Fork SDK for iOS

Fork Swift SDK is a library on top of HealthKit that helps with the data extraction and normalisation. It provides a unified single schema across all source datasets.

Table of contents

• Todo
• Requirements
• Installation
• Setup
• SDK usage
  1. Configure ForkSDK
  2. Create connection
  3. Permissions
  4. Extract data
• Background deliveries
• Logging
• Fork Data types
• Classes
• Errors and Exceptions
• Testing
• Data Samples
• Links

Todo

• [ ] Implement characteristic
• [ ] Add HKMetadataKeyIndoorBikeDistance, HKPhysicalEffortEstimationType, HKSWOLFScore, HKSwimmingStrokeStyle
• [ ] Add height, leanBodyMass, oxygenSaturation, vo2Max, walkingHeartRateAverage
• [ ] Serialize data to Open mHealth compliant JSON, Fast Healthcare Interoperability Resources (FHIR) or FSH (FHIR Shorthand)) formats rather than custom format
• [ ] Add a new ForkDataTypes type to allow retrieving Workouts by workout type rather than all workouts.
• [ ] Don’t create a new connection if one with same the appId, authToken and customerEndUserId and callBackUrl already exists.
• [ ] Add BackgroundTask handler
• [ ] Add tests
• [ ] Add support for long running queries https://developer.apple.com/documentation/healthkit/reading_data_from_healthkit#2962445
• [ ] Add support for Saving data to HealthKit
• [ ] Send unknown data type to internal monitoring tool which will log data on private endpoint. What about HIIPA then?
• [ ] Do we really need to Allow Clinical Health Records?
• [ ] FHIR, HL7v2, and DICOM formats

Requirements

• iOS 13.0+
• Xcode 15+
• Swift 5+

Instalation

Swift Package Manager

The Swift Package Manager is a tool for automating the distribution of Swift code and is integrated into the swift compiler. To integrate SpikeSDK into your Xcode project using Swift Package Manager, add it in your Package.swift or through the Project’s Package Dependencies tab:

dependencies: [
    .package(url: "https://github.com/forksdk/fork-ios-sdk", .upToNextMinor(from: "1.0.0"))
]

Alternatively, you can add a package dependency using Xcode.

Signing & Capabilities

To add HealthKit support to your application’s Capabilities.

• Open the folder of your project in Xcode
• Select the project name in the left sidebar
• Open Signing & Capabilities section
• In the main view select + Capability and double click HealthKit
• Allow Clinical Health Records and Background Delivery if needed.

Info.plist

Add Health Kit permissions descriptions to your Info.plist file. For projects created using Xcode 13 or later, set the usage key in the Target Properties list on the app’s Info tab. For projects created with Xcode 12 or earlier, set it in the apps Info.plist file.

<key>NSHealthShareUsageDescription</key>
<string>We will use your health information to better track workouts.</string>

<key>NSHealthUpdateUsageDescription</key>
<string>We will update your health information to better track workouts.</string>

<key>NSHealthClinicalHealthRecordsShareUsageDescription</key>
<string>We will use your health information to better track  workouts.</string>

You can find more details https://developer.apple.com/documentation/healthkit/setting_up_healthkit.

SDK usage

All Fork SDK async method calls should be wrapped into try catch block.

1. Configure ForkSDK

To set up the Fork SDK call ForkSDK.shared.configure with appId, authToken, region and optional param loggers. The SDK automatically manages connection persistence and restore connection if it finds one with the same appId, authToken and customerEndUserId. With each new connection creating a call callbackUrl could be overridden. Provide one or list of ForkLogging implementations for logging purposes.

import ForkSDK

ForkSDK.shared.configure(appId: "fork-demo-app", authToken: "super-secret-auth-token", loggers: [ForkConsoleLogger()])

import ForkSDK

ForkSDK.shared.setCustomerEndUserId(customerEndUserId: "demoEndUserId")

2. Create connection

To set up the SDK create ForkConnection instance with appId, authToken, customerEndUserId set using Fork and optional params callbackUrl. You can find the application ID and authentication token in the Fork developer console. Personal identifiable information, such as emails, should not be part of user IDs.SDK automatically manages connection persistence and restore connection if it finds one with the sameappId,authTokenandcustomerEndUserId. With each new connection creating a callcallbackUrl`. Provide ForkLogging implementation to handle connection logs.

import ForkSDK

var forkConnection = ForkSDK.createConnection(
  callbackUrl: callbackUrl // Optional, provides functionality to send data to webhook and use background deliveries.
);

3. Permissions

Provide permissions to access iOS HealthKit data. SDK method will check required permissions and request them if needed. Permission dialog may not be shown according on iOS permissions rules.

// conn was created in the previous step

// Method should be called on ForkSDK class
try await ForkSDK.ensurePermissionsAreGranted(permissions: [
    ForkDataTypes.activitiesStream,
    ForkDataTypes.steps
]) // Provide required data types

4. Extract data

Getting and using data

Once a connection has been created data can be retrieved using the extractData method. The below example shows how to retrieve daily steps for today which are returned as part of the activities summary (An instance of ForkData). The concrete type will depend on the data type requested.

// forkConnection was created in the previous step

forkConnection.extractData(
    ForkDataTypes.steps
) { result in
    switch result {
    case .success(let data):
        if let dataItem = data.data.first {
            self.steps = dataItem.data[ForkDataTypes.steps.rawValue]
        }
    case .failure(let error):
        print("Error: \(error.localizedDescription)")
    }
}

Extracting data by time range

Params from and to enable the extraction of local device data for the given time range. The maximum allowed single-query time interval is 7 days. If required, data of any longer time period can be accessed by iterating multiple queries of 7 days.

let calendar = Calendar.current

let toDate = Date() // Today's date
let fromDate = calendar.date(byAdding: .day, value: -7, to: toDate)!

// forkConnection was created in the previous step

// Get Weekly Steps
forkConnection.extractData(
    ForkDataTypes.steps,
    from: fromDate,
    to: toDate
) { result in
    switch result {
    case .success(let data):
        if let dataItem = data.data.first {
            self.steps = dataItem.data[ForkDataTypes.steps.rawValue]
        }
    case .failure(let error):
        print("Error: \(error.localizedDescription)")
    }
}

Background deliveries

Background delivery enables asynchronous data delivery to the customer backend by means of webhooks. It enables data updates to be sent to the backend even when the application is hidden or closed. Background delivery is only supported on iOS devices at the moment. Background deliveries will send whole day data to the webhook.

Configure for background deliveries

Under your project Signing & Capabilities section enable Background Delivery for HealthKit. Call configure methods on each app start to trigger background deliveries tasks. Add Fork initialization code to your AppDelegate inside application:didFinishLaunchingWithOptions: method.

If you plan on supporting background delivery, you need to set up all observer queries in your app delegate. The SDK will do it by calling the configure() method. Read more Receive Background Updates.

import Fork
...

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    ...
    ForkSDK.shared.configure(appId: "fork-demo-app", authToken: "super-secret-auth-token")
    ...
}

For SwiftUI based apps follow few steps:

1. Create a custom class that inherits from NSObject and conforms to the UIApplicationDelegate protocol, like this:

import Fork
...

class AppDelegate: NSObject, UIApplicationDelegate {
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
        ...
            ForkSDK.shared.configure(appId: "fork-demo-app", authToken: "super-secret-auth-token")
        ...
        return true
    }
}

1. And now in your App scene, use the UIApplicationDelegateAdaptor property wrapper to tell SwiftUI it should use your AppDelegate class for the application delegate.

@main
struct AppNameApp: App {
    @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate

    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

Register connection for background deliveries

Ensure callbackUrl was provided to ForkConnection, otherwise you will get ForkError.callbackUrlNotProvided error. Provide required Fork Data types to enableBackgroundDelivery method, it could be called after connection is created.

// forkConnection was created in the previous step

try await forkConnection.enableBackgroundDelivery(dataTypes: [
    ForkDataTypes.activitiesStream,
    ForkDataTypes.steps
])

• If forTypes is not empty, then a daemon task is started which will listen for data updates coming from the platform and send them via webhooks in the background; the operation is not compound and each method call will override enabled background data types list;

• If forTypes parameter is empty or null, then background data delivery is stopped for this connection if it was enabled;

You can check if connection have active background deliveries listeners. If background delivery is not enabled, an empty set is returned.

let dataTypes = try await forkConnection.getBackgroundDeliveryDataTypes()

Logging

Internally, the iOS SDK supports logging on various levels to assist with troubleshooting. However, to avoid imposing additional third-party dependencies on library users, the SDK expects a concrete logging implementation to be provided externally. This can be done by implementing the ForkLogging class and providing it when creating a connection.

Below is an example of how to implement a simple console logger.

import Fork

public class ForkConsoleLogger: ForkLogging {
    public var levels: [ForkLoggerLevel] = [.info, .debug, .warn, .error]

    public func log(_ message: String, onLevel level: ForkLoggerLevel) {
        print("\(messageHeader(forLevel: level)) \(message)")
    }
}

SDK provides background delivery process logs. This can be done by implementing the ForkBackgroundDeliveriesLogger class and providing it though connection’s setBackgroundDeliveryLogger method.

Below is an example of how to implement a simple console logger.

class BackgroundDeliveriesLogger: ForkBackgroundDeliveriesLogger {
    func onBackgroundLog(log: String) {
        print("[BACKGROUND_LOG] \(log)")
    }
}

Fork Data types

• ForkDataTypes.activitiesStream
• ForkDataTypes.activitiesSummary
• ForkDataTypes.breathing
• ForkDataTypes.calories
• ForkDataTypes.distance
• ForkDataTypes.glucose
• ForkDataTypes.heart
• ForkDataTypes.oxygenSaturation
• ForkDataTypes.sleep
• ForkDataTypes.steps

Fork

ForkConnection

ForkLogging

Abstract class allowing to receive notifications from the SDK’s processes.

ForkBackgroundDeliveriesLogger

Abstract class allowing to receive notifications from the background data delivery process.

ForkLoggerLevel

Type required to set Fork Logger level.

• ForkLoggerLevel.error
• ForkLoggerLevel.warn
• ForkLoggerLevel.info
• ForkLoggerLevel.debug
• ForkLoggerLevel.verbose

ForkRegion

Type required to set region.

• ForkRegion.US
• ForkRegion.EU

Errors and Exceptions

ForkError

• ForkError.generalError
• ForkError.notConfigured
• ForkError.invalidURL
• ForkError.noData
• ForkError.decodingError
• ForkError.encodingError
• ForkError.badRequest
• ForkError.unauthorized
• ForkError.notFound
• ForkError.healthDataNotAvailable
• ForkError.healthDataError
• ForkError.callbackUrlNotProvided
• ForkError.connectionIsClosed

Testing

There is a way to add sample data to simulator https://developer.apple.com/documentation/healthkit/samples/accessing_sample_data_in_the_simulator

Data Samples

Steps

{
  "start_date": 734946736.721469,
  "end_date": 735465136.721469,
  "source": [],
  "meta_data": {},
  "type": "steps",
  "data": [
    {
      "name": "steps",
      "meta_data": {},
      "id": "3D1763C4-74E3-48B6-A2F4-1717A1CCEAA4",
      "start_date": 734946736.721469,
      "data": {
        "steps": [
          {
            "id": "C901465E-96CB-4B9F-A608-F19524A2373F",
            "end_date": 734994000,
            "value": { "unit": "count", "quantity": 2344.558345717989 },
            "start_date": 734907600
          },
          {
            "id": "153B48D2-917D-43C5-96A4-1704CB7B65A2",
            "value": { "quantity": 4294.453550610938, "unit": "count" },
            "end_date": 735080400,
            "start_date": 734994000
          },
          {
            "value": { "quantity": 8930, "unit": "count" },
            "id": "48F1FDCA-5445-473E-AAF4-C168A558D257",
            "end_date": 735166800,
            "start_date": 735080400
          },
          {
            "start_date": 735166800,
            "end_date": 735253200,
            "id": "0A777063-E86D-47F9-AAA1-A551F66EA87E",
            "value": { "quantity": 4892, "unit": "count" }
          },
          {
            "start_date": 735253200,
            "id": "DD8542FB-47D3-4677-A776-05CBB9702C9E",
            "value": { "quantity": 6376.525936660553, "unit": "count" },
            "end_date": 735339600
          },
          {
            "end_date": 735426000,
            "value": { "quantity": 7647, "unit": "count" },
            "id": "0EC90C44-5F34-4EAA-9DAA-1ADF953B3F4F",
            "start_date": 735339600
          },
          {
            "end_date": 735512400,
            "value": { "quantity": 984, "unit": "count" },
            "id": "34FACA12-3DFB-4DEC-9DEA-016AC2BBBDED",
            "start_date": 735426000
          }
        ]
      },
      "end_date": 735465136.721469
    }
  ],
  "user_id": "demoEndUserId",
  "collected_at": 735465136.778602
}

Activities

{
  "collected_at": 735480150.573357,
  "end_date": 735480150.549528,
  "type": "activitiesStream",
  "data": [
    {
      "nested_data": {
        "workoutActivity_A3129EDF-E02F-4C95-A489-D4BF63729A1C": [
          {
            "data": {
              "HKQuantityTypeIdentifierBasalEnergyBurned": [
                {
                  "end_date": 735126820.286514,
                  "start_date": 735122925.921942,
                  "value": { "unit": "kcal", "quantity": 104.50254033979812 }
                }
              ],
              "HKQuantityTypeIdentifierHeartRate": [
                {
                  "start_date": 735122925.921942,
                  "value": { "unit": "Hz", "quantity": 2.183333333333333 },
                  "end_date": 735126820.286514
                }
              ],
              "HKQuantityTypeIdentifierDistanceWalkingRunning": [
                {
                  "value": { "quantity": 4009.039588627405, "unit": "m" },
                  "start_date": 735122925.921942,
                  "end_date": 735126820.286514
                }
              ],
              "HKQuantityTypeIdentifierActiveEnergyBurned": [
                {
                  "start_date": 735122925.921942,
                  "value": { "unit": "kcal", "quantity": 287.4444671286329 },
                  "end_date": 735126820.286514
                }
              ]
            },
            "nested_data": {
              "workoutEvents": [
                {
                  "end_date": 735123756.3896186,
                  "start_date": 735122925.921942,
                  "name": "Segment"
                },
                {
                  "start_date": 735122925.921942,
                  "name": "Segment",
                  "end_date": 735124274.3311791
                },
                {
                  "name": "Segment",
                  "start_date": 735123756.3896186,
                  "end_date": 735124625.1821542
                },
                {
                  "name": "Segment",
                  "start_date": 735124274.3311791,
                  "end_date": 735125994.5759654
                },
                {
                  "start_date": 735124625.1821542,
                  "name": "Segment",
                  "end_date": 735125822.8282287
                },
                {
                  "end_date": 735125115.952313,
                  "start_date": 735125115.952313,
                  "name": "Pause"
                },
                {
                  "end_date": 735125130.495051,
                  "name": "Resume",
                  "start_date": 735125130.495051
                },
                {
                  "name": "Segment",
                  "start_date": 735125822.8282287,
                  "end_date": 735126727.8450862
                },
                {
                  "start_date": 735125994.5759654,
                  "end_date": 735126799.7551417,
                  "name": "Segment"
                },
                {
                  "end_date": 735126799.7551417,
                  "start_date": 735126727.8450862,
                  "name": "Segment"
                }
              ]
            },
            "end_date": 735126820.286514,
            "name": "workoutActivity_A3129EDF-E02F-4C95-A489-D4BF63729A1C",
            "start_date": 735122925.921942,
            "id": "BC87CFA2-D778-4D90-BFF3-84CE0CA4AB1A"
          }
        ]
      },
      "end_date": 735126820.286514,
      "id": "54E23D18-6468-4953-A190-60D6529B76C3",
      "start_date": 735122925.921942,
      "meta_data": {
        "HKWeatherHumidity": { "quantity": 56.99999999999999, "unit": "%" },
        "duration": { "quantity": 3879.8218339681625, "unit": "TimeInterval" },
        "HKElevationAscended": { "quantity": 116, "unit": "m" },
        "HKTimeZone": { "quantity": 0, "unit": "Europe/Vilnius" },
