React Native 将 base64 图像保存到相册

Question

Third Party API return a "QR code image" in base64 encode,
I need save that image to User's Album.

• CamerRoll - not support saving base64 image to album
• React-Native-Fetch-Blob - https://github.com/wkh237/react-native-fetch-blob
  still looking into it
• React-Native-fs - https://github.com/itinance/react-native-fs
  I am trying this now
• There are few npm modules with very little Github star (<10)

the React-Native-Fetch-Blob maintainer gone missing, so no one answering Github Issue, createFile from React-Native-Fetch-Blob Document not working as expected(not saving image into album)

  import fetch_blob from 'react-native-fetch-blob';

  // json.qr variable are return from API

  const fs = fetch_blob.fs
  const base64 = fetch_blob.base64
  const dirs = fetch_blob.fs.dirs

  const file_path = dirs.DCIMDir + "/some.jpg"
  const base64_img = base64.encode(json.qr)

  fs.createFile(file_path, base64_img, 'base64')
  .then((rep) => { 
    alert(JSON.stringify(rep));
  })
  .catch((error) => {
    alert(JSON.stringify(error));
  });

Anyone deal with this problem before?

How to save a base64 encode Image string to User album? (as a jpg or png file)

because I fetch an API with no CORS header,
I can't debug it in Debug JS Remotely
Chrome would stop that request from happening,

I have to run that on my Android Phone to make it work
(no CORS control on real phone)

I am planing use Clipboard save base64 string,
and hardcode it in my code,
to debug what's wrong with react-native-fetch-blob createFile API

Answer 1

Remove data:image/png;base64, in your base64 string

var Base64Code = base64Image.split("data:image/png;base64,"); //base64Image is my image base64 string

const dirs = RNFetchBlob.fs.dirs;

var path = dirs.DCIMDir + "/image.png";

RNFetchBlob.fs.writeFile(path, Base64Code[1], 'base64')
.then((res) => {console.log("File : ", res)});

And then I solved my problem.

Answer 2

I solve the problem,
turn out I forgot data:image/png;base64, at beginning of the string.

I remove it with following code

  // json.qr is base64 string
  var image_data = json.qr.split('data:image/png;base64,');
  image_data = image_data[1];

and then save the image file

  import fetch_blob from 'react-native-fetch-blob';
  import RNFS from 'react-native-fs';

  const fs = fetch_blob.fs
  const dirs = fetch_blob.fs.dirs      
  const file_path = dirs.DCIMDir + "/bigjpg.png"

  // json.qr is base64 string "data:image/png;base64,..."

  var image_data = json.qr.split('data:image/png;base64,');
  image_data = image_data[1];

  RNFS.writeFile(file_path, image_data, 'base64')
  .catch((error) => {
    alert(JSON.stringify(error));
  });

I wrote a blog about this

http://1c7.me/react-native-save-base64-image-to-album/

Answer 3

 const path = `${RNFS.PicturesDirectoryPath}/My Album`; await RNFS.mkdir(path); return await fetch(uri) .then(res => res.blob()) .then(image => { RNFetchBlob.fs.readFile(uri, "base64").then(data => { RNFS.appendFile(`${path}/${image.data.name}`, data, "base64").catch( err => { console.log("error writing to android storage :", err); } ); }); }); 

Answer 4

I got this worked in following example

import RNFetchBlob from 'rn-fetch-blob';
import Permissions from 'react-native-permissions';

 takeSnapshot = async () => {
    const currentStatus = await Permissions.check('storage');

    if (currentStatus !== 'authorized') {
      const status = await Permissions.request('storage');

      if (status !== 'authorized') {
        return false;
      }
    }

    // put here your base64
    const base64 = '';

    const path = `${RNFetchBlob.fs.dirs.DCIMDir}/test11.png`;

    try {
      const data = await RNFetchBlob.fs.writeFile(path, base64, 'base64');
      console.log(data, 'data');
    } catch (error) {
      console.log(error.message);
    }
  };

Answer 5

this works for me.

I was wanna download base64 as an image in react native

this.state.base64img is my base64 without 'data:image/png;base64,'

checkPermision = async () => {
    if (Platform.OS === 'ios') {
      this.downloadImage();
    } else {
      try {
        const granted = await PermissionsAndroid.request(
          PermissionsAndroid.PERMISSIONS.WRITE_EXTERNAL_STORAGE,
          {
            title: 'Storage Permission Required',
            message: 'App needs access to your storage to download photos',
          },
        );
        if (granted === PermissionsAndroid.RESULTS.GRANTED) {
          console.log('Storage permission Granted');
          this.downloadImage();
        } else {
          console.log('Storage permission not Granted');
        }
      } catch (error) {
        console.log('errro', error);
      }
    }
  };

   downloadImage() {
    let date = new Date();
    const { fs} = RNFetchBlob;
    const dirs = RNFetchBlob.fs.dirs;
    let PictureDir = fs.dirs.PictureDir;

    var path =  PictureDir + '/image_' +
    Math.floor(date.getTime() + date.getSeconds() / 2) +
    '.png';
    console.log("path :-",path,"dirs :-",dirs)


    RNFetchBlob.fs.writeFile(path, this.state.base64img, 'base64').then(res => {
      console.log('File : ', res);
      alert('Image downloaded successfully.');
    }).catch((error) => {
         alert(JSON.stringify(error));
       });

  }

Answer 6

You can now use only react native fetch blob to achieve this.

Simply replace RNFS.writeFile with

RNFetchBlob.fs.writeFile(file_path, image_data, 'base64')

If you wish to view file in native OS viewer you can simply put

                if (isAndroid) {
                  RNFetchBlob.android.actionViewIntent(file_path, 'application/pdf');
                } else {
                  RNFetchBlob.ios.previewDocument(file_path);
                }