信箱剖析

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剖析信箱檔案

假設你儲存了目前目錄（或 PackagePath 中的其他地方）中的原始碼，名稱為 mboxparser.lua。在程式碼中，輸入

parse = require "mboxparser" 

主要函式，parse.mbox，接收以字串形式儲存的信箱檔案內容，並傳回一個表格，每個訊息只有一個項目。每個項目有下列結構

message = {
    headers = {
        [["name_1"]] = "value_1",
        [["name_2"]] = "value_2",
        ...           ...
        [["name_n"]] = "value_n",
    },
    body = "message body"
}
	

因此，如果信箱有下列內容

From  whoever@tecgraf.puc-rio.br  Thu Nov 22 13:59:05 2001
Date: Thu, 22 Nov 2001 13:59:04 -0200 (EDT)
From: Whoever Smith <whoever@tecgraf.puc-rio.br>
To: Other Smith <other@tecgraf.puc-rio.br>
Subject: This is a test message
Content-Type: TEXT/PLAIN; charset=US-ASCII

Hi, This is the message body.  Regards, Diego.
	

對它使用 parse.mbox 的話，會傳回下列表格

messages = {
  { 
    headers = {
      from = "Whoever Smith <whoever@tecgraf.puc-rio.br>", 
      subject = "This is a test message", 
      to = "Other Smith <other@tecgraf.puc-rio.br>", 
      date = "Thu, 22 Nov 2001 13:59:04 -0200 (EDT)", 
      ["content-type"] = "TEXT/PLAIN; charset=US-ASCII", 
    }, 
    body = "Hi, This is the message body.  Regards, Diego.",
  }
}
	

原始碼

local Public = {}
local strfind, strlower, gsub = string.find, string.lower, string.gsub
local strsub, tinsert = string.sub, table.insert

function Public.headers(headers_s)
    local headers = {}
    headers_s = "\n" .. headers_s .. "$$$:\n"
    local i, j = 1, 1
    local name, value, _
    while 1 do
        j = strfind(headers_s, "\n%S-:", i+1)
        if not j then break end
        _, _, name, value = strfind(strsub(headers_s, i+1, j-1), "(%S-):(.*)")
        value = gsub(value or "", "\r\n", "\n")
        value = gsub(value, "\n%s*", " ")
        name = strlower(name)
        if headers[name] then headers[name] = headers[name] .. ", " ..  value
        else headers[name] = value end
        i, j = j, i
    end
    headers["$$$"] = nil
    return headers
end

function Public.message(message_s)
    message_s = gsub(message_s, "^.-\n", "")
    local _, headers_s, body
    _, _, headers_s, body = strfind(message_s, "^(.-\n)\n(.*)")
    headers_s = headers_s or ""
    body = body or ""
    return { headers = Public.headers(headers_s), body = body }
end

function Public.mbox(mbox_s)
    local mbox = {}
    mbox_s = "\n" .. mbox_s .. "\nFrom "
    local i, j = 1, 1
    while 1 do
        j = strfind(mbox_s, "\nFrom ", i + 1)
        if not j then break end
        tinsert(mbox, Public.message(strsub(mbox_s, i + 1, j - 1)))
        i, j = j, i
    end
    return mbox
end

return Public
	

鳴謝

原始 Lua 4 程式碼是由 DiegoNehab 建立的，且用來測試 LuaSocket[1] 1.4 SMTP 程式碼。Lua 5 版本是由 DirkLaurie 製作的。