        "HKIndoorWorkout": { "unit": "bool", "quantity": 0 },
        "HKAverageMETs": {
          "unit": "kcal/hr·kg",
          "quantity": 4.8850719059101735
        }
      },
      "name": "Walking",
      "data": {
        "HKQuantityTypeIdentifierBasalEnergyBurned": [
          {
            "end_date": 735126820.286514,
            "start_date": 735122925.921942,
            "value": { "quantity": 104.50254033979812, "unit": "kcal" },
            "id": "25A7DBB7-FACF-4DA9-A2CF-4980AE478D81"
          }
        ],
        "HKQuantityTypeIdentifierHeartRate": [
          {
            "start_date": 735122925.921942,
            "end_date": 735126820.286514,
            "value": { "quantity": 2.183333333333333, "unit": "Hz" },
            "id": "9C941C9D-8481-4467-B876-27EAB652C78A"
          }
        ],
        "HKQuantityTypeIdentifierActiveEnergyBurned": [
          {
            "start_date": 735122925.921942,
            "end_date": 735126820.286514,
            "value": { "unit": "kcal", "quantity": 287.4444671286329 },
            "id": "CC8E0A4C-46E5-49DB-954F-3F6343E07E13"
          }
        ],
        "HKQuantityTypeIdentifierDistanceWalkingRunning": [
          {
            "end_date": 735126820.286514,
            "start_date": 735122925.921942,
            "value": { "quantity": 4009.039588627405, "unit": "m" },
            "id": "7B67626E-58BD-436A-B6EE-422425F28D67"
          }
        ]
      }
    },
    {
      "start_date": 734700495.466622,
      "end_date": 734706529.034525,
      "source": {
        "firmwareVersion": null,
        "name": "Apple Watch",
        "localIdentifier": null,
        "softwareVersion": "10.4",
        "udiDeviceIdentifier": null,
        "manufacturer": "Apple Inc.",
        "model": "Watch",
        "hardwareVersion": "Watch6,9"
      },
      "nested_data": {
        "workoutActivity_D27A81E3-CDA7-46B5-A309-6485E587AF57": [
          {
            "data": {
              "HKQuantityTypeIdentifierBasalEnergyBurned": [
                {
                  "value": { "quantity": 53.81176251367591, "unit": "kcal" },
                  "end_date": 734706529.034525,
                  "start_date": 734700495.466622
                }
              ],
              "HKQuantityTypeIdentifierActiveEnergyBurned": [
                {
                  "value": { "quantity": 45.895534867857656, "unit": "kcal" },
                  "start_date": 734700495.466622,
                  "end_date": 734706529.034525
                }
              ],
              "HKQuantityTypeIdentifierDistanceCycling": [
                {
                  "value": { "quantity": 3079.4581422669125, "unit": "m" },
                  "end_date": 734706529.034525,
                  "start_date": 734700495.466622
                }
              ],
              "HKQuantityTypeIdentifierHeartRate": [
                {
                  "start_date": 734700495.466622,
                  "end_date": 734706529.034525,
                  "value": { "unit": "Hz", "quantity": 1.9666666666666666 }
                }
              ]
            },
            "end_date": 734706529.034525,
            "nested_data": {
              "workoutEvents": [
                {
                  "start_date": 734700495.466622,
                  "name": "Segment",
                  "end_date": 734700863.9786217
                },
                {
                  "end_date": 734703725.1573002,
                  "start_date": 734700495.466622,
                  "name": "Segment"
                },
                {
                  "end_date": 734703928.8184234,
                  "start_date": 734700863.9786217,
                  "name": "Segment"
                },
                {
                  "end_date": 734701267.580869,
                  "name": "Pause",
                  "start_date": 734701267.580869
                },
                {
