Daily Ramblings

Ref: https://github.com/diegonehab/luasocket/issues/331

Short Description

HTTP calls do not work with Luasocket 5.4.3 and luasocket.

System Info

Lua: 5.4.3 Luasocket: LuaSocket 3.0-rc1 Distro Archlinux

Test code:

Requires lua-socket and lua-sec to be installed. If testing using lua5.3, then lua53-socket lua53-sec need to be installed.

local http = require "socket.http"

print("---")
print("Testing https")

print(http.request("https://ffl.shoeb.pw"))

print("---")
print("Testing http")


print(http.request("http://ffl.shoeb.pw"))

print("---")
print("End http")

Expected output:

$ lua5.3 t2.lua 
---
Testing https
Welcome to ffl.shoeb.pw. We shall be serving you soon!!!        200     table: 0x55a7c9e0f4d0   HTTP/1.1 200 OK
---
Testing http
Welcome to ffl.shoeb.pw. We shall be serving you soon!!!        200     table: 0x55a7c9e06510   HTTP/1.1 200 OK
---
End http

Observed output:

$ lua t2.lua 
---
Testing https
Welcome to ffl.shoeb.pw. We shall be serving you soon!!!        200     table: 0x5639643d1800   HTTP/1.1 200 OK
---
Testing http
lua: /usr/share/lua/5.4/socket/http.lua:54: bad argument #1 to 'receive' (string expected, got light userdata)
stack traceback:
        [C]: in function 'socket.http.request'
        t2.lua:12: in main chunk
        [C]: in ?

Explanation

HTTP call does not work. Diving into the source code to see what might be the cause yields the line:

 50 local function receiveheaders(sock, headers)
 51     local line, name, value, err
 52     headers = headers or {}
 53     -- get first line
 54     line, err = sock:receive()
 55     if err then return nil, err end
 56     -- headers go until a blank line is found
 57     while line ~= "" do

As you can see in the above code block, line 54 does not pass any arguments, so the argument the is passed will be self because of the : used in the function call.

I can confirm that this was working before my recent update to lua 5.4.3 So, mostly the recent update is what broke it as luasocket has not been updated for quite some time now.