[project/luci.git] / libs / lucid-http / luasrc / lucid / http / server.lua

--[[
LuCId HTTP-Slave
(c) 2009 Steven Barth <steven@midlink.org>

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

$Id$
]]--

local ipairs, pairs = ipairs, pairs
local tostring, tonumber = tostring, tonumber
local pcall, assert, type = pcall, assert, type

local os = require "os"
local nixio = require "nixio"
local util = require "luci.util"
local ltn12 = require "luci.ltn12"
local proto = require "luci.http.protocol"
local table = require "table"
local date = require "luci.http.protocol.date"

--- HTTP Daemon
-- @cstyle instance
module "luci.lucid.http.server"

VERSION = "1.0"

statusmsg = {
        [200] = "OK",
        [206] = "Partial Content",
        [301] = "Moved Permanently",
        [302] = "Found",
        [304] = "Not Modified",
        [400] = "Bad Request",
        [401] = "Unauthorized",
        [403] = "Forbidden",
        [404] = "Not Found",
        [405] = "Method Not Allowed",
        [408] = "Request Time-out",
        [411] = "Length Required",
        [412] = "Precondition Failed",
        [416] = "Requested range not satisfiable",
        [500] = "Internal Server Error",
        [503] = "Server Unavailable",
}

--- Create a new IO resource response.
-- @class function
-- @param fd File descriptor
-- @param len Length of data
-- @return IO resource
IOResource = util.class()

function IOResource.__init__(self, fd, len)
        self.fd, self.len = fd, len
end


--- Create a server handler.
-- @class function
-- @param name Name
-- @return Handler
Handler = util.class()

function Handler.__init__(self, name)
        self.name = name or tostring(self)
end

--- Create a failure reply.
-- @param code HTTP status code
-- @param msg Status message
-- @return status code, header table, response source
function Handler.failure(self, code, msg)       
        return code, { ["Content-Type"] = "text/plain" }, ltn12.source.string(msg)
end

--- Add an access restriction.
-- @param restriction Restriction specification
function Handler.restrict(self, restriction)
        if not self.restrictions then
                self.restrictions = {restriction}
        else
                self.restrictions[#self.restrictions+1] = restriction
        end
end

--- Enforce access restrictions.
-- @param request Request object
-- @return nil or HTTP statuscode, table of headers, response source
function Handler.checkrestricted(self, request)
        if not self.restrictions then
                return
        end

        local localif, user, pass
        
        for _, r in ipairs(self.restrictions) do
                local stat = true
                if stat and r.interface then    -- Interface restriction
                        if not localif then
                                for _, v in ipairs(request.server.interfaces) do
                                        if v.addr == request.env.SERVER_ADDR then
                                                localif = v.name
                                                break
                                        end
                                end
                        end
                        
                        if r.interface ~= localif then
                                stat = false
                        end
                end
                
                if stat and r.user then -- User restriction
                        local rh, pwe
                        if not user then
                                rh = (request.headers.Authorization or ""):match("Basic (.*)")
                                rh = rh and nixio.bin.b64decode(rh) or ""
                                user, pass = rh:match("(.*):(.*)")
                                pass = pass or ""
                        end
                        pwe = nixio.getsp and nixio.getsp(r.user) or nixio.getpw(r.user)
                        local pwh = (user == r.user) and pwe and (pwe.pwdp or pwe.passwd)
                        if not pwh or #pwh < 1 or nixio.crypt(pass, pwh) ~= pwh then
                                stat = false
                        end
                end
                
                if stat then
                        return
                end
        end
        
        return 401, {
                ["WWW-Authenticate"] = ('Basic realm=%q'):format(self.name),
                ["Content-Type"] = 'text/plain'
        }, ltn12.source.string("Unauthorized")
end

--- Process a request.
-- @param request Request object
-- @param sourcein Request data source
-- @return HTTP statuscode, table of headers, response source
function Handler.process(self, request, sourcein)
        local stat, code, hdr, sourceout
        
        local stat, code, msg = self:checkrestricted(request)
        if stat then    -- Access Denied
                return stat, code, msg
        end

