Rework opening a post by URL

Author: jkmassel

Modules/Sources/WordPressKit/ReaderPostServiceRemote+V2.swift

@@ -1,5 +1,10 @@
 import Foundation
 
+public struct ResolvedReaderPost: Decodable {
+    public let postId: UInt64
+    public let siteId: UInt64
+}
+
 extension ReaderPostServiceRemote {
     /// Returns a collection of RemoteReaderPost
     /// This method returns the best available content for the given topics.
@@ -31,6 +36,30 @@ extension ReaderPostServiceRemote {
         })
     }
 
+    public func resolveUrl(
+        _ url: URL,
+        success: @escaping (ResolvedReaderPost) -> Void,
+        failure: @escaping (Error) -> Void
+    ) {
+
+        wordPressComRESTAPI.get("/wpcom/v2/mobile/resolve-reader-url", parameters: [
+            "url": url.absoluteString
+        ]) { data, response in
+            guard
+                let responseDict = data as? [String: UInt64],
+                let siteId = responseDict["site_id"],
+                let postId = responseDict["post_id"]
+            else {
+                failure(CocoaError(.coderInvalidValue))
+                return
+            }
+
+            success(ResolvedReaderPost(postId: postId, siteId: siteId))
+        } failure: { error, response in
+            failure(error)
+        }
+    }
+
     private func postsEndpoint(for topics: [String], page: String? = nil) -> String? {
         var path = URLComponents(string: "read/tags/posts")
 

WordPress/Classes/Services/Reader Post/ReaderPostService.swift

@@ -4,6 +4,20 @@ import WordPressKit
 
 extension ReaderPostService {
 
+    // MARK: – WP.com URL resolution
+
+    /// Ask the server for details about a Reader Post.
+    ///
+    /// It's impossible to resolve a post URL into anything that the API can understand client-side. So we can ask the server to do it for us.
+    func resolvePostUrl(
+        _ url: URL,
+        success: @escaping (ResolvedReaderPost) -> Void,
+        failure: @escaping(Error) -> Void
+    ) {
+        let remoteService = ReaderPostServiceRemote(wordPressComRestApi: apiForRequest())
+        remoteService.resolveUrl(url, success: success, failure: failure)
+    }
+
     // MARK: - Fetch Unblocked Posts
 
     /// Fetches a list of posts from the API and filters out the posts that belong to a blocked author.

WordPress/Classes/Utility/Universal Links/RouteMatcher.swift

@@ -25,7 +25,7 @@ class RouteMatcher {
     func routesMatching(_ url: URL) -> [MatchedRoute] {
         let pathComponents = url.pathComponents
 
-        return routes.compactMap({ route in
+        return routes.compactMap({ route -> MatchedRoute? in
             let values = valuesDictionary(forURL: url)
 
             // If the paths are the same, we definitely have a match
@@ -40,23 +40,15 @@ class RouteMatcher {
                 return nil
             }
 
-            guard let placeholderValues = placeholderDictionary(forKeyComponents: routeComponents,
-                                                                valueComponents: pathComponents) else {
-                                                                    return nil
-            }
-
-            let allValues = values.merging(placeholderValues,
-                                           uniquingKeysWith: { (current, _) in current })
-
-            // If it's a wpcomPost reader route, then check if it's a valid wpcom url.
-            // Need to check since we have no guarantee that it's a valid wpcom url,
-            // other than the path having 4 components.
-            if let readerRoute = route as? ReaderRoute,
-               readerRoute == .wpcomPost,
-               !readerRoute.isValidWpcomUrl(allValues) {
+            guard let placeholderValues = placeholderDictionary(
+                forKeyComponents: routeComponents,
+                valueComponents: pathComponents
+            ) else {
                 return nil
             }
 
+            let allValues = values.merging(placeholderValues, uniquingKeysWith: { (current, _) in current })
+
             return route.matched(with: allValues)
         })
     }

