initial

lualib/socket/http.lua

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+-----------------------------------------------------------------------------
+-- HTTP/1.1 client support for the Lua language.
+-- LuaSocket toolkit.
+-- Author: Diego Nehab
+-- RCS ID: $Id: http.lua,v 1.70 2007/03/12 04:08:40 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)