App Store Integration

The mobile package provides app store integration features including version checking, force update prompts, maintenance mode, and platform-specific store URLs.

Quick Start

import "github.com/go-mizu/mizu/mobile"

// Create app info provider
provider := mobile.NewStaticAppInfo(
    "2.0.0",                                    // Current version
    "1.5.0",                                    // Minimum version
    "https://apps.apple.com/app/id123456789",   // Store URL
)

// Add version check endpoint
app.Get("/api/app-info", mobile.AppInfoHandler(provider))

App Info

type AppInfo struct {
    // CurrentVersion is the latest version in the store
    CurrentVersion string `json:"current_version"`

    // MinimumVersion is the minimum required version
    MinimumVersion string `json:"minimum_version"`

    // UpdateURL is the store URL for updating
    UpdateURL string `json:"update_url"`

    // ReleaseNotes is the latest release notes
    ReleaseNotes string `json:"release_notes,omitempty"`

    // ReleasedAt is when the current version was released
    ReleasedAt time.Time `json:"released_at,omitempty"`

    // ForceUpdate indicates if update is mandatory
    ForceUpdate bool `json:"force_update"`

    // MaintenanceMode indicates if the service is under maintenance
    MaintenanceMode bool `json:"maintenance_mode"`

    // MaintenanceMessage is the message to display during maintenance
    MaintenanceMessage string `json:"maintenance_message,omitempty"`

    // MaintenanceEndTime is when maintenance is expected to end
    MaintenanceEndTime *time.Time `json:"maintenance_end_time,omitempty"`

    // Features lists enabled feature flags
    Features map[string]bool `json:"features,omitempty"`
}

Static App Info Provider

For simple static configuration:

provider := mobile.NewStaticAppInfo(
    "2.0.0",  // Current version in store
    "1.5.0",  // Minimum required version
    "https://apps.apple.com/app/id123456789",
)

// Add platform-specific info
provider.WithPlatformApp(mobile.PlatformIOS, "*", &mobile.AppInfo{
    CurrentVersion: "2.0.0",
    MinimumVersion: "1.5.0",
    UpdateURL:      "https://apps.apple.com/app/id123456789",
    ReleaseNotes:   "Bug fixes and performance improvements",
})

provider.WithPlatformApp(mobile.PlatformAndroid, "*", &mobile.AppInfo{
    CurrentVersion: "2.0.1",  // Android may have different version
    MinimumVersion: "1.5.0",
    UpdateURL:      "https://play.google.com/store/apps/details?id=com.example.app",
    ReleaseNotes:   "Bug fixes and performance improvements",
})

Dynamic App Info Provider

For database-backed or API-driven configuration:

type DBAppInfoProvider struct {
    db *sql.DB
}

func (p *DBAppInfoProvider) GetAppInfo(
    ctx context.Context,
    platform mobile.Platform,
    bundleID string,
) (*mobile.AppInfo, error) {
    var info mobile.AppInfo

    err := p.db.QueryRowContext(ctx, `
        SELECT current_version, minimum_version, update_url,
               release_notes, released_at, force_update,
               maintenance_mode, maintenance_message, maintenance_end_time
        FROM app_versions
        WHERE platform = $1 AND (bundle_id = $2 OR bundle_id = '*')
        ORDER BY CASE WHEN bundle_id = $2 THEN 0 ELSE 1 END
        LIMIT 1
    `, platform.String(), bundleID).Scan(
        &info.CurrentVersion, &info.MinimumVersion, &info.UpdateURL,
        &info.ReleaseNotes, &info.ReleasedAt, &info.ForceUpdate,
        &info.MaintenanceMode, &info.MaintenanceMessage, &info.MaintenanceEndTime,
    )

    if err == sql.ErrNoRows {
        return nil, nil
    }
    if err != nil {
        return nil, err
    }

    return &info, nil
}

// Use it
provider := &DBAppInfoProvider{db: db}
app.Get("/api/app-info", mobile.AppInfoHandler(provider))

Update Status

The CheckUpdate function compares versions:

status := mobile.CheckUpdate(
    "1.4.0",  // Client version
    "2.0.0",  // Latest version
    "1.5.0",  // Minimum version
)

