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// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
import WebKit
struct DataSchemePolicyDecider: WKPolicyDecider {
var nextDecider: (any WKPolicyDecider)?
func policyForNavigation(action: NavigationAction) -> WKPolicy {
return .allow
}
func policyForNavigation(response: NavigationResponse) -> WKPolicy {
return .allow
}
func policyForPopupNavigation(action: NavigationAction) -> WKPolicy {
// Only filter top-level navigation, not on data URL subframes.
// If target frame is nil, we filter as well.
guard action.targetFrameInfo?.isMainFrame ?? true else {
return nextDecider?.policyForPopupNavigation(action: action) ?? .cancel
}
if shouldAllowDataScheme(for: action.url) {
return .allow
}
return nextDecider?.policyForPopupNavigation(action: action) ?? .cancel
}
func shouldAllowDataScheme(for url: URL?) -> Bool {
guard let url else { return false }
let urlString = url.absoluteString.lowercased()
// Allow certain image types
if urlString.hasPrefix("data:image/") && !urlString.hasPrefix("data:image/svg+xml") {
return true
}
// Allow video, and certain application types
if urlString.hasPrefix("data:video/")
|| urlString.hasPrefix("data:application/pdf")
|| urlString.hasPrefix("data:application/json") {
return true
}
// Allow plain text types.
// Note the format of data URLs is `data:[<media type>][;base64],<data>`
// with empty <media type> indicating plain text.
if urlString.hasPrefix("data:;base64,")
|| urlString.hasPrefix("data:,")
|| urlString.hasPrefix("data:text/plain,")
|| urlString.hasPrefix("data:text/plain;") {
return true
}
return false
}
}