boards/static/js/thread_update.js

/*
 @licstart  The following is the entire license notice for the
 JavaScript code in this page.


 Copyright (C) 2013-2014  neko259

 The JavaScript code in this page is free software: you can
 redistribute it and/or modify it under the terms of the GNU
 General Public License (GNU GPL) as published by the Free Software
 Foundation, either version 3 of the License, or (at your option)
 any later version.  The code is distributed WITHOUT ANY WARRANTY;
 without even the implied warranty of MERCHANTABILITY or FITNESS
 FOR A PARTICULAR PURPOSE.  See the GNU GPL for more details.

 As additional permission under GNU GPL version 3 section 7, you
 may distribute non-source (e.g., minimized or compacted) forms of
 that code without the copy of the GNU GPL normally required by
 section 4, provided you include this license notice and a URL
 through which recipients can access the Corresponding Source.

 @licend  The above is the entire license notice
 for the JavaScript code in this page.
 */

var CLASS_POST = '.post';

var POST_ADDED = 0;
var POST_UPDATED = 1;

// TODO These need to be syncronized with board settings.
var JS_AUTOUPDATE_PERIOD = 20000;
// TODO This needs to be the same for attachment download time limit.
var POST_AJAX_TIMEOUT = 30000;
var BLINK_SPEED = 500;

var ALLOWED_FOR_PARTIAL_UPDATE = [
    'refmap',
    'post-info'
];

var ATTR_CLASS = 'class';
var ATTR_UID = 'data-uid';

var unreadPosts = 0;
var documentOriginalTitle = '';

// Thread ID does not change, can be stored one time
var threadId = $('div.thread').children(CLASS_POST).first().attr('id');
var blinkColor = $('<div class="post-blink"></div>').css('background-color');

/**
 * Get diff of the posts from the current thread timestamp.
 * This is required if the browser was closed and some post updates were
 * missed.
 */
function getThreadDiff() {
    var all_posts = $('.post');

    var uids = '';
    var posts = all_posts;
    for (var i = 0; i < posts.length; i++) {
        uids += posts[i].getAttribute('data-uid') + ' ';
    }

    var data = {
        uids: uids,
        thread: threadId
    };

    var diffUrl = '/api/diff_thread/';

    $.post(diffUrl,
        data,
        function(data) {
            var updatedPosts = data.updated;
            var addedPostCount = 0;

            for (var i = 0; i < updatedPosts.length; i++) {
                var postText = updatedPosts[i];
                var post = $(postText);

                if (updatePost(post) == POST_ADDED) {
                    addedPostCount++;
                }
            }

            var hasMetaUpdates = updatedPosts.length > 0;
            if (hasMetaUpdates) {
                updateMetadataPanel();
            }

            if (addedPostCount > 0) {
                updateBumplimitProgress(addedPostCount);
            }

            if (updatedPosts.length > 0) {
                showNewPostsTitle(addedPostCount);
            }

            // TODO Process removed posts if any
            $('.metapanel').attr('data-last-update', data.last_update);

            if (data.subscribed == 'True') {
                var favButton = $('#thread-fav-button .not_fav');

                if (favButton.length > 0) {
                    favButton.attr('value', 'unsubscribe');
                    favButton.removeClass('not_fav');
                    favButton.addClass('fav');
                }
            }
        },
        'json'
    )
}

/**
 * Add or update the post on html page.
 */
function updatePost(postHtml) {
    // This needs to be set on start because the page is scrolled after posts
    // are added or updated
    var bottom = isPageBottom();

    var post = $(postHtml);

    var threadBlock = $('div.thread');

    var postId = post.attr('id');

    // If the post already exists, replace it. Otherwise add as a new one.
    var existingPosts = threadBlock.children('.post[id=' + postId + ']');

    var type;

    if (existingPosts.size() > 0) {
        replacePartial(existingPosts.first(), post, false);
        post = existingPosts.first();

        type = POST_UPDATED;
    } else {
        post.appendTo(threadBlock);

        if (bottom) {
            scrollToBottom();
        }

        type = POST_ADDED;
    }

    processNewPost(post);

    return type;
}

/**
 * Initiate a blinking animation on a node to show it was updated.
 */
function blink(node) {
    node.effect('highlight', { color: blinkColor }, BLINK_SPEED);
}

function isPageBottom() {
    var scroll = $(window).scrollTop() / ($(document).height()
        - $(window).height());

    return scroll == 1
}

function enableJsUpdate() {
    setInterval(getThreadDiff, JS_AUTOUPDATE_PERIOD);
    return true;
}

function initAutoupdate() {
    return enableJsUpdate();
}

function getReplyCount() {
    return $('.thread').children(CLASS_POST).length
}

function getImageCount() {
    return $('.thread').find('img').length
}

/**
 * Update post count, images count and last update time in the metadata
 * panel.
 */
function updateMetadataPanel() {
    var replyCountField = $('#reply-count');
    var imageCountField = $('#image-count');

    var replyCount = getReplyCount();
    replyCountField.text(replyCount);
    var imageCount = getImageCount();
    imageCountField.text(imageCount);