                  "name": "Resume",
                  "end_date": 734703631.39965,
                  "start_date": 734703631.39965
                },
                {
                  "end_date": 734706527.9993576,
                  "start_date": 734703725.1573002,
                  "name": "Segment"
                },
                {
                  "start_date": 734703928.8184234,
                  "name": "Segment",
                  "end_date": 734706391.3093979
                },
                {
                  "start_date": 734704740.18987,
                  "end_date": 734704740.18987,
                  "name": "Pause"
                },
                {
                  "end_date": 734705227.415145,
                  "name": "Resume",
                  "start_date": 734705227.415145
                },
                {
                  "end_date": 734705296.174271,
                  "start_date": 734705296.174271,
                  "name": "Pause"
                },
                {
                  "end_date": 734706118.187363,
                  "start_date": 734706118.187363,
                  "name": "Resume"
                },
                {
                  "name": "Segment",
                  "start_date": 734706391.3093979,
                  "end_date": 734706527.9993576
                },
                {
                  "end_date": 734706529.034525,
                  "name": "Pause",
                  "start_date": 734706529.034525
                }
              ]
            },
            "start_date": 734700495.466622,
            "id": "F35A8EDE-DA94-40A6-929B-32C4C04133C2",
            "name": "workoutActivity_D27A81E3-CDA7-46B5-A309-6485E587AF57"
          }
        ]
      },
      "id": "3D8F2F02-2842-48DA-9897-F0890B20442B",
      "meta_data": {
        "HKElevationAscended": { "quantity": 15.76, "unit": "m" },
        "HKIndoorWorkout": { "quantity": 0, "unit": "bool" },
        "HKAverageMETs": {
          "unit": "kcal/hr·kg",
          "quantity": 2.5574292423172995
        },
        "duration": { "unit": "TimeInterval", "quantity": 2360.510754942894 },
        "HKTimeZone": { "quantity": 0, "unit": "Europe/Vilnius" },
        "HKWeatherHumidity": { "quantity": 74, "unit": "%" }
      },
      "name": "Cycling",
      "source": {
        "name": "Apple Watch",
        "softwareVersion": "10.4",
        "firmwareVersion": null,
        "localIdentifier": null,
        "udiDeviceIdentifier": null,
        "hardwareVersion": "Watch6,9",
        "manufacturer": "Apple Inc.",
        "model": "Watch"
      },
      "data": {
        "HKQuantityTypeIdentifierActiveEnergyBurned": [
          {
            "id": "37499B34-B397-46B7-BB90-22BA772D35C1",
            "start_date": 734700495.466622,
            "value": { "quantity": 45.895534867857656, "unit": "kcal" },
            "end_date": 734706529.034525
          }
        ],
        "HKQuantityTypeIdentifierDistanceCycling": [
          {
            "id": "528A7191-1F69-4824-9259-31FF023B484D",
            "end_date": 734706529.034525,
            "value": { "unit": "m", "quantity": 3079.4581422669125 },
            "start_date": 734700495.466622
          }
        ],
        "HKQuantityTypeIdentifierHeartRate": [
          {
            "start_date": 734700495.466622,
            "end_date": 734706529.034525,
            "id": "09BCFC04-1A64-4E15-B5EF-203D0C4557AB",
            "value": { "quantity": 1.9666666666666666, "unit": "Hz" }
          }
        ],
        "HKQuantityTypeIdentifierBasalEnergyBurned": [
          {
            "id": "F6AD294E-11FE-4525-99CB-73CC7D1AD925",
            "end_date": 734706529.034525,
            "start_date": 734700495.466622,
            "value": { "quantity": 53.81176251367591, "unit": "kcal" }
          }
        ]
      }
    }
  ],
  "start_date": 734529750.549528,
  "source": [],
  "user_id": "demoEndUserId"
}

