iOS Swift + Alamofire upload photos with exif data

Question

I am using Alamofire to upload multiple files at the same time to Open Asset using their REST API and I am able to get this to work, however, most of the EXIF data is being stripped out. Unfortunately, the EXIF data is a must as we need the ability mine out the GPS tags and a few other things through various web clients.

After doing some research, I found the issue is because I'm using UIImageJPEGRepresentation to convert the photos to NSData (which is what Alamofire expects or a fileURL, which I don't think would work for me?).

I am also using the BSImagePicker library to allow the user to take/select multiple photos, which returns a an array of PHAsset s which then get converted to NSData . Here is my function to do this (where collectedImages is a global dictionary):

func compressPhotos(assets: [PHAsset]) -> Void {
        for asset in assets {
            let filename = self.getOriginalFilename(asset)
            let assetImage = self.getAssetPhoto(asset)

            let compressedImage = UIImageJPEGRepresentation(assetImage, 0.5)!  // bye bye metadata :(
            collectedImages[filename] = compressedImage
            print("compressed image: \(filename)")
        }
    }

I think I could retain the EXIF data if I could use the full path from the PHAsset to the image locally on the phone, but Alamofire does not appear to support that. I'm hoping I'm wrong about that. Here is my uploader:

func uploadPhotos(projectId: String, categoryId: String, data: [String: NSData], completionHandler: (AnyObject?, NSError?) -> ()) {
        var jsonBody = [AnyObject]()  //lazy
        Alamofire.upload(
            .POST,
            self.url + "/Files",
            multipartFormData: { multipartFormData in
                for (filename, img) in data {
                    jsonBody.append(["project_id": projectId, "category_id": categoryId, "original_filename": filename])
                    multipartFormData.appendBodyPart(data: img, name: "file", fileName: filename, mimeType: "image/jpeg")
                    print("img size: \(img.length)")

                }
                let jsonData = jsonToNSData(jsonBody)
                print("_jsonBody: \(jsonBody)")
                multipartFormData.appendBodyPart(data: jsonData!, name: "_jsonBody")
                print("multipart: \(multipartFormData)")
            },
            encodingCompletion: { encodingResult in
                switch encodingResult {
                case .Success(let upload, _, _):
                    upload.responseJSON { response in
                        debugPrint(response)
                        switch response.result {
                        case .Success(let value):
                            completionHandler(value as? NSArray, nil)
                        case .Failure(let error):
                            completionHandler(nil, error)
                        }

                    }
                case .Failure(let encodingError):
                    print(encodingError)
                }
            }
        )
    }

So my question is, how can I upload multiple photos (while passing in other parameters too) while maintaining all the EXIF data? Alamofire is an awesome library and I would like to use it here, but I'm not married to it for the upload process if I can't keep the EXIF data.

Answer 1

I think you can first get the file URL from the PHAsset then use that file URL in the call to multipartFormData.appendBodyPart(...). Something like this:

1. Get URL from PHAsset:

    [asset requestContentEditingInputWithOptions:editOptions completionHandler:^(PHContentEditingInput *contentEditingInput, NSDictionary *info) { NSURL *imageURL = contentEditingInput.fullSizeImageURL; }]; 

2. Use file URL in AlamoFire API:

   multipartFormData.appendBodyPart(fileURL: imageURL, name: "image")

Answer 2

I am not sure why I was having issues with the fullSizeImageURL , but I it did lead me to the right path as I was able to get this to work by getting the image as NSData from the file path like this:

asset.requestContentEditingInputWithOptions(PHContentEditingInputRequestOptions()) { (input, _) in
    let fileURL = input!.fullSizeImageURL?.filePathURL
    let data = NSData(contentsOfFile: fileURL!.path!)!

And then I just passed that in the Alamofire.request() as the data argument. This maintained all the original photo metadata.