luaapi – Lua library to read/write DiscoDBs

The lua API links against libdiscodb at runtime and provides a thin wrapper to the functionality.

This api is currently read only

The following examples demonstrate a prebuilt ddb obtained using

wget http://pkgs.bauman.space/discodb/myths.ddb -O /tmp/myths.ddb`

Examples

Basic discodb wrapper for Lua.

libdiscodb.so should be in LD_LIBRARY_PATH

Open and list keys

local ffi = require("ffi")
local ddblib = ffi.load("libdiscodb.so", true)  -- Load lib into global
local discodb = require("discodb")
local db = discodb.open("/tmp/myths.ddb")
local iter = db:keys()
for i = 1,#iter do
    print(i, iter:next())
end

Open and get individual key

local ffi = require("ffi")
local ddblib = ffi.load("libdiscodb.so", true)  -- Load lib into global
local discodb = require("discodb")
local db = discodb.open("/tmp/myths.ddb")
local iter = db:get("Major")
for i = 1,#iter do
    print(i, iter:next())
end

Check Key Exists Before Accessing

Depends on the control flow of choice.

Either handle the error of attempting to access next() on a nil iter or check iter is not nil before calling next() on it.

local ffi = require("ffi")
local ddblib = ffi.load("libdiscodb.so", true)  -- Load lib into global
local discodb = require("discodb")
local db = discodb.open("/tmp/myths.ddb")
local iter = db:get("Major")
iter = db:get("key-should-not-exist")
if iter then
    for i = 1,#iter do
        print(i, iter:next())
    end
else
    print("key does not exist")
end