thunder | Off-Chain Bitcoin payments using smart contracts | Blockchain library

The img tag loads all the images fine for the first call however, the problem is that when I do another zipcode and clicked search, the texts updated, but the img tag (the weather images) did not update ( i.e. first search 91001 everything looks great, searched again for 95133, name changed to San Jose but the weather forecast images did not update from 91001's to 95133's)

You always append forecast data to the forecast state but only reference the first 8 elements.

Your syntax is off:

I don't know how you set up your server, but you should have a middleware to parse the incoming data. for HTML form data you will need to use the following app.use(express.urlencoded({ extended: false }));

You can read here to learn more about express built-in middleware and their optional properties.

Also just noticed that you are using enctype="multipart/form-data", is there any reason for that? Your form looks basic enough so you should be able to use application/x-www-form-urlencoded which is the default, so you won't need to specify it.

.readAsDataURL() converts the file it reads into Base64, so it can be represented as a URL you can put into a browser. A very long URL, but still a URL.

If you store a Base 64 representation of an image into a file on your machine, then try to read it with an image-display program, the operation will fail: "This doesn't look like a .jpg, .png, or .gif" so I don't know what to do with it." That's what your Windows file manager error message means.

If you want the file's contents raw rather than Base64 encoded, you'll need to use .readAsArrayBuffer().

First of all, the number of cores is not necessarily the number of processors. On early computers days it was like 1-1, but with modern improvements one processor can offer more than one core. (Check this: https://www.tomshardware.com/news/cpu-core-definition,37658.html). So, if it detected 12 cores, you can use it as the basis for your calculus.

The number of processes means how many different parallel instances of your web application will be running in that server. WSGI first creates a master process that will coordinate things. Then it bootstraps your application and creates N clones of it (fork). These child forked processes are isolated, they don't share resources. If one process get's unhealthy for any reason (e.g. I/O problems), it can terminate or even be voluntarily killed by the master process while the rest of the clones keep working, so your application is still up and running. When a process is terminated/killed the master process can create another fresh clone to replace it (re-spawn).

It is OK to set the number of processes as a ratio of the available cores. But there's no benefit of increasing it too much. So, you definitely shouldn't set it to the limit (2784). Remember that the operating system will round-robin across all processes to give each one a chance of have some instructions processed. So, if it offers 12 cores and you create like 1000 different processes, you are just putting stress on the system and you'll end up getting the same throughput (or even a worse throughput since there's so much chaos).

Then we move on to the number of threads. For the sake of simplicity, let's just say that the number of threads means the number of parallel requests each of these child process can handle. While one thread is waiting for a database response to answer a request, another thread could be doing something else to answer another request.

You may say: why do I need multiple threads if I already have multiple processes?

A process is an expensive thing, but threads are just the way you can parallel the workload a process can handle. Imagine that a process is a Coffee Shop, and threads are the number of attendants you have inside. You can spread 10 different Coffee Shops units around the city. If one of them closes, there's still another 9 somewhere else the customer can go. But each shop need an amount of attendants to serve people the best way possible.

If you set just a single process with 100 threads, that means that 100 is your concurrency limit. If at some point there's 101 concurrent requests to your application, that last one will have to wait for one of the 100 first to be finished. That's when you start to get an increasing response time for some users. The more the requests are queued, the worse it gets (queuing theory).

Besides that, since you have a single process, if it crashes, all these 100 requests will fail with a server error (500). So, it's wiser to have more processes, let's say 4 processes handling 25 threads each one. You still have the 100 concurrency limit, but your application is more resilient.

It's up to you to get to know your application expected load so you can adjust these numbers properly. When you have external integrations like databases, you have to consider it's limitations also. Let's say a PostgreSQL Server that can handle 100 simultaneous connections. If you have 10 WSGI processes, 40 threads each (with a connection pool of size 40 as well), then there's the possibility that you stress the database with 400 connections, and then you have a big problem, but that's not your case!

So, just use the suggested number of processes (12 * 2 = 24) and set as much threads as needed to offer a certain desired level of concurrency.

If you don't know the expected load, I suggest you to make some sort of performance test that can simulate requests to your application and then you can experiment different loads and settings and check for it's side effects.

If you are running your application in a container orchestration platform, like Kubernetes, then you can probably have multiple balanced containers serving the same application. You can even make it dynamic so that the number of containers increases if memory or processing go beyond a threshold. That means that on top of all those WSGI fine tuning for a single server, there's also other modern layers of configurations that can help you face peaks and high load scenarios.

you can use an id for each card info as follow:

There are various approaches to this problem. A rather more traditional and exact (but also prone to issues with new words) is to use a thesaurus for French and English and check if the phrase is found in one or the other (full match or more words matching).

Another one is to use a package for language detection.

Yet another one would be to use an ML language model to classify phrases (e.g. SpaCy lang_detect model).