Sleep

{
  "user_id": "demoEndUserId",
  "type": "sleep",
  "start_date": 734696841.670022,
  "end_date": 735820041.670022,
  "collected_at": 735820041.696961,
  "data": [
    {
      "data": {
        "sleep": [
          {
            "end_date": 735790811.3217533,
            "value": { "unit": "REM", "quantity": 5 },
            "type": "HKCategoryTypeIdentifierSleepAnalysis",
            "id": "3B560752-961E-4E14-9979-3F98D0A95FB5",
            "start_date": 735790721.3217533
          },
          {
            "type": "HKCategoryTypeIdentifierSleepAnalysis",
            "id": "1123B2F6-4FA9-47F5-A7C6-7A955A0A653A",
            "start_date": 735790241.3217533,
            "end_date": 735790691.3217533,
            "value": { "unit": "REM", "quantity": 5 }
          },
          {
            "id": "37D29ECE-0FA5-49F8-B1E6-D24D8823F19E",
            "start_date": 735788891.3217533,
            "end_date": 735790241.3217533,
            "type": "HKCategoryTypeIdentifierSleepAnalysis",
            "value": { "quantity": 3, "unit": "Deep" }
          },
          {
            "end_date": 735788861.3217533,
            "value": { "quantity": 3, "unit": "Deep" },
            "id": "F1B16D09-312F-4589-809C-8723017036AF",
            "type": "HKCategoryTypeIdentifierSleepAnalysis",
            "start_date": 735788831.3217533
          },
          {
            "type": "HKCategoryTypeIdentifierSleepAnalysis",
            "start_date": 735788081.3217533,
            "value": { "quantity": 4, "unit": "4" },
            "end_date": 735788831.3217533,
            "id": "131D11B2-C448-4728-9D8A-5AE74807C6DB"
          },
          {
            "start_date": 735786101.3217533,
            "value": { "quantity": 3, "unit": "Deep" },
            "end_date": 735788081.3217533,
            "type": "HKCategoryTypeIdentifierSleepAnalysis",
            "id": "5C17D2CD-0C84-4352-8585-0A598BFEB5EC"
          },
          {
            "start_date": 735784181.3217533,
            "end_date": 735786101.3217533,
            "value": { "quantity": 5, "unit": "REM" },
            "id": "CE360689-E275-4045-A8AE-D87DBB9AF090",
            "type": "HKCategoryTypeIdentifierSleepAnalysis"
          },
          {
            "id": "58995F3B-7539-4967-BDAA-9B5893B09183",
            "value": { "unit": "REM", "quantity": 5 },
            "type": "HKCategoryTypeIdentifierSleepAnalysis",
            "end_date": 735784091.3217533,
            "start_date": 735783581.3217533
          },
          {
            "end_date": 735783581.3217533,
            "value": { "unit": "Deep", "quantity": 3 },
            "id": "C829AD5D-BC7B-4286-B77C-A53FCC2EC1F6",
            "type": "HKCategoryTypeIdentifierSleepAnalysis",
            "start_date": 735780191.3217533
          },
          {
            "start_date": 735778991.3217533,
            "end_date": 735780071.3217533,
            "value": { "unit": "4", "quantity": 4 },
            "id": "CAD485D6-95A6-446E-BF63-74797DBB838D",
            "type": "HKCategoryTypeIdentifierSleepAnalysis"
          },
          {
            "value": { "unit": "Deep", "quantity": 3 },
            "type": "HKCategoryTypeIdentifierSleepAnalysis",
            "end_date": 735778991.3217533,
            "id": "8D227DFB-9313-4561-B9DE-2D950F74CFFC",
            "start_date": 735777581.3217533
          },
          {
            "value": { "unit": "REM", "quantity": 5 },
            "end_date": 735777581.3217533,
            "start_date": 735776471.3217533,
            "type": "HKCategoryTypeIdentifierSleepAnalysis",
            "id": "CEFFF563-9118-4AC7-B663-EF0CF7B61ED7"
          },
          {
            "end_date": 735776411.3217533,
            "id": "ACB58AB9-1A38-4A94-9F2A-1DFCD8D0E10C",
            "type": "HKCategoryTypeIdentifierSleepAnalysis",
            "start_date": 735776141.3217533,
            "value": { "quantity": 5, "unit": "REM" }
          },
          {
            "type": "HKCategoryTypeIdentifierSleepAnalysis",
            "start_date": 735775451.3217533,
            "end_date": 735776141.3217533,
            "id": "E42769D7-0F84-4EE4-A8C2-C9B6CDB1DEF7",
            "value": { "quantity": 3, "unit": "Deep" }
          },
          {
            "id": "0CEEFC5D-DA25-49B5-8F47-F381B904EBF3",
            "end_date": 735775451.3217533,
            "value": { "quantity": 4, "unit": "4" },
            "start_date": 735774941.3217533,
            "type": "HKCategoryTypeIdentifierSleepAnalysis"
          },
          {
            "end_date": 735774941.3217533,
            "id": "E9C0A18C-1C36-4159-BA7A-BE76E6FC93AC",
            "value": { "quantity": 3, "unit": "Deep" },
            "type": "HKCategoryTypeIdentifierSleepAnalysis",
            "start_date": 735772721.3217533
          },
          {
            "start_date": 735772391.3217533,
            "id": "526D81FF-EAF4-4E01-8BDB-E676621BD140",
            "value": { "quantity": 3, "unit": "Deep" },
            "end_date": 735772571.3217533,
            "type": "HKCategoryTypeIdentifierSleepAnalysis"
          },
          {
            "type": "HKCategoryTypeIdentifierSleepAnalysis",
            "end_date": 735772181.3217533,
            "start_date": 735772031.3217533,
            "value": { "unit": "Deep", "quantity": 3 },
            "id": "C0A6FFC1-0700-4E92-AAAD-FBD572F7196B"
          }
        ]
      },
      "id": "C610DBF7-B056-428A-80F5-A8FC8BF60FFA",
      "name": "sleep",
      "end_date": 735772181.3217533,
      "start_date": 735790721.3217533
    }
  ]
}

Publishing application on the Play Store

The ForkSDK for Android devices integrates with Health Connect for data retrieval. Before publishing the application to the Play Store, application owners are required to complete the Developer Declaration Form available at the following link: Developer Declaration Form

