Using an existing database in an iMessage app (Swift)

Question

Currently building an iMessage app, and would like to experiment with using a database. I have a database that I would like to use in the app, and have included it in my project, and verified the target membership is correct. Using SQLite.Swift.

Whenever I try opening the connection to the database in simulator, I always get an error (unexpected nil) for the path of the database.

I've tried an image file the same way with no avail.

 let imagePath = Bundle.main.path(forResource: "db", ofType: ".sqlite")

    do {
        let db = try Connection(imagePath!, readonly: true)

    } catch {

    }

I work with Photos Extensions, and if I read you correctly, an "iMessage app" is actually more of a Messages *extension* than an actual *app*. I created one and "out of the box" I see two targets and no main view controller. Based on that (and my experience with Photo extensions) I think the issue is with `Bundle.main` - there is none. I use a Framework target, and there *is* a way to include images and scripts and find the location of the "bundle" in this. If you'd like, I can post that code as an answer. (Edit: I don't know if this will work with a db, but it should.) — , Jul 28 '17 at 23:03
https://stackoverflow.com/questions/23236554/sqlite3-from-bundle-resources-in-ios — john elemans, Jul 28 '17 at 23:37

score 1 · Accepted Answer · 2017-07-29T02:31:59.667

I believe the issue is more related to what an iMessage "app" is - which is actually an extension, not a true app. There's no initial VC, thus no real Bundle.main to get to.

One (maybe soon a second) app of mine has a Photo Editing Extension - basically what I always have called a "shell connection" to an Apple app. You really have either a "do nothing" app with a connection to one of their apps, or you have a stand-alone app an share the code with the extension.

My solution for sharing code is to use a Framework target. Yes, a third project. (App, extension, shared code.) I found a technique that I think should work for you - basically, for images, scripts (my apps use .cikernel files) you add them into the framework project and return what you need in a function call.

You may be able to streamline this with a need for a Framework target. YMMV. The basics are this:

Someplace in Xcode you have a "Bundle Identifier". Something like *"com.company.projectname".
Put your files into a folder, maybe on your desktop. Add an extension to this folder called ".bundle". macOS will give you a warning, accept it. All you are really doing is creating your bundle.
Drag this into your Xcode project.
Code to get to this bundle, and the files inside it. (I'm not sure if need a framework here - try to drag this into your "MessagesExtension" target first.

So lets say you have images you wish to share between projects, extensions, whatever. After moving them into a folder called "images", andrenaming the folder with a ".bundle" at the end, and finally dragging it into your Xcode project, you pretty much need to add this function:

public func returnImage(_ named:String) -> UIImage {
    let myBundle = Bundle.init(identifier: "com.company.project")
    let imagePath = (myBundle?.path(forResource: "images", ofType: "bundle"))! + "/" + named
    let theImage = UIImage(contentsOfFile: imagePath)
    return theImage!
}

For a text file you want:

public func returnKernel(_ named:String) -> String {
    let myBundle = Bundle.init(identifier: "com.company.project")
    let kernelPath = (myBundle?.path(forResource: "cikernels", ofType: "bundle"))! + "/" + named + ".cikernel"
    do {
        return try String(contentsOfFile: kernelPath)
    }
    catch let error as NSError {
        return error.description
    }
}

Usage, for an image called "Camera.png" which is part of a bundle called "images.bundle":

let cameraImage = returnImage("Camera")

Since I don't work with SQLite files I don't have the exact code, but I think this should work. Remember to change "com.company.project" to what you have for the bundle identifier.

Very instructional! Thank you! I'll try to give it a go later tonight. I'll update when I get something working. — itsinthekeys, Jul 29 '17 at 02:07
I apologize, I'm still new to Swift. In the functions, are you passing a String into the function? -- Never mind, I'm just a little slow sometimes, lol — itsinthekeys, Jul 29 '17 at 02:26
I went ahead and gave the image function a try first in my actual project and the second time in a new one. It crashes both times I tried. I could try using it as a framework instead? Pics: http://imgur.com/ub2xpMB http://imgur.com/y3E91z7 — itsinthekeys, Jul 29 '17 at 02:51
A couple of things: (1) In your .xcodeproj General properties, is your bundle ID "zb.test"? (2) Is the image "pic" a ".png" or ".jpg" - if it's the latter, you'll need to add the extension of the file. (3) Is the image in a ".bundle"? It looks like you might need to try a framework. — , Jul 29 '17 at 10:26
I got it working! I had two problems: I hadn't fully checked that the bundle ID was valid (I believe it said something about it not being unique enough), so I changed it. The other was adding ".MessagesExtension" to the end of the identifier in the function. Once I changed those things, your text file function works beautifully, even to find my database file. Thank you! — itsinthekeys, Jul 29 '17 at 15:53

Using an existing database in an iMessage app (Swift)

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