i have some pdf files and images stored in s3. I want to display (preview) them on my react app. currently, my react app is connected to java backend and as a user (on the frontend) I can download the files by calling an endpoint from my backend. how would i go about doing that? the s3 files can't be public
user
to display the preview of the pdf files and images in your react app, you can follow these steps:

1. **setup a new endpoint in your java backend to serve the files:** you will create a new route in your backend that serves the file from s3 as a stream (streaming), allowing you to display the preview without converting the s3 files to public.

here's a java snippet using aws sdk to serve a file from a private s3 bucket:

```java
import com.amazonaws.services.s3.amazons3;
import com.amazonaws.services.s3.model.getobjectrequest;
import com.amazonaws.services.s3.model.s3object;
import org.springframework.core.io.inputstreamresource;
import org.springframework.http.mediatype;
import org.springframework.http.responseentity;
import org.springframework.web.bind.annotation.getmapping;
import org.springframework.web.bind.annotation.pathvariable;
import org.springframework.web.bind.annotation.restcontroller;

@restcontroller
public class filecontroller {
    private final amazons3 amazons3;
    private final string bucketname = "your-private-s3-bucket";
    
    public filecontroller(amazons3 amazons3) {
        this.amazons3 = amazons3;
    }

    @getmapping("/s3-files/{filename}.{extension}")
    public responseentity<inputstreamresource> getfile(@pathvariable string filename, @pathvariable string extension) {
        // prepare getfilerequest
        getobjectrequest getobjectrequest = new getobjectrequest(bucketname, filename + "." + extension);
        s3object s3object = amazons3.getobject(getobjectrequest);
        
        // serve the file as inputstreamresource
        inputstreamresource inputstreamresource = new inputstreamresource(s3object.getobjectcontent());

        // set a suitable mediatype
        mediatype mediatype;
        if (extension.equalsignorecase("pdf")) {
            mediatype = mediatype.application_pdf;
        } else if (extension.equalsignorecase("jpg") || extension.equalsignorecase("jpeg")) {
            mediatype = mediatype.image_jpeg;
        } else if (extension.equalsignorecase("png")) {
            mediatype = mediatype.image_png;
        } else {
            mediatype = mediatype.application_octet_stream;
        }

        return responseentity.ok()
                .contenttype(mediatype)
                .body(inputstreamresource);
    }
}
```

2. **updating the frontend react app**: in your react app, you can utilize the `embed` tag for pdf files and the `img` tag for images to display the files, set the `src` attribute to point to the java backend route you just set up.

here's a minimal sample of a react component that displays a pdf and an image using the endpoint we created in step 1:

```javascript
import react from "react";

const filepreview = () => {
  const pdfurl = "/s3-files/sample-file.pdf";
  const imageurl = "/s3-files/sample-image.png";

  return (
    <div>
      <div>
        <embed
          src={pdfurl}
          type="application/pdf"
          width="100%"
          height="600px"
        />
      </div>
      <div>
        <img src={imageurl} alt="sample" />
      </div>
    </div>
  );
};

export default filepreview;
```

this way, you can display pdf files and images in your react app without making them public in s3.
assistant
To display the preview of the PDF files and images in your React app, you can follow these steps:

1. **Setup a new endpoint in your Java backend to serve the files:** You will create a new route in your backend that serves the file from S3 as a stream (streaming), allowing you to display the preview without converting the S3 files to public.

Here's a Java snippet using AWS SDK to serve a file from a private S3 bucket:

```java
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.model.GetObjectRequest;
import com.amazonaws.services.s3.model.S3Object;
import org.springframework.core.io.InputStreamResource;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class FileController {
    private final AmazonS3 amazonS3;
    private final String bucketName = "your-private-s3-bucket";
    
    public FileController(AmazonS3 amazonS3) {
        this.amazonS3 = amazonS3;
    }

    @GetMapping("/s3-files/{filename}.{extension}")
    public ResponseEntity<InputStreamResource> getFile(@PathVariable String filename, @PathVariable String extension) {
        // Prepare getFileRequest
        GetObjectRequest getObjectRequest = new GetObjectRequest(bucketName, filename + "." + extension);
        S3Object s3Object = amazonS3.getObject(getObjectRequest);
        
        // Serve the file as InputStreamResource
        InputStreamResource inputStreamResource = new InputStreamResource(s3Object.getObjectContent());

        // Set a suitable MediaType
        MediaType mediaType;
        if (extension.equalsIgnoreCase("pdf")) {
            mediaType = MediaType.APPLICATION_PDF;
        } else if (extension.equalsIgnoreCase("jpg") || extension.equalsIgnoreCase("jpeg")) {
            mediaType = MediaType.IMAGE_JPEG;
        } else if (extension.equalsIgnoreCase("png")) {
            mediaType = MediaType.IMAGE_PNG;
        } else {
            mediaType = MediaType.APPLICATION_OCTET_STREAM;
        }

        return ResponseEntity.ok()
                .contentType(mediaType)
                .body(inputStreamResource);
    }
}
```

2. **Updating the frontend React App**: In your React app, you can utilize the `embed` tag for PDF files and the `img` tag for images to display the files, set the `src` attribute to point to the Java backend route you just set up.

Here's a minimal sample of a React component that displays a PDF and an image using the endpoint we created in step 1:

```javascript
import React from "react";

const FilePreview = () => {
  const pdfUrl = "/s3-files/sample-file.pdf";
  const imageUrl = "/s3-files/sample-image.png";

  return (
    <div>
      <div>
        <embed
          src={pdfUrl}
          type="application/pdf"
          width="100%"
          height="600px"
        />
      </div>
      <div>
        <img src={imageUrl} alt="Sample" />
      </div>
    </div>
  );
};

export default FilePreview;
```

This way, you can display PDF files and images in your React app without making them public in S3.
assistant