Expo dev client can only connect with running dev server and not static files hosted using expo export

Summary

Currently the custom development client can only connect to a running dev server. (Unlike expo go). Connecting to static files served with Nginx only works with Expo Go, not with a custom development client

Managed or bare workflow? If you have made manual changes inside of the ios/ or android/ directories in your project, the answer is bare!

bare

What platform(s) does this occur on?

Android, iOS

Package versions

    "expo-dev-client": "^0.4.4",
    "expo-dev-launcher": "^0.6.4",
    "expo-dev-menu-interface": "^0.3.2",

Environment

  Expo CLI 4.9.1 environment info:
    System:
      OS: Linux 5.11 Ubuntu 21.04 (Hirsute Hippo)
      Shell: 5.8 - /usr/bin/zsh
    Binaries:
      Node: 14.17.1 - /usr/bin/node
      Yarn: 1.22.10 - ~/projects/differentlab/mobile-react/node_modules/.bin/yarn
      npm: 7.19.1 - /usr/bin/npm
    npmPackages:
      expo: ^42.0.0 => 42.0.1 
      react: 16.13.1 => 16.13.1 
      react-dom: 16.13.1 => 16.13.1 
      react-native: ~0.63.4 => 0.63.4 
      react-native-web: ~0.13.12 => 0.13.18 
    npmGlobalPackages:
      expo-cli: 4.7.3
    Expo Workflow: bare

Reproducible demo or steps to reproduce from a blank project

Use expo export to generate static files. Host it using either a local php/nginx/python server. Connect to it. Won’t work with your custom dev client but it does with Expo GO

Stacktrace (if a crash is involved)

No response

[esamelson]

Hey @Silvest89 - thanks for the report! We’re working on a fix for this, hang tight.

[esamelson]

I’m not able to reproduce this with a python SimpleHTTPServer; when I open http://0.0.0.0:8000/ios-index.json the response comes back with a content-type of application/json and my development client opens the app correctly. If you’re still having issues with this, I’d suggest verifying that the content-type of the response is correct.

The reason that Expo Go behaves differently is because custom clients also have the ability to load bundles from a plain react-native server (npx react-native start), which means we need to infer more information from the content-type header as not much other information is available from this kind of server.

Let us know if there are other content-type values that you’re expecting to work, but are causing this error in your client.