Wrong image data when fetching image

[vdkdamian]

New Issue Checklist

• I am not disclosing a vulnerability.
• I am not just asking a question.
• I have searched through existing issues.
• I can reproduce the issue with the latest version of Parse Swift.
• I can reproduce the issue with the latest version of Parse Server.

Issue Description

I am seeing issues when fetching an image. When i fetch an image for the first time, it loads the image corretly. But when it then tries to load for the second time, the image is broken. I looked at what the downloaded image looks like when opening in a text editor.

I noticed it doesn't contain data, but a path. This is an example:
file:\/\/\/var\/folders\/y5\/3qbps9t11cb2fz7lh1x8bw7w0000gn\/T\/com.app.myApp\/CFNetworkDownload_rDopeR.tmp

My uploaded images in the Database are valid images.

I want to point out that this way of fetching images always worked for me. It's since the Beta's that there is something wrong, but I don't find anything on the Apple Developer known issues page.

Steps to reproduce

This is an example of code I use.

let modelQuery =  Model.query()
modelQuery.find { result in
    switch result {
    case .success(let model):
        if let imageURL = model.image?.localURL {
            print("imageURL: \(imageURL)")
            if let imgData = try? Data(contentsOf: imageURL) {
                print("imgData: \(imgData)")
                print("imgData as string: \(String(decoding: imgData, as: UTF8.self))")
                self.imageData = imgData
            }
        } else {
            model.image?.fetch(completion: { result in
                switch result {
                case .success(let fetchedImage):
                    if let localImageUrl = fetchedImage.localURL {
                        print("localImageUrl: \(localImageUrl)")
                        if let imgData = try? Data(contentsOf: localImageUrl) {
                            print("imgData: \(imgData)")
                            print("imgData as string: \(String(decoding: imgData, as: UTF8.self))")
                            self.imageData = imgData
                        }
                    }
                case .failure(_):
                    break
                }
            })
        }
        self.model = model
    case .failure(_):
        break
    }
}

This is my log:

Actual Outcome

file:\/\/\/var\/folders\/y5\/3qbps9t11cb2fz7lh1x8bw7w0000gn\/T\/com.app.myApp\/CFNetworkDownload_rDopeR.tmp

Expected Outcome

Image data

Failing Test Case / Pull Request

• 🤩 I submitted a PR with a fix and a test case.
• 🧐 I submitted a PR with a failing test case.

Environment

Parse Swift

• SDK version: 1.9.8
• Operating system (iOS, macOS, watchOS, etc.): iOS, macOS
• Operating system version: iOS 15 Beta 8, Monterey 12.0 Beta 6

Server

• Parse Server version: 4.4.0
• Operating system: Back4App

Logs

localImageUrl: file:///Users/name/Library/Containers/com.app.myApp/Data/Library/Application%20Support/parse/com.app.myApp/Downloads/d48e0511e7660ab8e59fa2bb74cd48a4_1600.png
imgData: 123 bytes
imgData as string: "file:\/\/\/var\/folders\/y5\/3qbps9t11cb2fz7lh1x8bw7w0000gn\/T\/com.app.myApp\/CFNetworkDownload_rDopeR.tmp"

[cbaker6]

@novemTeam can you fill out the complete issue template? It looks like you removed information

[vdkdamian]

@cbaker6 I updated it. I still left out the Database info because I am just using Back4App

[cbaker6]

What happens when you use the latest version of Xcode 12? If this only occurs in Xcode 13 beta, it's probably not worth a fix until 13 goes Gold. If you can find some documentation that states Xcode 13 is changing the way downloaded data is handled, then I can take a look to see how to adjust.

[vdkdamian]

It did always work in Xcode 12.

[cbaker6]

PR #212 uses Xcode 13 beta 5. I believe there are test cases that cover this scenario that don't fail on Xcode 13. Can you look through them to verify?

Parse-Swift/Tests/ParseSwiftTests/ParseFileTests.swift

Lines 966 to 969 in 5994d63

	let fetchedFile2 = try parseFile.fetch(options: [.cachePolicy(.returnCacheDataDontLoad)])
	XCTAssertEqual(fetchedFile2.name, fetchedFile.name)
	XCTAssertEqual(fetchedFile2.url, fetchedFile.url)
	XCTAssertNotNil(fetchedFile2.localURL)

If I understand the issue you are saying is present,

Parse-Swift/Tests/ParseSwiftTests/ParseFileTests.swift

Line 969 in 5994d63

XCTAssertNotNil(fetchedFile2.localURL)

needs to check that there's an actual file at the URL?

Note that you can comment out these lines:

Parse-Swift/Tests/ParseSwiftTests/ParseFileTests.swift

Lines 944 to 955 in 5994d63

	let response = FileUploadResponse(name: "d3a37aed0672a024595b766f97133615_logo.svg",
	url: parseFileURL)
	let encoded: Data!
	do {
	encoded = try ParseCoding.jsonEncoder().encode(response)
	} catch {
	XCTFail("Should encode/decode. Error \(error)")
	return
	}
	MockURLProtocol.mockRequests { _ in
	return MockURLResponse(data: encoded, statusCode: 200, delay: 0.0)
	}

and set these to your Parse Server,

Parse-Swift/Tests/ParseSwiftTests/ParseFileTests.swift

Lines 31 to 35 in 5994d63

	ParseSwift.initialize(applicationId: "applicationId",
	clientKey: "clientKey",
	masterKey: "masterKey",
	serverURL: url,
	testing: true)

and test and debugger to see what's going on.

[vdkdamian]

@cbaker6 Sorry for the late response, kinda busy. I'll take a closer look this weekend.

[vdkdamian]

@cbaker6 I was unable to run the Tests because of lack of experience. But I do indeed think there should be a test to check if the file at .localURL is indeed a file.

Maybe something like this? I don't know if there is a better way to check if it is a image.

do {
     let data: Data = try Data(contentsOf: fetchedFile2.localURL!)
     XCTAssertGreaterThan(data.count, 200)
} catch {
     XCTFail("Should get data. Error \(error)")
     return
}

I also tried a few more things. I ran my project with Xcode 13 on my friends iPhone, and had the same issue. The images don't download correctly.

It also changes, 1/10 times it downloads correctly, the other times i get images with a path in it. See the screenshots

Here are some more screenshots

[cbaker6]

I checked this in Playgrounds (macOS) using Xcode 13 beta 5 (if you look in the folder directory, all of the ParseFiles are intact):

Parse-Swift/ParseSwift.playground/Pages/9 - Files.xcplaygroundpage/Contents.swift

Lines 42 to 97 in 1a30fb6

	//: Set the link online for the file.
	let linkToFile = URL(string: "https://parseplatform.org/img/logo.svg")!
	//: Create a new `ParseFile` for your picture.
	let profilePic = ParseFile(name: "profile.svg", cloudURL: linkToFile)
	//: Set the picture as part of your ParseObject
	score.profilePicture = profilePic
	/*: Save asynchronously (preferred way) - Performs work on background
	queue and returns to specified callbackQueue.
	If no callbackQueue is specified it returns to main queue.
	*/
	score.save { result in
	switch result {
	case .success(let savedScore):
	assert(savedScore.objectId != nil)
	assert(savedScore.createdAt != nil)
	assert(savedScore.updatedAt != nil)
	assert(savedScore.ACL == nil)
	assert(savedScore.score == 52)
	assert(savedScore.profilePicture != nil)
	print("Your profile picture has been successfully saved")
	//: To get the contents updated `ParseFile`, you need to fetch your GameScore.
	savedScore.fetch { result in
	switch result {
	case .success(let fetchedScore):
	guard let picture = fetchedScore.profilePicture,
	let url = fetchedScore.profilePicture?.url else {
	return
	}
	print("The new name of your saved profilePicture is: \(picture.name)")
	print("The profilePicture is saved to your Parse Server at: \(url)")
	print("The full details of your profilePicture ParseFile are: \(picture)")
	//: If you need to download your profilePicture
	picture.fetch { result in
	switch result {
	case .success(let fetchedFile):
	print("The file is now saved on your device at: \(String(describing: fetchedFile.localURL))")
	print("The full details of your profilePicture ParseFile are: \(fetchedFile)")
	case .failure(let error):
	assertionFailure("Error fetching: \(error)")
	}
	}
	case .failure(let error):
	assertionFailure("Error fetching: \(error)")
	}
	}
	case .failure(let error):
	assertionFailure("Error saving: \(error)")
	}
	}

