Skip to content

Latest commit

 

History

History
129 lines (85 loc) · 4.02 KB

README.md

File metadata and controls

129 lines (85 loc) · 4.02 KB

Use requests-wasm-polyfill to send HTTP(s) requests from inside WASM

These instructions guide you along the process of building the PyJS REPL with requests-wasm-polyfill plugin installed.

Instructions for this devcontainer

Tested with requests-wasm-polyfill 0.3.0, pyjs 1.1.0, empack 3.3.1 .

Following instructions are partially based on this doc.

Preparation

  1. Open this repo in devcontainer, e.g. using Github Codespaces. Type or copy/paste following commands to devcontainer's terminal.

Building

  1. cd into the folder of this example:
cd browser-requests-wasm-polyfill
  1. Clone emscripten-forge/sample-python-repl repo :
git clone --depth=1 https://github.com/emscripten-forge/sample-python-repl
  1. cd into the folder of sample-python-repl:
cd sample-python-repl
  1. Create new Mamba environment named pyjs-build-env to build the REPL example:
micromamba create -n pyjs-build-env -f build-environment.yaml -y

This will install into the pyjs-build-env lots of packages, including Python and empack.

  1. Activate the pyjs-build-env environment. In Codespace activation is a bit tricky, therefore it needs several steps. Firstly, initialize the .bashrc by:
micromamba shell init --shell=bash

  1. Secondly, Open an additional terminal tab using the bash shell.

  2. Thirdly, In the newly opened terminal tab, eventually activate the pyjs-build-env environment:

cd browser-requests-wasm-polyfill/sample-python-repl

micromamba activate pyjs-build-env

The command line's prompt should indicate the active environment.

  1. Add the requests-wasm-polyfill dependency to REPL's web package:
echo '  - requests-wasm-polyfill' >> web-environment.yaml
  1. Build the web package:
python3 build.py --env-name=web-package-build-env

The build.py script will create new Mamba environment using web-environment.yaml, and perform the build process there. After that, build.py will run empack, and put the result in build subdirectory.

  1. Patch the requests-wasm-polyfill to allow it run in the main browser frame. Need to comment out this line. This little patch is enough for demonstration purposes.

In the case the patch is not applied, the HTTP request will fail with this error: Error: Failed to set the 'responseType' property on 'XMLHttpRequest': The response type cannot be changed for synchronous requests made from a document.

The following command runs the bash script which extracts the requests-wasm-polyfill's archive, patches the api.py, and re-assembles the archive back:

bash ../patch-requests-wasm-polyfill-inside-archive.sh

Test with browser

  1. Run simple HTTP server to temporarily publish project to Web, serving the content from build subdirectory:
python3 -m http.server --directory build

Codespace will show you "Open in Browser" button. Just click that button or obtain web address from "Forwarded Ports" tab.

  1. As REPL is loaded into browser (about 21 MB) and ...done is displayed in the bottom frame, insert the following code in the REPL's code frame:
import requests

r = requests.get('https://httpbin.org/anything')
result = r.text
print(result)
  1. Click Run button in the REPL and see the results in the bottom REPL's frame.

Alternatively you can patch the script.js in a manner like in demo and re-run the build.py.

Finish

Perform your own experiments if desired.