Feedly Breaks MathML

post by jefftk (jkaufman) · 2023-09-25T13:40:05.759Z · LW · GW · 3 comments

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A few days ago I wrote about my experience with MathML, and despite being somewhat positive on it in that post I've decided to stop using it for now. The problem is, it doesn't display for people who follow my blog through RSS on (I'm guessing) most popular RSS system.

Here's a screenshot from my most recent MathML-containing post, on my website:

And here's the same portion of that post running in the web version of Feedly on the same browser:

Poking at developer tools, here's what Feedly is sending over the network to my browser: 

<p> It definitely does look nicer: </p> <p> </p> <p> On the other hand

This shows that they're removing the MathML on the server, instead of there being some issue once it gets to the client.

This also explains why it doesn't work in other RSS readers that use Feedly as a backend. For example, I see the same thing in Palabre.

I tried to file a bug with them, but as far as I can tell you need to be a paid subscriber to do that. Authors trying to let Feedly know about bugs that impact their readers seems not to be a thing they're open to?

Here's a test case to reproduce this issue: mathml-simple.rss.

For now I'm going to stop using MathML, and go back to ascii math.

This makes me sad: during Nora's nap yesterday I wrote the MathML Verbosifier I'd been thinking of, which lets me write: 

    a^2 + b^2 = c^2
as the relatively readable: 
    <msup>a 2</msup> + <msup>b 2</msup> = <msup>c 2</msup>
and automatically convert that into the spec-compliant: 
    <msup><mi>a</mi><mn>2</mn></msup><mo>+</mo><msup><mi>b</mi><mn>2</mn></msup><mo>=</mo><msup><mi>c</mi><mn>2</mn></msup>

(In the LW comments there was also discussion [LW(p) · GW(p)] of whether I should avoid using MathML for the benefit of people running pre-v109 Chrome. I don't think that makes sense: there have been several serious vulnerabilities since then, including the WebP zero-day, and I'm not interested in making changes to my site to support people running dangerous configurations.)

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comment by Kenny · 2023-09-28T22:02:44.149Z · LW(p) · GW(p)

I just reported this to Feedly.

Replies from: jkaufman
↑ comment by jefftk (jkaufman) · 2023-09-28T22:17:28.570Z · LW(p) · GW(p)

Thanks!

comment by Viliam · 2023-09-26T06:36:39.685Z · LW(p) · GW(p)

(You probably don't want this, I am just saying it as a possible solution.)

You could simply give up on rendering math in browser and instead create images on server. You are already willing to go the extra step of using the verbosifier. Why not instead use a program that will convert the expression to image (and automatically generate the HTML tag, including the alt attribute), and use that?

You could reuse the images by putting them in a separate "images/math" directory with an automatically created filename (could be a hash function of the math expression, or just keep an external list saying that "math0000.png" corresponds to this expression), so if you use the same equation twice, you will refer in both places to the same image.

Alternatively, you could create an endpoint that generates those pictures on the fly, and in the HTML code include "math.php?expr=a^2+b^2=c^2". Then you don't need to store the images. If needed, you could still cache the most frequently used ones.