WordPress/Classes/Utility/Universal Links/Routes+Reader.swift

@@ -113,9 +113,7 @@ extension ReaderRoute: NavigationAction {
                 presenter.showReader(path: .post(postID: postID, siteID: blogID))
             }
         case .wpcomPost:
-            if let urlString = values[MatchedRouteURLComponentKey.url.rawValue],
-               let url = URL(string: urlString),
-               isValidWpcomUrl(values) {
+            if let urlString = values[MatchedRouteURLComponentKey.url.rawValue], let url = URL(string: urlString) {
                 presenter.showReader(path: .postURL(url))
             }
         }
@@ -142,27 +140,6 @@ extension ReaderRoute: NavigationAction {
 
         return (blogID, postID)
     }
-
-    func isValidWpcomUrl(_ values: [String: String]) -> Bool {
-        let year = Int(values["post_year"] ?? "") ?? 0
-        let month = Int(values["post_month"] ?? "") ?? 0
-        let day = Int(values["post_day"] ?? "") ?? 0
-
-        // we assume no posts were made in the 1800's or earlier
-        func isYear(_ year: Int) -> Bool {
-            year > 1900
-        }
-
-        func isMonth(_ month: Int) ->  Bool {
-            (1...12).contains(month)
-        }
-
-        func isDay(_ day: Int) -> Bool {
-            (1...31).contains(day)
-        }
-
-        return isYear(year) && isMonth(month) && isDay(day)
-    }
 }
 
 // MARK: - RootViewPresenter (Extensions)

WordPress/Classes/ViewRelated/Reader/Detail/ReaderDetailCoordinator.swift

@@ -347,7 +347,7 @@ class ReaderDetailCoordinator {
                                         self?.post = post
                                         self?.renderPostAndBumpStats()
                                     }, failure: { [weak self] error in
-                                        self?.postURL == nil ? self?.showError(error: error) : self?.view?.showErrorWithWebAction()
+                                        self?.postURL == nil ? self?.showError(error: error) : self?.view?.showErrorWithWebAction(error: error)
                                         self?.reportPostLoadFailure()
                                     })
     }
@@ -357,15 +357,17 @@ class ReaderDetailCoordinator {
     /// Use this method to fetch a ReaderPost from a URL.
     /// - Parameter url: a post URL
     private func fetch(_ url: URL) {
-        readerPostService.fetchPost(at: url,
-                                    success: { [weak self] post in
-                                        self?.post = post
-                                        self?.renderPostAndBumpStats()
-                                    }, failure: { [weak self] error in
-                                        DDLogError("Error fetching post for detail: \(String(describing: error?.localizedDescription))")
-                                        self?.postURL == nil ? self?.showError(error: error) : self?.view?.showErrorWithWebAction()
-                                        self?.reportPostLoadFailure()
-                                    })
+        readerPostService.resolvePostUrl(url) { resolvedPost in
+            self.fetch(
+                postID: NSNumber(value: resolvedPost.postId),
+                siteID: NSNumber(value: resolvedPost.siteId),
+                isFeed: false
+            )
+        } failure: { error in
+            DDLogError("Error fetching post for detail: \(String(describing: error.localizedDescription))")
+            self.showError(error: error)
+            self.reportPostLoadFailure()
+        }
     }
 
     private func showError(error: Error?) {
@@ -476,8 +478,6 @@ class ReaderDetailCoordinator {
             presentWebViewController(url)
         } else if readerLinkRouter.canHandle(url: url) {
             readerLinkRouter.handle(url: url, shouldTrack: false, source: .inApp(presenter: viewController))
-        } else if url.isWordPressDotComPost {
-            presentReaderDetail(url)
         } else if url.isLinkProtocol {
             readerLinkRouter.handle(url: url, shouldTrack: false, source: .inApp(presenter: viewController))
         } else {
@@ -525,30 +525,6 @@ class ReaderDetailCoordinator {
                                      })
     }
 
