Google DWIMages

Direct links to images and pages on Google Images
当前为 2020-02-19 提交的版本，查看最新版本。
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// ==UserScript==
// @name          Google DWIMages
// @description   Direct links to images and pages on Google Images
// @author        chocolateboy
// @copyright     chocolateboy
// @version       2.0.0
// @namespace     https://github.com/chocolateboy/userscripts
// @license       GPL: http://www.gnu.org/copyleft/gpl.html
// @include       https://www.google.tld/*tbm=isch*
// @include       https://encrypted.google.tld/*tbm=isch*
// @require       https://code.jquery.com/jquery-3.4.1.min.js
// @require       https://cdn.jsdelivr.net/gh/eclecto/jQuery-onMutate@79bbb2b8caccabfc9b9ade046fe63f15f593fef6/src/jquery.onmutate.min.js
// @grant         GM_log
// @inject-into   content
// ==/UserScript==

// XXX note: the unused grant is a workaround for a Greasemonkey bug:
// https://github.com/greasemonkey/greasemonkey/issues/1614

let INITIALIZED = false, METADATA

// return the image metadata subtree (array) of the full metadata tree
function imageMetadata (tree) {
    return tree[31][0][12][2]
}

// register the listener for metadata requests and parse the data for the first ≈
// 100 images out of the SCRIPT element embedded in the page
function init () {
    window.XMLHttpRequest.prototype.open = hookXHROpen(window.XMLHttpRequest.prototype.open)

    const scripts = Array.from(document.scripts)
    const callbacks = scripts.filter(script => /^AF_initDataCallback\b/.test(script.text))

    try {
        const callback = callbacks.pop().text
        METADATA = imageMetadata(parseMetadata(callback))
    } finally {
        INITIALIZED = true
    }
}

// determine whether an XHR request is for another batch of image metadata
function isImageDataRequest (args) {
    return (args.length >= 2)
        && (args[0] === 'POST')
        && /\/batchexecute\?rpcids=/.test(String(args[1]))
}

// return the URL for the nth image (0-based)
function nthImageUrl (index) {
    return METADATA[index][1][3][0]
}

// return a version of XmlHttpRequest#open which checks for and intercepts image
// metadata requests before delegating to the original method
//
// if the URL matches, we append the new metadata to a global store
function hookXHROpen (oldOpen) {
    return function open (...args) {
        if (isImageDataRequest(args)) {
            this.addEventListener('load', () => {
                let parsed

                try {
                    const stringified = this.responseText.match(/("\[[\s\S]+\](?:\\n)?")/)[1]
                    const json = JSON.parse(stringified)
                    parsed = JSON.parse(json)
                } catch (e) {
                    console.error("Can't parse response:", e)
                    return
                }

                try {
                    METADATA = METADATA.concat(imageMetadata(parsed))

                    // run once against the new images
                    $.onCreate('div[data-ri][data-ved][jsaction]', onResults)
                } catch (e) {
                    console.error("Can't merge new metadata:", e)
                }
            })
        }

        return oldOpen.apply(this, args)
    }
}

// process a new batch of results (DIVs), assigning the image URL to the first
// link and disabling trackers
//
// used to process the original batch of results as well as the lazily-loaded
// updates
function onResults ($results) {
    $results.each(function () {
        if (!INITIALIZED) {
            try {
                init()
            } catch (e) {
                console.error("Can't parse metadata:", e)
                return false // i.e. break out of the +each+ loop
            }
        }

        if (!METADATA) {
            return false // break
        }

        // grab the metadata for this result
        const $result = $(this)
        const index = $result.data('ri') // 0-based index of the result

        let imageUrl

        try {
            imageUrl = nthImageUrl(index)
        } catch (e) {
            console.warn(`Can't find image URL for image #${index + 1}`)
            return // continue
        }

        // prevent new trackers being registered on this DIV and its descendant
        // elements
        $result.find('*').addBack().removeAttr('jsaction')

        // assign the correct/missing URI to the image link
        const $links = $result.find('a')
        const $imageLink = $links.eq(0)
        const $pageLink = $links.eq(1)

        $imageLink.attr('href', imageUrl)

        // pre-empt the existing trackers on elements which don't already have
        // direct listeners (the result element and the image link)
        $result.on('click focus mousedown', stopPropagation)
        $imageLink.on('click focus mousedown', stopPropagation)

        // and blast the trackers off the element which does (the page link)
        $pageLink.replaceWith($pageLink.clone())
    })
}

// extract the image metadata for the original batch of results from the
// contents of the SCRIPT tag
function parseMetadata (fragment) {
    // XXX not all browsers support the ES2018 /s (matchAll) flag
    // const json = callback.match(/(\[.+\])/s)[1]
    const json = fragment.match(/(\[[\s\S]+\])/)[1]
    return JSON.parse(json)
}

// event handler for images links, page links and results which prevents their
// click/mousedown events being hijacked for tracking
function stopPropagation (e) {
    e.stopPropagation()
}

$.onCreate('div[data-ri][data-ved]', onResults) // run once against the initial images