How to architect a collaborative web application for live updates?

When using collaborative applications like issue trackers, planning tools, etc. it can be very frustrating to have to keep hitting refresh to make sure you’re viewing the same state as your colleagues. Therefore I want to build my applications so that when one user changes something, it shows up on everyone’s screens. But I struggle to find good architectural discussions beyond "use polling" or "use web sockets".

I can imagine a few ways of doing it:

  1. Use event sourcing throughout the application. User actions are sent as commands to the server and the server responds with events. The client maintains its own projection.

    Pros: Only one round trip of latency. All the benefits of CQRS.

    Cons: Complex logic for maintaining consistency, fetching snapshots, etc., both on the server and the client. While conceptually simple, event sourcing can be quite complex, especially for ad-hoc implementations.

  2. A conventional server, but update notifications are sent to the client on a side channel. The client is then responsible for fetching the new data. A way of implementing this would be to build a conventional RESTful HTTP interface, but every time a PUT, POST or DELETE is made, clients receive the URL of the resource that changed, make another GET to it.

    Pros: Apart from the notification channel, it’s a mature design pattern as old as the web itself, supported by frameworks, relational databases, etc. and easy for everyone to grok.

    Cons: Double round trip latency. Needs a message queue or something if multiple back-end instances are used.

  3. When objects change, push entire new copies to the client. Instead of one-shot fetching, clients subscribe to resources. The server can be implemented according to either of the above strategies, with the associated pros and cons.

    Pros: One round trip latency. Very simple client.

    Cons: Could be wasteful to send a lot of big objects that the client might not even need.

SharePoint file updates reminder/push notification questions

I have an Excel sheet (worklog) in my SharePoint folder, I wonder if it is possible to have a feature that:

  • Send a push notification/or reminder to remind the people having access to the Excel sheet to do data entry at the end of each business day.

  • When changes are made to the Excel sheet by a person (e.g named A), the admin/or defined managing user group will receive a push notification telling that A has updated the file.

As long as those 2 needs can be achieved, I don’t mind if the solutions require external services or coding work. It would be great if the community can give me hint/map to follow for such requirements.

Thanks a lot.

Cheers,

Viet

root access – Stopping Android updates?

Ok, so I have a question with which android apps/files are responsible for phone updates and app updates?. For instance let’s say using a standard tracfone no particular brand or if needed Samsung A21. And I have the phone set up exactly how I want it and I want absolutely no updates to any system or application files. The phone is rooted. Which files would I remove to keep it exactly like it is? Android version would be of that of the new tracphones found at any walmart.

linux – x server fails to start after system updates

i rebooted my system after a few months (since april 2020).

just before reboot, i had updated the whole system (kernel, nvidia drivers etc) and since then, the x server fails to start normally.

i use xdm+i3wm combination for my daily usage.

the log files at /var/log/xdm and xorg are empty as well as ~/.local/share/xorg

the output from most recent boot can be found here http://sprunge.us/96m4nD

I’m unsure on how to proceed on this issue. I’ve tried

  • recreating the xorg.conf file from scratch using nvidia-xconfig
  • removing and reinstalling all nvidia+xorg packages
  • trying sddm/lxdm instead of xdm

any help would be appreciated

sharepoint enterprise – Flow Updates Library Column with ID from PowerApps

I am still in desparate need of resolution.

I have a Gallery in which I enter data – including a User created ‘JobUnqID’. I am Patching the ‘JobUnqID’ to the List. I am uploading a document the an attachment control to a ‘JobDocsLibrary’. The Flow is below. Where do I add the language the will Patch (as this is a new document) the appropriate and specific ‘JobCQUnqID’ along side the document in the Library as a result of the Patch / Flow action. I’ve gotten it to kinda work; but its overwritting the wrong item (or multiple wrong items) in the Library.

Flow:

When and item is created

Site

List Name: JobsLibrary

Get Files (properties only)

Site (same as above)

Library Name: JobsDocLibrary

(Both of the above have a column for ‘JobCQUnqID’; the ‘JobCQUnqID’ is being created in the PowerApps Gallery and Patched to the ‘JobsList’)

Apply to each

Value

Update file properties

Site

Library Name: ‘JobDocsLibrary’

Id: SpID (items(‘Apply_to_each_2’)?(ID)

JobCQUnqID: (items((‘Apply_to_each_2’)?(‘JobCQUnqID’)

customization – Possible to create a “variant” page template that only contains differences and is therefore resilient to updates of original (ie page.php)?

I would like to create a page template in my child theme called “Services” – this template is identical to page.php in design (I just want to add some https://schema.org/Service JSON LD markup to these pages).

However I’m concerned that in the event of a theme update, that my template will become “orphaned”… that is, page.php will get changed fundamentally on the parent theme, but my services-page.php file will not reflect those changes.

As such:

Is there a smarter way of creating a template so that I don’t need to use a “snapshot” of the entire page.php file, but could (eg) only include the changed (schema) code, and then call the original page.php for the rest of it – so that it always matches the parent theme’s page.php template otherwise?

I hope that all makes sense – I am open to another solution but so far a template seems to be the easiest way to insert this code on these services pages.

Thanks!

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Thanks

automatic updates – is it right choose to connect database in template page directly in WordPress site?

i’m a little bit new in WordPress and for now working on WordPress site that some information will insert to database from forms … i design some page template and use mysqli_connect() to connect database and mysqli_query() to insert data to database .

the question i wonder is , am i do mistake ? is it possible that pages or piece of database erase after WordPress updates or totaly Could something bad happen? should change anything or not ?

i will thanks to anyone that help me. 🙂

c# – Dúvida com relação a UPDATES com JOIN no Entity Framework

Tenho o seguinte SQL (que roda perfeitamente no SQL Server) e gostaria de converter para seu equivalente no Entity Framework (dotnet core 5):

UPDATE A
   SET A.Valor = A.Valor + B.OutroValor
  FROM TabelaA A INNER JOIN TabelaB B ON (B.CampoQualquer = 1 AND B.Codigo = A.Codigo)

Tem algum jeito de fazer isso sem recorrer a foreach, while, etc?