How to convert items in optional Dictionary to individual strings - ios

Question

I am trying to convert items in an optional dictionary into individual strings so I can loop through them and convert them into URLs. But have been unable to do so.
Here is function which I use to fetch images from firebase which returns this optional dictionary which is also included below:
func fetchAllUsersImages() {
print("inside func")
self.ref.child("Posts").child(self.userID).child(self.postNum).observe(.childAdded, with: { snapshot in
print("inside closure")
// print(URL(string: snapshot.value as! String))
// let postSnap = snapshot.childSnapshot(forPath: self.postNum)
// let imageUrlSnap = postSnap.childSnapshot(forPath: "ImageUrl")
print(snapshot.value, "value")
// guard let allImages = imageUrlSnap.children.allObjects as? [DataSnapshot] else { return print("the code failed here")}
guard let allImages = snapshot.value as? [DataSnapshot] else { return print("the code failed here")}
// let snapshotVal = snapshot.value
// let snapshotValValue = snapshotVal as! String
// print(snapshotValValue, "snapshot as string value")
for image in allImages {
print(image, "image")
}
print(snapshot.key, "key")
print(snapshot.value, "value")
print(snapshot.children, "cjildren")
print(allImages)
print()
})
}
Output of snapshot.value:
Optional({
image1 = "https://firebasestorage.googleapis.com/v0/b/base.appspot.com/o/ijzAnEdyKNbhPsQVH6a8mOa1QpN2%2Fpost1%2Fimage1?alt=media&token=c2f396fd-717d-4192-909a-db390dd23143";
image2 = "https://firebasestorage.googleapis.com/v0/b/atabase.appspot.com/o/ijzAnEdyKNbhPsQVH6a8mOa1QpN2%2Fpost1%2Fimage2?alt=media&token=359b8527-f598-4f9a-934e-079cee21fd15";
})
Based on the answer provided I did the followoing:
func fetchAllUsersImages() {
print("inside func")
self.ref.child("Posts").child(self.userID).child(self.postNum).observe(.childAdded, with: { snapshot in //error here
var images: [URL] = []
if let snapShotValue = snapshot.value as? [String: String] {
for (_, value) in snapShotValue {
if let imageURL = URL(string: value) {
print(imageURL, "image url here")
let imageAsData = try Data(contentsOf: imageURL)
let image = UIImage(data: imageAsData)
let ImageObject = Image()
ImageObject.image = image
self.arrayOfImgObj.append(ImageObject)
self.tableView.reloadData()
}
}
}
})
}
However on the 3rd line I get
Unable to infer closure type in the current context
Edit:
To fix this error put the code, at the deepest part of the code, in a do block amd include a catch block also. This will fix the error.

Answer 1

Well first you need to check if the optional Dictionary exists then loop the dictionary for each key-value pair. Here is a way to do it:
var imageURLs: [URL] = []
if let snapShotValue = snapshot.value as? [String: String] { // Cast optional dictionary to a Dictionary of String keys and String values
// Cast would fail if snapshot.value is nil or has a different Dictionary setup.
for (key, value) in snapShotValue { // you can change key to _ since we are not using it
if let imageURL = URL(string: value) { // Get URL value from string
imageURLs.append(imageURL) // Add new URL to parsed URLs
}
}
}
So once the process is finished you'll have the images in imageURLs variable.