The closest i've gotten to figuring this out, came from this post Understanding how to access values in array of tables in lua which actually has the most useful information i've seen. However, I'm still running into a minor issue that I hope someone could help me make more sense of it.
As the title states, I'm trying to access an object in lua. I've learned that dot notation doesn't work, so the alternative is to use [] brackets. I have this object here that I can't seem to access.
[1] = ▼ {
["CopperOre"] = ▼ {
["Counter"] = 0,
["Earned"] = 0
}
}
This was a paste from the ROBLOX studio console, for those who are familiar with it. This object can easily be seen by calling the object name print(obj)
However, I can't seem to access anything inside of the object. obj.CopperOre returns nil, same with obj['CopperOre']
How exactly do I access the parts of the object?
You are forgetting to pass the index into the obj array to access the object stored there.
So to properly access the CopperOre table, you need to reference it like this :
print(obj[1].CopperOre)
-- or
print(obj[1]["CopperOre"])
Related
I am very confused about something and I would appreciate some insight here.
Say I want to build a GUI that visualizes what is going on inside JShell, i.e. how the, by snippets created objects reference each other and what, by Snippets created objects are contained inside my running instance of JShell. How do I access these objects, and most of all, how do I access how they reference each other?
A concrete example: I create a JShell instance, pass it a few snippets created by the user, which cause the creation of, for example, an ArrayList, a few objects, and add said objects to said ArrayList.
How do I access this ArrayList and the objects contained within it to visualize this in a GUI?
To clarify further:
//say I create a Jshell:
JShell jShell = JShell.create();
//Which then evauletes user code passed from the GUI:
jShell.eval(userCode)
//userCode could be following lines each passed as separate Strings:
“ArrayList<TestObject> allObj = new ArrayList<TestObject>();”
“TestObject tst = new TestObject();”
“TestObject tst2 = new TestObject();”
“allObj.add(tst);”
“allObj.add(tst2);”
How do I access “allObj”?
How do I access “tst” and the object it points to? (the “TestObject”instance that “tst” points to);
I know eval() returns a list of SnippetEvents which contain the changed/added snippets, however, I can’t get my head around how to access the objects created by those snippets.
Assuming your classpath has access to the TestObj you could implement Serializable on that object. Upon completion of the eval run another method automatically that serializes the output. Then you can deserialize that object inside your code.
I'm struggling to work out how to retrieve the property values from a filter query in a CosmosDb stored procedure. I'm sure this must be relatively simple, but just can't seem to find the right combination.
var result = __.chain()
.filter(function(doc) {
return doc.id ==="1stDocId";
})
.map(function(doc) {
return {
id: doc.id,
propertyA: doc.propertyA
};
})
.value();
if(!result.isAccepted) throw new Error("The call was not accepted");
Using the above code, or similar, I'm wanting to retrieve the value of propertyA, and then use it in a second query, and so on.
Using response.setBody to return the value of result at this point, I can see it is sat in an array, but can't work out the correct code to access it.
result[0].PropertyA, result[0][0].PropertyA don't work, can someone point me in the right direction?
I'm able to do this sort of thing using the queryDocuments function, but ultimately my stored procedure needs to execute 5 or 6 select statements, manipulating the retrieved values in between. Utilising nested callbacks seems very messy, and pretty confusing once you're a few levels deep. Is there a better way?
Thanks.
Well I gave in, and wrote the procedure using nested callbacks and 'queryDocuments'. Since at one point my procedure requires a switch statement, which either performs a db lookup, or provides a hard value, I had to duplicate the rest of the queryDocument calls in the db lookup branch callback, which feels plain wrong.
However, whilst not being pretty, my stored procedure now works, returning the correct values in all cases.
i started learning lua and now i'm trying to deal with nested tables.
