Monitorear datos con flujos de cambios

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// Watch for changes in a collection by using a change stream
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import { MongoClient } from "mongodb";
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// Replace the uri string with your MongoDB deployment's connection string.
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const uri = "<connection string uri>";
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const client = new MongoClient(uri);
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// Declare a variable to hold the change stream
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let changeStream;
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// Define an asynchronous function to manage the change stream
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async function run() {
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  try {
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    const database = client.db("insertDB");
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    const haikus = database.collection("haikus");
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    // Open a Change Stream on the "haikus" collection
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    changeStream = haikus.watch();
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    // Print change events as they occur
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    for await (const change of changeStream) {
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      console.log("Received change:\n", change);
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    }
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    // Close the change stream when done
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    await changeStream.close();
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  } finally {
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    // Close the MongoDB client connection
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    await client.close();
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  }
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}
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run().catch(console.dir);

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/* Change stream listener */
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import { MongoClient } from "mongodb";
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// Replace the uri string with your MongoDB deployment's connection string
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const uri = "<connection string uri>";
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const client = new MongoClient(uri);
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const simulateAsyncPause = () =>
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  new Promise(resolve => {
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    setTimeout(() => resolve(), 1000);
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  });
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let changeStream;
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async function run() {
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  try {
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    const database = client.db("insertDB");
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    const haikus = database.collection("haikus");
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    // Open a Change Stream on the "haikus" collection
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    changeStream = haikus.watch();
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    // Set up a change stream listener when change events are emitted
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    changeStream.on("change", next => {
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      // Print any change event
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      console.log("received a change to the collection: \t", next);
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    });
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    // Pause before inserting a document
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    await simulateAsyncPause();
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    // Insert a new document into the collection
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    await myColl.insertOne({
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      title: "Record of a Shriveled Datum",
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      content: "No bytes, no problem. Just insert a document, in MongoDB",
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    });
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    // Pause before closing the change stream
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    await simulateAsyncPause();
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    // Close the change stream and print a message to the console when it is closed
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    await changeStream.close();    
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    console.log("closed the change stream");
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  } finally {
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    // Close the database connection on completion or error
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    await client.close();
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  }
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}
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run().catch(console.dir);