Web View Controller

Relevant source files

LinkSDK/LinkWebViewController/LinkWebViewViewController.swift

The Web View Controller is the core UI component of LinkSDK that manages the web-based interface for financial account linking and transfer operations. The LinkWebViewViewController class serves as the primary container for web content, JavaScript-to-native communication bridge, and navigation policy enforcement.

For information about the main SDK API classes that create and manage this controller, see LinkSDK and LinkHandler. For details about authentication-specific web components, see Authentication Components.

Architecture Overview

The LinkWebViewViewController acts as a bridge between the native iOS application and web-based content from the Mesh Connect platform. It provides a secure, controlled environment for web content while enabling bidirectional communication through a JavaScript message handler.

Web View Controller Architecture

External Integrations

Security Controls

JavaScript Messages

LinkWebViewViewController

webView

WKWebView

topBar

Native Navigation

jsMessageHandler

JavaScript Bridge

configuration

LinkConfiguration

JSMessageType.brokerageAccountAccessToken

JSMessageType.transferFinished

JSMessageType.showNativeNavbar

JSMessageType.openTrueAuth

JSMessageType.integrationSelected

allowedUrls

External URL List

whitelistedOrigins

Domain Whitelist

decidePolicyFor

Navigation Policy

SFSafariViewController

Safari Integration

TrueAuthWebViewController

Authentication Flow

UIApplication

External App Launch

Sources: LinkSDK/LinkWebViewController/LinkWebViewViewController.swift69-228

JavaScript Message Bridge

The controller implements a sophisticated JavaScript-to-native communication system using WKScriptMessageHandler. This enables the web content to trigger native callbacks and operations.

JavaScript Message Flow

"Host Application""LinkConfiguration""LinkWebViewController""jsMessageHandler""Web Content""Host Application""LinkConfiguration""LinkWebViewController""jsMessageHandler""Web Content"alt[brokerageAccountAccessToken][transferFinished][showNativeNavbar][openTrueAuth][integrationSelected]"JavaScript message""userContentController:didReceive:""Parse JSMessageType""onIntegrationConnected(.accessToken)""Integration callback""onTransferFinished(.success/.error)""Transfer callback""showNativeNavbar(show)""present TrueAuthWebViewController""evaluateJavaScript handleNativeLink"

The supported message types are defined in the JSMessageType enum:

Message Type	Purpose	Payload Processing
`brokerageAccountAccessToken`	Integration completion	Decoded to `AccessTokenPayload`
`delayedAuthentication`	Delayed auth flow	Decoded to `DelayedAuthPayload`
`transferFinished`	Transfer operation result	Decoded to success/error payload
`showNativeNavbar`	Navigation bar visibility	Boolean show/hide flag
`integrationSelected`	External app integration	Native link URL handling
`openTrueAuth`	Authentication initiation	Present `TrueAuthWebViewController`
`loaded`	Page load completion	Inject SDK configuration

Sources: LinkSDK/LinkWebViewController/LinkWebViewViewController.swift51-62 LinkSDK/LinkWebViewController/LinkWebViewViewController.swift382-463

Navigation Policy System

The controller implements strict navigation policies to ensure security and proper external app integration. The WKNavigationDelegate methods control which URLs can load within the web view versus being opened externally.

URL Routing Decision Tree


Yes

No

Yes

No

Yes

No

Yes

No

Yes

No

WeekNavigationAction URL

HTTP/HTTPS scheme?

URL in allowedUrls?

Custom scheme?

Open in Safari

Domain whitelisting disabled?

Load in WebView

Domain in whitelistedOrigins?

UIApplication.canOpenURL?

Cancel navigation

Open in external app

Log unsupported scheme

The security is enforced through two key arrays:

Allowed External URLs (opened in Safari):

https://link.trustwallet.com
https://appopener.meshconnect.com
https://www.coinbase.com
https://api.cb-device-intelligence.com

Whitelisted Domains (loaded in WebView):

.meshconnect.com, .walletconnect.com, .walletconnect.org
.okx.com, .gemini.com, .robinhood.com
.google.com (for reCAPTCHA), .hcaptcha.com
Various stripe and payment processor domains

Sources: LinkSDK/LinkWebViewController/LinkWebViewViewController.swift19-49 LinkSDK/LinkWebViewController/LinkWebViewViewController.swift310-343

Theme Management

The controller supports dynamic theming based on URL parameters and system appearance. Theme colors are applied to the status bar background and overall interface.

Theme Color Constants

Theme Selection Logic

Dark Theme

Light Theme

dark

light

system

Yes

No

LIGHT_THEME_COLOR_TOP: 0xF3F4F5

LIGHT_THEME_COLOR_BOTTOM: 0xFBFBFB

DARK_THEME_COLOR_TOP: 0x1E1E24

DARK_THEME_COLOR_BOTTOM: 0x0E0D0D

getThemeFromLinkUrl()

Theme Parameter

isDarkTheme = true

isDarkTheme = false

Use traitCollection.userInterfaceStyle

System Dark Mode?

The theme affects:

Status bar style (preferredStatusBarStyle)
Background colors for statusBarBackgroundView and main view
Navigation button tint colors

Sources: LinkSDK/LinkWebViewController/LinkWebViewViewController.swift14-17 LinkSDK/LinkWebViewController/LinkWebViewViewController.swift198-218

UI Component Structure

The controller uses a structured view hierarchy with Auto Layout constraints to manage the interface layout.

View Hierarchy

Button Configuration

Layout Constraints

topBar height: 68pt

button size: 44x44pt

button margins: 6pt

LinkWebViewViewController.view

statusBarBackgroundView

stackView (UIStackView)

topBar (UIView)

webView (WKWebView)

backButton (UIButton)

closeButton (UIButton)

chevron.left icon

backTapped action

xmark icon

closeTapped action

The native navigation bar (topBar) visibility is controlled dynamically based on:

JavaScript showNativeNavbar messages
Navigation completion events
URL change detection through KVO on the web view's URL property

Sources: LinkSDK/LinkWebViewController/LinkWebViewViewController.swift78-127 LinkSDK/LinkWebViewController/LinkWebViewViewController.swift260-305 LinkSDK/LinkWebViewController/LinkWebViewViewController.swift246-258

External Integration Capabilities

The controller provides several mechanisms for integrating with external applications and services:

Safari View Controller Integration

For URLs that require external browser access, the controller can present a SFSafariViewController that is automatically dismissed when the app enters the background.

External App Launch

Custom URL schemes (like wallet://) are detected and opened in external applications using UIApplication.shared.open(). The controller checks canOpenURL() before attempting to launch.

TrueAuth Authentication Flow

When receiving an openTrueAuth JavaScript message, the controller presents a dedicated TrueAuthWebViewController for authentication operations, passing an atomic token and result handler.

External Integration Flow

"TrueAuthWebViewController""External App""SFSafariViewController""LinkWebViewController""Web Content""TrueAuthWebViewController""External App""SFSafariViewController""LinkWebViewController""Web Content"alt[Allowed URL][Custom Scheme][TrueAuth Message]"Navigation to external URL""decidePolicyFor navigationAction""Open in Safari""Cancel WebView navigation""UIApplication.shared.open()""Cancel WebView navigation""Present authentication flow""Return result via JavaScript"

Sources: LinkSDK/LinkWebViewController/LinkWebViewViewController.swift449-459 LinkSDK/LinkWebViewController/LinkWebViewViewController.swift329-339 LinkSDK/LinkWebViewController/LinkWebViewViewController.swift151-154