        -- Detect request Method
        local hname = "handle_" .. request.env.REQUEST_METHOD
        if self[hname] then
                -- Run the handler
                stat, code, hdr, sourceout = pcall(self[hname], self, request, sourcein)

                -- Check for any errors
                if not stat then
                        return self:failure(500, code)
                end
        else
                return self:failure(405, statusmsg[405])
        end

        return code, hdr, sourceout
end


--- Create a Virtual Host.
-- @class function
-- @return Virtual Host
VHost = util.class()

function VHost.__init__(self)
        self.handlers = {}
end

--- Process a request and invoke the appropriate handler. 
-- @param request Request object
-- @param ... Additional parameters passed to the handler
-- @return HTTP statuscode, table of headers, response source 
function VHost.process(self, request, ...)
        local handler
        local hlen = -1
        local uri = request.env.SCRIPT_NAME
        local sc = ("/"):byte()

        -- SCRIPT_NAME
        request.env.SCRIPT_NAME = ""

        -- Call URI part
        request.env.PATH_INFO = uri
        
        for k, h in pairs(self.handlers) do
                if #k > hlen then
                        if uri == k or (uri:sub(1, #k) == k and uri:byte(#k+1) == sc) then
                                handler = h
                                hlen = #k
                                request.env.SCRIPT_NAME = k
                                request.env.PATH_INFO   = uri:sub(#k+1)
                        end
                end
        end
        
        if handler then
                return handler:process(request, ...)
        else
                return 404, nil, ltn12.source.string("No such handler")
        end
end

--- Get a list of registered handlers.
-- @return Table of handlers
function VHost.get_handlers(self)
        return self.handlers
end

--- Register handler with a given URI prefix.
-- @oaram match URI prefix
-- @param handler Handler object
function VHost.set_handler(self, match, handler)
        self.handlers[match] = handler
end

-- Remap IPv6-IPv4-compatibility addresses back to IPv4 addresses.
local function remapipv6(adr)
        local map = "::ffff:"
        if adr:sub(1, #map) == map then
                return adr:sub(#map+1)
        else
                return adr
        end 
end

-- Create a source that decodes chunked-encoded data from a socket.
local function chunksource(sock, buffer)
        buffer = buffer or ""
        return function()
                local output
                local _, endp, count = buffer:find("^([0-9a-fA-F]+);?.-\r\n")
                while not count and #buffer <= 1024 do
                        local newblock, code = sock:recv(1024 - #buffer)
                        if not newblock then
                                return nil, code
                        end
                        buffer = buffer .. newblock  
                        _, endp, count = buffer:find("^([0-9a-fA-F]+);?.-\r\n")
                end
                count = tonumber(count, 16)
                if not count then
                        return nil, -1, "invalid encoding"
                elseif count == 0 then
                        return nil
                elseif count + 2 <= #buffer - endp then
                        output = buffer:sub(endp+1, endp+count)
                        buffer = buffer:sub(endp+count+3)
                        return output
                else
                        output = buffer:sub(endp+1, endp+count)
                        buffer = ""
                        if count - #output > 0 then
                                local remain, code = sock:recvall(count-#output)
                                if not remain then
                                        return nil, code
                                end
                                output = output .. remain
                                count, code = sock:recvall(2)
                        else
                                count, code = sock:recvall(count+2-#buffer+endp)
                        end
                        if not count then
                                return nil, code
                        end
                        return output
                end
        end
end

-- Create a sink that chunk-encodes data and writes it on a given socket.
local function chunksink(sock)
        return function(chunk, err)
                if not chunk then
                        return sock:writeall("0\r\n\r\n")
                else
                        return sock:writeall(("%X\r\n%s\r\n"):format(#chunk, chunk))
                end
        end
end


--- Create a server object.
-- @class function
-- @return Server object
Server = util.class()

function Server.__init__(self)
        self.vhosts = {}
end

--- Get a list of registered virtual hosts.
-- @return Table of virtual hosts
function Server.get_vhosts(self)
        return self.vhosts
end

