Lua http socket evaluation

Question

I use lua 5.1 and the luaSocket 2.0.2-4 to retrieve a page from a web server. I first check if the server is responding and then assign the web server response to lua variables.

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)

Everything works as expected but the request is executed two times. I wonder if I could do Something like (which doesn't work obviously):

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

user703016 · Accepted Answer · 2011-05-16 15:38:26Z

6

Yes, something like this :

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

Request will be sent only once, and function will exit if it failed.

edited May 16, 2011 at 15:38

answered May 16, 2011 at 9:52

user703016

38.2k10 gold badges91 silver badges113 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

ripat Over a year ago

That will do it. Thanks for the lightning fast answer.

Stuart P. Bentley · Accepted Answer · 2011-05-16 18:14:50Z

1

Even better, when request fails, the second return is the reason:

In case of failure, the function returns nil followed by an error message.

(From the documentation for http.request)

So you can print the problem straight from the socket's mouth:

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

edited May 16, 2011 at 18:14

answered May 16, 2011 at 17:50

Stuart P. Bentley

10.9k11 gold badges60 silver badges86 bronze badges

1 Comment

Stuart P. Bentley Over a year ago

@Heandel: No, httpCode will hold the socket error message. See citation.

Collectives™ on Stack Overflow

Lua http socket evaluation

2 Answers 2

1 Comment

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related