Someone just invented a whole new level of hell for devs who maintain code.
First it was untrained consultants and VB or Delphi (Pascal)
Then came the JS monkeys mixing up plain JS with jQuery and SQL injections.
Now it's time for data scientists and pi/sketch users to feel the pain of an uncharted domain...
I can't find any real world use case there. If you want to run ML Models you can build them to Onnx https://onnxruntime.ai/docs/tutorials/web/ . Will this efficient to build browser based app in place of JS/TS ?
Perhaps some people don't want to touch JS/TS
TS is actually has better typing than Python (mypy). And the whole React (Vue, etc) infrastructure around it. Without these two things I wouldn't even bother writing frontend code.
The browser doesn't support TS though. The browser does support Python via PyScript/pyodide/etc.
You can't run TS in the browser unless you jump through the same hoops that PyScript is.
Yet, type annotations are being discussed for JavaScript, eventually the browsers will be running Typescript.
The browsers are already running anything via custom WASM interpreters, like Pyodide for Python.
With a huge performance hit and leaky abstractions.
I thought I read somewhere that the Chrome team tried typed JS, found out that there was a performance hit, and they ended the experiment? Is this a continuation of that or a new effort? Sounds interesting.
Maybe as part of the Flutter/Dart sales story?
Here is the current status of the standard proposal.
‘npx vite build’ is what you call hoops?
You can offline transpile anything to JS to later run in the browser, TS isn't special in this way.
With PyScript you can see and modify the actual code in your browser, just like vanilla JS.
Do you actually see and modify code in your browser today? I mean for like 5 years all you see in the browser is minified and obfuscated to the point its almost impossible to make any practical sense out of it.
Idk they're just different tradeoffs to me. Types are real and enforceable at runtime in Python (e.g, pydantic). Types in TS/JS are a fake veneer that add a build step. Is that categorically better? I don't love Python typing syntax.
I want my types to be verified before runtime, what should I do with type error at runtime? Yes it will leave me a better error message in logs, but build-time type check will prevent me even rolling this code out.
So yes, its categorically better.
I want my types to be verified before runtime, what should I do with type error at runtime?
It is weird to me you cannot think of uses for types and handling their errors at runtime. Look at projects like FastAPI (which uses pydantic) for an an example where having types at runtime has been handy.
Also, if types are enforced at runtime logging is better, debugging is better, and you have more options for data validation and doing dynamic or metaprogramming likely more easily because you can evaluate these things at runtime. By types being built in, the language gives you a richer set of tools to work with and more options when and how to enforce types.
Look at projects like FastAPI (which uses pydantic) for an an example where having types at runtime has been handy.
What is it, they have nice error messages? I don't expect them to fix code at runtime when type error happens.
Also, if types are enforced at runtime logging is better, debugging is better
These can't even happen with type checking in the first place.
you have more options for data validation
In my experience serializing/deserializing data is pretty much the only place where its useful, and it doesn't have to be built-in on a language level, Pydantic is doing it well enough.
doing dynamic or metaprogramming likely more easily
This is where you lose me, I have never seen it being useful in reasonable large projects in popular languages. Dynamic or metaprogramming only works in a very specific category of languages (lisp-likes), doing it in any other language will become a problem sooner or later.
more options when and how to enforce types
Again its only on serialization level, apart from that type checking will cover everything before runtime, it's weird to me how you can think that encountering problem later has any advantage of doing it earlier.
Programming language ought to be decoupled from deployment environment.
Not a fan of JavaScript in the browser either then?
For folks interested in seeing a usecase, I have a panel dashboard of Dallas crime statistics at:
https://crimede-coder.com/graphs/Dallas_Dashboard
Startup takes around a minute (which includes installing various python libraries + loading an external 5mb dataset). But once up and running it is quite responsive. (And works fine on my iphone.)
Many businesses I work with use Tableau free versions, and just manually update the data (since the free doesn't allow direct connections to a datastore). This is a free alternative (I use github actions to build a zipped up csv file that is pulled into the environment).
Memory usage seems quite high. According to Browser Task Manager, the tab is consuming 657MB compared to 25-70MB most other tabs are using.
Woah, what browser/page combination can fit into ~50Mb these days? I am simply used to the fact that most pages take at least 200Mb RAM in task manager.
did you use the in browser or another external task manager? most pages without videos or some kind of gpu process uses 20~30 MB here (like hacker news for example).
Youd see the sme for any competent pyhon app.
