FileSaver-eligrey

一个允许在客户端保存文件的解决方案

Questo script non dovrebbe essere installato direttamente. È una libreria per altri script da includere con la chiave // @require https://update.greasyfork.org/scripts/450828/1090308/FileSaver-eligrey.js 

function enableSaveAs() {

    /*
    * FileSaver.js
    * A saveAs() FileSaver implementation.
    *
    * By Eli Grey, http://eligrey.com
    *
    * License : https://github.com/eligrey/FileSaver.js/blob/master/LICENSE.md (MIT)
    * source  : http://purl.eligrey.com/github/FileSaver.js
    */

    // The one and only way of getting global scope in all environments
    // https://stackoverflow.com/q/3277182/1008999
    var _global = typeof window === 'object' && window.window === window
        ? window : typeof self === 'object' && self.self === self
            ? self : typeof global === 'object' && global.global === global
                ? global
                : this

    function bom(blob, opts) {
        if (typeof opts === 'undefined') opts = { autoBom: false }
        else if (typeof opts !== 'object') {
            console.warn('Deprecated: Expected third argument to be a object')
            opts = { autoBom: !opts }
        }

        // prepend BOM for UTF-8 XML and text/* types (including HTML)
        // note: your browser will automatically convert UTF-16 U+FEFF to EF BB BF
        if (opts.autoBom && /^\s*(?:text\/\S*|application\/xml|\S*\/\S*\+xml)\s*;.*charset\s*=\s*utf-8/i.test(blob.type)) {
            return new Blob([String.fromCharCode(0xFEFF), blob], { type: blob.type })
        }
        return blob
    }

    function download(url, name, opts) {
        var xhr = new XMLHttpRequest()
        xhr.open('GET', url)
        xhr.responseType = 'blob'
        xhr.onload = function () {
            saveAs(xhr.response, name, opts)
        }
        xhr.onerror = function () {
            console.error('could not download file')
        }
        xhr.send()
    }

    function corsEnabled(url) {
        var xhr = new XMLHttpRequest()
        // use sync to avoid popup blocker
        xhr.open('HEAD', url, false)
        try {
            xhr.send()
        } catch (e) { }
        return xhr.status >= 200 && xhr.status <= 299
    }

    // `a.click()` doesn't work for all browsers (#465)
    function click(node) {
        try {
            node.dispatchEvent(new MouseEvent('click'))
        } catch (e) {
            var evt = document.createEvent('MouseEvents')
            evt.initMouseEvent('click', true, true, window, 0, 0, 0, 80,
                20, false, false, false, false, 0, null)
            node.dispatchEvent(evt)
        }
    }

    // Detect WebView inside a native macOS app by ruling out all browsers
    // We just need to check for 'Safari' because all other browsers (besides Firefox) include that too
    // https://www.whatismybrowser.com/guides/the-latest-user-agent/macos
    var isMacOSWebView = _global.navigator && /Macintosh/.test(navigator.userAgent) && /AppleWebKit/.test(navigator.userAgent) && !/Safari/.test(navigator.userAgent)

    var saveAs = _global.saveAs || (
        // probably in some web worker
        (typeof window !== 'object' || window !== _global)
            ? function saveAs() { /* noop */ }

            // Use download attribute first if possible (#193 Lumia mobile) unless this is a macOS WebView
            : ('download' in HTMLAnchorElement.prototype && !isMacOSWebView)
                ? function saveAs(blob, name, opts) {
                    var URL = _global.URL || _global.webkitURL
                    // Namespace is used to prevent conflict w/ Chrome Poper Blocker extension (Issue #561)
                    var a = document.createElementNS('http://www.w3.org/1999/xhtml', 'a')
                    name = name || blob.name || 'download'

                    a.download = name
                    a.rel = 'noopener' // tabnabbing

                    // TODO: detect chrome extensions & packaged apps
                    // a.target = '_blank'

                    if (typeof blob === 'string') {
                        // Support regular links
                        a.href = blob
                        if (a.origin !== location.origin) {
                            corsEnabled(a.href)
                                ? download(blob, name, opts)
                                : click(a, a.target = '_blank')
                        } else {
                            click(a)
                        }
                    } else {
                        // Support blobs
                        a.href = URL.createObjectURL(blob)
                        setTimeout(function () { URL.revokeObjectURL(a.href) }, 4E4) // 40s
                        setTimeout(function () { click(a) }, 0)
                    }
                }

                // Use msSaveOrOpenBlob as a second approach
                : 'msSaveOrOpenBlob' in navigator
                    ? function saveAs(blob, name, opts) {
                        name = name || blob.name || 'download'

                        if (typeof blob === 'string') {
                            if (corsEnabled(blob)) {
                                download(blob, name, opts)
                            } else {
                                var a = document.createElement('a')
                                a.href = blob
                                a.target = '_blank'
                                setTimeout(function () { click(a) })
                            }
                        } else {
                            navigator.msSaveOrOpenBlob(bom(blob, opts), name)
                        }
                    }

                    // Fallback to using FileReader and a popup
                    : function saveAs(blob, name, opts, popup) {
                        // Open a popup immediately do go around popup blocker
                        // Mostly only available on user interaction and the fileReader is async so...
                        popup = popup || open('', '_blank')
                        if (popup) {
                            popup.document.title =
                                popup.document.body.innerText = 'downloading...'
                        }

                        if (typeof blob === 'string') return download(blob, name, opts)

                        var force = blob.type === 'application/octet-stream'
                        var isSafari = /constructor/i.test(_global.HTMLElement) || _global.safari
                        var isChromeIOS = /CriOS\/[\d]+/.test(navigator.userAgent)

                        if ((isChromeIOS || (force && isSafari) || isMacOSWebView) && typeof FileReader !== 'undefined') {
                            // Safari doesn't allow downloading of blob URLs
                            var reader = new FileReader()
                            reader.onloadend = function () {
                                var url = reader.result
                                url = isChromeIOS ? url : url.replace(/^data:[^;]*;/, 'data:attachment/file;')
                                if (popup) popup.location.href = url
                                else location = url
                                popup = null // reverse-tabnabbing #460
                            }
                            reader.readAsDataURL(blob)
                        } else {
                            var URL = _global.URL || _global.webkitURL
                            var url = URL.createObjectURL(blob)
                            if (popup) popup.location = url
                            else location.href = url
                            popup = null // reverse-tabnabbing #460
                            setTimeout(function () { URL.revokeObjectURL(url) }, 4E4) // 40s
                        }
                    }
    )

    _global.saveAs = saveAs.saveAs = saveAs

    if (typeof module !== 'undefined') {
        module.exports = saveAs;
    }
}