55 lines
1.5 KiB
ReStructuredText
55 lines
1.5 KiB
ReStructuredText
.. _tornado_change_stream_example:
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Tornado Change Stream Example
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=============================
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.. currentmodule:: motor.motor_tornado
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Watch a collection for changes with :meth:`MotorCollection.watch` and display
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each change notification on a web page using web sockets.
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Instructions
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------------
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Start a MongoDB server on its default port and run this script. Then visit:
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http://localhost:8888
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Open a ``mongo`` shell in the terminal and perform some operations on the
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"test" collection in the "test" database:
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.. code-block:: none
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> use test
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switched to db test
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> db.test.insertOne({})
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> db.test.updateOne({}, {$set: {x: 1}})
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> db.test.deleteOne({})
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The application receives each change notification and displays it as JSON on
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the web page:
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.. code-block:: none
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Changes
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{'documentKey': {'_id': ObjectId('5a2a6967ea2dcf7b1c721cfb')},
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'fullDocument': {'_id': ObjectId('5a2a6967ea2dcf7b1c721cfb')},
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'ns': {'coll': 'test', 'db': 'test'},
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'operationType': 'insert'}
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{'documentKey': {'_id': ObjectId('5a2a6967ea2dcf7b1c721cfb')},
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'ns': {'coll': 'test', 'db': 'test'},
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'operationType': 'update',
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'updateDescription': {'removedFields': [], 'updatedFields': {'x': 1.0}}}
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{'documentKey': {'_id': ObjectId('5a2a6967ea2dcf7b1c721cfb')},
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'ns': {'coll': 'test', 'db': 'test'},
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'operationType': 'delete'}
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Display change notifications over a web socket
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----------------------------------------------
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.. literalinclude:: tornado_change_stream_example.py
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:language: python3
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