    var lastUpdate = $('.post:last').children('.post-info').first()
        .children('.pub_time').first().html();
    if (lastUpdate !== '') {
        var lastUpdateField = $('#last-update');
        lastUpdateField.html(lastUpdate);
        blink(lastUpdateField);
    }

    blink(replyCountField);
    blink(imageCountField);
}

/**
 * Update bumplimit progress bar
 */
function updateBumplimitProgress(postDelta) {
    var progressBar = $('#bumplimit_progress');
    if (progressBar) {
        var postsToLimitElement = $('#left_to_limit');

        var oldPostsToLimit = parseInt(postsToLimitElement.text());
        var postCount = getReplyCount();
        var bumplimit = postCount - postDelta + oldPostsToLimit;

        var newPostsToLimit = bumplimit - postCount;
        if (newPostsToLimit <= 0) {
            $('.bar-bg').remove();
        } else {
            postsToLimitElement.text(newPostsToLimit);
            progressBar.width((100 - postCount / bumplimit * 100.0) + '%');
        }
    }
}

/**
 * Show 'new posts' text in the title if the document is not visible to a user
 */
function showNewPostsTitle(newPostCount) {
    if (document.hidden) {
        if (documentOriginalTitle === '') {
            documentOriginalTitle = document.title;
        }
        unreadPosts = unreadPosts + newPostCount;

        var newTitle = null;
        if (unreadPosts > 0) {
            newTitle = '[' + unreadPosts + '] ';
        } else {
            newTitle = '* ';
        }
        newTitle += documentOriginalTitle;

        document.title = newTitle;

        document.addEventListener('visibilitychange', function() {
            if (documentOriginalTitle !== '') {
                document.title = documentOriginalTitle;
                documentOriginalTitle = '';
                unreadPosts = 0;
            }

            document.removeEventListener('visibilitychange', null);
        });
    }
}


/**
 * When the form is posted, this method will be run as a callback
 */
function updateOnPost(response, statusText, xhr, form) {
    var json = $.parseJSON(response);
    var status = json.status;

    showAsErrors(form, '');
    $('.post-form-w').unblock();

    if (status === 'ok') {
        resetForm();
        getThreadDiff();
        scrollToBottom();
    } else {
        var errors = json.errors;
        for (var i = 0; i < errors.length; i++) {
            var fieldErrors = errors[i];

            var error = fieldErrors.errors;

            showAsErrors(form, error);
        }
    }
}


/**
 * Run js methods that are usually run on the document, on the new post
 */
function processNewPost(post) {
    addScriptsToPost(post);
    blink(post);
}

function replacePartial(oldNode, newNode, recursive) {
    if (!equalNodes(oldNode, newNode)) {
        // Update parent node attributes
        updateNodeAttr(oldNode, newNode, ATTR_CLASS);
        updateNodeAttr(oldNode, newNode, ATTR_UID);

        // Replace children
        var children = oldNode.children();
        if (children.length == 0) {
            oldNode.replaceWith(newNode);
        } else {
            var newChildren = newNode.children();
            newChildren.each(function(i) {
                var newChild = newChildren.eq(i);
                var newChildClass = newChild.attr(ATTR_CLASS);

                // Update only certain allowed blocks (e.g. not images)
                if (ALLOWED_FOR_PARTIAL_UPDATE.indexOf(newChildClass) > -1) {
                    var oldChild = oldNode.children('.' + newChildClass);

                    if (oldChild.length == 0) {
                        oldNode.append(newChild);
                    } else {
                        if (!equalNodes(oldChild, newChild)) {
                            if (recursive) {
                                replacePartial(oldChild, newChild, false);
                            } else {
                                oldChild.replaceWith(newChild);
                            }
                        }
                    }
                }
            });
        }
    }
}

/**
 * Compare nodes by content
 */
function equalNodes(node1, node2) {
    return node1[0].outerHTML == node2[0].outerHTML;
}

/**
 * Update attribute of a node if it has changed
 */
function updateNodeAttr(oldNode, newNode, attrName) {
    var oldAttr = oldNode.attr(attrName);
    var newAttr = newNode.attr(attrName);
    if (oldAttr != newAttr) {
        oldNode.attr(attrName, newAttr);
    }
}

$(document).ready(function() {
    if (initAutoupdate()) {
        // Post form data over AJAX
        var threadId = $('div.thread').children('.post').first().attr('id');

        var form = $('#form');

        if (form.length > 0) {
            var options = {
                beforeSubmit: function(arr, form, options) {
                    $('.post-form-w').block({ message: gettext('Sending message...') });
                },
                success: updateOnPost,
                error: function(xhr, textStatus, errorString) {
                    var errorText = gettext('Server error: ') + textStatus;
                    if (errorString) {
                        errorText += ' / ' + errorString;
                    }
                    showAsErrors(form, errorText);
                    $('.post-form-w').unblock();
                },
                url: '/api/add_post/' + threadId + '/',
                timeout: POST_AJAX_TIMEOUT
            };

            form.ajaxForm(options);

            resetForm();
        }
    }
});