// status.Available = true (1.4.0 < 2.0.0)
// status.Required = true (1.4.0 < 1.5.0)

Update Status Response

type UpdateStatus struct {
    Available      bool   `json:"update_available"`
    Required       bool   `json:"update_required"`
    CurrentVersion string `json:"current_version"`
    LatestVersion  string `json:"latest_version"`
    MinimumVersion string `json:"minimum_version,omitempty"`
    UpdateURL      string `json:"update_url,omitempty"`
    ReleaseNotes   string `json:"release_notes,omitempty"`
}

Example response:

{
  "update_available": true,
  "update_required": true,
  "current_version": "1.4.0",
  "latest_version": "2.0.0",
  "minimum_version": "1.5.0",
  "update_url": "https://apps.apple.com/app/id123456789",
  "release_notes": "New features and bug fixes"
}

App Info Handler

The built-in handler automatically:

Extracts device info from mobile middleware context
Fetches app info from provider
Checks for maintenance mode
Compares versions and builds response
Sets X-Min-App-Version header

app.Use(mobile.New())
app.Get("/api/app-info", mobile.AppInfoHandler(provider))

Maintenance Mode Response

When maintenance mode is enabled:

{
  "maintenance": true,
  "message": "We're upgrading our servers. Back soon!",
  "end_time": "2024-01-15T10:00:00Z",
  "minimum_version": "1.5.0"
}

HTTP Status: 503 Service Unavailable

Store URLs

Helper functions for platform store URLs:

// iOS App Store
url := mobile.NewIOSStoreURL("123456789")
// "https://apps.apple.com/app/id123456789"

// Google Play Store
url := mobile.NewAndroidStoreURL("com.example.app")
// "https://play.google.com/store/apps/details?id=com.example.app"

Store URLs by Platform

type StoreURLs struct {
    iOS     string `json:"ios,omitempty"`
    Android string `json:"android,omitempty"`
    Windows string `json:"windows,omitempty"`
    Web     string `json:"web,omitempty"`
}

urls := mobile.StoreURLs{
    iOS:     "https://apps.apple.com/app/id123456789",
    Android: "https://play.google.com/store/apps/details?id=com.example.app",
    Windows: "ms-windows-store://pdp/?ProductId=12345",
    Web:     "https://example.com/download",
}

// Get URL for platform
url := urls.URLFor(device.Platform)

Force Update Middleware

Block outdated apps from accessing the API:

func forceUpdateMiddleware(provider mobile.AppInfoProvider) mizu.Middleware {
    return func(next mizu.Handler) mizu.Handler {
        return func(c *mizu.Ctx) error {
            device := mobile.DeviceFromCtx(c)
            if device == nil {
                return next(c)
            }

            info, err := provider.GetAppInfo(c.Context(), device.Platform, "")
            if err != nil || info == nil {
                return next(c)
            }

            // Check maintenance
            if info.MaintenanceMode {
                return mobile.SendError(c, 503, mobile.NewError(
                    mobile.ErrMaintenance,
                    info.MaintenanceMessage,
                ).WithDetails("end_time", info.MaintenanceEndTime))
            }

            // Check version
            if device.AppVersion != "" && info.MinimumVersion != "" {
                if mobile.CompareVersions(device.AppVersion, info.MinimumVersion) < 0 {
                    c.Header().Set(mobile.HeaderMinVersion, info.MinimumVersion)

                    return mobile.SendError(c, 426, mobile.NewError(
                        mobile.ErrUpgradeRequired,
                        "Please update to continue using the app",
                    ).WithDetails("current_version", device.AppVersion).
                      WithDetails("minimum_version", info.MinimumVersion).
                      WithDetails("update_url", info.UpdateURL))
                }
            }

            return next(c)
        }
    }
}

// Apply to all API routes
app.Use(forceUpdateMiddleware(provider))

Feature Flags

Include feature flags in app info:

provider := &FeatureFlagProvider{db: db}

func (p *FeatureFlagProvider) GetAppInfo(
    ctx context.Context,
    platform mobile.Platform,
    bundleID string,
) (*mobile.AppInfo, error) {
    info := &mobile.AppInfo{
        CurrentVersion: "2.0.0",
        MinimumVersion: "1.5.0",
        Features: map[string]bool{
            "dark_mode":      true,
            "new_checkout":   platform == mobile.PlatformIOS, // iOS only
            "beta_features":  false,
        },
    }

    return info, nil
}

Response:

