How to send messages to Webhook from Lua using io.read

Question

I'm need it for Webhook so i not tired to type from editing

local message = [[ {"username":"example","avatar_url": "example.com","content": (where io.read will be content)

Answer 1

By using the ]] and [[ and concat (..) do it like...

Lua 5.3.5  Copyright (C) 1994-2018 Lua.org, PUC-Rio
>  message = [[ {"username":"example","avatar_url": "example.com","content":"]] .. io.read() .. [["}]]
content
> print(message)
 {"username":"example","avatar_url": "example.com","content":"content"}

Also it looks better when Output something (prompt) before io.read()...

io.write('Content: ')
local message = [[ {"username":"example","avatar_url": "example.com","content":"]] .. io.read() .. [["}]]
print(message)

Answer 2

Discord webhooks use JSON. You can use a JSON library such as lunajson to properly escape your inputs. It is written in pure Lua and can therefore always be used when Lua is available (doesn't require any C libraries / compilation / complex installation).

local lunajson = require"lunajson"
local content = io.read()
local json_message = lunajson.encode{
    username = "example",
    avatar_url = "example.com",
    content = content
}

as you can see this also makes your code much more readable (you get syntax highlighting for the table that you're encoding using JSON).

Do not use naive string interpolation: It will break when quotes are used (which is common in English language messages) and can be abused to send requests differing from what you intended.

If for whatever reason you do not want to use lunajson, insisting on buggy string manipulation, at the very least escape your input to remove double quotes; you also don't need long strings [[...]], single quotes suffice and string.format further helps with improving readability:

-- HACK don't do this
local content = io.read()
local json_message = ('{"username":"example","avatar_url":"example.com","content": "%s"}'):format(content:gsub('"', '\\"'))

Note also that "example.com" points to a webpage rather than an image file.