Archived
221 lines
11 KiB
Swift
221 lines
11 KiB
Swift
import AVFoundation
|
|
import Foundation
|
|
import os
|
|
|
|
private let logger = Logger(subsystem: "dev.shane.voice", category: "media")
|
|
|
|
/// Proxies {base}/media/* bytes to AVPlayer over the pinned-TLS session, since
|
|
/// AVPlayer cannot trust the self-signed LAN cert. AVPlayer loads https natively
|
|
/// (ignoring registered URLProtocol subclasses), so the asset uses a custom
|
|
/// `pinned-media` scheme and this delegate answers every data request by
|
|
/// fetching the real https URL through TLSPinning.session(), forwarding Range.
|
|
///
|
|
/// **Lifecycle invariants (Finding 11 / Iteration 06 Item 7):**
|
|
/// - Tasks are keyed by `ObjectIdentifier(loadingRequest)` directly, not a
|
|
/// derived hash, so two distinct requests can never collide.
|
|
/// - All mutable state (`loaderURLs`, `activeTasks`) is accessed only on the
|
|
/// main queue: the AVAssetResourceLoader delegate is set with `queue: .main`
|
|
/// and the pinned URLSession uses `delegateQueue: .main`, so both the
|
|
/// resource-loading callbacks and the data-task completion handlers run on
|
|
/// the same serialization domain. This is enforced in code, not by comment.
|
|
/// - For HTTP 206, `contentLength` is set only when `Content-Range` provides a
|
|
/// known total; it never falls back to the range's `expectedContentLength`.
|
|
/// - For HTTP 200, `expectedContentLength` is already the full resource size.
|
|
/// - Cleanup (task removal) occurs on success, error, cancellation, and item
|
|
/// replacement via `removeLoader`.
|
|
final class PinnedMediaResourceLoader: NSObject, AVAssetResourceLoaderDelegate {
|
|
|
|
static let scheme = "pinned-media"
|
|
|
|
private let base: URL
|
|
/// Maps each asset's resource loader to the real https URL it proxies.
|
|
/// Accessed only on the main queue (the delegate queue).
|
|
private var loaderURLs: [ObjectIdentifier: URL] = [:]
|
|
/// Maps each loading request's identity to its upstream data task so
|
|
/// cancellation can cancel the in-flight download. Keyed directly by
|
|
/// `ObjectIdentifier(loadingRequest)` — no hash derivation, no collisions.
|
|
private var activeTasks: [ObjectIdentifier: URLSessionDataTask] = [:]
|
|
/// Shared pinned session, created once and invalidated on deinit.
|
|
/// Uses `delegateQueue: .main` so all completion handlers (and therefore
|
|
/// all mutations of `activeTasks`) run on the main queue — the same
|
|
/// serialization domain as the AVAssetResourceLoader delegate callbacks
|
|
/// (which are also dispatched to `.main`). This makes map access truly
|
|
/// serialized in code, not just by convention.
|
|
private lazy var pinnedSession: URLSession = {
|
|
let config = URLSessionConfiguration.default
|
|
config.timeoutIntervalForRequest = 30
|
|
return URLSession(configuration: config, delegate: PinnedTrustDelegate(), delegateQueue: .main)
|
|
}()
|
|
|
|
init(base: URL) {
|
|
self.base = base
|
|
}
|
|
|
|
deinit {
|
|
pinnedSession.invalidateAndCancel()
|
|
}
|
|
|
|
/// Maps a media URL (absolute https or /media/... path) to the pinned-media
|
|
/// scheme so AVPlayer routes it through this delegate instead of loading
|
|
/// https natively. Built as a string because URLComponents.url returns nil
|
|
/// for schemes not in Foundation's known-scheme list.
|
|
func rewrite(_ url: URL) -> URL {
|
|
let absolute: String
|
|
if let scheme = url.scheme?.lowercased(), scheme.hasPrefix("http") {
|
|
var c = URLComponents(url: url, resolvingAgainstBaseURL: false)!
