Lua http socket评估

Question

我使用lua 5.1和luaSocket 2.0.2-4从Web服务器检索页面。我首先检查服务器是否正在响应，然后将Web服务器响应分配给lua变量。

local mysocket = require("socket.http") 
if mysocket.request(URL) == nil then 
    print('The server is unreachable on:\n'..URL) 
    return 
end 
local response, httpCode, header = mysocket.request(URL) 

一切正常，但请求被执行两次。我不知道如果我可以做喜欢的事（这并不明显工作）：

local mysocket = require("socket.http") 
if (local response, httpCode, header = mysocket.request(URL)) == nil then 
    print('The server is unreachable on:\n'..URL) 
    return 
end 

Answer 1

是的，是这样的：

local mysocket = require("socket.http") 
local response, httpCode, header = mysocket.request(URL) 

if response == nil then 
    print('The server is unreachable on:\n'..URL) 
    return 
end 

-- here you do your stuff that's supposed to happen when request worked 

请求将只发送一次，和功能将退出，如果它失败。

Answer 2

更好的是，当请求失败，第二复位的原因是：

在故障的情况下，该函数返回nil后跟一个错误消息。

（从the documentation for http.request）

所以，你可以直接从插座的嘴打印问题：

local http = require("socket.http") 
local response, httpCode, header = http.request(URL) 

if response == nil then 
    -- the httpCode variable contains the error message instead 
    print(httpCode) 
    return 
end 

-- here you do your stuff that's supposed to happen when request worked