Basically i want to create a kind of local "database" using json interaction with lua (i found out that was the best thing to store my values)...
what i supposed to do is to scan all members inside a chatgroup (i'm using an unofficial telegram api) and store some values inside a table. I was able to retrieve all datas needed, so here's the structure declared in main function:
local dbs = load_data("./data/database.json")
dbs[tostring(msg.to.id)] = {
gr_name = {},
timestamp = "",
user = { --user changes into user ids
us_name = {},
us_nickname = {},
us_role = ""
},
}
where msg.to.id contains a valid number. This is what i tried to do:
dbs[tostring(id)]['users'][tostring(v.peer_id)]['us_nickname'] = v.username
this one works but this one:
dbs[tostring(id)]['users'][tostring(v.peer_id)] = table.insert(us_name,v.print_name)
(id is a correct number and matches with first field, same as all values passed like v.peer_id and v.print_name so those are not the problem)
gives error "table expected"... i'm pretty sure i have totally no idea of how to insert an element in such a table like mine.
Can anyone of you be so kind to help me? I hope to be clear enough explaining my issue.
Thanks in advance to everyone :)
To add new user name to an existing user you probably want to insert it into the sub-table like this:
table.insert(dbs[tostring(id)]['users'][tostring(v.peer_id)].us_name, v.print_name)
I have a model M that has a column C. At a certain point in my project I have a specific instance of M stored in memory, m. I also have the string "c", and I have found that both of these lines do the same thing (as far as I can tell):
m.send("c")
m["c"]
Is there a difference? Is there any reason to use one over the other?
P.S. - If you can come up with a better title, please comment, I had a hard time making an appropriate title.
You should just be using:
m.c
m["c"] is a shortcut for m.attributes['c'].
m.send("c") is used when you need to construct the method name to call dynamically:
index_type = "chapter"
m.send("open_to_#{index_type}", 1) # calls m.open_to_chapter(1)
Basically this comes up as one of the related posts:
Isn't it dangerous to have query information in javascript using breezejs?
It was someone what my first question was about, but accepting the asnwers there, i really would appreciate if someone had examples or tutorials on how to limit the scope of whats visible to the client.
I started out with the Knockout/Breeze template and changed it for what i am doing. Sitting with a almost finished project with one concern. Security.
I have authentication fixed and is working on authorization and trying to figure out how make sure people cant get something that was not intended for them to see.
I got the first layer fixed on the root model that a member can only see stuff he created or that is public. But a user may hax together a query using extend to fetch Object.Member.Identities. Meaning he get all the identities for public objects.
Are there any tutorials out there that could help me out limiting what the user may query.?
Should i wrap the returned objects with a ObjectDto and when creating that i can verify that it do not include sensitive information?
Its nice that its up to me how i do it, but some tutorials would be nice with some pointers.
Code
controller
public IQueryable<Project> Projects()
{
//var q = Request.GetQueryNameValuePairs().FirstOrDefault(k=>k.Key.ToLower()=="$expand").Value;
// if (!ClaimsAuthorization.CheckAccess("Projects", q))
// throw new WebException("HET");// UnauthorizedAccessException("You requested something you do not have permission too");// HttpResponseException(HttpStatusCode.MethodNotAllowed);
return _repository.Projects;
}
_repository
public DbQuery<Project> Projects
{
get
{
var memberid = User.FindFirst("MemberId");
if (memberid == null)
return (DbQuery<Project>)(Context.Projects.Where(p=>p.IsPublic));
var id = int.Parse(memberid.Value);
return ((DbQuery<Project>)Context.Projects.Where(p => p.CreatedByMemberId == id || p.IsPublic));
}
}
Look at applying the Web API's [Queryable(AllowedQueryOptions=...)] attribute to the method or doing some equivalent restrictive operation. If you do this a lot, you can subclass QueryableAttribute to suit your needs. See the Web API documentation covering these scenarios.
It's pretty easy to close down the options available on one or all of your controller's query methods.
Remember also that you have access to the request query string from inside your action method. You can check quickly for "$expand" and "$select" and throw your own exception. It's not that much more difficult to block an expand for known navigation paths (you can create white and black lists). Finally, as a last line of defense, you can filter for types, properties, and values with a Web API action filter or by customizing the JSON formatter.
The larger question of using authorization in data hiding/filtering is something we'll be talking about soon. The short of it is: "Where you're really worried, use DTOs".