How to save & retrive image to/from mysql? - mysql

Question

Two part quersion.
Part 1:
Im uploading an image to my server and want to save it to my database.
So far:
table:
resolver:
registerPhoto: inSequence([
async (obj, { file }) => {
const { filename, mimetype, createReadStream } = await file;
const stream = createReadStream();
const t = await db.images.create({
Name: 'test',
imageData: stream ,
});
},
])
executing query:
Executing (default): INSERT INTO `images` (`Id`,`imageData`,`Name`) VALUES (DEFAULT,?,?);
But nothing is saved.
Im new to this and im probably missing something but dont know what.
Part2:
This is followed by part 1, lets say I manage to save the image, how do I read it and send it back to my FE?
An edit: Ive read alot of guides saving the an image name to the db and then tha actuall image in a folder. This is NOT what im after, want to save the image to the DB and then be able to fetch it from the DB abd present it.

Answer 1

This took me some time but I finaly figured it out.
First step (saving to the db):
Have to get the entire stream data and read it like this:
export const readStream = async (stream, encoding = 'utf8') => {
stream.setEncoding('base64');
return new Promise((resolve, reject) => {
let data = '';
// eslint-disable-next-line no-return-assign
stream.on('data', chunk => (data += chunk));
stream.on('end', () => resolve(data));
stream.on('error', error => reject(error));
});
};
use like this:
const streamData = await readStream(stream);
Before saving I tur the stream into a buffer:
const buff = Buffer.from(streamData);
Finaly the save part:
db.images.create(
{
Name: filename,
imageData: buff,
Length: stream.bytesRead,
Type: mimetype,
},
{ transaction: param }
);
Note that I added Length and Type parameter, this is needed if you like to return a stream when you return the image.
Step 2 (Retrieving the image).
As #xadm said multiple times you can not return an image from GRAPHQL and after some time I had to accept that fact, hopefully graphql will remedy this in the future.
S What I needed to do is set up a route on my fastify backend, send a image Id to this route, fetch the image and then return it.
I had a few diffirent approaches to this but in the end I simpy returned a binary and on the fronted I encoded it to base64.
Backend part:
const handler = async (req, reply) => {
const p: postParams = req.params;
const parser = uuIdParserT();
const img = await db.images.findByPk(parser.setValueAsBIN(p.id));
const binary = img.dataValues.imageData.toString('binary');
const b = Buffer.from(binary);
const myStream = new Readable({
read() {
this.push(Buffer.from(binary));
this.push(null);
},
});
reply.send(myStream);
};
export default (server: FastifyInstance) =>
server.get<null, any>('/:id', opts, handler);
Frontend part:
useEffect(() => {
// axiosState is the obj that holds the image
if (!axiosState.loading && axiosState.data) {
// #ts-ignore
const b64toBlob = (b64Data, contentType = '', sliceSize = 512) => {
const byteCharacters = atob(b64Data);
const byteArrays = [];
for (let offset = 0; offset < byteCharacters.length; offset += sliceSize) {
const slice = byteCharacters.slice(offset, offset + sliceSize);
const byteNumbers = new Array(slice.length);
// #ts-ignore
// eslint-disable-next-line no-plusplus
for (let i = 0; i < slice.length; i++) {
byteNumbers[i] = slice.charCodeAt(i);
}
const byteArray = new Uint8Array(byteNumbers);
byteArrays.push(byteArray);
}
const blob = new Blob(byteArrays, { type: contentType });
return blob;
};
const blob = b64toBlob(axiosState.data, 'image/jpg');
const urlCreator = window.URL || window.webkitURL;
const imageUrl = urlCreator.createObjectURL(blob);
setimgUpl(imageUrl);
}
}, [axiosState]);
and finaly in the html:
<img src={imgUpl} alt="NO" className="imageUpload" />
OTHER:
For anyone who is attempting the same NOTE that this is not a best practice thing to do.
Almost every article I found saved the images on the sever and save an image Id and other metadata in the datbase. For the exact pros and cons for this I have found the following helpful:
Storing Images in DB - Yea or Nay?
I was focusing on finding out how to do it if for some reason I want to save an image in the datbase and finaly solved it.

Answer 2

There are two ways to store images in your SQL database. You either store the actual image on your server and save the image path inside your mySql db OR you create a BLOB using the image and store it in db.
Here is a handy read https://www.technicalkeeda.com/nodejs-tutorials/nodejs-store-image-into-mysql-database

Answer 3

you should save the image in a directory and save the link of this image in the database