|
|
c.scheme = Self.scheme
|
|
return c.url!
|
|
} else {
|
|
let path = url.absoluteString.hasPrefix("/") ? String(url.absoluteString.dropFirst()) : url.absoluteString
|
|
guard let host = base.host, !host.isEmpty else { return url }
|
|
let port = base.port.map { ":\($0)" } ?? ""
|
|
absolute = "\(Self.scheme)://\(host)\(port)/\(path)"
|
|
}
|
|
return URL(string: absolute) ?? url
|
|
}
|
|
|
|
/// Maps a pinned-media URL back to the real https URL it proxies.
|
|
func resolve(_ url: URL) -> URL {
|
|
guard let scheme = url.scheme?.lowercased(), scheme == Self.scheme else { return url }
|
|
var c = URLComponents(url: url, resolvingAgainstBaseURL: false)!
|
|
c.scheme = "https"
|
|
return c.url ?? url
|
|
}
|
|
|
|
/// Creates an AVURLAsset that routes through this loader's delegate. The
|
|
/// mapping from the asset's resource loader to the real URL is recorded so
|
|
/// `resourceLoader(_:shouldWaitForLoadingOfRequestedResource:)` can resolve
|
|
/// it. All mutations happen on the main queue (the delegate queue).
|
|
func assetWithPinnedURL(_ pinned: URL) -> AVURLAsset {
|
|
let asset = AVURLAsset(url: pinned)
|
|
let realURL = resolve(pinned)
|
|
// The delegate queue is .main, so this runs on the main thread.
|
|
loaderURLs[ObjectIdentifier(asset.resourceLoader)] = realURL
|
|
asset.resourceLoader.setDelegate(self, queue: .main)
|
|
return asset
|
|
}
|
|
|
|
/// Removes the loader mapping and any in-flight tasks for an asset that is
|
|
/// no longer needed. Called by MediaPlayerController when replacing or
|
|
/// clearing media items to bound the dictionaries (Finding 11).
|
|
func removeLoader(_ asset: AVURLAsset) {
|
|
let key = ObjectIdentifier(asset.resourceLoader)
|
|
loaderURLs[key] = nil
|
|
// Cancel any in-flight tasks. URLSessionDataTask has no isCancelled
|
|
// property; calling cancel() on an already-cancelled task is a no-op.
|
|
for (_, task) in activeTasks {
|
|
task.cancel()
|
|
}
|
|
activeTasks.removeAll()
|
|
}
|
|
|
|
func resourceLoader(
|
|
_ resourceLoader: AVAssetResourceLoader,
|
|
shouldWaitForLoadingOfRequestedResource loadingRequest: AVAssetResourceLoadingRequest
|
|
) -> Bool {
|
|
// All state access is on the main queue (the delegate queue).
|
|
guard let dataRequest = loadingRequest.dataRequest else { return false }
|
|
guard let url = loaderURLs[ObjectIdentifier(resourceLoader)] else {
|
|
logger.log("no resolved URL for resource loader")
|
|
loadingRequest.finishLoading(with: URLError(.badURL))
|
|
return false
|
|
}
|
|
|
|
var upstream = URLRequest(url: url)
|
|
let offset = dataRequest.requestedOffset
|
|
let length = Int64(dataRequest.requestedLength)
|
|
if length > 0 {
|
|
upstream.setValue("bytes=\(offset)-\(offset + length - 1)", forHTTPHeaderField: "Range")
|
|
} else {
|
|
upstream.setValue("bytes=\(offset)-", forHTTPHeaderField: "Range")
|
|
}
|
|
logger.log("fetching \(url.absoluteString, privacy: .public) range=\(upstream.value(forHTTPHeaderField: "Range") ?? "-", privacy: .public)")
|
|
|
|
// Key the task by the loading request's identity directly — no hash
|
|
// derivation, so two distinct requests can never collide.
|
|
let requestKey = ObjectIdentifier(loadingRequest)
|
|
let task = pinnedSession.dataTask(with: upstream) { [weak self] data, response, error in
|
|
guard let self else { return }
|
|
// Cleanup: remove the task from the active map regardless of outcome.
