Resurrect the Toga-web backend using Pyscript #1475
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Hi, Is there a plan to move forward (resurrect) with toga-web? I saw the examples in pyscript but did not see roadmap or discussion. |
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@aeroaks Yes - the web backend is on our todo list; however, in terms of priorities, it's a little lower than solidifying the desktop and mobile platforms. In terms of roadmaps, I wouldn't expect to see big changes from the Toga side unless someone contributes them. |
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In a way it would work out for me, as I can spend a limited time in contribution. I was thinking of picking up small tasks to e.g., make the tutorials in the Toga documentation work (in a similar way as the tutorials added in the pyscript repo). But for that I would need some alignment how and where to begin. |
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I tested using the temperature conversion app and everything worked correctly, except as noted below.
| @@ -479,6 +479,27 @@ def _layout_column_children(self, node, available_width, available_height, scale | |||
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| def __css__(self): | |||
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I'm curious about the rationale for putting this here rather than in the web backend. Is it because we eventually intend to define the Pack algorithm in terms of CSS (#1544), so it makes sense for both realizations of the algorithm to be in the same file so they can be kept consistent?
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Essentially yes, but I'd phrase it a slightly different way. It's not so much about defining Pack in terms of CSS; it's more a matter of saying that a style engine can define any set of rules you want, but you have to be able to define a mapping to CSS if you want your style engine to be compatible with web deployment.
This implementation of __css__() is specific to Pack, and describes how Pack's style rules map to "pure" CSS; the implementation for Colosseum will be a 1-1 mapping of the literal style declarations. Other style engines could define complete arbitrary rules, as long as they provide an analogous CSS mapping.
The connection with #1544 is more about using CSS as a reliable known reference implementation; the Pack CSS mapping rendered in a browser should provide the same output as a Pack implementation in native widget layout.
src/web/toga_web/app.py
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| toga.Command( | ||
| None, | ||
| "Preferences", | ||
| group=toga.Group.HELP, |
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Doesn't look as if this is being used anywhere.
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Correct - it's a placeholder that acts as a tease for future functionality (in the hope it will jolt someone into potentially contributing).
| except ModuleNotFoundError: | ||
| # To ensure the code can be imported, provide a js symbol | ||
| # as a fallback | ||
| js = None |
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Running the test suite in CI would be the obvious case. The interface compliance tests are part of the web backend, so we need to be able to import toga_web on non-web platforms.
| [tool.briefcase.app.tutorial.web] | ||
| requires = [ | ||
| '../../src/web', | ||
| ] | ||
| style_framework = "Bootstrap v4.6" |
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None of these will work, because they're all called "tutorial" rather than the actual name of the app.
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🤦 I'm really firing on all cylinders at the moment...
Codecov Report
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PyScript was announced at PyCon 2022. This provides an easy-to-deploy Python in the browser.
This doesn't implement every widget, but it's enough to get Tutorial 0 and 1 (hello world and the F2C calculator) going, plus the first few stages of the BeeWare tutorial (up until the point
httpxis imported); and the general approach being used should be broadly compatible with other widgets.It pairs well with beeware/briefcase#898 as a means of deploying apps using this backend.
PR Checklist: