I want to get a value out of a website.
I want to get the ARS$ 3.435,63 out of this div and put it into a varible to calculate with.
<span class="market_commodity_orders_header_promote">ARS$ 3.435,63</span>
I have searched up some stuff but couldn't find anything to help me so if anybody know how to to this in lua that will be nice.
note: I am intermediate at lua
I have not tried "luasocket" because the download page is gone
To download a webpage using only the lua standard library, you can call curl if your system has it installed.
-- Download webpage
local file = assert(io.popen("curl site.name.com", "r"))
local htmlText = assert(f:read("*a"))
file:close()
-- Find commodity cost
local _, _, cost = htmlText:find("<span class=\"market_commodity_orders_header_promote\">(ARS\$ [0-9.,]+)<\/span>")
print(cost) -- Should print "ARS$ 3.435,63"
Related
I’m sure this is not a unique question about Lua 5.1 (especially an embedded instance, where you can’t install modules, your only options is pure Lua files/reference, therefore I can’t install something like luacurl ). I’ve seen this matter referred to in various SO places, and tried them, but I can’t seem to find a fix to make an https file download request work in this particular Lua environment..
To give you an example, the code below aims to download 2 different files, the http call works fine, returning a 200 code, but the https one doesn’t, it doesn’t return anything ?
Both targets can be access directly via the browser..
Please could some highlight what I’m missing in the https call to make it work?
print("--------DOWNLOAD http---------")
local http = require("socket.http")
local body, code = http.request("http://pbs.twimg.com/media/CCROQ8vUEAEgFke.jpg")
print(code)
if not body then error(code) end
local f = assert(io.open('mnt/nas/webtest1.jpg', 'wb')) -- open in "binary" mode
f:write(body)
f:close()
print("--------DOWNLOAD https---------")
local https = require "ssl.https" --luasec
local body, code = https.request("https://u.cubeupload.com/jbcooper/16146313918060.jpg")
print(code)
if not body then error(code) end
local f = assert(io.open('mnt/nas/webtest2.jpg', 'wb')) -- open in "binary" mode
f:write(body)
f:close()
As requested, the following returns nothing at all..
local https = require "ssl.https" --luasec
print(https.request("https://u.cubeupload.com/jbcooper/16146313918060.jpg"))
If it helps, if I run the following it returns 0.4
local https = require("ssl.https")
local httpsVersion = string.sub(https._VERSION,1,3)
print (httpsVersion)
I'm using Lua in Scite on Windows, but hopefully this is a general Lua question.
Let's say I want to write a temporary string content to a temporary file in Lua - which I want to be eventually read by another program, - and I tried using io.tmpfile():
mytmpfile = assert( io.tmpfile() )
mytmpfile:write( MYTMPTEXT )
mytmpfile:seek("set", 0) -- back to start
print("mytmpfile" .. mytmpfile .. "<<<")
mytmpfile:close()
I like io.tmpfile() because it is noted in https://www.lua.org/pil/21.3.html :
The tmpfile function returns a handle for a temporary file, open in read/write mode. That file is automatically removed (deleted) when your program ends.
However, when I try to print mytmpfile, I get:
C:\Users\ME/sciteLuaFunctions.lua:956: attempt to concatenate a FILE* value (global 'mytmpfile')
>Lua: error occurred while processing command
I got the explanation for that here Re: path for io.tmpfile() ?:
how do I get the path used to generate the temp file created by io.tmpfile()
You can't. The whole point of tmpfile is to give you a file handle without
giving you the file name to avoid race conditions.
And indeed, on some OSes, the file has no name.
So, it will not be possible for me to use the filename of the tmpfile in a command line that should be ran by the OS, as in:
f = io.popen("python myprog.py " .. mytmpfile)
So my questions are:
Would it be somehow possible to specify this tmpfile file handle as the input argument for the externally ran program/script, say in io.popen - instead of using the (non-existing) tmpfile filename?
If above is not possible, what is the next best option (in terms of not having to maintain it, i.e. not having to remember to delete the file) for opening a temporary file in Lua?
You can get a temp filename with os.tmpname.
local n = os.tmpname()
local f = io.open(n, 'w+b')
f:write(....)
f:close()
os.remove(n)
If your purpose is sending some data to a python script, you can also use 'w' mode in popen.
--lua
local f = io.popen(prog, 'w')
f:write(....)
#python
import sys
data = sys.stdin.readline()
In my Vim's configuration file init.vim I am using code, that sets a default viewer for practically any kind of file suffix. Here I will demonstrate only an example for .md files:
let g:netrw_browsex_viewer="-"
function! NFH_md(f)
call asyncrun#run("", "cwd", "typora " . a:f)
endfunction
First paragraph makes sure to choose the function based on suffix of the file ("URI under cursor"). Second paragraph shows a function whose name i.e. NFH_md implies that this is the function opened when .md file is in the "URI under the cursor". Inside this function there is an call that opens an external program typora asynchronously so that I am still able to continue using Vim.
If you want to know more use :help netrw_browsex_viewer.
I tried porting the mentioned Vim script to Neovim & Lua but I only managed to port first line:
vim.g.netrw_browsex_viewer="-"
For I don't know, how to properly port the second paragraph. This is why for now I just use Vimscript source code like this:
vim.api.nvim_exec(
[[
function! NFH_md(f)
call asyncrun#run("", "cwd", "marktext " . a:f)
endfunction
]],
false
)
But I would love to translate all the code to Lua - Could anyone help a bit to translate this remaining Vimscript code to Lua?
