How to Put an Image in a Realm Database

How to put an image in a Realm database?

You can store images as NSData. Given you have the URL of an image, which you want to store locally, here is a code snippet how that can be achieved.

class MyImageBlob {
    var data: NSData?
}

// Working Example
let url = NSURL(string: "http://images.apple.com/v/home/cb/images/home_evergreen_hero_iphone_medium.jpg")!
if let imgData = NSData(contentsOfURL: url) {
    var myblob = MyImageBlob()
    myblob.data = imgData 

    let realm = try! Realm()
    try! realm.write {
        realm.add(myblob)
    }
}

May be it is a bad idea to do that?

The rule is simple:
If the images are small in size, the number of images is small and they are rarely changed, you can stick with storing them in the database.

If there is a bunch images, you are better off writing them directly to the file system and just storing the path of the image in the database.

Here is how that can be done:

class MyImageStorage{
    var imagePath: NSString?
}

let url = NSURL(string: "http://images.apple.com/v/home/cb/images/home_evergreen_hero_iphone_medium.jpg")!
if let imgData = NSData(contentsOfURL: url) {
    // Storing image in documents folder (Swift 2.0+)
    let documentsPath = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0]
    let writePath = documentsPath?.stringByAppendingPathComponent("myimage.jpg")

    imgData.writeToFile(writePath, atomically: true)

    var mystorage = MyImageStorage()
    mystorage.imagePath = writePath

    let realm = try! Realm()
    try! realm.write {
         realm.add(mystorage)
    }
}

Please note: Both code samples are not reliable methods for downloading images since there are many pitfalls. In real world apps / in production, I'd suggest to use a library intended for this purpose like AFNetworking or AlamofireImage.

Insert image into Realm database in Android

First, convert bitmap to byte array

Bitmap bmp = intent.getExtras().get("data");
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bmp.compress(Bitmap.CompressFormat.PNG, 100, stream);
byte[] byteArray = stream.toByteArray();

Later, save byte[] into Realm

Notice: Strings and byte arrays (byte[]) cannot be larger than 16 MB (from Realm Documentation)

Field types

Realm supports the following field types: boolean, byte, short, ìnt,
long, float, double, String, Date and byte[]. The integer types byte,
short, int, and long are all mapped to the same type (long actually)
within Realm. Moreover, subclasses of RealmObject and RealmList are supported to model relationships.

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