Andrey Borisko 建议使用磁盘缓存来检索资源。我的方案效率不高,但是你不需要解压文本文件。
在向resource.received 事件处理程序注册资源后,我使用 XMLHttpRequest 检索所有资源。然后我将资源过滤为图像、css 和字体。当前的限制是无法正确处理包含 ../ 或 ./ 之类的远程资源路径。
我使用getHTML 检索当前页面内容并遍历所有捕获的资源以用随机生成的文件名替换标记中使用的路径,该路径由完整资源 URL 的一部分标识。文件扩展名是根据资源的内容类型创建的。它是使用mimeType from this gist 转换的。
由于 CSS 文件可能包含背景图像或字体,因此必须在保存到磁盘之前对其进行处理。提供的loadResource 函数加载资源,但不保存。
由于使用 XMLHttpRequest 下载资源,必须使用 --web-security=false 标志调用脚本:
casperjs script.js --web-security=false
script.js
var casper = require("casper").create();
var utils = require('utils');
var fs = require('fs');
var mimetype = require('./mimetype'); // URL provided below
var cssResources = [];
var imgResources = [];
var fontResources = [];
var resourceDirectory = "resources";
var debug = false;
fs.removeTree(resourceDirectory);
casper.on("remote.message", function(msg){
this.echo("remote.msg: " + msg);
});
casper.on("resource.error", function(resourceError){
this.echo("res.err: " + JSON.stringify(resourceError));
});
casper.on("page.error", function(pageError){
this.echo("page.err: " + JSON.stringify(pageError));
});
casper.on("downloaded.file", function(targetPath){
if (debug) this.echo("dl.file: " + targetPath);
});
casper.on("resource.received", function(resource){
// don't try to download data:* URI and only use stage == "end"
if (resource.url.indexOf("data:") != 0 && resource.stage == "end") {
if (resource.contentType == "text/css") {
cssResources.push({obj: resource, file: false});
}
if (resource.contentType.indexOf("image/") == 0) {
imgResources.push({obj: resource, file: false});
}
if (resource.contentType.indexOf("application/x-font-") == 0) {
fontResources.push({obj: resource, file: false});
}
}
});
// based on http://docs.casperjs.org/en/latest/modules/casper.html#download
casper.loadResource = function loadResource(url, method, data) {
"use strict";
this.checkStarted();
var cu = require('clientutils').create(utils.mergeObjects({}, this.options));
return cu.decode(this.base64encode(url, method, data));
};
function escapeRegExp(string) {
// from https://stackoverflow.com/a/1144788/1816580
return string.replace(/([.*+?^=!:${}()|\[\]\/\\])/g, "\\$1");
}
function replaceAll(find, replace, str) {
// from https://stackoverflow.com/a/1144788/1816580
return str.replace(find, replace);
}
var wrapFunctions = [
function wrapQuot1(s){
return '"' + s + '"';
},
function wrapQuot2(s){
return "'" + s + "'";
},
function csswrap(s){
return '(' + s + ')';
}
];
function findAndReplace(doc, resources, resourcesReplacer) {
// change page on the fly
resources.forEach(function(resource){
var url = resource.obj.url;
// don't download again
if (!resource.file) {
// set random filename and download it **or** call further processing which in turn will load ans write to disk
resource.file = resourceDirectory+"/"+Math.random().toString(36).slice(2)+"."+mimetype.ext[resource.obj.contentType];
if (typeof resourcesReplacer != "function") {
if (debug) casper.echo("download resource (" + resource.obj.contentType + "): " + url + " to " + resource.file);
casper.download(url, resource.file, "GET");
} else {
resourcesReplacer(resource);
}
}
wrapFunctions.forEach(function(wrap){
// test the resource url (growing from the back) with a string in the document
var lastURL;
var lastRegExp;
var subURL;
// min length is 4 characters
for(var i = 0; i < url.length-5; i++) {
subURL = url.substring(i);
lastRegExp = new RegExp(escapeRegExp(wrap(subURL)), "g");
if (doc.match(lastRegExp)) {
lastURL = subURL;
break;
}
}
if (lastURL) {
if (debug) casper.echo("replace " + lastURL + " with " + resource.file);
doc = replaceAll(lastRegExp, wrap(resource.file), doc);
}
});
});
return doc;
}
function capturePage(){
// remove all <script> and <base> tags
this.evaluate(function(){
Array.prototype.forEach.call(document.querySelectorAll("script"), function(scr){
scr.parentNode.removeChild(scr);
});
Array.prototype.forEach.call(document.querySelectorAll("base"), function(scr){
scr.parentNode.removeChild(scr);
});
});
// TODO: remove all event handlers in html
var page = this.getHTML();
page = findAndReplace(page, imgResources);
page = findAndReplace(page, cssResources, function(cssResource){
var css = casper.loadResource(cssResource.obj.url, "GET");
css = findAndReplace(css, imgResources);
css = findAndReplace(css, fontResources);
fs.write(cssResource.file, css, "wb");
});
fs.write("page.html", page, "wb");
}
casper.start("http://www.themarysue.com/").wait(3000).then(capturePage).run(function(){
this.echo("DONE");
this.exit();
});
奇迹发生在findAndReplace。 capturePage 是完全同步的,因此可以在任何地方放下它而不会感到头疼。
mimetype.js 的网址