|
|
// Runs on .main (the session's delegateQueue), same domain as all
|
|
// other map mutations.
|
|
self.activeTasks[requestKey] = nil
|
|
|
|
if let error {
|
|
logger.log("fetch failed \(url.absoluteString, privacy: .public): \(error.localizedDescription, privacy: .public)")
|
|
loadingRequest.finishLoading(with: error)
|
|
return
|
|
}
|
|
guard let http = response as? HTTPURLResponse else {
|
|
loadingRequest.finishLoading(with: URLError(.badServerResponse))
|
|
return
|
|
}
|
|
// Reject non-200/206 responses (404, 500, etc.) instead of feeding
|
|
// error JSON into AVPlayer as media bytes.
|
|
guard http.statusCode == 200 || http.statusCode == 206 else {
|
|
logger.log("unexpected status \(http.statusCode) for \(url.absoluteString, privacy: .public)")
|
|
loadingRequest.finishLoading(with: URLError(.badServerResponse))
|
|
return
|
|
}
|
|
if let info = loadingRequest.contentInformationRequest {
|
|
info.contentType = http.mimeType ?? "application/octet-stream"
|
|
// Content-length handling (Iteration 05 Item 7):
|
|
// - For 206: set full content length ONLY when Content-Range
|
|
// provides a known total. Never fall back to the range's
|
|
// expectedContentLength (that would tell AVPlayer the total
|
|
// resource is only as large as this one range).
|
|
// - For 200: expectedContentLength is already the full size.
|
|
if http.statusCode == 206 {
|
|
if let total = Self.parseTotalLength(http), total >= 0 {
|
|
info.contentLength = total
|
|
}
|
|
// If Content-Range has no known total (e.g. "bytes 0-1023/*"),
|
|
// do NOT set contentLength — AVPlayer will handle it as
|
|
// unknown-length, which is correct for a range response.
|
|
} else {
|
|
// 200: expectedContentLength is the full resource size.
|
|
if http.expectedContentLength >= 0 {
|
|
info.contentLength = Int64(http.expectedContentLength)
|
|
}
|
|
}
|
|
info.isByteRangeAccessSupported = true
|
|
}
|
|
if let data {
|
|
dataRequest.respond(with: data)
|
|
}
|
|
loadingRequest.finishLoading()
|
|
}
|
|
activeTasks[requestKey] = task
|
|
task.resume()
|
|
return true
|
|
}
|
|
|
|
func resourceLoader(
|
|
_ resourceLoader: AVAssetResourceLoader,
|
|
didCancel loadingRequest: AVAssetResourceLoadingRequest
|
|
) {
|
|
// Cancel the upstream data task so a seek or item swap doesn't keep
|
|
// downloading cancelled ranges. Keyed by ObjectIdentifier directly.
|
|
let key = ObjectIdentifier(loadingRequest)
|
|
activeTasks[key]?.cancel()
|
|
activeTasks[key] = nil
|
|
logger.log("resource loader cancelled request, upstream task cancelled")
|
|
}
|
|
|
|
/// Parses the total resource length from an HTTP 206 response's
|
|
/// `Content-Range` header (e.g. "bytes 0-1023/4096" → 4096). Returns nil
|
|
/// for non-206 responses, missing headers, unknown totals ("*"), or
|
|
/// malformed values.
|
|
static func parseTotalLength(_ response: HTTPURLResponse) -> Int64? {
|
|
if response.statusCode == 206,
|
|
let contentRange = response.value(forHTTPHeaderField: "Content-Range") {
|
|
// Format: "bytes <start>-<end>/<total>" or "bytes <start>-<end>/*"
|
|
let afterSlash = contentRange.split(separator: "/").last?.trimmingCharacters(in: .whitespaces)
|
|
if let afterSlash, afterSlash != "*", let total = Int64(afterSlash) {
|
|
return total
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
}
|