I have web application written with Spine.js. It has 2 language translations. I want to store current application's translation in Spine Model.
My model:
class Translation extends Spine.Model
#configure "Translation", "lang"
#getLang: ->
Translation.all()
module.exports = Translation
I have function which changes translation in application and i save new translation to the model in this function:
changeLang: (locale) ->
lang = Translation.create({lang: locale})
lang.save()
But when i try to fetch data from Translation model from another controller i get empty result:
Translation = require("models/translation")
...
alert(Translation.getLang())
I got empty alert. How can i make it correctly?
Thank you.
The Translation.all() returns copies of all instances of Translation class. It seems, from snippets you provided, that when you call Translation.getLang() there are no such instances. You should make sure that changeLang has been called (I suppose that it is the only place where new instances of Translation are created) before calling alert(Translation.getLang()).
Related
Suppose I have a person.proto file-
syntax = "proto3";
/* Class Person */
message Person{
string name = 2;
}
Then, I use protoc to generate the source code in Python, or C++.
Question 1:
Suppose I generated the API code, now what I can do to create an object of Person class, is:
person = person_pb2.Person() # In Python
Person person; // In C++
What I want is, every time I create an object of Person class, the reference to this object is stored with a unique ID inside a map.
Basically, I want to create something like a map, to store the reference of every object of each class that is ever created.
One way to achieve this I thought of is to add a custom line of code (which calls a different function) to the classes' constructor, such that every time an object is created, that function will add reference to it to the map.
Is this approach good? If yes, then how to achieve this- customizing class constructors of protoc generated source code (in every language- C++, Python, Java, etc.). If no, then what could be a better solution?
Question 2: For the fields, we have setters and getters. e.g.
person.name = ... # In Python
person.set_name(...) // In CPP
So, what if I want to add something more to the set_name() function, how can we do that?
Like if I want to call a function inside set_name(), then how to achieve that?
In short, both the questions sum up as "How to make changes to the functions of API that protoc generates (in all the languages)?"
Is there something to do with plugins? Or with descriptor files? Or something else?
We are working on a Top-Down-RPG-like Multiplayer game for learning purposes (and fun!) with some friends. We already have some Entities in the Game and Inputs are working, but the network implementation gives us headache :D
The Issues
When trying to convert with dict some values will still contain the pygame.Surface, which I dont want to transfer and it causes errors when trying to jsonfy them. Other objects I would like to transfer in a simplyfied way like Rectangle cannot be converted automatically.
Already functional
Client-Server connection
Transfering JSON objects in both directions
Async networking and synchronized putting into a Queue
Situation
A new player connects to the server and wants to get the current game state with all objects.
Data-Structure
We use a "Entity-Component" based architecture, so we separated the game logic very strictly into "systems", while the data is stored in the "components" of each Entity. The Entity is a very simple container and has nothing more than a ID and a list of components. Example Entity (shorten for better readability):
Entity
|-- Component (Moveable)
|-- Component (Graphic)
| |- complex datatypes like pygame.SURFACE
| `- (...)
`- Component (Inventory)
We tried different approaches, but all seems not to fit very well or feel "hacky".
pickle
Very Python near, so not easy to implement other clients in future. And I´ve read about some security risks when creating items from network in this dynamic way how pickle it offers. It does not even solve the Surface/Rectangle issue.
__dict__
Still contains the reference to the old objects, so a "cleanup" or "filter" for unwanted datatypes happens also in the origin. A deepcopy throws Exception.
