Preview: Enable published posts preview

editor/components/post-preview-button/index.js

@@ -16,43 +16,49 @@ export class PostPreviewButton extends Component {
 		super( ...arguments );
 
 		this.saveForPreview = this.saveForPreview.bind( this );
-
-		this.state = {
-			isAwaitingSave: false,
-		};
 	}
 
-	componentWillReceiveProps( nextProps ) {
-		const { modified, link } = nextProps;
-		const { isAwaitingSave } = this.state;
-		const hasFinishedSaving = (
-			isAwaitingSave &&
-			modified !== this.props.modified
-		);
+	componentDidUpdate( prevProps ) {
+		const { previewLink } = this.props;
 
-		if ( hasFinishedSaving && this.previewWindow ) {
-			this.previewWindow.location = link;
-			this.setState( { isAwaitingSave: false } );
+		// This relies on the window being responsible to unset itself when
+		// navigation occurs or a new preview window is opened, to avoid
+		// unintentional forceful redirects.
+		if ( previewLink && previewLink !== prevProps.previewLink ) {
+			this.setPreviewWindowLink( previewLink );
 		}
 	}
 
+	/**
+	 * Sets the preview window's location to the given URL, if a preview window
+	 * exists and is not already at that location.
+	 *
+	 * @param {string} url URL to assign as preview window location.
+	 */
+	setPreviewWindowLink( url ) {
+		const { previewWindow } = this;
+		if ( ! previewWindow || previewWindow.location.href === url ) {
+			return;
+		}
+
+		previewWindow.location = url;
+	}
+
 	getWindowTarget() {
 		const { postId } = this.props;
 		return `wp-preview-${ postId }`;
 	}
 
 	saveForPreview( event ) {
 		const { isDirty, isNew } = this.props;
+
 		// Let default link behavior occur if no changes to saved post
 		if ( ! isDirty && ! isNew ) {
 			return;
 		}
 
 		// Save post prior to opening window
 		this.props.autosave();
-		this.setState( {
-			isAwaitingSave: true,
-		} );
 
 		// Open a popup, BUT: Set it to a blank page until save completes. This
 		// is necessary because popups can only be opened in response to user
@@ -63,10 +69,6 @@ export class PostPreviewButton extends Component {
 			this.getWindowTarget()
 		);
 
-		// When popup is closed, delete reference to avoid later assignment of
-		// location in a post update.
-		this.previewWindow.onbeforeunload = () => delete this.previewWindow;
-
 		const markup = `
 			<div>
 				<p>Please wait&hellip;</p>
@@ -92,16 +94,20 @@ export class PostPreviewButton extends Component {
 
 		this.previewWindow.document.write( markup );
 		this.previewWindow.document.close();
+
+		// When popup is closed or redirected by setPreviewWindowLink, delete
+		// reference to avoid later assignment of location in a post update.
+		this.previewWindow.onbeforeunload = () => delete this.previewWindow;
 	}
 
 	render() {
-		const { link, isSaveable } = this.props;
+		const { currentPostLink, isSaveable } = this.props;
 
 		return (
 			<Button
 				className="editor-post-preview"
 				isLarge
-				href={ link }
+				href={ currentPostLink }
 				onClick={ this.saveForPreview }
 				target={ this.getWindowTarget() }
 				disabled={ ! isSaveable }
@@ -116,7 +122,8 @@ export default compose( [
 	withSelect( ( select ) => {
 		const {
 			getCurrentPostId,
-			getEditedPostPreviewLink,
+			getCurrentPostAttribute,
+			getAutosaveAttribute,
 			getEditedPostAttribute,
 			isEditedPostDirty,
 			isEditedPostNew,
@@ -128,12 +135,12 @@ export default compose( [
 		const postType = getPostType( getEditedPostAttribute( 'type' ) );
 		return {
 			postId: getCurrentPostId(),
-			link: getEditedPostPreviewLink(),
+			currentPostLink: getCurrentPostAttribute( 'link' ),
+			previewLink: getAutosaveAttribute( 'preview_link' ),
 			isDirty: isEditedPostDirty(),
 			isNew: isEditedPostNew(),
 			isSaveable: isEditedPostSaveable(),
 			isViewable: get( postType, [ 'viewable' ], false ),
-			modified: getEditedPostAttribute( 'modified' ),
 		};
 	} ),
 	withDispatch( ( dispatch ) => ( {

editor/components/post-preview-button/test/index.js

@@ -9,11 +9,55 @@ import { shallow } from 'enzyme';
 import { PostPreviewButton } from '../';
 
 describe( 'PostPreviewButton', () => {
-	describe( 'constructor()', () => {
-		it( 'should initialize with non-awaiting-save', () => {
-			const instance = new PostPreviewButton( {} );
+	describe( 'setPreviewWindowLink()', () => {
+		it( 'should do nothing if there is no preview window', () => {
+			const url = 'https://wordpress.org';
+			const setter = jest.fn();
+			const wrapper = shallow( <PostPreviewButton /> );
 