--- Register a virtual host with a given name.
-- @param name Hostname
-- @param vhost Virtual host object
function Server.set_vhost(self, name, vhost)
        self.vhosts[name] = vhost
end

--- Send a fatal error message to given client and close the connection.
-- @param client Client socket
-- @param code HTTP status code
-- @param msg status message
function Server.error(self, client, code, msg)
        hcode = tostring(code)
        
        client:writeall( "HTTP/1.0 " .. hcode .. " " ..
         statusmsg[code] .. "\r\n" )
        client:writeall( "Connection: close\r\n" )
        client:writeall( "Content-Type: text/plain\r\n\r\n" )

        if msg then
                client:writeall( "HTTP-Error " .. code .. ": " .. msg .. "\r\n" )
        end
        
        client:close()
end

local hdr2env = {
        ["Content-Length"] = "CONTENT_LENGTH",
        ["Content-Type"] = "CONTENT_TYPE",
        ["Content-type"] = "CONTENT_TYPE",
        ["Accept"] = "HTTP_ACCEPT",
        ["Accept-Charset"] = "HTTP_ACCEPT_CHARSET",
        ["Accept-Encoding"] = "HTTP_ACCEPT_ENCODING",
        ["Accept-Language"] = "HTTP_ACCEPT_LANGUAGE",
        ["Connection"] = "HTTP_CONNECTION",
        ["Cookie"] = "HTTP_COOKIE",
        ["Host"] = "HTTP_HOST",
        ["Referer"] = "HTTP_REFERER",
        ["User-Agent"] = "HTTP_USER_AGENT"
}

--- Parse the request headers and prepare the environment.
-- @param source line-based input source
-- @return Request object
function Server.parse_headers(self, source)
        local env = {}
        local req = {env = env, headers = {}}
        local line, err

        repeat  -- Ignore empty lines
                line, err = source()
                if not line then
                        return nil, err
                end
        until #line > 0
        
        env.REQUEST_METHOD, env.REQUEST_URI, env.SERVER_PROTOCOL =
                line:match("^([A-Z]+) ([^ ]+) (HTTP/1%.[01])$")
                
        if not env.REQUEST_METHOD then
                return nil, "invalid magic"
        end
        
        local key, envkey, val
        repeat
                line, err = source()
                if not line then
                        return nil, err
                elseif #line > 0 then   
                        key, val = line:match("^([%w-]+)%s?:%s?(.*)")
                        if key then
                                req.headers[key] = val
                                envkey = hdr2env[key]
                                if envkey then
                                        env[envkey] = val
                                end
                        else
                                return nil, "invalid header line"
                        end
                else
                        break
                end
        until false
        
        env.SCRIPT_NAME, env.QUERY_STRING = env.REQUEST_URI:match("([^?]*)%??(.*)")
        return req
end

--- Handle a new client connection.
-- @param client client socket
-- @param env superserver environment
function Server.process(self, client, env)
        local sourcein  = function() end
        local sourcehdr = client:linesource()
        local sinkout
        local buffer
        
        local close = false
        local stat, code, msg, message, err
        
        client:setsockopt("socket", "rcvtimeo", 5)
        client:setsockopt("socket", "sndtimeo", 5)
        
        repeat
                -- parse headers
                message, err = self:parse_headers(sourcehdr)

                -- any other error
                if not message or err then
                        if err == 11 then       -- EAGAIN
                                break
                        else
                                return self:error(client, 400, err)
                        end
                end

                -- Prepare sources and sinks
                buffer = sourcehdr(true)
                sinkout = client:sink()
                message.server = env
                
                if client:is_tls_socket() then
                        message.env.HTTPS = "on"
                end
                
                -- Addresses
                message.env.REMOTE_ADDR = remapipv6(env.host)
                message.env.REMOTE_PORT = env.port
                
                local srvaddr, srvport = client:getsockname()
                message.env.SERVER_ADDR = remapipv6(srvaddr)
                message.env.SERVER_PORT = srvport
                