Links

• https://developer.apple.com/documentation/healthkit/about_the_healthkit_framework
• https://github.com/CardinalKit/Granola/blob/main/Pod/Classes/OMHSerializer.m
• https://dmtopolog.com/healthkit-changes-observing/
• https://github.com/kingstinct/react-native-healthkit
• https://www.npmjs.com/package/@jonstuebe/react-native-healthkit
• https://www.npmjs.com/package/react-native-google-fit
• https://github.com/klandell/react-native-healthier
• https://gero.dev/blog/heart-rate-graphs-with-swift-charts
• https://gitlab.com/spike_api/spike-ios-sdk
• https://cloud.google.com/healthcare-api
• https://www.avanderlee.com/swift-charts/bar-chart-creation-using-swift-charts/?utm_campaign=This%2BWeek%2Bin%2BSwift&utm_medium=email&utm_source=This_Week_in_Swift_159
• https://github.com/realm/SwiftLint
• https://github.com/Quick/Quick
• https://www.swift.org/documentation/docc/
• https://github.com/stripe/stripe-ios
• https://github.com/ResearchKit/SageResearch
• https://github.com/openmhealth/Granola
• xcodebuild -list -json
• xcodebuild -resolvePackageDependencies

Units HKUnit)

Unit strings are composed of the following units:

International System of Units (SI) units:

• g (grams) [Mass]
• m (meters) [Length]
• L,l (liters) [Volume]
• Pa (pascals) [Pressure]
• s (seconds) [Time]
• J (joules) [Energy]
• K (kelvin) [Temperature]
• S (siemens) [Electrical Conductance]
• Hz (hertz) [Frequency]
• mol (moles) [Mass] is the number of grams per mole. For example, mol<180.1558>

SI units can be prefixed as follows:

• da (deca-) = 10 d (deci-) = 1/10
• h (hecto-) = 100 c (centi-) = 1/100
• k (kilo-) = 1000 m (milli-) = 1/1000
• M (mega-) = 10^6 mc (micro-) = 10^-6
• G (giga-) = 10^9 n (nano-) = 10^-9
• T (tera-) = 10^12 p (pico-) = 10^-12

Non-SI units:

[Mass]

• oz (ounces) = 28.3495 g
• lb (pounds) = 453.592 g
• st (stones) = 6350.0 g

[Length]

• in (inches) = 0.0254 m
• ft (feet) = 0.3048 m
• mi (miles) = 1609.34 m

[Pressure]

• mmHg (millimeters of mercury) = 133.3224 Pa
• cmAq (centimeters of water) = 98.06650 Pa
• atm (atmospheres) = 101325.0 Pa

[Volume]

• fl_oz_us (US customary fluid ounces)= 0.0295735295625 L
• fl_oz_imp (Imperial fluid ounces) = 0.0284130625 L
• pt_us (US customary pint) = 0.473176473 L
• pt_imp (Imperial pint) = 0.56826125 L
• cup_us (US customary cup) = 0.2365882365 L
• cup_imp (Imperial cup) = 0.284130625 L

[Time]

• min (minutes) = 60 s
• hr (hours) = 3600 s
• d (days) = 86400 s

[Energy]

• cal (calories) = 4.1840 J
• kcal (kilocalories) = 4184.0 J

[Temperature]

• degC (degrees Celsius) = 1.0 K - 273.15
• degF (degrees Fahrenheit) = 1.8 K - 459.67

[Conductance]

• S (siemens)

[Pharmacology]

• IU (international unit)

[Scalar]

• count = 1
• % = 1/100

Units can be combined using multiplication (. or *) and division (/), and raised to integral powers (^). For simplicity, only a single ‘/’ is allowed in a unit string, and multiplication is evaluated first. So “kg/m.s^2” is equivalent to “kg/(m.s^2)” and “kg.m^-1.s^-2”.

VO₂ Max

// let kgmin = HKUnit.gramUnit(with: .kilo).unitMultiplied(by: .minute())
// let mL = HKUnit.literUnit(with: .milli)
// let VO₂Unit = mL.unitDivided(by: kgmin)

let VO₂Unit = HKUnit(from: "ml/kg*min")

let writeHKMetric = HKQuantityType.quantityType(forIdentifier: HKQuantityTypeIdentifier.vo2Max)!
let writeHKQuantity = HKQuantity(unit: VO₂Unit, doubleValue: 1)
print(writeHKQuantity)