Lua socket error on connection

Question

I'm trying to make a http get, using Lua Socket:

local client = socket.connect('warm-harbor-2019.herokuapp.com',80)
if client then
    client:send("GET /get_tweets HTTP/1.0\r\n\r\n")
      s, status, partial = client:receive(1024)
    end
end

I expect s to be a tweet, since the get that I'm making returns one. But I'm getting:

http/1.1 404 object not found

catwell · Accepted Answer · 2014-05-19T20:52:26.220

Here is a runnable version of your code example (that exhibit the problem you described):

local socket = require "socket"
local client = socket.connect('warm-harbor-2019.herokuapp.com',80)
if client then
    client:send("GET /get_tweets HTTP/1.0\r\n\r\n")
    local s, status, partial = client:receive(1024)
    print(s)
end

If you read the error page returned, you can see that its title is Heroku | No such app.

The reason for that is that the Heroku router only works when a Host header is provided. The easiest way to do it is to use the actual HTTP module of LuaSocket instead of TCP directly:

local http = require "socket.http"
local s, status, headers = http.request("http://warm-harbor-2019.herokuapp.com/get_tweets")
print(s)

If you cannot use socket.http you can pass the Host header manually:

local socket = require "socket"
local client = socket.connect('warm-harbor-2019.herokuapp.com',80)
client:send("GET /get_tweets HTTP/1.0\r\nHost: warm-harbor-2019.herokuapp.com\r\n\r\n")
local s, status, partial = client:receive(1024)
print(s, status, partial)

With my version of LuaSocket, s will be nil, status will be "closed" and partial will contain the full HTTP response (with headers etc).

Looks solid, but my require 'socket.http' is not working, only require 'socket'. Do I need to add a file to the project? Right now, i just have one lua file. — Matheus Lima, May 18 '14 at 19:49
This is probably because you use an old version of LuaSocket. If you require "socket" (without assigning it to a local variable) does `socket.http` exist? If so replace `http.request` by `socket.http.request`. — catwell, May 18 '14 at 21:42
Ok, I'm using NCLua. I did what you told, in a separated file, and it worked fine. But for some reason 'socket' is working, but 'socket.http' is not. Is there a way to do it with 'socket' ? — Matheus Lima, May 18 '14 at 22:22

Lua socket error on connection

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