...\Python\Python36\lib\copy.py", line 169, in deepcopy
rv = reductor(4)
TypeError: can't pickle pygame.Surface objects
Show some code
The method of the "EnitityManager" Class which should generate the Snapshot of all Entities, including their components. This Snapshot should be converted to JSON without any errors - and if possible without much configuration in this core-class.
class EnitityManager:
def generate_world_snapshot(self):
""" Returns a dictionary with all Entities and their components to send
this to the client. This function will probably generate a lot of data,
but, its to send the whole current game state when a new player
connects or when a complete refresh is required """
# It should be possible to add more objects to the snapshot, so we
# create our own Snapshot-Datastructure
result = {'entities': {}}
entities = self.get_all_entities()
for e in entities:
result['entities'][e.id] = deepcopy(e.__dict__)
# Components are Objects, but dictionary is required for transfer
cmp_obj_list = result['entities'][e.id]['components']
# Empty the current list of components, its going to be filled with
# dictionaries of each cmp which are cleaned for the dump, because
# of the errors directly coverting the whole datastructure to JSON
result['entities'][e.id]['components'] = {}
for cmp in cmp_obj_list:
cmp_copy = deepcopy(cmp)
cmp_dict = cmp_copy.__dict__
# Only list, dict, int, str, float and None will stay, while
# other Types are being simply deleted including their key
# Lists and directories will be cleaned ob recursive as well
cmp_dict = self.clean_complex_recursive(cmp_dict)
result['entities'][e.id]['components'][type(cmp_copy).__name__] \
= cmp_dict
logging.debug("EntityMgr: Entity#3: %s" % result['entities'][3])
return result
Expectation and actual results
We can find a way to manually override elements which we dont want. But as the list of components will increase we have to put all the filter logic into this core class, which should not contain any components specializations.
Do we really have to put all the logic into the EntityManager for filtering the right objects? This does not feel good, as I would like to have all convertion to JSON done without any hardcoded configuration.
How to convert all this complex data in a most generic approach?
Thanks for reading so far and thank you very much for your help in advance!
Interesting articles which we were already working threw and maybe helpful for others with similar issues
https://gafferongames.com/post/what_every_programmer_needs_to_know_about_game_networking/
http://code.activestate.com/recipes/408859/
https://docs.python.org/3/library/pickle.html
UPDATE: Solution - thx 2 sloth
We used a combination of the following architecture, which works really great so far and is also good to maintain!
Entity Manager now calls the get_state() function of the entity.
class EntitiyManager:
def generate_world_snapshot(self):
""" Returns a dictionary with all Entities and their components to send
this to the client. This function will probably generate a lot of data,
but, its to send the whole current game state when a new player
connects or when a complete refresh is required """
# It should be possible to add more objects to the snapshot, so we
# create our own Snapshot-Datastructure
result = {'entities': {}}
entities = self.get_all_entities()
for e in entities:
result['entities'][e.id] = e.get_state()
return result
The Entity has only some basic attributes to add to the state and forwards the get_state() call to all the Components:
class Entity:
def get_state(self):
state = {'name': self.name, 'id': self.id, 'components': {}}
for cmp in self.components:
state['components'][type(cmp).__name__] = cmp.get_state()
return state
The components itself now inherit their get_state() method from their new superclass components, which simply cares about all simple datatypes:
class Component:
def __init__(self):
logging.debug('generic component created')
def get_state(self):
state = {}
for attr, value in self.__dict__.items():
if value is None or isinstance(value, (str, int, float, bool)):
state[attr] = value
elif isinstance(value, (list, dict)):
# logging.warn("Generating state: not supporting lists yet")
pass
return state
class GraphicComponent(Component):
# (...)
Now every developer has the opportunity to overlay this function to create a more detailed get_state() function for complex types directly in the Component Classes (like Graphic, Movement, Inventory, etc.) if it is required to safe the state in a more accurate way - which is a huge thing for maintaining the code in future, to have these code pieces in one Class.
Next step is to implement the static method for creating the items from the state in the same Class. This makes this working really smooth.
Thank you so much sloth for your help.
Do we really have to put all the logic into the EntityManager for filtering the right objects?
No, you should use polymorphism.
You need a way to represent your game state in a form that can be shared between different systems; so maybe give your components a method that will return all of their state, and a factory method that allows you create the component instances out of that very state.
(Python already has the __repr__ magic method, but you don't have to use it)
So instead of doing all the filtering in the entity manager, just let him call this new method on all components and let each component decide that the result will look like.
Something like this:
...
result = {'entities': {}}
entities = self.get_all_entities()
for e in entities:
result['entities'][e.id] = {'components': {}}
for cmp in e.components:
result['entities'][e.id]['components'][type(cmp).__name__] = cmp.get_state()
...
And a component could implement it like this:
class GraphicComponent:
def __init__(self, pos=...):
self.image = ...
self.rect = ...
self.whatever = ...
def get_state(self):
return { 'pos_x': self.rect.x, 'pos_y': self.rect.y, 'image': 'name_of_image.jpg' }
#staticmethod
def from_state(state):
return GraphicComponent(pos=(state.pos_x, state.pos_y), ...)
And a client's EntityManager that recieves the state from the server would iterate for the component list of each entity and call from_state to create the instances.
I have a simple example model where I would like to generate names for the objects of the Position rule that were not given a name with as <NAME>. This is needed so that I can find them later with the built-in FQN scope provider.
My idea would be to do this in the position_name_generator object processor but that will be only be called after the whole model is parsed. I don´t really understand the reason for that, since by the time I would need a Position object in the Project, the objects are already created, still the object processor will not be called.
Another idea would be to do this in a custom scope provider for Position.location which would then first do the name generation and then use the built-in FQN to find the Location object. Although this would work, I consider this hacky and I would prefer to avoid it.
What would be the textX way of solving this issue?
(Please take into account that this is only a small example. In reality a similar functionality is required for a rather big and complex model. To change this behaviour with the generated names is not possible since it is a requirement.)
import textx
MyLanguage = """
Model
: (locations+=Location)*
(employees+=Employee)*
(positions+=Position)*
(projects+=Project)*
;
Project
: 'project' name=ID
('{'
('use' use=[Position])*
'}')?
;
Position
: 'define' 'position' employee=[Employee|FQN] '->' location=[Location|FQN] ('as' name=ID)?
;
Employee
: 'employee' name=ID
;
Location
: 'location' name=ID
( '{'
(sub_location+=Location)+
'}')?
;
FQN
: ID('.' ID)*
;
Comment:
/\/\/.*$/
;
"""
MyCode = """
location Building
{
location Entrance
location Exit
}
employee Hans
employee Juergen
// Shall be referred to with the given name: "EntranceGuy"
define position Hans->Building.Entrance as EntranceGuy
// Shall be referred to with the autogenerated name: <Employee>"At"<LastLocation>
define position Juergen->Building.Exit
project SecurityProject
{
use EntranceGuy
use JuergenAtExit
}
"""
def position_name_generator(obj):
if "" == obj.name:
obj.name = obj.employee.name + "At" + obj.location.name
def main():
meta_model = textx.metamodel_from_str(MyLanguage)
meta_model.register_scope_providers({
"Position.location": textx.scoping.providers.FQN(),
})
meta_model.register_obj_processors({
"Position": position_name_generator,
})
model = meta_model.model_from_str(MyCode)
assert model, "Could not create model..."
if "__main__" == __name__:
main()
What is the textx way to solve this...
The use case you describe is to define the name of an object based on other model elements, including a reference to other model elements. This is currently not part of any test and use cases included in our test suite and the textx docu.
Object processors are executed at defined stages during model construction (see http://textx.github.io/textX/stable/scoping/#using-the-scope-provider-to-modify-a-model). In the described setup they are executed after reference resolution. Since the name to be defined/deduced itself is required for reference resolution, object processors cannot be used here (even if we allow to control when object processors are executed, before or after scope resolution, the described setup still will not work).
Given the dynamics of model loading (see http://textx.github.io/textX/stable/scoping/#using-the-scope-provider-to-modify-a-model), the solution is located within a scope provider (as you suggested). Here, we allow to control the order of reference resolution, such that references to the object being named by a custom procedure are postponed, until references required to deduce/define the name resolved.