-			expect( instance.state.isAwaitingSave ).toBe( false );
+			wrapper.instance().setPreviewWindowLink( url );
+
+			expect( setter ).not.toHaveBeenCalled();
+		} );
+
+		it( 'should do nothing if the preview window is already at url location', () => {
+			const url = 'https://wordpress.org';
+			const setter = jest.fn();
+			const wrapper = shallow( <PostPreviewButton /> );
+			wrapper.instance().previewWindow = {
+				get location() {
+					return {
+						href: url,
+					};
+				},
+				set location( value ) {
+					setter( value );
+				},
+			};
+
+			wrapper.instance().setPreviewWindowLink( url );
+
+			expect( setter ).not.toHaveBeenCalled();
+		} );
+
+		it( 'set preview window location to url', () => {
+			const url = 'https://wordpress.org';
+			const setter = jest.fn();
+			const wrapper = shallow( <PostPreviewButton /> );
+			wrapper.instance().previewWindow = {
+				get location() {
+					return {
+						href: 'about:blank',
+					};
+				},
+				set location( value ) {
+					setter( value );
+				},
+			};
+
+			wrapper.instance().setPreviewWindowLink( url );
+
+			expect( setter ).toHaveBeenCalledWith( url );
 		} );
 	} );
 
@@ -28,23 +72,21 @@ describe( 'PostPreviewButton', () => {
 	} );
 
 	describe( 'componentDidUpdate()', () => {
-		it( 'should change popup location if save finishes', () => {
+		it( 'should change popup location if preview link is available', () => {
 			const wrapper = shallow(
 				<PostPreviewButton
 					postId={ 1 }
-					link="https://wordpress.org/?p=1"
+					currentPostLink="https://wordpress.org/?p=1"
 					isSaveable
 					modified="2017-08-03T15:05:50" />
 			);
-			wrapper.instance().previewWindow = {};
-			wrapper.setState( { isAwaitingSave: true } );
+			wrapper.instance().previewWindow = { location: {} };
 
-			wrapper.setProps( { modified: '2017-08-03T15:05:52' } );
+			wrapper.setProps( { previewLink: 'https://wordpress.org/?p=1' } );
 
 			expect(
 				wrapper.instance().previewWindow.location
 			).toBe( 'https://wordpress.org/?p=1' );
-			expect( wrapper.state( 'isAwaitingSave' ) ).toBe( false );
 		} );
 	} );
 
@@ -71,13 +113,11 @@ describe( 'PostPreviewButton', () => {
 			if ( isExpectingSave ) {
 				expect( autosave ).toHaveBeenCalled();
 				expect( preventDefault ).toHaveBeenCalled();
-				expect( wrapper.state( 'isAwaitingSave' ) ).toBe( true );
 				expect( window.open ).toHaveBeenCalled();
 				expect( wrapper.instance().previewWindow.document.write ).toHaveBeenCalled();
 			} else {
 				expect( autosave ).not.toHaveBeenCalled();
 				expect( preventDefault ).not.toHaveBeenCalled();
-				expect( wrapper.state( 'isAwaitingSave' ) ).not.toBe( true );
 				expect( window.open ).not.toHaveBeenCalled();
 			}
 
@@ -118,7 +158,7 @@ describe( 'PostPreviewButton', () => {
 				<PostPreviewButton
 					postId={ 1 }
 					isSaveable
-					link="https://wordpress.org/?p=1" />
+					currentPostLink="https://wordpress.org/?p=1" />
 			);
 
 			expect( wrapper.prop( 'href' ) ).toBe( 'https://wordpress.org/?p=1' );
@@ -130,7 +170,7 @@ describe( 'PostPreviewButton', () => {
 			const wrapper = shallow(
 				<PostPreviewButton
 					postId={ 1 }
-					link="https://wordpress.org/?p=1" />
+					currentPostLink="https://wordpress.org/?p=1" />
 			);
 
 			expect( wrapper.prop( 'disabled' ) ).toBe( true );

editor/store/actions.js

@@ -391,7 +391,7 @@ export function editPost( edits ) {
  *
  * @return {Object} Action object.
  */
-export function savePost( options ) {
+export function savePost( options = {} ) {
 	return {
 		type: 'REQUEST_POST_UPDATE',
 		options,

editor/store/effects.js

@@ -98,7 +98,7 @@ export default {
 		const { dispatch, getState } = store;
 		const state = getState();
 		const post = getCurrentPost( state );
-		const isAutosave = get( action.options, [ 'autosave' ], false );
+		const isAutosave = !! action.options.autosave;
 
