root/luci/trunk/libs/lucid-http/luasrc/lucid/http/server.lua @ 5157

--[[
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 set_memory_limit = set_memory_limit

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
            request.env.HTTP_AUTH_USER, request.env.HTTP_AUTH_PASS = user, pass
            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
    
    if self.default and uri == "/" then
        return 302, {Location = self.default}
    end

    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, tostring(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
    
    env.config.memlimit = tonumber(env.config.memlimit)
    if env.config.memlimit and set_memory_limit then
        set_memory_limit(env.config.memlimit)
    end

    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"] and not close 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
                if not headers["Transfer-Encoding"] then
                    stat, code, msg = sourceout.fd:copyz(client, sourceout.len)
                    sourceout = nil
                else
                    sourceout = sourceout.fd:blocksource(nil, sourceout.len)
                end
            end

            if sourceout then
                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