waiter | 🕰️ Loading screens for Shiny | Data Visualization library

I am writing a script which creates various CloudFormation stacks, and want to start next stack when previous is done. Instead of 'sleep WHATEVER' I wish to use 'stack-exists' subcommand. ID of the stack in question is in StackId variable, and also is in StackId plaintext file. Here's the thing:

I am making a python-based mac app that uses discord.py to do stuff with discord. As I knew from previous experience making discord bots, running discord bots requires that you run Install Certificates.command in your version of python. However, if another users uses this app, I don't want to require them to install python. I took a snippet of code from Install Certificates.command, thinking it would put the certificate in the right place on a user's computer. However, a tester got this error running the app on their computer:

This code works on Windows 10 but not on Linux. Linux does not seem to receive any keyboard events at all. When interrupting the program on Linux with Ctrl-C, this is the stack trace:

This question is in the continuity of this one: Is it possible to stop executing of R code inside shiny (without stopping the shiny process)?.

The plot that I display in my app takes some time to produce, and I want the users to be able to stop its creation (for instance if they made a mistake in the options). I found this blog post about using callr in Shiny. The workflow is the following:

• create an empty list of jobs/plots
• clicking on "start" creates a background process to create the plot
  • if the user doesn't do anything, the plot is computed in the background. I use invalidateLater() every second to check if the background process is finished. If it is, then I display the plot.
  • if the user clicks on "stop" before the end of the process, the process is killed, removed from the list, and the previous plot is displayed (if there was no plot produced before, nothing is displayed)

First, I'm not sure how this would scale when several people use the app at the same time. Since every background process is independent, I don't think one user would be blocking the others, but I may be wrong.

Second, I'd like to show a waiting indicator on the plot. So far, I used the package waiter to do that, but the problem here is that renderPlot() is being invalidated every second to check if the background process is finished. Therefore, waiter appears and disappears repeatedly as the output is being invalidated.

Below is an example app that mimics the behavior I'd like to have:

I am trying to deploy an EC2 instance and associate an EIP to it, but I am getting and error when trying to associate the EIP because the instance is not running. This is my code:

Starting in iOS13, one can monitor the progress of an OperationQueue using the progress property. The documentation states that only operations that do not override start() count when tracking progress. However, asynchronous operations must override start() and not call super() according to the documentation.

Does this mean asynchronous operations and progress are mutually exclusive (i.e. only synchronous operations can be used with progress)? This seems like a massive limitation if this is the case.

In my own project, I removed my override of start() and everything appears to work okay (e.g. dependencies are only started when isFinished is set to true on the dependent operation internally in my async operation base class). BUT, this seems risky since Operation explicitly states to override start().

Thoughts?

Documentaiton references:

https://developer.apple.com/documentation/foundation/operationqueue/3172535-progress

By default, OperationQueue doesn’t report progress until totalUnitCount is set. When totalUnitCount is set, the queue begins reporting progress. Each operation in the queue contributes one unit of completion to the overall progress of the queue for operations that are finished by the end of main(). Operations that override start() and don’t invoke super don’t contribute to the queue’s progress.

https://developer.apple.com/documentation/foundation/operation/1416837-start

If you are implementing a concurrent operation, you must override this method and use it to initiate your operation. Your custom implementation must not call super at any time. In addition to configuring the execution environment for your task, your implementation of this method must also track the state of the operation and provide appropriate state transitions.

Update: I ended up ditching my AysncOperation for a simple SyncOperation that waits until finish() is called (using a semaphore).

I was playing with some web frameworks for Python, when I tried to use the framework aiohhtp with this code (taken from the documentation):

How to return for loop values without any html template in flask , in the below code I need to get all jokes values having multiple jokes route but i want them to be displayed as a list one below the other , currently the output I am getting is as a whole list item , I am aware i can use jinja for this but here i want to do without creating any html page

I have a website which I'm querying after solving a CAPTCHA. After solving the CAPTCHA my query downloads a PDF file. My issue is that I cannot get FireFox to download the file automatically to the current working directory without user interaction.

I also cannot figure out how to determine if the file already exists, which would prompt my code to display either a dialog or a message.

Here's my current code, which does everything correctly until the file download popup.