hurricane/security_camera/resources/cloud_server/functions/addImage.js - v4.1

// The Cloud Functions for Firebase SDK to create Cloud Functions and setup triggers.
const functions = require('firebase-functions');
const admin = require('firebase-admin');
const uuid = require('uuid');
const config = require('./config/firebase-config');
const db = admin.firestore()
const storage = admin.storage()
const DEFAULT_CAMERA_SETTINGS = {
    contrast: 0,
    saturation: 0,
    brightness: 0,
    resolution: 6,
    quality: 5,
    mirror: false,
    flip: false,
    filter: 0,
    interval: 3*60*1000 // 3min
}
/**************************************************************************************************
 * Add image to database
 * The call sequence is:
 * 1. Device writes image message to DMS
 * 2. DMS forwards message to Firebase
 * 3. Firebase executes this cloud function
 * 4. This cloud function retrieve or creates the device in the database
 * 5. This cloud function saves the image file to storage
 * 6. This cloud functions writes image metadata to the database
 * 7. Prune any old images
 */
module.exports = functions.https.onRequest((req, res) => {
    // console.log('Received request: ' + JSON.stringify(req.body));
    const authToken = req.get('authorization');
    // Ensure this request is coming from the DMS webhook
    if(authToken !== config.DMS_WEBHOOK_AUTH_TOKEN) {
        return res.status(403).send('Unauthorized');
    }
    const data = req.body.data
    if(!data) {
        return res.status(400).send('Missing data field');
    }
    // Validate the message arguments
    const uuid = data.uuid
    const code = data.code
    const timestamp = data.timestamp
    const meta = data.meta
    const imageData = data.img
    if(!uuid) {
        return res.status(400).send('Missing uuid field');
    }
    if(!code) {
        return res.status(400).send('Missing code field');
    }
    if(!timestamp) {
        return res.status(400).send('Missing timestamp field');
    }
    if(!imageData || !imageData.data) {
        return res.status(400).send('Missing img field');
    }
    let context = {
        uuid: uuid.toUpperCase(),
        code: code.toUpperCase(),
        timestamp: timestamp,
        meta: meta,
        data: imageData.data,
        imageCount: 0
    }
    return addNewImage(context).then(() => {
        return res.status(200).send(context.settings);
    }).catch((err) => {
        console.log(`Failed to add image to db, err: ${err.message ||err.description || err}`)
        return res.status(400).send(`Error: ${err.message || err}`);
    })
});
/*************************************************************************************************/
const addNewImage = (context) => {
    return retrieveOrCreateDevice(context).then(() => {
        return addImageToStorage( context)
    }).then(() => {
        return addImageToDatabase(context)
    })
}
/*************************************************************************************************/
const retrieveOrCreateDevice = (context) => {
    const query = db.collection('devices').where('uuid', '==', context.uuid)
    return query.get().then((results) => {
        if(results.size > 0){
            console.log(`Device already exists: ${context.uuid}`)
            context.deviceRef = results.docs[0].ref
            context.settings = results.docs[0].get('settings')
            context.imageCount = results.docs[0].get('imageCount')
            return Promise.resolve()
        } else {
            return createDevice(context)
        }
    })
}
/*************************************************************************************************/
const createDevice = (context) => {
    console.log(`Creating new device: ${context.uuid}`)
    return db.collection('devices').add({
        uuid: context.uuid,
        code: context.code,
        settings: DEFAULT_CAMERA_SETTINGS,
        imageCount: 0
    }).then((deviceRef) => {
        context.deviceRef = deviceRef
        context.settings = DEFAULT_CAMERA_SETTINGS
        context.imageCount = 0
        return Promise.resolve()
    })
}
/*************************************************************************************************/
const addImageToStorage = (context) => {
    const bucket = storage.bucket();
    const imgBuffer = Buffer.from(context.data);
    console.log(`Current image count: ${context.imageCount}`)
    pruneOldImages(context);
    console.log('Adding image to storage ...');
    context.filePath = `images/${context.uuid}/${context.timestamp}.jpg`;
    context.imgFile = bucket.file(context.filePath);
    return context.imgFile.save(imgBuffer, {resumable: false, public:true}).then(() => {
        return setImageMetaData(context)
    })
}
/*************************************************************************************************/
const setImageMetaData = (context) => {
    context.token = uuid.v4();
    const metadata = {
        contentType: 'image/jpeg',
        firebaseStorageDownloadTokens: context.token
    };
    // https://firebasestorage.googleapis.com/v0/b/[BUCKET_NAME]/o/[FILE_PATH]?alt=media&token=[THE_TOKEN_YOU_CREATED]
    return context.imgFile.setMetadata(metadata);
}
/*************************************************************************************************/
const addImageToDatabase = (context) => {
    console.log('Adding image to database ...');
    return context.deviceRef.collection('images').add({
        timestamp: context.timestamp,
        path: context.filePath,
        token: context.token,
        meta: context.meta
    }).then(() => {
        return context.deviceRef.update({imageCount: context.imageCount + 1})
    })
}
/*************************************************************************************************/
const pruneOldImages = (context) => {
    const imageOverflowCount = context.imageCount - config.MAX_STORED_IMAGES
    // To limit accesses to the DB, we only prune old images
    // when the count exceeds 50% of the max
    if(imageOverflowCount > config.MAX_STORED_IMAGES * 0.5) {
        context.imageCount = config.MAX_STORED_IMAGES
        // Return a list of the images for the given device ordered by timestamp in ascending order
        // We remove imageOverflowCount of the oldest images
        const query = context.deviceRef.collection('images').orderBy('timestamp', 'asc').limit(imageOverflowCount);
        query.get().then((results) => {
            console.log(`Pruning ${results.size} images`)
            for (let i = 0; i < results.size; i++) {
                deleteOldImage(results.docs[i])
            }
            return null;
        }).catch((err) => {
            console.log(`Error while pruning images, err:${err.message || err}`)
        })
    }
}
/*************************************************************************************************/
const deleteOldImage = (doc) => {
    const bucket = storage.bucket();
    const filepath = doc.get('path')
    const file = bucket.file(filepath)
    // Delete the file from storage, ignoring errors
    file.delete().catch((err) => {
        console.log(`Failed to delete ${filepath} from storage, err:${err.message || err}`)
    })
    // Delete the record from the database, ignoring errors
    console.log(`Pruning image: ${doc.id}`)
    doc.ref.delete().catch((err) => {
        console.log(`Failed to delete image, err: ${err.message || err.description || err}`)
    })
}