Yes this is part of the price of running it client side instead of having a server do all the data manipulation. It is pretty much a wash for RAM for me vs running locally (local is 200-300 for python + 100-200 for chrome for just that web-page).
Does it work on firefox for anyone? The spinner keeps spinning on my MacBook Air.
Working fine for me, Firefox 128.0.3 on Fedora
Awesome example of using in production! Nice work.
I wish we get over with the loading hickups soon. Do you know if there is any work going on to make it start faster/smaller/less janky?
Maybe some kind of snapshot feature, where you can just load an snapshot of the already initialized state?
Startup takes around a minute
I wonder what your bottleneck was? It was about 20 seconds for me on domestic broadband.
Based on the temperature of my phone after clicking that link, probably CPU or memory.
Cool site!
Many businesses I work with use Tableau free versions, and just manually update the data
Why not just use e.g React/ Angular?
Or is it a question of needing python for the data analytics, and for server cost reasons not wanting it to be run on the server side?
This example could be all javascript (and I try to do that in some scenarios). Most of the other demo's on my site are just javascript/D3 or other libraries even with some slightly more advanced metrics, https://crimede-coder.com/demos.
There are some cases in which I do want python numerical libraries though. Say I wanted to do a forecast ARIMA model based on arbitrary combined inputs for the graphs, or do different types of spatial clustering of the geographic data. Those would be cases pyscript would make sense.
The public dashboards yes IMO easier to not have to worry about server.
That's pretty cool. In case anyone reading this is generally interested in crime statistics dashboards, I'll link to the NYPD's: https://compstat.nypdonline.org/
You can connect tableau public to google sheets
Could you somehow "snapshot" the runtime after the initial processing is ready and have clients just load that?
I imagine there's a ton of preprocessing that could be, well, preprocessed.
The homepage left me confused, and also after reading the documentation, I'm not sure what this is.
I tinkered a bit to try it myself.
Turns out you can throw this into your website and it will display "Hello World":
<script type="module" src="https://pyscript.net/releases/2024.8.2/core.js"></script>
<script type="py">
import js
js.document.querySelector("body").innerText = "Hello World"
</script>
On the other hand, the demo on the homepage is a repl. And the title says "platform". So I'm still confused.
transpiles them from Python to JavaScript
There are projects that do that, but it looks like PyScript instead runs Python code directly. It uses a Python interpreter compiled to WebAssembly - either CPython (from Pyodide) or MicroPython.
does this mean we can install FastAPI in the browser?
I mean, maybe, but you'd have trouble with sandboxing when you try to open a socket.
how would i go about doing that? open up a socket via webrtc to the internet and translate incoming webrtc calls to HTTP for fastapi
What would be the point?
You can't have a listening socket anyway. And if the browser has to imitate the connection, there are numerous less oblique ways than running fastAPI.
Yes, with pycafe that is possible: https://py.cafe/snippet/asgi/v1#c=H4sIABN3wGYAA41UTW_bMAz9K4...
And the title says "platform". So I'm still confused.
I hate it when people say "platform" or use other vague/ill defined terms. Just say it's a JS implementation of Python that evaluates code in script tags for python, or some such.
It isn't a JS implementation. It's implemented in Web Assembly and can communicate with JS if needed.
PyScript is a platform for using Python in the browser to build actual applications.
Without actually reading the documentation or source code -- I guess "js" package is just an API that somehow maps to the real "window" object and calls those DOM methods via some sort of Proxy object.
Probably. It is part of Pyodide, not something this PyScript project adds:
https://pyodide.org/en/stable/usage/quickstart.html#accessin...
I found some info about the terminal here: https://docs.pyscript.net/2024.8.2/user-guide/terminal/
(I was hoping to be able to run Python in the browser's console.)
Our phones are getting faster every year, we must find a way to slow things down even more.
The dawn of the PyScript web frameworks is upon us...
I wrote one. https://puepy.dev
You, sir, are a mad man.
We must think of the lessons of docker, the lessons of conda. Why, what with the web environments, so many, is there not a way to unify an environment? Of course! A virtual environment of python, on a virtual environment of the docker machine, on a virtual web browser, and there can be JIT throughout to make it only painfully slow and not excruciatingly slow! Abstraction is a Good Thing (TM) and the more abstraction, the better. There really ought to be an object oriented abstraction layer factory generator factory using Java OOP best practices, also a good thing (TM). If all goes well we may even be able to reach abstraction tier 17, which is two more layers of abstraction than the industry standard 15.
