作为用户从前端下载图像（我有链接）？

Question

I want to allow my user to download a image, i know that if i have a file i can use the tag download and it will work, but it doesn't work if i have the link

I have already tried the download tag, and read the google cloud storage downloading-objects docs but the problem with the last one is that it gets downloaded on my server, also i tried to return the file but it is just a promise with no file info

Front-end with the download code (doesn't work), i have tried it with download={preview}

      <div className={classes.fileInputs}>
        <a download href={preview} title="Imagen">
          <img
            src={preview}
            alt='Preview obj'
            className={classes.imgPreview}
          />
        </a>

This is how i thought it should work but it didn't, download triggers a request to the back-end but the image is downloaded in my server

<Button color="inherit" onClick={() => download()}>
   Download
</Button>

I just want that a click in the button download will make the client have its image

Answer 1

If you want you can use axios:

axios({
url: 'http://localhost:5000/static/example.jpg',
method: 'GET',
responseType: 'blob', // important
}).then((response) => {
const url = window.URL.createObjectURL(new Blob([response.data]));
const link = document.createElement('a');
link.href = url;
link.setAttribute('download', 'file.jpg');
document.body.appendChild(link);
link.click();
});

You can check it in more details here

Answer 2

To set type of file and filename from "content-disposition" -header you can use this:

const blob = new Blob([response.data], {type: response.data.type});

const url = window.URL.createObjectURL(blob);

const link = document.createElement('a');

link.href = url;

const contentDisposition = response.headers['content-disposition'];

let fileName = 'unknown';

if (contentDisposition) {

const fileNameMatch = contentDisposition.match(/filename="(.+)"/);

if (fileNameMatch.length === 2)

    fileName = fileNameMatch[1];

}

link.setAttribute('download', fileName);

document.body.appendChild(link);

link.click();

link.remove();

window.URL.revokeObjectURL(url);