                -- keep-alive
                if message.env.SERVER_PROTOCOL == "HTTP/1.1" then
                        close = (message.env.HTTP_CONNECTION == "close")
                else
                        close = not message.env.HTTP_CONNECTION 
                                or message.env.HTTP_CONNECTION == "close"
                end

                -- Uncomment this to disable keep-alive
                close = close or env.config.nokeepalive
        
                if message.env.REQUEST_METHOD == "GET"
                or message.env.REQUEST_METHOD == "HEAD" then
                        -- Be happy
                        
                elseif message.env.REQUEST_METHOD == "POST" then
                        -- If we have a HTTP/1.1 client and an Expect: 100-continue header
                        -- respond with HTTP 100 Continue message
                        if message.env.SERVER_PROTOCOL == "HTTP/1.1" 
                        and message.headers.Expect == '100-continue' then
                                client:writeall("HTTP/1.1 100 Continue\r\n\r\n")
                        end
                        
                        if message.headers['Transfer-Encoding'] and
                         message.headers['Transfer-Encoding'] ~= "identity" then
                                sourcein = chunksource(client, buffer)
                                buffer = nil
                        elseif message.env.CONTENT_LENGTH then
                                local len = tonumber(message.env.CONTENT_LENGTH)
                                if #buffer >= len then
                                        sourcein = ltn12.source.string(buffer:sub(1, len))
                                        buffer = buffer:sub(len+1)
                                else
                                        sourcein = ltn12.source.cat(
                                                ltn12.source.string(buffer),
                                                client:blocksource(nil, len - #buffer)
                                        )
                                end
                        else
                                return self:error(client, 411, statusmsg[411])
                        end

                        close = true
                else
                        return self:error(client, 405, statusmsg[405])
                end


                local host = self.vhosts[message.env.HTTP_HOST] or self.vhosts[""]
                if not host then
                        return self:error(client, 404, "No virtual host found")
                end
                
                local code, headers, sourceout = host:process(message, sourcein)
                headers = headers or {}
                
                -- Post process response
                if sourceout then
                        if util.instanceof(sourceout, IOResource) then
                                if not headers["Content-Length"] then
                                        headers["Content-Length"] = sourceout.len
                                end
                        end
                        if not headers["Content-Length"] then
                                if message.env.SERVER_PROTOCOL == "HTTP/1.1" then
                                        headers["Transfer-Encoding"] = "chunked"
                                        sinkout = chunksink(client)
                                else
                                        close = true
                                end
                        end
                elseif message.env.REQUEST_METHOD ~= "HEAD" then
                        headers["Content-Length"] = 0
                end
                
                if close then
                        headers["Connection"] = "close"
                elseif message.env.SERVER_PROTOCOL == "HTTP/1.0" then
                        headers["Connection"] = "Keep-Alive"
                end 

                headers["Date"] = date.to_http(os.time())
                local header = {
                        message.env.SERVER_PROTOCOL .. " " .. tostring(code) .. " " 
                                .. statusmsg[code],
                        "Server: LuCId-HTTPd/" .. VERSION
                }

                
                for k, v in pairs(headers) do
                        if type(v) == "table" then
                                for _, h in ipairs(v) do
                                        header[#header+1] = k .. ": " .. h
                                end
                        else
                                header[#header+1] = k .. ": " .. v
                        end
                end

                header[#header+1] = ""
                header[#header+1] = ""
                
                -- Output
                stat, code, msg = client:writeall(table.concat(header, "\r\n"))

                if sourceout and stat then
                        if util.instanceof(sourceout, IOResource) then
                                stat, code, msg = sourceout.fd:copyz(client, sourceout.len)
                        else
                                stat, msg = ltn12.pump.all(sourceout, sinkout)
                        end
                end


                -- Write errors
                if not stat then
                        if msg then
                                nixio.syslog("err", "Error sending data to " .. env.host ..
                                        ": " .. msg .. "\n")
                        end
                        break
                end
                
                if buffer then
                        sourcehdr(buffer)
                end
        until close
        
        client:shutdown()
        client:close()
end