Just one more abstraction layer will fix it.
You're replacing one interpreted language for another.
Yes, Python is among the slower interpreted languages out there, but still. The debate between fast execution and programmer productivity is not a new one. Given Python's popularity, I'd say it's settled.
I suppose you didn't run any of the examples on the website.
I'm not sure what you mean. The PyScript website?
Yes, they link to examples and all of them run way slower than the equivalent JS version. Most likely because python has to ship its interpreter in the WASM bundle.
If the user experience is significantly worse, I don't care if it was easier for you to write the code.
I agree with the sentiment but the purpose of WebAssembly is to be a compiler target for other languages, so we're not stuck with Javascript until the end of time, right? Will this always necessarily be substantially slower than Javascript?
Will this always necessarily be substantially slower than Javascript?
Yes, interpreted Python will always be slower than JIT-compiled JavaScript.
PyPy.js [0] is a JIT compiler for Python that runs in the browser - its performance could be similar to JS but its development is currently “sleeping”.
This is sadly to be expected in regards to PyPy, it was never taken seriously by the Python community, regardless of their heroic efforts.
How is this different from pyodide[0]?
This uses pyodide. It's more like a Python to JS transpiler (even if it's not). It's to create browser apps using Python. So it's Pyodide + a browser API.
They also support MicroPython as an option now and not just Pyodide,
https://pyscript.net/tech-preview/micropython/about.html
In fact the main PyScript site uses MicroPython now, I see in the dev console (micropython.mjs and micropython.wasm).
Its a wrapper.
Pyodide is a port of CPython to the WebAssembly platform. PyScript is a framework that uses Pyodide to provide a framework for developing Python applications in the browser. Its elevator pitch would be "python inside script tags via pyodide".
Pyodide is a runtime.
PyScript can use Pyodide or MicroPython. MicroPython is actually quite small.
On top of the runtime, PyScript gives you some pleasantries and a lot of quality-of-life improvements for actually using Python for web programming, not just being able to run Python code.
Isn't this the same concept as brython? (BRowser pYTHON)
Brython seems to be a Python => JS translator, rather than an in-browser Python implementation. Similar end result, but works in a completely different way.
AFAIK Brython cannot translate some of popular Python libraries. Python libraries, esp. Data science ones, are often the reason why developers pick Python.
Yes, this is an advantage of Pyodide, and thus PyScript too, they have a fair number of packages that work directly:
https://pyodide.org/en/stable/usage/packages-in-pyodide.html
What i would like, if i could write scripts in firefox, which act the browser, like doing the evaluation at any stage i like. At GET the page, after ALL GETs. After javascript evaluation or before.
Is there something which can do this? and with full power of python also accessible to the host?
Would selenium Python bindings meet your needs? https://www.selenium.dev/documentation/
Does this work with Firefox?
Yes
I wonder if this could be combined with fastHTML to have a full python html rendered client side
We plan to support fastHTML at https://py.cafe/
This also uses pyodide, but supports more frameworks out of the box.
yep. would be nice as well to have LLMs trained on these things for fast prototyping
First thing I tried was a small lambda function and it worked! Then I tried some Fibonacci with tail recursion and surprisingly that worked too. I'm impressed, because often when people reimplement the Python interpreter they get those wrong.
that's because it's not a reimplementation, it is cpython recompiled to wasm.
Then I tried some Fibonacci with tail recursion and surprisingly that worked too. I'm impressed, because often when people reimplement the Python interpreter they get those wrong.
Huh? I thought Python didn't have TCO anyway. Guido had a whole blog post about why it supposedly doesn't belong in Python: https://neopythonic.blogspot.com/2009/04/tail-recursion-elim...
What other language would people choose in a browser? Lua ?
> What other language would people choose in a browser? Lua?
Brendan Eich originally wanted to use Scheme. There are some Scheme in Javascript implementations:
Yeah but I was mostly wondering about mainstream programmers. The chance of people liking a lisp are still low(to my own sadness)
The examples were about as slow as I imagined they would be. 20 seconds to draw a simple graph.
The majority of that is the upfront one-off loading time for pyodide to get going along with required packages. Subsequent runs for things will be substantially faster.
That is a subsequent run (because I also wondered if caching etc would improve hot loads, but it doesn't).
The big limitation that's very annoying with any WASM setup is that at the end of the day you still can't call many APIs or scrape sites because of CORS. Ofcourse, CORS is important to avoid XSS and the like but I wish there was a way to deal with this other than setting up a proxy to strip CORS, which then leaves you with a non residential IP that's more likely to get blocked.
