mirror of https://github.com/pyodide/pyodide.git
68 lines
2.1 KiB
Markdown
68 lines
2.1 KiB
Markdown
# Using Pyodide from Javascript
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This document describes using Pyodide directly from Javascript. For information
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about using Pyodide from Iodide, see [Using Pyodide from
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Iodide](using_pyodide_from_iodide.md).
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## Startup
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Include `pyodide.js` in your project.
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This has a single `Promise` object which bootstraps the Python environment:
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`languagePluginLoader`. Since this must happen asynchronously, it is a
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`Promise`, which you must call `then` on to complete initialization. When the
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promise resolves, pyodide will have installed a namespace in global scope:
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`pyodide`.
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```javascript
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languagePluginLoader.then(() => {
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// pyodide is now ready to use...
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console.log(pyodide.runPython('import sys\nsys.version'));
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});
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```
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## Running Python code
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Python code is run using the `pyodide.runPython` function. It takes as input a
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string of Python code. If the code ends in an expression, it returns the result
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of the expression, converted to Javascript objects (See [type
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conversions](type_conversions.md)).
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```javascript
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pyodide.runPython('import sys\nsys.version'));
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```
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## Loading packages
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Only the Python standard library and `six` are available after importing
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Pyodide. To use other libraries, you'll need to load their package using
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`pyodide.loadPackage`. This downloads the file data over the network (as a
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`.data` and `.js` index file) and installs the files in the virtual filesystem.
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Packages can be loaded by name, for those included in the official pyodide
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repository (e.g. `pyodide.loadPackage('numpy')`). It is also possible to load
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packages from custom URLs (e.g.
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`pyodide.loadPackage('https://foo/bar/numpy.js')`), in which case the URL must
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end with `<package-name>.js`.
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When you request a package from the official repository, all of that package's
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dependencies are also loaded. Dependency resolution is not yet implemented
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when loading packages from custom URLs.
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Multiple packages can also be loaded in a single call,
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```js
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pyodide.loadPackage(['cycler', 'pytz'])
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```
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`pyodide.loadPackage` returns a `Promise`.
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```javascript
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pyodide.loadPackage('matplotlib').then(() => {
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// matplotlib is now available
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});
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```
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## Complete example
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TODO
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