JarCastingps2-census-java
ps2-census is an unofficial wrapper of the Planetside 2 Census API written in Java. The project itself was inspired by spascou's ps2-census for python and its methods and class structure leans heavily on his. This design choice was made to ensure that usage of this tool is as intuitive as possible. The description and structure of this readme have been adopted from spascou and adjusted for this project.
Features:
- Build queries through method chaining
- Join collections and nest them through method chaining
- Get raw (deserialized) responses as JsonNodes
- Parse raw (deserialized) responses into a corresponding list of tree structures
- Access common enums directly
- Subscribe to event streams
By default the example service ID is used; however it is not recommended for production. You should get your own service ID from the webside below and supply it to the client whenever needed.
More information about the Census API is available on the official Census documentation here.
Iridar's blog is also recommended to understand the quirks of this particular API as this knowledge is necessary to use ps2-census properly.
Installation
Apache Maven
<dependency>
<groupId>io.github.luiziffer</groupId>
<artifactId>ps2-census</artifactId>
<version>0.1.5</version>
</dependency>
Gradle
implementation 'io.github.luiziffer:ps2-census:0.1.5'
Query building
Queries are made on collections with optional joins on other collections as well as various commands that alter the output.
A Census API collection is analog to a relation in a generic relational database system, and a Census API join is analog to a join between these relations.
Basic query
To build a query, instantiate the Query class with a Collection (and your service ID, though it will be omitted in next examples for conciseness):
import census.Query;
import census.anatomy.Collection;
Query query = new Query(Collection.ITEM, service_id=YOUR_SERVICE_ID);
Chain methods to alter the query further:
Query query = new Query(Collection.ITEM)
.lang("en")
.sort(("item_id", 1), ("faction_id", -1))
.limit(30)
[...];
Available methods are:
filter(String, SearchModifier, String...): filter the query on a field;census.anatomy.SearchModifiercontains all the modifiers made available by the Census API (SearchModifier.CONTAINS,SearchModifier.LESS_OR_EQUAL, ...)show(String...): only return the provided fields in resultshide(String...): do not return the provided fields in resultssort(Pair<String,Integer>...): sort the results by field, either in increasing or decreasing orderhas(String...): only return results which have the specified fieldscase(boolean): whetherfilter()s are case sensive or not; default toTruelimit(int arg): limit the return to at mostargresults; required in tendem withstart()for queries having too large of a result and therefore fail; defaults to1limit_per_db(int arg): limit the return to at mostarg * databases countresults; useful when querying theCollection.CHARACTERcollection whose objects are randomly distributed among multiple databases in order to have more predictable resultsstart(int): start with theargth object within the results of the queryinclude_null(boolean): whether to include keys withNonevalues in results; defaults toFalselang(String): only keep the supplied language for internationalized stringsjoin(census.Join): perform a collection join; see the following documentation for additional detailstree(census.Tree): rearrange lists of data into trees; see the following documentation for additional detailstiming(boolean): show query timing informationexact_match_first(boolean): when usingfilter()s withSearchModifiers, put exact matches at the top of the results list disregardingsort()sdistinct(String): get the distinct values for a certain fieldretry(boolean): retry queries at most one time before failing; defaults toTrue
Execute the query in one of the 2 ways made available by the Census API:
.count()to get the items count
query.count();
> 21048
.get()to get the results
query.get();
> {'item_list': [{...}, {...}, ...], 'returned': 30}
count() and get() calls are when the query is actually sent to the Census API endpoint. They will raise status exceptions if appropriate.
Simple join
In order to perform joins instantiate the Join class with a Collection, add any additional chained methods to it, and pass it to the Query object via query.join():
import census.Query;
import census.Join;
import census.anatomy.Collection;
Query query = new Query(Collection.ITEM)
.join(
new Join(Collection.WEAPON_DATASHEET)
.outer(0)
.on("item_id")
.to("item_id")
.inject_at("weapon_datasheet")
[...]
);
Available Join methods are:
join(Join...): nest another join within this one; see the following documentation for additional detailson(String): specify the field on this collection (theQueryor parentJoin) to join on; if not provided will default to this collection's ID ({this_type}_id)to(String): specify the field on the other collection (theJoin's) to join to; if not provided will default to theonvaluelist(int): whether the joined data is a list (and therefore will result in a list of objects) or not;1if it is a list,0if not; default to0show(String...): only keep the provided fields in resultshide(String...): do not keep the provided fields in resultsinject_at(String): the field name where the joined data will be injected in the parent element (Queryresult item or parentJoinelement)terms(Pair<String,String>[]): filter the join result by a dictionary of conditions (eg.{"faction_id": 1, "skill_set_id": 129})outer(int): whether the join will perform an outer join (include non-matches) of an inner join (exclude non-matches);1for outer,0for inner; defaults to1
Multiple joins can be performed one after another on the same Query and the trees will be merged in the result:
Query query = new Query(Collection.ITEM)
.join(
new Join(Collection.WEAPON_DATASHEET)
)
.join(
new Join(Collection.ITEM_TO_WEAPON)
);
Nesting joins
Joins can be nested one into another both deeply and lateraly. Nesting is done by reference: each Join instance contains a list of references to its nested Joins.
Note: be careful about modifying the Join instances after their creation if you assign them to locals for convenience, as shown in the following examples. As nesting is done by reference and the whole structure is "compiled" (into a querystring) on the call to query.join(), if any modification is done to an instance between its creation and the resolution, it will indirectly impact the result of any other parent and/or nested Join.