as well as in a sample app (iOS) of mine that heavily uses ParseFile for pictures: https://github.com/netreconlab/SnapCat

I didn't see the issue you mentioned and everything seems to be working correctly. I recommend looking into other areas of how you are handling files in your app or maybe your server configuration.

Tested with Parse Server 4.5.0 and 4.10.3

[cbaker6]

You should also checkout your cache policy:

Parse-Swift/Sources/ParseSwift/Parse.swift

Lines 70 to 74 in 1a30fb6

	- parameter requestCachePolicy: The default caching policy for all http requests that determines
	when to return a response from the cache. Defaults to `useProtocolCachePolicy`. See Apple's [documentation](https://developer.apple.com/documentation/foundation/url_loading_system/accessing_cached_data)
	for more info.
	- parameter cacheMemoryCapacity: The memory capacity of the cache, in bytes. Defaults to 512KB.
	- parameter cacheDiskCapacity: The disk capacity of the cache, in bytes. Defaults to 10MB.

You can enable CORS in your index.js on your server by:

const cors = require('cors');

var app = express();
app.use(cors());
...

[vdkdamian]

@cbaker6 is this something I can change when using Back4App?

Also, did you run your test on iOS 15? Because I really can't see what I could be doing wrong when downloading images...

I just followed the documentation

[cbaker6]

@cbaker6 is this something I can change when using Back4App?

I’m not sure how Back4app works as I self-host, but if you have access to your index.js file you can add it.

Also, did you run your test on iOS 15? Because I really can't see what I could be doing wrong when downloading images...

My tests in #226 (comment) Used iOS 15 specifically and I didn’t have any issues.

[vdkdamian]

if let iconIcon = icon.iconImage {
    iconIcon.fetch { result in
        switch result {
        case .success(let fetchedFile):
            print("fetchedFile.data: \(String(describing: fetchedFile.data))")
            if let dataFromWebsiteIcon = try? Data(contentsOf: fetchedFile.localURL!) {
                print("dataFromWebsiteIcon: \(dataFromWebsiteIcon)")
                let websiteIcon = websiteFolder.appendingPathComponent("Icon.png")
                if fileManager.fileExists(atPath: websiteIcon.path) {
                    do {
                        try dataFromWebsiteIcon.write(to: websiteIcon)
                    } catch {
                        assertionFailure("Error writing Icon image: \(error)")
                    }
                } else {
                    fileManager.createFile(atPath: websiteIcon.path, contents: dataFromWebsiteIcon, attributes: nil)
                }
            } else {
                print("Error: couldn't get data from file.")
            }
        case .failure(let error):
            assertionFailure("Error fetching: \(error)")
        }
    }
}

I get these logs:

fetchedFile.data: nil
dataFromWebsiteIcon: 137 bytes

Really breaking my head around this. Can't find what's going on

[cbaker6]

This is how I fetch files:

https://github.com/netreconlab/SnapCat/blob/8218047ef311c7610da8f4cde6db0dd1108c0047/SnapCat/Utility.swift#L28-L44

[vdkdamian]

Update:
I changed my App Groups path name and then it downloaded my images again in a correct way. If I then delete the folder with the images, and redownload the icons, it's broken again.

So I am able to download images the first time, but then there is something wrong with the data at fetchedFile.localURL! if I read the data from this, I get that path, and not the image