I have a document in Cloud firestore to which I listen for updates. It has 2 fields, it has a field description and a field for a picture. The picture is approximately 0.2 mb and description is a few words. I wanted to know what would happen if I made changes to the description in the document, I wanted to know if addSnapshotListener actually downloads a fresh new copy of the document or just the field that has been changed.
I indeed see, by looking at how much data is being downloaded in Xcode, a new fresh copy of the document is downloaded.
This is not efficient at all, since the picture field is rarely changed, only the description might change in my application.
Is there a way to optimize this?
Is there a way to optimize this?
Yes! Don't do that.
Firestore (and the realtime database) is not intended to store images or large datasets per field.
You should explore Storage and keep a reference (url) to the item stored in storage in your Firebase.
Cloud Storage is built for app developers who need to store and serve
user-generated content, such as photos or videos.
By leveraging storage if you need to update or change a field in Firestore, you're only working with a small amount of data instead of an entire image worth.
To answer the question; if you read a document from Firebase, it does read the Document and it's child data.
Here's a link to the Storage Docs which shows how to capture a reference to the item uploaded to storage.
https://firebase.google.com/docs/storage/ios/upload-files
If you want to automatically sync the images to all clients and have them available offline, just put them in a separate document.
// Store your small, frequently changing text here:
db.collection('users').doc(userId).set({email: vince#example.com})
// Store your image here:
db.collection('user_profile_pic').doc(userId).set({data: <imagedata>})
Related
I wanna create a chatapp for my friend, and now remote serve I will use firestore and locally sqlite, but I realized it is default for firestore to save data offline, so my question is I have some data like message, or sending setting for the app, is it ok just to save them in firestore offline which seems automatically and no extra costs.
It depends on what you want or need.
If you want to use the offline persistance only for storing in case internet is not there at all. Firebase supports that out of the box. But you need to keep in mind to do you calls carefully. Because on a slow internet connection, if you tell the Firebase access to wait for the online behavior. It will not be using the local first and you might not be able to show the data. Check the question here
Also if you want to use the offline persistance from Firebase, be mindful that the data size has a default of 40 megabytes of limit. You might assign that by your self. You can check this link
BUT, if you want to have heavy data manipulations and have more control over your data SQLite is more suggested.
My opionion: I think Firebase Offline persistance would be enough for you, so go for it.
As Firestore charges by the read/write, it would be super helpful to keep the changes in memory during the session and only commit them when the user exists either the entire app or a specific section. Is there a way to do that in a Flutter web application?
I think one problem with this approach is that the user might just close the tab including your app. In this case, you have no time to send your data to Firestore.
This aside, you could use packages like Hive to store your documents offline and later run a function to add the data to Firestore later.
You also have 50k reads and 20k writes for free with Firebase, which is sufficient for smaller apps. If you exceed this limit, your app is probably big enough to earn money with it anyway.
I'm making an app where the user can take a picture and add a title and description. But now I need to store the picture and the titles. I’ve tried making an object that contains title, description and image properties.
When it’s done I save an array of custom objects with the information on it with UserDefaults. My idea is showing in another view a table view with all the content and pictures the user has taken on the cells. I tried getting back the information with user defaults. It was working well until the user saves too many pictures. When the viewController with the tableview loads, then my app gets slower, and eventually it crashes.
I suppose the problem is when I load all the array with all custom objects, all the pictures are loaded into memory although they aren’t used and displayed for users. So I think it isn’t the best way to make what I want to make.
Is there any way better to make what I’m making or store data more efficiently and use it in tableview without using all the memory of the device?
I’m making the app from 0 again.
Can you show me how to store data and images efficiently?
There are several options for permanently storing user data on the device such that it will survive app and phone restarts. NSUserDefaults typically is for small amounts of data, such as user preferences.
When it comes time to store a lot of data, in particular big binary objects like photos, you need to decide which design you want to use. One option:
store all the photos in one directory in your apps documents and then use some simple lookup store (perhaps Core Data, or SQLite, or even a flat file) to index the photos and their metadata. Or if you don't care about indexing you can read the list of file names from the directory and sort them by time.
The other problem you are maybe having is that you are trying to load all of the photos at once for the user. As you have discovered, once you have more than a handful of photos this system falls apart. You need some mechanism to load only a few photos at a time, preferably only the ones the user needs to be displayed at that moment.
So, for example, if you are displaying the photos in a tableview, you want to only load the 10-15 photos that are visible in the table at any given time.
When storing this kind of data, you have 2 options (In fact you have more than 3 options, but saving image to the disk is IMHO complicated for this.) -
UserDefaults
Database like CoreData/Realm/FireBase...
The first one is recommended when there is not much data to save... For operating with more data, I would use database - CoreData...
For you operation you can use CoreData and NSFetchedResultsController (which is designed especially for fetching objects from the database)...
you can read the FetchedResultsController doc here... and core data basics here
Wish you best luck!
I want to store some photos that I take from a web service to my phone for the case when I don't have internet connectivity. I am storing data to a database but i have a question: should I store in the database the URL of the photo and the photo in a folder, or store the image in the database? The volume of photos shouldn't be great; something like 200-300 small pics, at approx 30-40kB each.
If you already have a database, i would organize my photos in database with only the path to the photo. And the photos can be stored on memorycard or on local disk.
The basic rule of thumb is to put big data objects like images right onto the disk and only reference the URLs. This might come in handy for loading/processing the images anyway.
30-40 kB per image is not that much, but then I'd consider 6-12 MB for the database quite extensive, especially it's probably the majority of your database volume.
I'm not real familiar with iOS. But my understanding is that it supports XML files. If the database is just being used to store the paths (instead of images), why not use an xml file to store the paths?
If you need the db, with small images, I don't see it being a problem if the phone is just using it. Either way, I don't think it'll be an issue. Someone else can probably give you a better answer as far as efficiency. That's outside my jurisdiction.
Store all the pics in document folder, and when there is no internet connection get them from document folder of your iPhone.
I am in the middle of developing an app which harvests tweets, Facebook statuses and Facebook photos for a user. Currently the user sets out exactly when and to they want this harvest to occur and a spider pulls the data during this period. The when and to is stored in a MySQL db and my plan was to store all the tweets, status and photo meta-data in MongoDB (with the actual images on S3).
I was thinking I would just create one collection for each of the periods the user wants to harvest for and then store all the tweets etc from that period in that particular collection.
Does this seem like a reasonable approach?
Does this seem like a reasonable approach?
What the #1 user query? Is it "find activity by period"? If users only ever want to "find by period", then this makes sense.
However, if users want an accumulated view, now you have to gather history for a user and merge it for display.
If you want both a "by this period" and an "accumulated", then I suggest simply stuffing all data into a single user object. It's easy to tag the individual actions with a "harvest run" and a "timestamp".
Mongo Details: MongoDB can handle individual documents up to about 4MB. Most recent versions up this to 8 or 16MB. If you're only using this space for text, please realize that this is a lot of text. A copy of war & peace is just over 3MBs. So you're talking about hundreds of pages of text in 4MB. With 8 or 16MB, you can probably store status updates & tweets for years on most people.
Note that MongoDB has GridFS for storing binary data (like image files), so you'll typically store just pointers to these in the User document.