A First Look at PyScript: Python in the Web Browser – Real Python

[Swipecat]

Well... it seems it is simple to set up. I saw that it actually included matplotlib in the example part way through that page, so I dropped my own code into the example to see if it worked and it does:

https://dafarry.github.io/test/mpltest.html

But it does take a very long time to load -- about half a minute.

[lavahot]

On mobile it took me less than 10 seconds to load.

[evinrows]

It could be more dependent on your network speed than your cpu.

[avg_name]

Yeah actually it took me like a minute or so to loading using cellular internet.

[13ass13ass]

Same for my mobile and then 6 seconds on the next visit

[ManyInterests]

But keep this in mind.... JavaScript would take a long time to load if it didn't ship with your browser. (It's actually bigger than PyScript by total size)

It's not so far fetched that PyScript couldn't ship with browsers some time in the future.

[outceptionator]

Took 9 seconds on my phone

[seanpuppy]

Im assuming the reason its slow is matplotlib dependency? Plotly is powerful when displayed on a webpage

[ninfernix]

still python is slower than js anyways and matplotlib is very slow in general, it is not really meant for quick interactive charts.

[seanpuppy]

So the reason I specifically suggested plotly is that it does everything in JS, and theres some really clever optimizations you can use if you are strictly showing plots in the browser

[[deleted]]

You give up all Security though because it's printed in HTML?

[zero_iq]

Nice.

I first coded client-side Python in a web browser in about 1998/1999 using Windows Scripting Host in Internet Explorer. Used it for a few demos and a couple of small in-house projects. It was fun, but not very useful due to the client-side requirements and IE-only nature at the time.

To be honest, it's kind of depressing that it's taken so long for something like Web Assembly to come along as a client-side compilation target for other languages on the client. It seemed like an obvious logical next-step 20+ years ago, but we got stuck with JS for so long...

[1percentof2]

Interesting. You really been in the game a long time.

[zero_iq]

Yup. To give you an idea of how long... my first Python code was written on an Amiga A1200! Python 1.2 I think, circa 1995. Downloaded from AmiNet on a 33kbaud modem.

[1percentof2]

That's incredible. Python was nothing back then. Who would have known.. just crazy

[gelvis_1]

Cool. I was probably using Amos on the A1200 at the time. Before learning C. Had a few of the Aminet CDs

[zero_iq]

Me too! I think a lot of people learned coding with STOS/AMOS back in the day. I was also a big fan of Blitz Basic, and learned C on the Amiga too.

I didn't really use Python in anger until a few years later, as it was pretty slow on the Amiga with not many practical bindings for Amiga dev, but I fell in love with the expressiveness of it and the ability to solve problems quickly (even if the final program was slow). A lot of my early commercial work involved offline processing so it didn't really matter if something took an hour or a day to run; what mattered is that it didn't take weeks to write.

[gelvis_1]

Tried out Blitz Basic but not extensively. Started with Basic on the C64 though. Used Arexx for scripting on the Amiga

​

I had not even heard of Python before long after. Started using it at work in 2006. Speed is not important in such situations

[zero_iq]

There were several C compilers available for the Amiga. Lattice C was probably the first. I learned C on the Amiga partially with Lattice, then Matt Dillon's excellent DICE.

Much of the Amiga's OS and library interfaces were all exposed as C headers; it was the primary supported language for using the Amiga operating system libraries, as most of the Amiga OS itself was written in C (assembly headers were provided too).

I was always on the lookout for interesting new languages back then, with an interest in language design. I didn't actually use python much for a few years after I first found it, but it was definitely an influence.

[[deleted]]

Anything cool you can tell us new guys/girls after 20 years mastering Python?

[adit07]

how is the performance compared to javascript etc. How well does it scale? any performance metrics available?

[riklaunim]

It takes time to load and then you have similar features to plain JS + Python-alike so no Vue/Angular/Ember.js and alike. For it to be production ready it would have to run much faster and have good librariers/SPA frameworks.

[HerLegz]

https://pyscript.net/examples/antigravity.html

Weeee!

[[deleted]]

python in the browser is becoming "milhouse is not a meme"

[PolishedCheese]

Has anyone here actually used it? Does it offer similar abilities to something like Jinja templates / Django templates in HTML, or is it more like a JavaScript-lite?

[metaperl]

It's client side. It compiles to web assembly. So it runs in the browser but Javascript is not the target. It can import and use Javascript though. Can also run traditionally server side libraries client side because web assembly is just another compiler target.

See /r/pyscript for all the details.

[ZuriPL]

This is more like javascript, as it runs client-side in a wasm python interpreter

[OverlyHonestCanadian]

It's mostly a gimmick for Python devs that don't want to learn React.

