wget.lua

-- Author: InDieTasten on tekkit.lycodon.com
-- Date created: 2018-02-24
-- Lua script for use in ComputerCraft

local args = {...}

local function printUsage()
    local pathToMe = shell.getRunningProgram()
    local fileName = fs.getName(pathToMe)
    print("Usage:")
    print(string.format("%s <url> <filename>", fileName))
    print(" url      - HTTP(S) url of a file in the www")
    print(" filename - Target file to download to")
end

local function main(args)

    if (#args ~= 2) then
        printUsage()
        return
    end

    local url = args[1]
    local filePath = args[2]


    -- test url
    if (http.checkURI) then
        if (not http.checkURI(url)) then
            printError("Provided URL is not whitelisted in the ComputerCraft config")
            return
        end
    end

    -- download content
    term.write("Downloading...")
    local success, requestHandle = pcall(http.get, url)
    if (not success) then
        printError(requestHandle)
    end
    if (requestHandle == nil) then
      printError("Not found")
      return
    end
    local responseBody = requestHandle.readAll()
    requestHandle.close()
    print(string.format("done (%i bytes)", #responseBody))

    -- check for existing file
    local resolvedFilePath = shell.resolve(filePath)
    if (fs.exists(resolvedFilePath)) then
        printError(string.format("File %q already exists", resolvedFilePath))
        return
    end

    -- write to file
    term.write("Writing to file...")
    local fileHandler = fs.open(resolvedFilePath, "w")
    if (not fileHandler) then
        printError("Write-access to %q was denied", resolvedFilePath)
        return
    end
    fileHandler.write(responseBody)
    fileHandler.close()
    print("done")
end

main({...})