localuser.lua

http = require("socket.http")
ltn12 = require("ltn12")

function fsize (file)
    local current = file:seek()      -- get current position
    local size = file:seek("end")    -- get file size
    file:seek("set", current)        -- restore position
    return size
end

pathToLocalFile="/tmp/server.py"
file = io.open(pathToLocalFile, "r")
sizeOfFile= fsize(file)
print(sizeOfFile)
file:close()

function upload ()
    local response_body={}
    socket.http.request{
        url = "http://localhost:8000/upload",
        method = "POST",
        headers = {
            ["Content-Type"] =  "multipart/form-data",
            ["Content-Length"] = sizeOfFile
        },
        source = ltn12.source.file(io.open(pathToLocalFile)),
        sink = ltn12.sink.table(response_body)
                }
    print(response_body[1])
end