I was trying to log in using LibCurl. Actually I am using LuaCurl the binding of libCurl in Lua. I am referring to this web page: http://www.hackthissite.org/articles/read/1078
I tried this:
> require("libcurl")
> c=curl.new()
> c:setopt(curl.OPT_USERAGENT,"Mozilla/4.0")
> c:setopt(curl.OPT_AUTOREFERER,true)
> c:setopt(curl.OPT_FOLLOWLOCATION,true)
> c:setopt(curl.OPT_COOKIEFILE,"")
> c:setopt(curl.OPT_URL,"https://www.chase.com")
> res=c:perform()
But after this last operation the program is stuck as if waiting for something. What am I doing wrong here?
Thanks
I tried your program and it seems to work fine. What I get is the content of the given site pumped to stdout. It seems you are just having networking issues...
If you want to capture the whole output as a string and process it later, you have to provide a callback using OPT_WRITEFUNCTION which will be called with more data which you can save. Here is a simplified version of how I implemented the GET method in my simple web-mining toolbox WDM.
local c = curl.new()
...
function get(url)
c:setopt(curl.OPT_URL,url)
local t = {} -- output will be stored here
c:setopt(curl.OPT_WRITEFUNCTION, function (a, b)
local s
-- luacurl and Lua-cURL friendly way
if type(a) == "string" then s = a else s = b end
table.insert(t, s) -- store this piece of data
return #s
end)
assert(c:perform())
return table.concat(t) -- return the whole content
end
Related
I am currently doing 2 steps in my code and I just realized I can combine both steps in a LUA script.
I am doing:
SPOP on my set
calling a lua script to do other things.
The value from step#1 is being passed and stored in the local variable ele.
My lua script looks like:
local ele = KEYS[1]
local p = KEYS[2]
local u = KEYS[3]
if redis.call("SISMEMBER", u, ele) == 0 then
..
..
return "OK"
else
return "EXISTS"
end
How can I call SPOP from inside my lua script and store it in a variable.
I need to do:
local popped = redis.call("SPOP", "my-set-here")
I'm not sure if that will work, but then I have to check if it is null or has a value I guess. Just want to make sure I am following best practise.
BTW, as a side note, what is the fastest way to create and test lua scripts?
You can check the value of popped for non-nillness with something like:
if popped then
-- do something
end
As for developing Redis Lua scripts, have a look at Zerobrane's integration:
http://notebook.kulchenko.com/zerobrane/redis-lua-debugging-with-zerobrane-studio
https://redislabs.com/blog/zerobrane-studio-plugin-for-redis-lua-scripts/
Disclosure: I was involved in the integration effort ;)
I'm using Corona SDK for the first time and read up on how to call functions from other files, but I seem to be having issues. Here are the two scripts so far:
timer.lua
local M = {}
function M.Timer(n, count) --(period, how many times repeated)
if count > 0 then
local iter= os.time()+n
while iter ~= os.time() do
end
M.onTime(count)
count = count - 1
M.Timer(n,count)
end
end
function M.onTime(count)
display.newtext(count,250,50,native.systemFont,16)
end
return M
main.lua
local timeTool = require("timer")
timeTool.Timer(1,5)
They are located in the same directory. When I run main.lua on the simulator, I get the error attempt to call field 'Timer' (a nil value). This leads me to believe that the main file failed in acquiring the contents of the timer script, but from what I've seen, I am using the correct syntax. Is there something I missed, or am I using the wrong method for calling functions from other scripts?
I'm quite new to Lua and Embedded programming. I'm working on a project:
IoT node that can be abstractedinto two parts: sensor and a board that runs Open WRT with Lua 5.1. I'm writing script that would be called from crontab every minute.
In my script I'm accessing data from the sensor via package written with C. The result of reading data from sensor is 'hexadecimal numbers returned in string:
4169999a4180cccd41c9851f424847ae4508e0003ddb22d141700000418e666641c87ae14248147b450800003dc8b439
Then convert it (string) to values I need and POST it to API.
Problem:
Sometimes API is not reachable due to poor network connection.
