I am receiving a ReadableStream from a server, returned from my fetch call.
A ReadableStream is returned but I don't know how to trigger a download from this stage. I can't use the url in an href because it requires an Authorization token.
I don't want to install fs
on the client so what options do I have?
try {
const res = await fetch(url, {
method: 'GET',
headers: {
Authorization: `Bearer ${token}`,
'Content-Type': 'application/octet-stream'
}
});
const blob = await res.blob();
const newBlob = new Blob([blob]);
const newUrl = window.URL.createObjectURL(newBlob);
const link = document.createElement('a');
link.href = newUrl;
link.setAttribute('download', 'filename');
document.body.appendChild(link);
link.click();
link.parentNode.removeChild(link);
window.URL.revokeObjectURL(newBlob);
} catch (error) {
console.log(error);
}
Update 1
I converted the file to a Blob, then passed it into a newly generated href. Successfully downloaded a file. The end result was the ReadStream contents as a .txt file.
Meaning stuff like this
x:ÚêÒÓ%¶âÜTb∞\܃
To retrieve data from a JavaScript ReadableStream object, we need to call a conversion method to convert the ReadableStream to the actual data we can use. to make a GET request to https://httpbin.org/ip with fetch . fetch returns a promise that resolves to a ReadableStream object which we assigned to response .
The locked read-only property of the ReadableStream interface returns whether or not the readable stream is locked to a reader. A readable stream can have at most one active reader at a time, and is locked to that reader until it is released. A reader might be obtained using ReadableStream.
Readable Stream. A readable stream lets you read data from a source. The source can be anything. It can be a simple file on your file system, a buffer in memory or even another stream. As streams are EventEmitters , they emit several events at various points.
The ReadableStream interface of the Streams API represents a readable stream of byte data. The Fetch API offers a concrete instance of a ReadableStream through the body property of a Response object. ReadableStream is a transferable object.
I have found 2 solutions, both worked but I was missing a simple addition to make them work.
The native solution is
try {
const res = await fetch(url, {
method: 'GET',
headers: {
Authorization: `Bearer ${token}`
}
});
const blob = await res.blob();
const newBlob = new Blob([blob]);
const blobUrl = window.URL.createObjectURL(newBlob);
const link = document.createElement('a');
link.href = blobUrl;
link.setAttribute('download', `${filename}.${extension}`);
document.body.appendChild(link);
link.click();
link.parentNode.removeChild(link);
// clean up Url
window.URL.revokeObjectURL(blobUrl);
This version is using the npm package steamSaver for anyone who would prefer it.
try {
const res = await fetch(url, {
method: 'GET',
headers: {
Authorization: `Bearer ${token}`
}
});
const fileStream = streamSaver.createWriteStream(`${filename}.${extension}`);
const writer = fileStream.getWriter();
const reader = res.body.getReader();
const pump = () => reader.read()
.then(({ value, done }) => {
if (done) writer.close();
else {
writer.write(value);
return writer.ready.then(pump);
}
});
await pump()
.then(() => console.log('Closed the stream, Done writing'))
.catch(err => console.log(err));
The key for why it was not working was because I did not include the extension, so it either errored out because of the mimetype was wrong or it opens a .txt file with a string of the body instead of the image.
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