{
  "update_available": false,
  "update_required": false,
  "current_version": "2.0.0",
  "features": {
    "dark_mode": true,
    "new_checkout": true,
    "beta_features": false
  }
}

Client Implementation

iOS (Swift)

struct AppInfo: Decodable {
    let updateAvailable: Bool
    let updateRequired: Bool
    let currentVersion: String
    let latestVersion: String
    let minimumVersion: String?
    let updateUrl: String?
    let releaseNotes: String?
    let features: [String: Bool]?

    enum CodingKeys: String, CodingKey {
        case updateAvailable = "update_available"
        case updateRequired = "update_required"
        case currentVersion = "current_version"
        case latestVersion = "latest_version"
        case minimumVersion = "minimum_version"
        case updateUrl = "update_url"
        case releaseNotes = "release_notes"
        case features
    }
}

class AppUpdateManager {
    func checkForUpdates() async {
        do {
            let info: AppInfo = try await api.get("/api/app-info")

            if info.updateRequired {
                showForceUpdateAlert(info)
            } else if info.updateAvailable {
                showOptionalUpdateAlert(info)
            }

            // Cache feature flags
            FeatureFlags.shared.update(info.features ?? [:])

        } catch let error as APIException where error.isMaintenance {
            showMaintenanceScreen(error)
        } catch {
            // Handle silently or show error
        }
    }

    private func showForceUpdateAlert(_ info: AppInfo) {
        let alert = UIAlertController(
            title: "Update Required",
            message: "Please update to continue using the app.",
            preferredStyle: .alert
        )

        alert.addAction(UIAlertAction(title: "Update", style: .default) { _ in
            if let url = URL(string: info.updateUrl ?? "") {
                UIApplication.shared.open(url)
            }
        })

        // No cancel button - force update
        rootViewController?.present(alert, animated: true)
    }
}

Android (Kotlin)

data class AppInfo(
    @SerializedName("update_available") val updateAvailable: Boolean,
    @SerializedName("update_required") val updateRequired: Boolean,
    @SerializedName("current_version") val currentVersion: String,
    @SerializedName("latest_version") val latestVersion: String,
    @SerializedName("minimum_version") val minimumVersion: String?,
    @SerializedName("update_url") val updateUrl: String?,
    @SerializedName("release_notes") val releaseNotes: String?,
    val features: Map<String, Boolean>?
)

class AppUpdateManager(
    private val api: ApiService,
    private val context: Context
) {
    suspend fun checkForUpdates() {
        try {
            val info = api.getAppInfo()

            when {
                info.updateRequired -> showForceUpdateDialog(info)
                info.updateAvailable -> showOptionalUpdateDialog(info)
            }

            // Update feature flags
            info.features?.let { FeatureFlags.update(it) }

        } catch (e: MaintenanceException) {
            showMaintenanceScreen(e.message, e.endTime)
        }
    }

    private fun showForceUpdateDialog(info: AppInfo) {
        AlertDialog.Builder(context)
            .setTitle("Update Required")
            .setMessage("Please update to continue using the app.")
            .setCancelable(false)
            .setPositiveButton("Update") { _, _ ->
                val intent = Intent(Intent.ACTION_VIEW).apply {
                    data = Uri.parse(info.updateUrl)
                }
                context.startActivity(intent)
            }
            .show()
    }
}

Flutter (Dart)

class AppInfo {
  final bool updateAvailable;
  final bool updateRequired;
  final String currentVersion;
  final String latestVersion;
  final String? minimumVersion;
  final String? updateUrl;
  final String? releaseNotes;
  final Map<String, bool>? features;

