1 # This file is part of NIT ( http://www.nitlanguage.org ).
3 # Copyright 2016 Alexandre Terrasa <alexandre@moz-code.org>
5 # Licensed under the Apache License, Version 2.0 (the "License");
6 # you may not use this file except in compliance with the License.
7 # You may obtain a copy of the License at
9 # http://www.apache.org/licenses/LICENSE-2.0
11 # Unless required by applicable law or agreed to in writing, software
12 # distributed under the License is distributed on an "AS IS" BASIS,
13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 # See the License for the specific language governing permissions and
15 # limitations under the License.
17 # Repositories for data management.
19 # Repositories are used to apply persistence on instances (or **documents**).
20 # Using repositories one can store and retrieve instance in a clean and maintenable
23 # This module provides the base interface `Repository` that defines the persistence
24 # services available in all kind of repos.
25 # `JsonRepository` factorizes all repositories dedicated to Json data or objects
26 # serializable to Json.
28 # `MongoRepository` is provided as a concrete example of repository.
29 # It implements all the services from `Repository` using a Mongo database as backend.
31 # Repositories can be used in Popcorn app to manage your data persistence.
32 # Here an example with a book management app:
35 # # First we declare the `Book` class. It has to be serializable so it can be used
36 # # within a `Repository`.
39 # import popcorn::pop_repos
41 # # Serializable book representation.
46 # var id: String = (new MongoObjectId).id is serialize_as "_id"
53 # redef fun to_s do return title
54 # redef fun ==(o) do return o isa SELF and id == o.id
55 # redef fun hash do return id.hash
58 # # We then need to subclass the `MongoRepository` to provide Book specific services.
60 # # Book repository for Mongo
62 # super MongoRepository[Book]
64 # # Find books by title
65 # fun find_by_title(title: String): Array[Book] do
66 # var q = new JsonObject
72 # # The repository can be used in a Handler to manage book in a REST API.
79 # # Return a json array of all books
81 # # If the get parameters `title` is provided, returns a json array of books
82 # # matching the `title`.
83 # redef fun get(req, res) do
84 # var title = req.string_arg("title")
85 # if title == null then
86 # res.json new JsonArray.from(repo.find_all)
88 # res.json new JsonArray.from(repo.find_by_title(title))
93 # redef fun post(req, res) do
94 # var title = req.string_arg("title")
95 # if title == null then
99 # var book = new Book(title)
105 # # Let's wrap it all together in a Popcorn app:
108 # var mongo = new MongoClient("mongodb://localhost:27017/")
109 # var db = mongo.database("tests_app_{100000.rand}")
110 # var coll = db.collection("books")
114 # var repo = new BookRepo(coll)
115 # app.use("/books", new BookHandler(repo))
116 # app.listen("localhost", 3000)
120 import popcorn
::pop_config
123 import mongodb
::queries
125 redef class AppConfig
127 # Default database host string for MongoDb
128 var default_db_host
= "mongodb://localhost:27017/"
130 # Default database hostname
131 var default_db_name
= "popcorn"
134 var opt_db_host
= new OptionString("MongoDb host", "--db-host")
136 # MongoDb database name
137 var opt_db_name
= new OptionString("MongoDb database name", "--db-name")
139 # MongoDB server used for data persistence
140 fun db_host
: String do return opt_db_host
.value
or else ini
["db.host"] or else default_db_host
142 # MongoDB DB used for data persistence
143 fun db_name
: String do return opt_db_name
.value
or else ini
["db.name"] or else default_db_name
147 add_option
(opt_db_host
, opt_db_name
)
151 var client
= new MongoClient(db_host
) is lazy
154 var db
: MongoDb = client
.database
(db_name
) is lazy
157 # A Repository is an object that can store serialized instances.
159 # Repository is the base class of all kind of persistance processes. It offers
160 # the base CRUD services to save (add/update), find and delete instances.
162 # Instances are stored in their serialized form. See the `serialization` package
163 # for more documentation.
164 interface Repository[E
: Serializable]
166 # Kind of queries accepted
168 # Can be redefined to accept more precise queries depending on the backend used.
169 type QUERY: RepositoryQuery
171 # Find an instance by it's `id`
173 # `id` is an abstract thing at this stage
174 # TODO maybe introduce the `PrimaryKey` concept?
175 fun find_by_id
(id
: String): nullable E
is abstract
177 # Find an instance based on `query`
178 fun find
(query
: QUERY): nullable E
is abstract
180 # Find all instances based on `query`
182 # Using `query` == null will retrieve all the document in the repository.
183 fun find_all
(query
: nullable QUERY, skip
, limit
: nullable Int): Array[E
] is abstract
185 # Count instances that matches `query`
186 fun count
(query
: nullable QUERY): Int is abstract
189 fun save
(instance
: E
): Bool is abstract
191 # Remove the instance with `id`
192 fun remove_by_id
(id
: String): Bool is abstract
194 # Remove the instance based on `query`
195 fun remove
(query
: nullable QUERY): Bool is abstract
197 # Remove all the instances matching on `query`
198 fun remove_all
(query
: nullable QUERY): Bool is abstract
200 # Remove all instances
201 fun clear
: Bool is abstract
203 # Serialize an `instance` to a String.
204 fun serialize
(instance
: nullable E
): nullable String is abstract
206 # Deserialize a `string` to an instance.
207 fun deserialize
(string
: nullable String): nullable E
is abstract
210 # An abstract Query representation.
212 # Since the kind of query available depends on the database backend choice or
213 # implementation, this interface is used to provide a common type to all the
216 # Redefine `Repository::QUERY` to use your own kind of query.
217 interface RepositoryQuery end
219 # A Repository for JsonObjects.
221 # As for document oriented databases, Repository can be used to store and retrieve
223 # Serialization from/to Json is used to translate from/to nit instances.
225 # See `MongoRepository` for a concrete implementation example.
226 abstract class JsonRepository[E
: Serializable]
229 redef fun serialize
(item
) do
230 if item
== null then return null
231 var stream
= new StringWriter
232 var serializer
= new RepoSerializer(stream
)
233 serializer
.serialize item
238 redef fun deserialize
(string
) do
239 if string
== null then return null
240 var deserializer
= new JsonDeserializer(string
)
241 return deserializer
.deserialize
.as(E
)
245 private class RepoSerializer
248 # Remove caching when saving refs to db
249 redef fun serialize_reference
(object
) do serialize object
252 # A Repository that uses MongoDB as backend.
256 # import popcorn::pop_repos
258 # # First, let's create a User abstraction:
260 # # Serializable user representation.
269 # var password: String is writable
271 # redef fun to_s do return login
274 # # We then need to subclass the `MongoRepository` to provide User specific services:
276 # # User repository for Mongo
278 # super MongoRepository[User]
280 # # Find a user by its login
281 # fun find_by_login(login: String): nullable User do
282 # var q = new JsonObject
288 # # The repository can then be used with User instances:
291 # var mongo = new MongoClient("mongodb://localhost:27017/")
292 # var db = mongo.database("tests")
293 # var coll = db.collection("test_pop_repo_{100000.rand}")
295 # # Create a user repo to store User instances
296 # var repo = new UserRepo(coll)
298 # # Create some users
299 # repo.save(new User("Morriar", "1234"))
300 # repo.save(new User("Alex", "password"))
302 # assert repo.find_all.length == 2
303 # assert repo.find_by_login("Morriar").password == "1234"
305 # assert repo.find_all.length == 0
307 class MongoRepository[E
: Serializable]
308 super JsonRepository[E
]
310 redef type QUERY: JsonObject
312 # MongoDB collection used to store objects
313 var collection
: MongoCollection
315 redef fun find_by_id
(id
) do
316 var query
= new JsonObject
321 redef fun find
(query
) do
322 var res
= collection
.find
(query
)
323 if res
== null then return null
324 return deserialize
(res
.to_json
)
327 redef fun find_all
(query
, skip
, limit
) do
328 var res
= new Array[E
]
329 for e
in collection
.find_all
(query
or else new JsonObject, skip
, limit
) do
330 res
.add deserialize
(e
.to_json
).as(E
)
335 redef fun count
(query
) do
336 return collection
.count
(query
or else new JsonObject)
339 redef fun save
(item
) do
340 var json
= serialize
(item
).as(String)
341 var obj
= json
.parse_json
.as(JsonObject)
342 return collection
.save
(obj
)
345 redef fun remove_by_id
(id
) do
346 var query
= new JsonObject
351 redef fun remove
(query
) do
352 return collection
.remove
(query
or else new JsonObject)
355 redef fun remove_all
(query
) do
356 return collection
.remove_all
(query
or else new JsonObject)
359 redef fun clear
do return collection
.drop
361 # Perform an aggregation query over the repo.
362 fun aggregate
(pipeline
: JsonArray): Array[E
] do
363 var res
= new Array[E
]
364 for obj
in collection
.aggregate
(pipeline
) do
365 var instance
= deserialize
(obj
.to_json
)
366 if instance
== null then continue
373 # Base serializable entity that can go into a JsonRepository
375 # Provide boiler plate implementation of all object serializable to json.
377 # `id` is used as a primary key for `find_by_id`.
379 # Subclassing RepoObject makes it easy to create a serializable class:
381 # import popcorn::pop_repos
392 # Do not forget the `serialize` annotation else the fields will not be serialized.
394 # It is also possible to redefine the `id` primary key to use your own:
396 # import popcorn::pop_repos
402 # redef var id = "order-{get_time}"
408 abstract class RepoObject
413 # This attribute is serialized under the key `_id` to be used
414 # as primary key by MongoDb
415 var id
: String = (new MongoObjectId).id
is writable, serialize_as
"_id"
417 # Base object comparison on ID
419 # Because multiple deserialization can exists of the same instance,
420 # we use the ID to determine if two object are the same.
421 redef fun ==(o
) do return o
isa SELF and id
== o
.id
423 redef fun hash
do return id
.hash
424 redef fun to_s
do return id
427 # JsonObject can be used as a `RepositoryQuery`.
430 redef class JsonObject
431 super RepositoryQuery