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Framework guide

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Expo vs bare React Native

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Expo: expo-document-picker

npx expo install expo-document-picker

import * as DocumentPicker from "expo-document-picker";

const result = await DocumentPicker.getDocumentAsync({ type: "application/pdf" });
if (!result.canceled) {
  const asset = result.assets[0]; // { uri, name, mimeType, size }
}

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Bare RN: react-native-document-picker

npm install react-native-document-picker
cd ios && pod install

import DocumentPicker from "react-native-document-picker";

const [file] = await DocumentPicker.pick({ type: [DocumentPicker.types.pdf] });
// { uri, name, type, size }

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Permisos

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Where does the API key live?

1. Proxy on your backend (recommended for production): the app calls your own endpoint, which in turn calls markpdf with the key saved server-side. The app never sees the markpdf key.
2. Embedded low privilege key: if you do not have your own backend, use a key dedicated only to that app, with limited usage and billing limits, assuming it can be leaked.
3. Build environment variables (EAS Secrets in Expo, .env + react-native-config in bare): they prevent hardcoding the key in the versioned source code, but they do not prevent it from ending up in the final decompilable bundle. Useful to not commit the key to the repo, not to hide it from the end user.

// Expo: read at build time from EAS Secrets/app.config.ts -> extra
import Constants from "expo-constants";
const client = new MarkpdfClient({ apiKey: Constants.expoConfig?.extra?.markpdfApiKey });

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Networking en segundo plano