-    /// Given a URL presents it in a new Reader detail screen
-    ///
-    private func presentReaderDetail(_ url: URL) {
-
-        // In cross post Notifications, if the user tapped the link to the original post in the Notification body,
-        // use the original post's info to display reader detail.
-        // The API endpoint used by controllerWithPostID returns subscription flags for the post.
-        // The API endpoint used by controllerWithPostURL does not return this information.
-        // These flags are needed to display the `Follow conversation by email` option.
-        // So if we can call controllerWithPostID, do so. Otherwise, fallback to controllerWithPostURL.
-        // Ref: https://github.com/wordpress-mobile/WordPress-iOS/issues/17158
-
-        let readerDetail: ReaderDetailViewController = {
-            if let post,
-               selectedUrlIsCrossPost(url) {
-                return ReaderDetailViewController.controllerWithPostID(post.crossPostMeta.postID, siteID: post.crossPostMeta.siteID)
-            }
-
-            return ReaderDetailViewController.controllerWithPostURL(url)
-        }()
-
-        viewController?.navigationController?.pushViewController(readerDetail, animated: true)
-    }
-
     private func selectedUrlIsCrossPost(_ url: URL) -> Bool {
         // Trim trailing slashes to facilitate URL comparison.
         let characterSet = CharacterSet(charactersIn: "/")

WordPress/Classes/ViewRelated/Reader/Detail/ReaderDetailViewController.swift

@@ -14,7 +14,7 @@ protocol ReaderDetailView: AnyObject {
     func renderRelatedPosts(_ posts: [RemoteReaderSimplePost])
     func showLoading()
     func showError(subtitle: String?)
-    func showErrorWithWebAction()
+    func showErrorWithWebAction(error: Error?)
     func scroll(to: String)
     func updateHeader()
     func updateLikesView(with viewModel: ReaderDetailLikesViewModel)
@@ -109,6 +109,11 @@ class ReaderDetailViewController: UIViewController, ReaderDetailView {
         return coordinator?.post
     }
 
+    /// The URL to a post can change – we might set it when we instantiate the controller, but then when we fetch the details from the server, we know
+    /// that `https://wordpress.com/reader/{site_id}/posts/{post_id}` is actually `https://example.com/foo/bar`. We need to keep
+    /// an unchanging reference to the URL so that we can identify the content this view is presenting before we fetch the post from the server.
+    private var originalUrl: URL? = nil
+
     /// The related posts for the post being shown
     var relatedPosts: [RelatedPostsSection] = []
 
@@ -399,8 +404,8 @@ class ReaderDetailViewController: UIViewController, ReaderDetailView {
     }
 
     /// Shown an error with a button to open the post on the browser
-    func showErrorWithWebAction() {
-        displayLoadingViewWithWebAction(title: LoadingText.errorLoadingTitle)
+    func showErrorWithWebAction(error: Error?) {
+        displayLoadingViewWithWebAction(title: LoadingText.errorLoadingTitle, error: error)
     }
 
     /// Scroll the content to a given #hash
@@ -832,7 +837,7 @@ class ReaderDetailViewController: UIViewController, ReaderDetailView {
         let coordinator = ReaderDetailCoordinator(view: controller)
         coordinator.postURL = url
         controller.coordinator = coordinator
-
+        controller.originalUrl = url
         return controller
     }
 
@@ -1122,10 +1127,13 @@ private extension ReaderDetailViewController {
         showLoadingView()
     }
 
-    func displayLoadingViewWithWebAction(title: String, accessoryView: UIView? = nil) {
-        noResultsViewController.configure(title: title,
-                                          buttonTitle: LoadingText.errorLoadingPostURLButtonTitle,
-                                          accessoryView: accessoryView)
+    func displayLoadingViewWithWebAction(title: String, error: Error? = nil, accessoryView: UIView? = nil) {
+        noResultsViewController.configure(
+            title: title,
+            buttonTitle: LoadingText.errorLoadingPostURLButtonTitle,
+            subtitle: error?.localizedDescription,
+            accessoryView: accessoryView
+        )
         showLoadingView()
     }
 
@@ -1321,6 +1329,10 @@ extension ReaderDetailViewController: ContentIdentifiable {
             return "https://wordpress.com/reader/feeds/\(siteId)/posts/\(postId)"
         }
 
+        if let originalUrl {
+            return originalUrl.absoluteString
+        }
+
         return nil
     }
 }