MyApp | React Native 工程化实践 | State Container library

a) Even if obviously it could be better, is this solution is acceptable or not at all ?

I think it has some problems you want to address, but the general idea of using the filesystem and storing just filenames can be acceptable, depending on how many users you need to serve and what guarantees regarding data consistency and concurrent accesses you want to make.

I would consider the uploaded file temporary data that may be lost on system failure. If you want to provide any guarantees of not losing the data, you want to store it in a database instead of on the filesystem.

b) I pass 'uploaded_file' from one view to another using "request.session" is it a good practice? Is there another way to do it without using GET variables?

There are up- and downsides to using request.session.

• attackers can not change the filename and thus retrieve data of other users. This is also the reason why you should not use a GET parameter here: If you used one, attackers could simpy change that parameter and get access to files of other users.
• users can upload a file, go and do other stuff, and later come back to actually import the file, however:
• if users end their session, you lose the filename. Also, users can not upload the file on one device, change to another device, and then go on with the import, since the other device will have a different session.

The last point correlates with the leftover files problem: If you lose your information about which files are still needed, it makes cleaning up harder (although, in theory, you can retrieve which files are still needed from the session store).

If it is a problem that sessions might end or change because users clear their cookies or change devices, you could consider adding the filename to the UserProfile in the database. This way, it is not bound to sessions.

c) At first my wish was to avoid to save the csv-file. But I could not figure out how to do it? Reading all the file to request.session seems not a good idea for me. Is there some possibility to upload the file into memory in Django?

You want to store state. The go-to ways of storing state are the database or a session store. You could load the whole CSVFile and put it into the database as text. Whether this is acceptable depends on your databases ability to handle large, unstructured data. Traditional databases were not originally built for that, however, most of them can handle small binary files pretty well nowadays. A database could give you advantages like ACID guarantees where concurrent writes to the same file on the file system will likely break the file. See this discussion on the dba stackexchange

Your database likely has documentation on the topic, e.g. there is this page about binary data in postgres.

d) If I have to use the tmp-file. How should I handle the situation if user abandon upload at the middle (for example, he sees the confirmation page, but does not click "yes" and decide to re-write his file). How to remove the tmp-file?

Some ideas:

• Limit the count of uploaded files per user to one by design. Currently, your filename is based on a timestamp. This breaks if two users simultaneously decide to upload a file: They will both get the same timestamp, and the file on disk may be corrupted. If you instead use the user's primary key, this guarantees that you have at most one file per user. If they later upload another file, their old file will be overwritten. If your user count is small enough that you can store one leftover file per user, you don't need additional cleaning. However, if the same user simultaneusly uploads two files, this still breaks.
• Use a unique identifier, like a UUID, and delete the old stored file whenever the user uploads a new file. This requires you to still have the old filename, so session storage can not be used with this. You will still always have the last file of the user in the filesystem.
• Use a unique identifier for the filename and set some arbitrary maximum storage duration. Set up a cronjob or similar that regularly goes through the files and deletes all files that have been stored longer than your specified maximum duration. If a user uploads a file, but does not do the actual import soon enough, their data is deleted, and they would have to do the upload again. Here, your code has to handle the case that the file with the stored filename does not exist anymore (and may even be deleted while you are reading the file).

You probably want to limit your server to one file stored per user so that attackers can not fill your filesystem.

e) Small additional question : what kind of checks there are in Django about uploaded file? For example, how could I check that the file is at least a text-file? Should I do it?

You definitely want to set up some maximum file size for the file, as described e.g. here. You could limit the allowed file extensions, but that would only be a usability thing. Attackers could also give you garbage data with any accepted extension.

Keep in mind: If you only store the csv as text data that you load and parse everytime a certain view is accessed, this can be an easy way for attackers to exhaust your servers, giving them an easy DoS attack.

Overall, it depends on what guarantees you want to make, how many users you have and how trustworthy they are. If users might be malicious, you want to keep all possible kinds of data extraction and resource exhaustion attacks in mind. The filesystem will not scale out (at least not as easily as a database).

I know of a similar setup in a project where only a handful of priviliged users are allowed to upload stuff, and we can tolerate deletion of all temporary files on failure. Users will simply have to reupload their files. This works fine.

The issue with default guard. So it should be web

it looks like the variable that has value is amp;code; not code. Do you have 2 ampersands somewhere by any chance? Yes you do -

What can I do to ensure that it's only called once?

Nothing, that's how it's meant to work. In the View system you would not ask "Why is my view invalidated 3 times?". The framework invalidates (recomposes) the view as it needs, you should not need to know or care when that happens.

The issue with your code is that your Composable is reading the old value from preferences, that is not how it should work, that value should be provided by the viewmodel as part of the state. Instead of providing just the new price, expose a Data Class that has both the new and old price and then use those 2 values in your composable to determine what color to show, or expose the price and the color to use.

The SAP IAS Tenant was configured with OpenID connect. For some reason, logout functionality is not working with OpenID Connect and there is not clear document on this. Once switched from OpenID Connect to SAML, logout functionality is working fine. This is a work around and may not be an actual solution. It's an issue with SAP CF. They have to solve it.

This Blog will help you configure your IAS Tenant.

Note: Logout is not working with default identity provider too. And IAS Tenant is not available for trial accounts.

I'm running on Windows, and your code has the same problem.

The first thing I noticed was that you do not have a backend specified. On my system clicking the button just shows an image without a GUI. In this situation there is nothing for click events to be connected to, and there is no GUI window to close.

I'm assuming on MacOS a plot figure shows up and lets you click on the graph several times. Once you close the graph print("ok1") is run. If this is the case plt.show() is blocking and waiting for the window to close. This is really a matplotlib issue. I tried running plt.show(block=True) which did not work with PySide2. There could be a PySide2 compatibility issue or a configuration file or the system setting causes different behavior.

The code below does checks if the figure.canvas is visible and blocks until it is closed.

Is it possible to do this?

Yes: add -u main to your link line.

To understand what's wrong with your command line, read this or this.

Keep in mind that Ionic came before the Capacitor and understand that both are from the same creators.

Using Ionic you may build Android, iOS, PWA, Desktop using the same code. You may also choose your preferred framework to use with Ionic like Angular, VueJS, React and so on.

Capacitor is responsible for the bridge between your code and the device's functionalities.

Advantages: custom animations, components customization, web components, design to match native iOS13, iOS Segment design, collapsible header, large title in iOS, Searchbar inside of the collapsible header, swipe to close Modals, new iOS Menu design overlay with updated animation, refresher pulling icon in iOS, Material Design refresher as well, lists Header in iOS, open source animations utility, free and open source icon library, Back Button, Card, Segment, Split Pane, encapsulate styles, full support for Ivy Angular’s new renderer and so on... More on this Article.

Appflow is a service that is offered by Ionic Team.

I just Found a Solution to this problem! Basically the FireFlutter Team had fixed a production level bug and inturn that exposed a flaw of the Dart SDK. As this was only a Development only bug (bug only during Hot Restart), it was not given importance.

In my Research I have found that the last version combination that supports StreamBuilder and Hot Restart is

firebase_auth: 0.20.1; firebase_core 0.7.0

firebase_auth: 1.1.0; firebase_core: 1.0.3

These are the only versions that It works properly on. Every subsequent version has the new upgrade that has exposed the bug.

The Solution is very Simple! Works for the latest version (1.2.0) of the firebase_auth and firebase_core plugins too!

Firstly Import Sharedpreferences