Possible workaround
A preliminary sketch of how your use case can be solved is discussed in a https://github.com/textX/textX/pull/194 (with an attached issue https://github.com/textX/textX/issues/193). This textx PR contains a version of scoping.py you could probably use for your project (just copy and rename the module). A full-fledged solution could be part of the textx TEP-001, where we plan to make scoping more controllable to the end-user.
Playing around with this absolutely interesting issue revealed new aspects to me for the textx framework.
names dependent on model contents (involving unresolved references). This name resolution, which can be Postponed (in the referenced PR, see below), in terms of our reference resolution logic.
Even more interesting are the consequences of that: What happens to references pointing to locations, where unresolved names are found? Here, we must postpone the reference resolution process, because we cannot know if the name might match when resolved...
Your example is included: https://github.com/textX/textX/blob/analysis/issue193/tests/functional/test_scoping/test_name_resolver/test_issue193_auto_name.py
I'm using com.hp.hpl.jena.rdf.model.Model.listNameSpaces() to obtain the namespaces in a Jena RDF model.
But I've noticed that the model can contain statement objects with namespaces not listed by the listNameSpaces method.
For example, the camera graph (http://www-users.cs.york.ac.uk/~jc/teaching/arin/camera.owl.turtle) contains the following objects, but their namespace does not appear in the namespace list:
http://www.dbpedia.org/resource/ Nikon
http://www.w3.org/2001/XMLSchema# decimal
Does anybody know why those two ns would not be listed? Thanks.
//condensed code:
Model model = ModelFactory.createDefaultModel();
RDFReader reader = model.getReader("TURTLE");
InputStream in = FileManager.get().open("http://www-users.cs.york.ac.uk/~jc/teaching/arin/camera.owl.turtle");
reader.read(model, in, null);
NsIterator listNameSpaces = model.listNameSpaces();
while (listNameSpaces.hasNext())
{
System.out.println("Namespace from iterator: " + listNameSpaces.next());
}
The API documentation for that method says:
The namespaces returned are those of (a) every URI used as a property in the model and (b) those of every URI that appears as the object of an rdf:type statement.
Since dbpedia:Nikon and xsd:decimal are used as object and type of a Literal, respectively, the method doesn't return the namespace.
The docs also state:
(You probably don't want this method; more likely you want the PrefixMapping methods that Model supports.)
They are documented here.
i'm using CSS3 accordion effect, and i want to detect if a hacker will
make a script to make a parallel request; ie:
i've a login form and a registration form in the same page, but only
one is visible because there is a CSS3: to access the page, the user
agent must be HTML5 compatible.
the tip i use is:
class Register(tornado.web.RequestHandler):
def post(self):
tt = self.get_argument("_xsrf") + str(time.time())
rtime = float(tt.replace(self.get_argument("_xsrf"), ""))
print rtime
class LoginHandler(BaseHandler):
def post(self):
tt = self.get_argument("_xsrf") + str(time.time())
ltime = float(tt.replace(self.get_argument("_xsrf"), ""))
print ltime
i've used the xsrf variable because it's unique for every user, to
avoid making the server think that the request is coming from the same
machine.
now what i want: how to make the difference between time values:
abs(ltime - rtime) ; mean, how do i access to rtime outside the class,
i just know how to access the value outside the method, i want to make
this operation to detect if the value is small, then the user is using
a script to make a parallel request to kill the server!
in other words (for general python users)
if i have:
class Product:
def info(self):
self.price = 1000
def show(self):
print self.price
>>> car = Product()
>>> car.info()
>>> car.show()
1000
but what if i've another
class User:
pass
then how do make a method that prints me the self.price, i've tried
inheritance, but got error: AttributeError: User instance has no
attribute 'price', so only methods are passed, not attributs?
It sounds like you need to understand Model objects and patterns that use persistant storage of data. tornado.web.RequestHandler and any object that you subclass from it only exists for the duration of your request. From when the URL is received on the server to when data is sent back to the browser via a self.write() or self.finish().
I would recommend you look at some of the Django or Flask tutorials for some basic ideas of how to build a MVC application in Python (There is no Tornado Tutorials that cover this that I know of).