  AppInfo.fromJson(Map<String, dynamic> json)
      : updateAvailable = json['update_available'],
        updateRequired = json['update_required'],
        currentVersion = json['current_version'],
        latestVersion = json['latest_version'],
        minimumVersion = json['minimum_version'],
        updateUrl = json['update_url'],
        releaseNotes = json['release_notes'],
        features = json['features']?.cast<String, bool>();
}

class AppUpdateService {
  Future<void> checkForUpdates(BuildContext context) async {
    try {
      final response = await api.get('/api/app-info');
      final info = AppInfo.fromJson(response.data);

      if (info.updateRequired) {
        _showForceUpdateDialog(context, info);
      } else if (info.updateAvailable) {
        _showOptionalUpdateDialog(context, info);
      }

      // Update feature flags
      if (info.features != null) {
        FeatureFlags.update(info.features!);
      }
    } on MaintenanceException catch (e) {
      _showMaintenanceScreen(context, e);
    }
  }

  void _showForceUpdateDialog(BuildContext context, AppInfo info) {
    showDialog(
      context: context,
      barrierDismissible: false,
      builder: (context) => AlertDialog(
        title: const Text('Update Required'),
        content: const Text('Please update to continue using the app.'),
        actions: [
          TextButton(
            onPressed: () => launchUrl(Uri.parse(info.updateUrl!)),
            child: const Text('Update'),
          ),
        ],
      ),
    );
  }
}

Best Practices

Check on App Launch

Check for updates when the app launches and periodically while running:

// Backend: track when clients check
app.Get("/api/app-info", func(c *mizu.Ctx) error {
    device := mobile.DeviceFromCtx(c)

    // Log version distribution
    metrics.RecordAppVersion(device.Platform, device.AppVersion)

    return mobile.AppInfoHandler(provider)(c)
})

Gradual Rollouts

Use minimum version to gradually force updates:

Release 2.0.0 to stores
Set minimum to 1.8.0 initially
Monitor crash rates and feedback
Gradually raise minimum to 2.0.0

Maintenance Windows

Schedule maintenance during low-traffic periods:

func (p *DBProvider) GetAppInfo(ctx context.Context, platform mobile.Platform, bundleID string) (*mobile.AppInfo, error) {
    info := &mobile.AppInfo{
        CurrentVersion: "2.0.0",
        MinimumVersion: "1.5.0",
    }

    // Check scheduled maintenance
    maintenance, _ := p.db.GetScheduledMaintenance(time.Now())
    if maintenance != nil {
        info.MaintenanceMode = true
        info.MaintenanceMessage = maintenance.Message
        info.MaintenanceEndTime = &maintenance.EndTime
    }

    return info, nil
}

Next Steps

Templates

Available mobile templates

Production

Production deployment guide

API Reference

Complete API documentation

Getting Started

Core Concepts

Backend Features

Native Platforms

Cross-Platform

Web & Games

Deployment

Templates

Reference

App Store Integration

Quick Start

App Info

Static App Info Provider

Dynamic App Info Provider

Update Status

Update Status Response

App Info Handler

Maintenance Mode Response

Store URLs

Store URLs by Platform

Force Update Middleware

Feature Flags

Client Implementation

iOS (Swift)

Android (Kotlin)

Flutter (Dart)

Best Practices

Check on App Launch

Gradual Rollouts

Maintenance Windows

Next Steps

Templates

Production

API Reference

Getting Started

Core Concepts

Backend Features

Native Platforms

Cross-Platform

Web & Games

Deployment

Templates

Reference

​Quick Start

​App Info

​Static App Info Provider

​Dynamic App Info Provider

​Update Status

​Update Status Response

​App Info Handler

​Maintenance Mode Response

​Store URLs

​Store URLs by Platform

​Force Update Middleware

​Feature Flags

​Client Implementation

​iOS (Swift)

​Android (Kotlin)

​Flutter (Dart)

​Best Practices

​Check on App Launch

​Gradual Rollouts

​Maintenance Windows

​Next Steps

Templates

Production

API Reference

Quick Start

App Info

Static App Info Provider

Dynamic App Info Provider

Update Status

Update Status Response

App Info Handler

Maintenance Mode Response

Store URLs

Store URLs by Platform

Force Update Middleware

Feature Flags

Client Implementation

iOS (Swift)

Android (Kotlin)

Flutter (Dart)

Best Practices

Check on App Launch

Gradual Rollouts

Maintenance Windows

Next Steps