POST"
end
local code, headers, status = socket.skip(1, trequest(reqt))
return table.concat(t), code, headers, status
end
request = socket.protect(function(reqt, body)
if base.type(reqt) == "string" then return srequest(reqt, body)
else return trequest(reqt) end
end)