Simon Willison’s Weblog

Abusing DuckDB-WASM by making SQL draw 3D graphics (Sort Of) (via) Brilliant hack by Patrick Trainer who got an ASCII-art Doom clone running in the browser using convoluted SQL queries running against the WebAssembly build of DuckDB. Here’s the live demo, and the code on GitHub.

The SQL is so much fun. Here’s a snippet that implements ray tracing as part of a SQL view:

CREATE OR REPLACE VIEW render_3d_frame AS
WITH RECURSIVE
    -- ...
    rays AS (
        SELECT 
            c.col, 
            (p.dir - s.fov/2.0 + s.fov * (c.col*1.0 / (s.view_w - 1))) AS angle 
        FROM cols c, s, p
    ),
    raytrace(col, step_count, fx, fy, angle) AS (
        SELECT 
            r.col, 
            1, 
            p.x + COS(r.angle)*s.step, 
            p.y + SIN(r.angle)*s.step, 
            r.angle 
        FROM rays r, p, s 
        UNION ALL 
        SELECT 
            rt.col, 
            rt.step_count + 1, 
            rt.fx + COS(rt.angle)*s.step, 
            rt.fy + SIN(rt.angle)*s.step, 
            rt.angle 
        FROM raytrace rt, s 
        WHERE rt.step_count < s.max_steps 
          AND NOT EXISTS (
              SELECT 1 
              FROM map m 
              WHERE m.x = CAST(rt.fx AS INT) 
                AND m.y = CAST(rt.fy AS INT) 
                AND m.tile = '#'
          )
    ),
    -- ...

# 22nd April 2025, 4:29 pm / sql, webassembly, duckdb

Introducing Enhance WASM (via) “Backend agnostic server-side rendering (SSR) for Web Components”—fascinating new project from Brian LeRoux and Begin.

The idea here is to provide server-side rendering of Web Components using WebAssembly that can run on any platform that is supported within the Extism WASM ecosystem.

The key is the enhance-ssr.wasm bundle, a 4.1MB WebAssembly version of the enhance-ssr JavaScript library, compiled using the Extism JavaScript PDK (Plugin Development Kit) which itself bundles a WebAssembly version of QuickJS.

# 8th April 2024, 7:44 pm / javascript, web-components, webassembly, quickjs

Bringing Python to Workers using Pyodide and WebAssembly (via) Cloudflare Workers is Cloudflare’s serverless hosting tool for deploying server-side functions to edge locations in their CDN.

They just released Python support, accompanied by an extremely thorough technical explanation of how they got that to work. The details are fascinating.

Workers runs on V8 isolates, and the new Python support was implemented using Pyodide (CPython compiled to WebAssembly) running inside V8.

Getting this to work performantly and ergonomically took a huge amount of work.

There are too many details in here to effectively summarize, but my favorite detail is this one:

“We scan the Worker’s code for import statements, execute them, and then take a snapshot of the Worker’s WebAssembly linear memory. Effectively, we perform the expensive work of importing packages at deploy time, rather than at runtime.”

# 2nd April 2024, 4:09 pm / python, serverless, cloudflare, webassembly, pyodide

AI photo sorter (via) Really interesting implementation of machine learning photo classification by Alexander Visheratin. This tool lets you select as many photos as you like from your own machine, then provides a web interface for classifying them into labels that you provide. It loads a 102MB quantized CLIP model and executes it in the browser using WebAssembly. Once classified, a “Generate script” button produces a copyable list of shell commands for moving your images into corresponding folders on your own machine. Your photos never get uploaded to a server—everything happens directly in your browser.

# 2nd April 2023, 4:27 am / machine-learning, webassembly, openai, clip

PyScript demos (via) PyScript was announced at PyCon this morning. It’s a new open source project that provides Web Components built on top of Pyodide, allowing you to use Python directly within your HTML pages in a way that is executed using a WebAssembly copy of Python running in your browser. These demos really help illustrate what it can do—it’s a fascinating new piece of the Python web ecosystem.

# 30th April 2022, 9:50 pm / python, web-components, webassembly, pyodide

Mac OS 8 emulated in WebAssembly (via) Absolutely incredible project by Mihai Parparita. This is a full, working copy of Mac OS 8 (from 1997) running in your browser via WebAssembly—and it’s fully loaded with games and applications too. I played with Photoshop 3.0 and Civilization and there’s so much more on there to explore too—I finally get to try out HyperCard!

# 26th April 2022, 7:16 pm / computer-history, mac, webassembly

How Zoom’s web client avoids using WebRTC (via) It turns out video conferencing app Zoom uses their own WebAssembly compiled video and audio codecs and transmits H264 over WebSockets.

# 18th April 2019, 6:20 pm / websockets, webassembly

Pyodide: Bringing the scientific Python stack to the browser (via) More fun with WebAssembly: Pyodide attempts (and mostly succeeds) to bring the full Python data stack to the browser: CPython, NumPy, Pandas, Scipy, and Matplotlib. Also includes interesting bridge tools for e.g. driving a canvas element from Python. Really interesting project from the Firefox Data Platform team.

# 17th April 2019, 4:23 am / mozilla, pandas, python, scipy, webassembly, numpy, pyodide

Wasmer: a Python library for executing WebAssembly binaries. This is a really interesting new tool: “pip install wasmer” and now you can load code that has been compiled to WebAssembly and call those functions directly from Python. It’s built on top of the wasmer universal WebAssembly runtime, written over just the past year in Rust by a team lead by Syrus Akbary, the author of the Graphene GraphQL library for Python.

# 16th April 2019, 6:04 pm / python, rust, webassembly