So I need to implement system where I would read a data from a sensor and then if API is not responding, I would save it to a FIFO queue (buffer). And then next time when script is called to read it would be sending 'old' records first and the newest one and the end.
local queue_filespec = [[/path/to/your/queue/file]]
-- Initially your "queue file" (regular file!) must contain single line:
-- return {}
local function operation_with_queue(func)
local queue = dofile(queue_filespec)
local result = func(queue)
for k, v in ipairs(queue) do
queue[k] = ("%q,\n"):format(v)
end
table.insert(queue, "}\n")
queue[0] = "return {\n"
queue = table.concat(queue, "", 0)
local f = assert(io.open(queue_filespec, "w"))
f:write(queue)
f:close()
return result
end
function add_to_queue(some_data)
operation_with_queue(
function(queue)
table.insert(queue, some_data)
end
)
end
function extract_from_queue()
-- returns nil if queue is empty
return operation_with_queue(
function(queue)
return table.remove(queue, 1)
end
)
end
Usage example:
add_to_queue(42)
add_to_queue("Hello")
print(extract_from_queue()) --> 42
print(extract_from_queue()) --> Hello
print(extract_from_queue()) --> nil
I'm writting a lua script as wireshark(1.12.4) plugin to dissect my private protocols,I can get it work as normal dissector,which binding a certain port(such as 80) to DissectorTable "tcp.port".The pseudo-code as follows：
local my_pro = Proto("MyPro","My Protocol")
local my_pro_field_1 = ProtoField.uint16("MyPro.filed_1","Field 1",base.HEX)
local my_pro_field_2 = ProtoField.uint16("MyPro.filed_2","Field 2",base.HEX)
my_pro.fields = {my_pro_field_1,my_pro_field_2}
local data_dis = Dissector.get("data")
function my_pro.dissector(buf,pkt,root)
if (buf(0,2):uint() ~= 1 or buf(2,2):uint() ~= 1) then
data_dis:call(buf,pkt,root)
return false
end
pkt.cols.protocol = "My Protocol"
local tree = root:add(my_pro,buf(0,buf:len()))
tree:add_le(my_pro_field_1,buf(0,2))
tree:add_le(my_pro_field_2,buf(2,2))
return true
end
local tcp_encap_table = DissectorTable.get("tcp.port")
tcp_encap_table:add(80,my_pro)
The problem is:
What if My protocol is not running on a certain port,as I don't want to modify the port above every time,I actually want the dissector to be wise enough to dynamically identify some kind of pattern and do the right dissecting then.
I've searched out there's a so called "heuristic" dissector,I add codes below to test but I could't get it work.
local function my_heur_dissector(buf,pkt,root)
local ret = my_pro.dissector(buf,pkt,root)
if (not ret) then
return false
end
pkt.conversation = my_pro
return true
end
my_pro:register_heuristic("tcp",my_heur_dissector)
When I change the port,the packets're not parsed as my protocol,so I have to use "Decode as" menu.
So,how can I get the heuristic dissector work base on my code?Have I missed something?
BTW,the answer with code is appreciated.
Sadly, if you need a heuristic dissector (HD) it cannot be done in a plugin manner, and you need to write a new HD.
https://github.com/wireshark/wireshark/blob/master/doc/README.heuristic
(Yes, it has been over 2 years, but if some future-googler finds it...)
I'm generating some (non-html) documentation for a Lua library that I developed. I will generate the documentation by hand, but I'd appreciate some kind of automation if possible (i.e. generating skeletons for each function so I can fill them in)
I'd like to know if there's a way for lua to know the names of the parameters that a function takes, from outside it.
For example, is there a way to do this in Lua?
function foo(x,y)
... -- any code here
end
print( something ... foo ... something)
-- expected output: "x", "y"
Thanks a lot.
ok,here is the core code:
function getArgs(fun)
local args = {}
local hook = debug.gethook()
local argHook = function( ... )
local info = debug.getinfo(3)
if 'pcall' ~= info.name then return end
for i = 1, math.huge do
local name, value = debug.getlocal(2, i)
if '(*temporary)' == name then
debug.sethook(hook)
error('')
return
end
table.insert(args,name)
end
end
debug.sethook(argHook, "c")
pcall(fun)
return args
end
and you can use like this:
print(getArgs(fun))
Try my bytecode inspector library. In Lua 5.2 you'll be able to use debug.getlocal.
Take a look at debug.getinfo, but you probably need a parser for this task. I don't know of any way to fetch the parameters of a function from within Lua without actually running the function and inspecting its environment table (see debug.debug and debug.getlocal).
function GetArgs(func)
local args = {}
for i = 1, debug.getinfo(func).nparams, 1 do
table.insert(args, debug.getlocal(func, i));
end
return args;
end
function a(bc, de, fg)
end
for k, v in pairs(GetArgs(a)) do
print(k, v)
end
will print
1 bc
2 de
3 fg
Basically we use debug.getinfo to retrieve the nparams attribute (which gives us the information of how many parameters the function takes) and debug.getlocal to access the name of the parameters.
Tested and working with Lua 5.4
Take a look at the luadoc utility. It is sort of like Doxygen, but for Lua. It is intended to allow the documentation to be written in-line with the source code, but it could certainly be used to produce a template of the documentation structure to be fleshed out separately. Of course, the template mechanism will leave you with a maintenance issue down the road...