Is this only an issue with cross-origin isolation enabled with COOP and COEP?
I recently went down the rabbit hole of using PyScript for running a Python CLI app in the browser.
It felt hacky the whole time, especially when dependencies were involved. I had to create wrapper classes to work around Pydantic 2.x not being available to use. I tried to put all logic into the Python files but found some things missing that I had to put in JavaScript.
I think it could be good in use cases where you want some simple UI with custom UI logic on top of your Python code but maybe Streamlit or Gradio could be more suitable.
GitHub repo: https://github.com/data-catering/data-contract-playground
Website: https://data-catering.github.io/data-contract-playground/
The Rustification of a lot of Python projects is making it more difficult that necessary to use Python everywhere.
I tried to write a POC Firefox extension in pyscript but ended up having to fall back to pyodide. Was a fun experiment anyway.
https://n8henrie.com/2023/06/write-a-firefox-extension-in-py...
I've been seeking to do this for a very long time!
I've been looking for something like this, but I'm still unsure it quite hits the spot. I think that this would be very interesting if it allows a person to run a blog like a Jupyter notebook.
I have a lightweight hack [1] that runs Python in markdown documents and can output basic images/graphs - which is embedded into static pages. The point was being able to write an article that somebody else could see the code behind it and test themselves, e.g. [2]. One of the browsers I test in is Netsurf with JS disabled. Unfortunately it doesn't look great in Lynx.
[1] https://gitlab.com/danbarry16/pandoc-highlight-filter
[2] https://coffeespace.org.uk/projects/langtons-ant-universe.ht...
There is jupyerlite which does exactly that https://github.com/jupyterlite/jupyterlite
Kernels are compiled to wasm and can therefore run in the browser.
Try it out at: https://jupyterlite.readthedocs.io/en/stable/_static/lab/ind...
Its easy to create your own deployments, there is a template repo for that https://github.com/jupyterlite/demo
Careful Anaconda will change the license on you and then sue...
Fun joke but Anaconda has a track record of creating OSS and then turning it over to community governance. This includes the conda tool itself, libraries like bokeh, dask, numba, jupyterlab, and many more. And while PyScript project governance isn't in NumFOCUS, all of the code is permissively-licensed BSD/MIT.
The commercial licenses for the products and commercial repository is what supports all of this OSS development work.
For those exploring, here was one of the best “Python in the browser” projects I found:
Also check out https://py.cafe/ (I work on this project)
It supports streamlit, dash, virzo and solara. Frameworks like shiny, gradio and panel are planned (maybe even fasthtml).
It's also really nice to integrate this into your documentation: https://mkdocs.py.cafe/
Also, check out PySheets (https://pysheets.app), which leverages PyScript to run Python logic in a spreadsheet UI, which is written entirely in Python. The PySheets UI uses LTK (https://github.com/pyscript/ltk), a fully client-side UI rendering library for PyScript.
Also check out pyscript.com, to create and host PyScript apps.
If I may toot my own horn, I wrote a somewhat more opinionated, reactive, frontend framework using PyScript. It's inspired by Vue.js, a bit: https://puepy.dev
Why does it require signing in just to try it out? Someone else below mentioned that it's just adding a <script> tag to your HTML.
How’s it work? Webassembly? Webile?
Reminds me of my first "tech" job (computer store/ISP/web dev shop, circa 1998) where the owner wrote some VBScript for the browser and wondered why it didn't work in Netscape.
I used this to create a Markdown renderer a while back. You can see the very simple source code here: https://pyscript.com/@stuartmaxwell/markdown-previewer-v2/la...
The app won't run well on mobile but should be fine on desktop.
I used this code in a blog application I was writing in Django.
This is from Anaconda and built on Pyodide:
PyScript is currently built on Pyodide, which is a “port of CPython to WebAssembly/Emscripten.” PyScript supports writing and running Python code in a browser.
Like conda I find the whole thing very confusing and slow, but I suppose it will be marketed to academics as "the thing to do web development with". It will also be soft-abandoned.
Just use Javascript, PHP or Scala like lichess.org, which is a professional website.
Does something built off this or Pyodide exist that's effectively a replacement to using React?
Honestly, WebAssembly with C#'s Blazor is the best development experience I've ever had. I can fully debug the front-end and back-end within Visual Studio.
But then you have to use Visual Studio.
One of the best IDE's I've ever used. JetBrains IDE's come close, but Visual Studio is a gem.
