react-native-pdf-view - How to populate pdfView with base64 or blob

问题

I am using the react-native-pdf-view library and I am having trouble populating the PDFView with a pdf.

How my project works is that I receive a base64 pdf from the server where I then save to the android file system by using the library react-native-fs like so:
(This works fine)

saveFile(filename){

   var base64Image = this.state.imageBase64;

   // create a path you want to write to
   var path = RNFS.DocumentDirectoryPath + '/' + filename;

   // write the file
   RNFS.writeFile(path, base64Image, 'base64').then((success) => {
     console.log('FILE WRITTEN!');
     this.setState(
       {pdf_dirPath: path}
     );
     this._display_fileAttachment()
   })
   .catch((err) => {
     console.log(err.message);
   });
 }

I then try populate the pdf view with this:

<PDFView
  ref={(pdf)=>{this.pdfView = pdf;}}
  src={"path/To/base64/pdf"}
  style={styles.pdf}
 />

Question

Does the react-native-pdf-view have to take a file location or can it take a base64 pdf or a blob.

If it can take a base64 or blob please explain or give sample code on how to do it.
Thanks

Nb: This StackOverflow question is very similar but I need to know how in what form to save or retrieve the base64 from the file system and how to populate the pdf.

回答1:

It seems like there's a much easier way to do this. Just tell RNFletchBlob to save directly to disk like so. Note that you'll have to clean up the file later.

RNFetchBlob
  .config({
    // add this option that makes response data to be stored as a file. 
    fileCache : true,
    appendExt : 'pdf'
  })
  .fetch('GET', 'http://www.example.com/file/example.zip', {
    //some headers ..
  })
  .then((res) => {
    // the temp file path 
    this.setState({fileLocation: res.path()});
    console.log('The file saved to ', res.path())
  })

And then later

<PDFView 
  ref={(pdf)=>{this.pdfView = pdf;}}
  path={this.state.fileLocation}
  onLoadComplete = {(pageCount)=>{
    this.pdfView.setNativeProps({
      zoom: 1.0
    });
    console.log("Load Complete. File has " + pageCount + " pages.");
  }}
  style={styles.pdf}/>

回答2:

For anyone having the same problem, here is the solution.

Solution

react-nativive-pdf-view must take the file path to the pdf_base64.

Firstly, I used the react-native-fetch-blob to request the pdf base64 from the server.(Because RN fetch API does not yet support BLOBs).

Also I discovered that react-native-fetch-blob also has a FileSystem API which is way better documented and easier to understand than the 'react-native-fs' library. (Check out its FileSystem API documentation)

Receiving base64 pdf and saving it to a file path:

var RNFetchBlob = require('react-native-fetch-blob').default;

const DocumentDir = RNFetchBlob.fs.dirs.DocumentDir;

getPdfFromServer: function(uri_attachment, filename_attachment) {
   return new Promise((RESOLVE, REJECT) => {

      // Fetch attachment
      RNFetchBlob.fetch('GET', config.apiRoot+'/app/'+uri_attachment)
      .then((res) => {

          let base64Str = res.data;
          let pdfLocation = DocumentDir + '/' + filename_attachment;

          RNFetchBlob.fs.writeFile(pdfLocation, pdf_base64Str, 'base64');
          RESOLVE(pdfLocation);
      })
   }).catch((error) => {
       // error handling
       console.log("Error", error)
   });
}

What I was doing wrong was instead of saving the pdf_base64Str to the file location like I did in the example above. I was saving it like this:

var pdf_base64= 'data:application/pdf;base64,'+pdf_base64Str;

which was wrong.

Populate PDF view with file path:

<PDFView
    ref={(pdf)=>{this.pdfView = pdf;}}
    src={pdfLocation}
    style={styles.pdf}
/>

来源：https://stackoverflow.com/questions/38658716/react-native-pdf-view-how-to-populate-pdfview-with-base64-or-blob