How to use the sharp library to resize a Parse file img? - parse-server

Question

I have a Parse Cloud afterSave trigger from where I can access the obj and inside the obj a field that has a store parse file img.
I want to use sharp to resize it and save it in another field but I'm struggling and getting an error when I use sharp. Here is a summary of the code I already have inside the cloud trigger:
let file = obj.get("photo");
sharp(file)
.resize(250, 250)
.then((data) => {
console.log("img-----", data);
})
.catch((err) => {
console.log("--Error--", err);
});

Answer 1

After some research, I managed to figure out how to create Parse Cloud afterSave trigger which resizes and then saves the img, I couldn't find much information on it so ill post my solution so others can use it if it's helpful.
Parse.Cloud.afterSave("Landmarks", async (req) => {
const obj = req.object;
const objOriginal = req.original;
const file = obj.get("photo");
const condition = file && !file.equals(objOriginal.get("photo"));
if (condition) {
Parse.Cloud.httpRequest({ url: file.url() })
.then((res) => {
sharp(res.buffer)
.resize(250, 250, {
fit: "fill",
})
.toBuffer()
.then(async (dataBuffer) => {
const data = { base64: dataBuffer.toString("base64") };
const parseFile = new Parse.File(
"photo_thumbnail",
data
);
await parseFile.save();
await obj.save({ photo_thumb: parseFile });
})
.catch((err) => {
console.log("--Sharp-Error--", err);
});
})
.catch((err) => {
console.log("--HTTP-Request-Error--", err);
});
} else {
console.log("--Photo was deleted or did not change--");
}
});
So to break this down a bit, what i did first was get the obj and the objOriginal so i can compare them and check for a change in a specific field. This condition is necessery since in my case i wanted to save the resized img in parse which would cause an infinite loop otherwise.
After that i did a Parse.Cloud.httpRequest({ url: file.url()}).then() which is the way i found to get the buffer from the photo. The buffer is stored inside res.buffer and we need it for sharp.
Next i use sharp(res.buffer) since sharp also accepts buffers and resize it to the desired dimensions (i used the fit config for it). Then we turn the resulted img into another buffer using .toBuffer(). Furthermore, i use a .then().catch() blocks and if sharp is succesful i turned the outputed buffer into a base64 and passed it in Parse.File(), note that the specific syntax { base64: 'insert buffer here' } is important.
And finally i just save the file and the obj. Is this the best way to do it, absolytely not, but its the one i found that works. Another possible solution is instead of using buffers and base64 is to create a temporary dir which you save the images there, use them and then delete the directory. I tried this as well but had issues making it work.