Visual Studio is nice but I vastly prefer Rider, even on Windows. It feels bit snappier, especially when you're comparing Visual Studio + Resharper versus Rider. TBH this is probably a matter of what is familiar though.
I use Rider on other platforms.
IMO, it's somewhat polarising. Some people love it, but I personally can't stand it. It feels too heavy, trying to dominate every aspect of writing code. I prefer lightweight editors, but I recognise it's a personal thing.
Its totally a personal thing. I feel VS Code is the right combination of light weight, light touch, and keeps my focus where I need it whilst still having the ability to get to helpers that make life easier.
Visual Studio is really good if you are doing C# development on Windows.
MonoDevelop was also really nice. So much so, it looks like they copied it into Visual Studio for Mac???[0]
In any regard, C# has some of the richest tooling I've seen for any programming language, I do wish Microsoft would invest even marginally into MonoDevelop again.
[0]: https://www.monodevelop.com/
VS4Mac is MonoDevelop. Well, it was - VS4Mac is dead now as it has been stagnating, and at the end of its life was likely more harmful to .NET adoption by developers using macOS.
Its niche is now replaced by VS Code, particularly after base C# extension switched to Roslyn LSP from Omnisharp, and, of course, Rider which has been a strong cross-platform offering for a long time.
With that said, I heard only positive things about MonoDevelop back in the day and my impression from the feedback is that it was something its authors really put care into. I suppose it is part of history now.
On Blazor - both Rider and VS Code support it. Contrary to the belief of slowly but surely diminishing group of developers that think .NET is still stuck in Windows land, there is nothing that ties you to Windows here.
Not really.
The original VS4Mac was Mono Develop.
Afterwards the team started to share code between Visual Studio and VS4Mac, written in .NET Standard libraries, until they started the full rewrite, using .NET Core proper with Cocoa bindings, as the team did not consider MAUI with Catalyst mature enough for the rewrite.
Only to have the project cancelled and replaced by our Electron shell friend, after they reached the 1.0 of the rewrite efforts.
Which still doesn't have the graphical tooling and storyboards integration from VS4Mac.
Most folks are rather adopting Rider.
The 2nd coming of Web Forms, or Silverlight, take your pick.
In the case of WASM though, does it really matter? Ideally I want to see other languages do the same thing.
It matters when debugging pile of WASM code, and the performance loss switching back and forth to JavaScript engine.
The very reason I haven't bothered that much with Blazor, are my debugging scars from Web Forms and JSF.
Given the choice, I will go with stuff that works directly with script tags and the built-in developer tools.
I'm curious what widgets/frontend tooling you use.
This is, I assume, Visual Studio for Windows. Have you tried it at all in VS Code or is that a non-starter?
If you could write VB (VB6) in WASM, that would make some things so much simpler!!! (I work on a legacy codebase)
Thats mean you want to embed VB code into Browser Like in ActiveX days?
Actually I think Blazor might support class libraries written in VB.NET.
They do and it appears to work really well (I have only experimented with it.)
Isn't it the same thing as a SPA or any other WASM? The only real difference now is that it is now accepted and the browsers assist with cross platform APIs (and some security) instead of pure Windows APIs. (Ok, so I made it a bit more simple than it is, but that is how I see it.)
Anaconda Code is what you're looking for! It's Python (via PyScript) running as an Excel plug-in, that has full access to the spreadsheet and can harness a big part of the core PyData stack (including matplotlib, sklearn, pandas, etc.)
The whole thing runs via PyScript/WASM, and lives locally inside the Excel spreadsheet. https://www.anaconda.com/blog/introducing-anaconda-code-add-...
Please don't tell people I work with about this.
Arguably, VB6 and Ruby have a pretty similar syntax. And Wasm is first class in the Ruby build farm. https://github.com/ruby/ruby.wasm
Oh man that would be so cool. Kinda like the Ruffle Flash player!
Thats what I am thinking too. Integrating code of DS/ML people into backend is painful enonugh. Imagine maintaining frontend code of those who had never done proper forntend development...
If it's not something that needs extensive testing, I'd rather maintain that codebase than a "proper" one. Data science people don't pump out 100 files with 20 layers of OOP, and they don't know how to use Redux or whatever overkill navigation lib. It'll be a main.py that just does what you want. Maybe there will be copy-pasted code, but even that can be more readable sometimes.
You are right about over engineered redux and react, It would be a lot less painful to maintain main.py and a lot more grepable
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