solution to get files from android using rn-fetch-blob

Open efstathiosntonas opened this issue 5 years ago • 0 comments

Here's the code in case someone wants to read files that start with content:// on Android:

import RNFS from "react-native-fs";
import { Base64 } from "js-base64";
import fileType from "file-type";
import RNFetchBlob from "rn-fetch-blob";
import { Platform } from "react-native";

function min(a, b) {
  return a < b ? a : b;
}

function FileType(path) {
  return new Promise((resolve, reject) => {
    if (Platform.OS === "ios") {
      RNFS.stat(path)
        .then((statResult) => {
          const numberBytes = min(statResult.size, 64);
          RNFS.read(path, numberBytes, 0, "base64").then((fileData) => {
            let convertedData = CovertBase64ToArrayBuffer(fileData);
            convertedData = new Uint8Array(convertedData);

            let type = fileType(convertedData);
            if (type === undefined || type === null) {
              let decodedData = String.fromCharCode.apply(null, convertedData);

              if (decodedData.startsWith("<html>") || decodedData.endsWith("</html>")) {
                type = { ext: "html", mime: "text/html" };
              }
            }

            resolve(type);
          });
        })
        .catch((reason) => {
          reject(reason);
        });
    } else {
      RNFetchBlob.fs
        .stat(path)
        .then((file) => {
          const numberBytes = min(file.size, 64);
          RNFetchBlob.fs.readFile(path, "base64", numberBytes).then((fileData) => {
            let convertedData = CovertBase64ToArrayBuffer(fileData);
            convertedData = new Uint8Array(convertedData);

            let type = fileType(convertedData);
            if (type === undefined || type === null) {
              let decodedData = String.fromCharCode.apply(null, convertedData);

              if (decodedData.startsWith("<html>") || decodedData.endsWith("</html>")) {
                type = { ext: "html", mime: "text/html" };
              }
            }
            resolve(type);
          });
        })
        .catch((reason) => {
          reject(reason);
        });
    }
  });
}

function CovertBase64ToArrayBuffer(data) {
  let UTF8Data = Base64.atob(data);
  let UTF8DataLength = UTF8Data.length;

  let bytes = new Uint8Array(UTF8DataLength);

  for (var i = 0; i < UTF8DataLength; i++) {
    bytes[i] = UTF8Data.charCodeAt(i);
  }
  return bytes.buffer;
}

export default FileType;

Apr 29 '20 11:04 efstathiosntonas