I have tested Firebase functions for storage successfully. However, I havn't seen anywhere a hint how to only invoke the function when a file is added into a folder inside my bucket. The only hint I have seen about scoping the function is for different buckets here.
Is it possible to scope the function to a folder inside my bucket , if yes how? Or would I need to have multiple buckets instead of folders to separate different tasks.
You may check inside the function. Get the "filePath" or "fileDir" on your function and check if it is the folder you want.
const path = require('path');
const filePath = event.data.name;
const fileDir = path.dirname(filePath);
//if you want to check the posts folder only then:
if (fileDir != 'posts') {
console.log('This is not in post folder');
return null;
}
Please note that Google Cloud Storage works on a flat filesystem. So practically there are no directories. If you're storing a file like /users/profile_pictures/photo.jpg it is basically all part of the file name. So in reality, there are no directories. There are just files. Which is why there cannot be a trigger on a directory per se. Of course you can work that around by checking the name of the file itself and see whether its start matches a particular string or not.
export const generateThumbnailTrigger = functions.storage.object().onFinalize(async (object) => {
const filePath = object.name;
if (filePath?.startsWith('temp/')) {
console.log('start doing something with the file');
} else {
return false;
}
});