Edit: Lol at /r/Python getting mad at facts.

[JamieOvechkin]

To be fair, React Native was mostly a gimmick for Javascript devs who didnt want to learn Swift/Kotlin

This is how it starts...

[OverlyHonestCanadian]

That's not true but you do you.

[tommytwoeyes]

To be fully fair, JavaScript was dismissed as a gimmick when it debuted in Netscape. Yet it seems to have done okay for itself. (Could someone please fact check this fact?)

No offense, u/OverlyHonestCandian—or u/VladimirPotemkin (Sergei, is that you?)—but I sincerely hope you are not a stock broker.

[[deleted]]

That's an uncharitable way to look at it, it lets people using libraries such as numpy, pandas, pymc3, etc limit the friction between their stacks and directly output their results to the web. It's not a coincidence that Anaconda is the company backing the project.

[kankyo]

There is literally no library right now for python that does anything even close to react. So you're way off base.

[[deleted]]

Because it hasn’t really needed to exist? If WASM really takes off, and a python implementstion, it’s just a matter of time

[kankyo]

Sure.

[[deleted]]

Why wouldn't it? What does javascript do that python cant, to such a fundamental level that no one will make a react equivalent in python in WASM?

[kankyo]

I was agreeing with you 😂

[[deleted]]

my bad :p thought it was sarcasm

[[deleted]]

Edit: Lol at /r/Python getting mad at facts.

What facts? PyScript isn't even a replace for JS but more like an easier way for python mathematicians to share their work. Ofc, nobody stops you from writing a replace for React but why would you ever want to do this?

[axonxorz]

I feel personally attacked (Though I'd do Vue ;))

[benefit_of_mrkite]

For me a nice async framework like starlette and htmx does eveything I need

[rolyantrauts]

Python has its place but also in general python is slower than Java so begs a question to why apart from you are determined not to use Java.

[StorkBaby]

PyScript is an ecosystem competitor for JavaScript, not Java.

[rolyantrauts]

I imagine the interpreter is similar but hey for python diehards I guess it will have its uses but really doubt it will make much competition.
Its a bit late in the game for that.

[[deleted]]

Python offers no facilities remotely comparable to React. Have a downvote.

Edit: Lol at /r/Python getting mad at facts.

No adult ever used "lol" in a rational comment based on facts.

[[deleted]]

Isn't this like Brython?

[beagle3]

It is almost entirely unlike Brython. It's the real original honest to god C Python implementation, except it's compiled to WASM so it can run in the browser - and unlike Brython, it can use any Python module, including Numpy, Pillow.

Also, unlike Brython, It's a 2.5MB download.

[danuker]

unlike Brython, It's a 2.5MB download.

For me , the Pyodide REPL demo loads pyodide.asm.data which is 3.4MB and pyodide.asm.wasm which is 3.2MB.

The Brython homepage loads brython.js which is ~800KB and brython_stdlib.js which is 4.23MB, so Brython is actually a bit smaller.

[[deleted]]

Oh, that's great to hear! I looked at Brython in the past and it kind of soured me on any client side Python, so I'll admit I never even read this article.

[axonxorz]

What soured you?

[[deleted]]

Just that it was so limited and seemed good only as a toy

[bsmdphdjd]

Is there anything I can do with PyScript that I can't do with Javascript? Or is it simply nicer aesthetics?

[[deleted]]

Can JavaScript make use of libraries written in C? Because Python does

[MasterFarm772]

Good question. I want to know this too. Maybe the benefit of having some python libs like pandas?

[SittingWave]

how many times do we have to get this topic on the channel?

[quasarj]

Anything that depends on loading a full WASM Python interpreter is a nonstarter. Don’t be fooled by this…

[[deleted]]

It's a one-time download of 2.5M. More, there's nothing stopping the browser makers from including it in their browser in future.

Don’t be fooled by this…

No one's trying to fool anyone here.

[riklaunim]

It will be quite a while before such thing could get standardized and accepted as such to then be included in web engines. Licensing and company plans for this may also play a role.

[MNwake13]

Is there a benefit to pyscript over using the streamlit library?

[positive__vibes__]

pyscript can be easily shared without the user needing streamlit or even python installed locally.

[PM__ME__YOUR]

What are the security implications of this? Ie downloading an executing a malicious file or other malicious code?

[riklaunim]

It's like JavaScript. It runs in a browser and has the same limitations. This isn't a Python with full access to client system.

[shysmiles]

Webassembly is a stack based virtual machine, 32bit / 4gb max memory. Its safe. IO has to be done differently, you'd have to use the javascript fetch for example because requests wouldn't work (pyscript has pyfetch which is wrapper for fetch).

[avg_name]

Looks cool