Deeply nested join
Deeply nested join are necessary in order to access data structures deeper in the collections tree. To deeply nest joins, instantiate the Join class multiple times and combine them through join1.join(join2.join(join3)) where join3 is nested within join2 and join2 is nested within join1:
import census.Query;
import census.Join;
import census.anatomy.Collection;
import census.enums;
Join item_to_weapon_join = new Join(Collection.ITEM_TO_WEAPON)
.on("item_id")
.to("item_id")
.inject_at("item_to_weapon");
Join weapon_join = new Join(Collection.WEAPON)
.on("weapon_id")
.to("weapon_id")
.inject_at("weapon");
Join weapon_to_fire_group_join = new Join(Collection.WEAPON_TO_FIRE_GROUP)
.on("weapon_id")
.to("weapon_id")
.inject_at("weapon_to_fire_group");
Query query = new Query(Collection.ITEM)
.filter("item_type_id", ItemType.WEAPON)
.join(
item_to_weapon_join.join(
weapon_join.join(
weapon_to_fire_group_join
)
)
);
Lateraly nested joins
Lateraly nested joins are necessary in order to access data structures at the same depth in the collections tree. To laterally nest joins, instantiate the Join class multiple times and combine them through join1.join(join2).join(join3) or join1.join(join2, join3) where join2 and join3 are nested within join1:
import census.Query;
import census.Join;
import census.anatomy.Collection;
Join fire_group_to_fire_mode_join = new Join(Collection.FIRE_GROUP_TO_FIRE_MODE)
.outer(0)
.on("fire_group_id")
.to("fire_group_id")
.list(1)
.inject_at("fire_group_to_fire_modes");
Join fire_mode_join = new Join(Collection.FIRE_MODE_2)
.outer(0)
.on("fire_mode_id")
.to("fire_mode_id")
.inject_at("fire_mode");
Join fire_mode_to_projectile_join = new Join(Collection.FIRE_MODE_TO_PROJECTILE)
.outer(0)
.on("fire_mode_id")
.to("fire_mode_id")
.inject_at("fire_mode_to_projectile");
Join player_state_group_join = new Join(Collection.PLAYER_STATE_GROUP_2)
.outer(0)
.on("player_state_group_id")
.to("player_state_group_id")
.list(1)
.inject_at("player_state_groups");
Query query = new Query(Collection.WEAPON_TO_FIRE_GROUP)
.join(
fire_group_to_fire_mode_join
.join(
fire_mode_join
.join(fire_mode_to_projectile_join)
.join(player_state_group_join)
)
)
)
Tree
Trees are also built using their own class, Tree, then passed to the Query object:
import census.Query;
import census.Tree;
import census.anatomy.Collection;
Query query = new Query(Collection.ITEM)
.tree(
new Tree("name.en")
.prefix("en_name_")
[...]
);
This will return a list of items with their english name prefixed by en_name_ as keys and the objects themselves as values, instead of a flat list of items.
Available methods are:
list(int):0if tree data is not a list,1if it is a list; defaults to0prefix(String): prefix to add to the field valuestart(String): where the tree starts; defaults to the root (root list objects will be formatted as a tree)
Common enums
Census API data uses a lot of integer enumerations that are collections themselves.
For example the faction_id key in items from Collection.ITEM is an integer that represents a specific fation, refering to Collection.FACTION: Vanu is 1, NC is 2 etc.
In order to reduce the amount of necessary joins, which are arguably the most complex part of Census queries, some common enumerations are provided in census.enums, including:
- ArmorFacing
- FacilityType
- Faction
- FireModeType
- ItemType
- ItemCategory
- MetagameEventState
- PlayerState
- ProjectileFlightType
- ResistType
- ResourceType
- RewardType
- TargetType
- Vehicle
- World
These typically do not change often and ps2-census will be updated whenever there is such a change.
They can be used just for reference, but also in queries for filtering.
See the following example for filtering weapon items only using census.enums.ItemType:
import census.query;
import census.enums.ItemType;
Query query = new Query(Collection.ITEM)
.filter("item_type_id", ItemType.WEAPON.toString());
Event Stream
ps2-census offers a client that handles connection to the WebSocket endpoint, subscription to various streams and reception of the events. In the event of a disconnect, the client will wait for roughly 90 seconds and then close the websocket connection. This will likely cause the client to call the onFailure(...) methods contained in the listeners. The connection can be resumed by the resume() method.
Usage
This is a basic example on how to connect and subscribe. For more in depth information have a look at the examples folder. The GenericEventPrinter class inherits from EventStreamListener and simply prints any messages or status changes to standard out. This example will connect to the event stream, subscribe to all player deaths, print everything for 10 seconds and then disconnect.
EventStreamClient client = EventStreamClient.getInstance();
GenericEventPrinter listener = new GenericEventPrinter();
client.addEventListeners(listener);
client.connect();
client.subscribe(GenericCharacter.ALL.toString(), CharacterEvent.DEATH);
try {
TimeUnit.SECONDS.sleep(10);
client.close();
} catch (InterruptedException | IOException e) {
e.printStackTrace();
Thread.interrupted();
}
NOTE: The following example works, but doesn't call the onClosing(...) and onClosed(...) methods of listeners. To circumvent this issue simply add a one or two second delay after the connection was closed.
try (EventStreamClient client = EventStreamClient.getInstance())
{
GenericEventPrinter listener = new GenericEventPrinter();
client.addEventListeners(printer);
client.connect();
client.subscribe(GenericCharacter.ALL.toString(), CharacterEvent.DEATH);
try {
TimeUnit.SECONDS.sleep(10);
} catch (InterruptedException | IOException e) {
e.printStackTrace();
Thread.interrupted();
}
}
//Add delay here
More information about the Planetside2 Census event stream can be found at here.
Similar projects
- leonhard-s' auraxium
- spascou ps2-census