 		// Prevent save if not saveable.
 		const isSaveable = isAutosave ? isEditedPostAutosaveable : isEditedPostSaveable;
@@ -157,49 +157,14 @@ export default {
 
 		request.then(
 			( newPost ) => {
+				const reset = isAutosave ? resetAutosave : resetPost;
+				dispatch( reset( newPost ) );
+
 				// An autosave may be processed by the server as a regular save
 				// when its update is requested by the author and the post was
 				// draft or auto-draft.
 				const isRevision = newPost.id !== post.id;
 
-				// Thus, the following behaviors occur:
-				//
-				//  - If it was a revision, it is treated as latest autosave
-				//    and updates optimistically applied are reverted.
-				//  - If it was an autosave but not revision under the above
-				//    noted conditions, cherry-pick updated properties since
-				//    the received revision entity shares some but not all
-				//    properties of a post.
-				//  - Otherwise, it was a full save and the received entity
-				//    can be considered the new reset post.
-				let updateAction;
-				if ( isRevision ) {
-					updateAction = resetAutosave( newPost );
-				} else if ( isAutosave ) {
-					const revisionEdits = pick( newPost, [
-						// Autosave content fields.
-						'title',
-						'content',
-						'excerpt',
-
-						// UI considers save to have occurred if modified date
-						// of post changes (e.g. PostPreviewButton).
-						//
-						// TODO: Consider formalized pattern for identifying a
-						// save as having completed.
-						'date',
-						'date_gmt',
-						'modified',
-						'modified_gmt',
-					] );
-
-					updateAction = updatePost( revisionEdits );
-				} else {
-					updateAction = resetPost( newPost );
-				}
-
-				dispatch( updateAction );
-
 				dispatch( {
 					type: 'REQUEST_POST_UPDATE_SUCCESS',
 					previousPost: post,

editor/store/reducer.js

@@ -1085,7 +1085,19 @@ export function autosave( state = null, action ) {
 				'content',
 			].map( ( field ) => getPostRawValue( post[ field ] ) );
 
-			return { title, excerpt, content };
+			return {
+				title,
+				excerpt,
+				content,
+				preview_link: post.preview_link,
+			};
+
+		case 'REQUEST_POST_UPDATE':
+			// Invalidate known preview link when autosave starts.
+			if ( state && action.options.autosave ) {
+				return omit( state, 'preview_link' );
+			}
+			break;
 	}
 
 	return state;

editor/store/selectors.js

@@ -182,6 +182,21 @@ export function getPostEdits( state ) {
 	return get( state, [ 'editor', 'present', 'edits' ], {} );
 }
 
+/**
+ * Returns an attribute value of the saved post.
+ *
+ * @param {Object} state         Global application state.
+ * @param {string} attributeName Post attribute name.
+ *
+ * @return {*} Post attribute value.
+ */
+export function getCurrentPostAttribute( state, attributeName ) {
+	const post = getCurrentPost( state );
+	if ( post.hasOwnProperty( attributeName ) ) {
+		return post[ attributeName ];
+	}
+}
+
 /**
  * Returns a single attribute of the post being edited, preferring the unsaved
  * edit if one exists, but falling back to the attribute for the last known
@@ -201,9 +216,31 @@ export function getEditedPostAttribute( state, attributeName ) {
 			return getEditedPostContent( state );
 	}
 
-	return edits[ attributeName ] === undefined ?
-		state.currentPost[ attributeName ] :
-		edits[ attributeName ];
+	if ( ! edits.hasOwnProperty( attributeName ) ) {
+		return getCurrentPostAttribute( state, attributeName );
+	}
+
+	return edits[ attributeName ];
+}
+
+/**
+ * Returns an attribute value of the current autosave revision for a post, or
+ * null if there is no autosave for the post.
+ *
+ * @param {Object} state         Global application state.
+ * @param {string} attributeName Autosave attribute name.
+ *
+ * @return {*} Autosave attribute value.
+ */
+export function getAutosaveAttribute( state, attributeName ) {
+	if ( ! hasAutosave( state ) ) {
+		return null;
+	}
+
+	const autosave = getAutosave( state );
+	if ( autosave.hasOwnProperty( attributeName ) ) {
+		return autosave[ attributeName ];
+	}
 }
 
 /**