I am learning the Lua IO library. I'm having trouble with io.write(). In Programming Design in Lua, there is a piece of code that iterates through the file line by line and precedes each line with a serial number.
This is the file I`m working on:
test file: "iotest.txt"
This is my code
io.input("iotest.txt")
-- io.output("iotest.txt")
local count = 0
for line in io.lines() do
count=count+1
io.write(string.format("%6d ",count), line, "\n")
end
This is the result of the terminal display, but this result cannot be written to the file, whether I add IO. Output (" iotest.txt ") or not.
the results in terminal
This is the result of file, we can see there is no change
The result after code running
Just add io.flush() after your write operations to save the data to the file.
io.input("iotest.txt")
io.output("iotestout.txt")
local count = 0
for line in io.lines() do
count=count+1
io.write(string.format("%6d ",count), line, "\n")
end
io.flush()
io.close()
Refer to Lua 5.4 Reference Manual : 6.8 - Input and Output Facilities
io.flush() will save any written data to the output file which you set with io.output
See koyaanisqatsi's answer for the optional use of file handles. This becomes especially useful if you're working on multiple files at a time and gives you more control on how to interact with the file.
That said you should also have different files for input and output. You'll agree that it doesn't make sense to read and write from and to the same file alternatingly.
For writing to a file you need a file handle.
This handle comes from: io.open()
See: https://www.lua.org/manual/5.4/manual.html#6.8
A file handle has methods that acts on self.
Thats the function after the : at file handle.
So io.write() puts out on stdout and file:write() in a file.
Example function that can dump a defined function to a file...
fdump=function(func,path)
assert(type(func)=="function")
assert(type(path)=="string")
-- Get the file handle (file)
local file,err = io.open(path, "wb")
assert(file, err)
local chunk = string.dump(func,true)
file:write(chunk)
file:flush()
file:close()
return 'DONE'
end
Here are the methods, taken from io.stdin
close = function: 0x566032b0
seek = function: 0x566045f0
flush = function: 0x56603d10
setvbuf = function: 0x56604240
write = function: 0x56603e70
lines = function: 0x566040c0
read = function: 0x56603c90
This makes it able to use it directly like...
( Lua console: lua -i )
> do io.stdout:write('Input: ') local result=io.stdin:read() return result end
Input: d
d
You are trying to open the same file for reading and writing at the same time. You cannot do that.
There are two possible solutions:
Read from file X, iterate through it and write the result to another file Y.
Read the complete file X into memory, close file X, then delete file X, open the same filename for writing and write to it while iterating through the original file (in memory).
Otherwise, your approach is correct although file operations in Lua are more often done using io.open() and file handles instead of io.write() and io.read().
In the embeded lua environment (World of Warcraft - WoW) is missing the require function.
I want port one existing lua source code (an great OO-library) for the use it in the WoW. The library itself is relatively small (approx 8 small files) but of course it heavily uses the require.
World of Warcraft loads files and libraries by defining it in an XML file, like:
<Ui xsi:schemaLocation="http://www.blizzard.com/wow/ui/">
<Script file="LibOne.lua"/>
<Script file="LibTwo.lua"/>
</Ui>
but i don't know how the low level library manipulation is done in the WoW.
AFAIK in the WoW is missing even the package. table too. :(
So the question(s): For me, the streamlined way would be write an function which will emulate the require function using the interface available in WoW. The question is how. Could someone give me some directions?
Or as alternative, for the porting the mentioned existing source to WoW, I need replace the require Some.Other.Module lines in the lua sources to something what WoW will understand. What is the equivalent/replacement for such require Some.Module in the WoW?
How the WoW handles modules/libraries at low-level?
You could merge all files into one using one of the various amalgamation scripts, e.g. amalg. Then you can load this file and a stub that implements the require function using the usual WoW way:
<Ui xsi:schemaLocation="http://www.blizzard.com/wow/ui/">
<Script file="RequireStub.lua"/>
<Script file="AllModules.lua"/><!-- amalgamated Lua modules -->
<Script file="YourCode.lua"/>
</Ui>
The file RequireStub.lua could look like:
package = {}
local preload, loaded = {}, {
string = string,
debug = debug,
package = package,
_G = _G,
io = io,
os = os,
table = table,
math = math,
coroutine = coroutine,
}
package.preload, package.loaded = preload, loaded
function require( mod )
if not loaded[ mod ] then
local f = preload[ mod ]
if f == nil then
error( "module '"..mod..[[' not found:
no field package.preload[']]..mod.."']", 1 )
end
local v = f( mod )
if v ~= nil then
loaded[ mod ] = v
elseif loaded[ mod ] == nil then
loaded[ mod ] = true
end
end
return loaded[ mod ]
end
This should emulate enough of the package library to get you a working require that loads modules in the amalgamated file. Different amalgamation scripts might need different bits from package, though, so you probably will have to take a look at the generated Lua source code.
And in the specific case of Coat you might need to implement stubs for other Lua functions as well. E.g. I've seen that Coat uses the debug library ...
WoW environment doesn't have dofile or any other means to read external files at all. You need to explicitly mention all files that must be loaded in .toc file or .xml referenced from .toc.
You can then write your own implementation of require to maintain compatibility with your library, which would be quite trivial as it would only need to parse module name and retrieve it's content from modules.loaded table, but you'd still need to alter original source to make files register in that table and you'll need to manually arrange all files into correct order of loading.
Alternatively you can rearrange files into separate WoW-addons and use its own built-in Dependencies/OptionalDeps facilities or popular LibStub framework to handle loading order automatically.