What steps are needed to set up app.json to support various connection types for incoming requests, including HTTP?

Within my Expo React Native application, I am encountering issues with fetching data from my Ruby on Rails API due to restrictions on http connections.

I have explored various solutions that involve modifying the AndroidManifest.xml in Android and Info.plist in iOS, but since I prefer to work within Expo without ejecting, these options are not viable for me. I attempted changing the host from localhost to 127.0.0.1, 10.0.2.2, and even my machine's IP address, but unfortunately none of these changes were successful. Despite checking the documentation on configuration with app.json and networking, I could not find any information on configuring App Transport Security within Expo. My current setup involves using Expo on android 9.0 Pie.

fetch(`http://localhost:3000/api/v1/trainers`, {
    headers: { 
    Accept: 'application/json',
    "Content-Type": "application/json" 
},
}).then(res => res.json())
.catch(err => console.log(err));

TypeError: Network request failed
    at XMLHttpRequest.xhr.onerror (420454d9-7271-44d5-b…-3a968d130699:48065)
    at XMLHttpRequest.dispatchEvent (420454d9-7271-44d5-b…-3a968d130699:53513)
    at XMLHttpRequest.setReadyState (420454d9-7271-44d5-b…-3a968d130699:52368)
    at XMLHttpRequest.__didCompleteResponse (420454d9-7271-44d5-b…-3a968d130699:52195)
    at 420454d9-7271-44d5-b…-3a968d130699:52305
    at RCTDeviceEventEmitter.emit (420454d9-7271-44d5-b…-3a968d130699:22482)
    at MessageQueue.__callFunction (420454d9-7271-44d5-b…-3a968d130699:22097)
    at 420454d9-7271-44d5-b…-3a968d130699:21854
    at MessageQueue.__guard (420454d9-7271-44d5-b…-3a968d130699:22051)
    at MessageQueue.callFunctionReturnFlushedQueue (420454d9-7271-44d5-b…-3a968d130699:21853)
javascriptandroidreact-nativeexpofetch-api

Answer №1

Which domain is hosting your REST API? I encountered a similar issue when trying to fetch data from a React Native app (running on an emulator) to a node.js/express REST API. I couldn't find a solution within React.

However, I managed to resolve this by using ngrok (). This tool allows you to expose a local domain and port to the external environment, enabling me to successfully fetch data from my app to the REST API.

While I can't confirm if the problem lies with React Native, I suspect that my firewall was blocking the connection. Rather than adjusting various settings, I opted to use ngrok for a seamless connection.

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