https://github.com/mitar/web-mongo

An experiment connecting to MongoDB server from web browser and using Change Streams for reactive updates.
https://github.com/mitar/web-mongo

mongodb nodejs reactive vue web

Last synced: about 1 month ago
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An experiment connecting to MongoDB server from web browser and using Change Streams for reactive updates.

• Host: GitHub
• URL: https://github.com/mitar/web-mongo
• Owner: mitar
• Created: 2018-03-12T16:36:32.000Z (almost 7 years ago)
• Default Branch: master
• Last Pushed: 2018-03-12T18:21:25.000Z (almost 7 years ago)
• Last Synced: 2024-10-19T15:18:45.461Z (3 months ago)
• Topics: mongodb, nodejs, reactive, vue, web
• Language: JavaScript
• Homepage:
• Size: 108 KB
• Stars: 18
• Watchers: 4
• Forks: 1
• Open Issues: 5
• Metadata Files:
  • Readme: README.md

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README

        
This is an experiment connecting to MongoDB server from web browser and using

[Change Streams](https://docs.mongodb.com/manual/changeStreams/) for reactive updates.

The idea is that by allowing web clients to directly connect to a MongoDB database server we remove all the overhead

and latency introduced by intermediary code: multiple serializations and deserializations, memory buffers, etc. Because

web browsers cannot directly connect to a TCP port, the web app exposes a thin WebSockets-TCP proxy which does not

process packets but just passes them back and forth.

Change Streams is an official MongoDB API since MongoDB 3.6 to hook into the oplog and receive a stream

of notifications as documents in a collection are being modified.

This web app then uses [Vue](https://vuejs.org/) to render the example reactive collection.

Considerations:

* You will probably want to enable authentication on the MongoDB server and expose only some collections as

  read-only for an user the web app would be connecting as. You would provide this user's username and password

  as part of your web app code.

* Modifications to database should come through regular RPC calls through the web app instead of directly

  modifying the database from the web app.

* This requires MongoDB to be publicly available on the Internet. Even with enabled authentication it is unclear

  how secure this is. This is not how MongoDB is generally deployed and it might be that there are some unknown

  security issues with such deployment.

* There is a suggested (not sure if hard) limit of 1000 Change Streams queries per MongoDB data node. So not

  sure how scalable this is, but you could try to increase number of replicas and introduce sharding.

* If you do not want to send change stream for the whole collection to the client and you use `$match` to limit

  changes being streamed, note that there will be no change notification when a document stops matching a query.

  Because of this the best is to build your reactive collection around fields you never change.

* This simple web app's bundle is already 1.2 MB minimized.

## How to run ##

You should have a MongoDB instance with replica set configured. You can do this by running MongoDB in a Docker container:

```

$ docker run -d --rm -p 27017:27017 --name mongo mongo:3.6.3 --replSet app

$ echo 'rs.initiate({_id: "app", members: [{_id: 0, host: "127.0.0.1:27017"}]})' | docker exec -i mongo mongo

```

After that you can run this web app:

```

$ npm run build

$ npm run start

```

Open [http://localhost:5000/](http://localhost:5000/).

You can click "Add event" button to add a random message to the event log, which is then reactively shown to you.