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我正在开发一个网络爬虫应用程序。当我运行该程序时,我收到以下错误消息:
运行程序超过 3 小时后,我遇到了这些错误。我尝试通过将 eclipse.ini 设置更改为 2048 MB ram 来分配内存,如 this topic 中所述。但 3 小时或更短时间后仍然出现相同的错误。我应该不间断地运行该程序 2-3 天以上才能分析结果。
你能告诉我我在这里缺少什么才能得到下面的这些错误吗?
这些是我的类(class):
seeds.txt
http://www.stanford.edu
http://www.archive.org
WebCrawler.java
package pkg.crawler;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.MalformedURLException;
import java.net.SocketTimeoutException;
import java.util.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.PriorityBlockingQueue;
import java.util.concurrent.TimeUnit;
import org.jsoup.HttpStatusException;
import org.jsoup.UnsupportedMimeTypeException;
import org.joda.time.DateTime;
public class WebCrawler {
public static Queue <LinkNodeLight> queue = new PriorityBlockingQueue <> (); // priority queue
public static final int n_threads = 5; // amount of threads
private static Set<String> processed = new LinkedHashSet <> (); // set of processed urls
private PrintWriter out; // output file
private PrintWriter err; // error file
private static Integer cntIntra = new Integer (0); // counters for intra- links in the queue
private static Integer cntInter = new Integer (0); // counters for inter- links in the queue
private static Integer dub = new Integer (0); // amount of skipped urls
public static void main(String[] args) throws Exception {
System.out.println("Running web crawler: " + new Date());
WebCrawler webCrawler = new WebCrawler();
webCrawler.createFiles();
try (Scanner in = new Scanner(new File ("seeds.txt"))) {
while (in.hasNext()) {
webCrawler.enque(new LinkNode (in.nextLine().trim()));
}
} catch (IOException e) {
e.printStackTrace();
return;
}
webCrawler.processQueue();
webCrawler.out.close();
webCrawler.err.close();
}
public void processQueue(){
/* run in threads */
Runnable r = new Runnable() {
@Override
public void run() {
/* queue may be empty but process is not finished, that's why we need to check if any links are being processed */
while (true) {
LinkNode link = deque();
if (link == null)
continue;
link.setStartTime(new DateTime());
boolean process = processLink(link);
link.setEndTime(new DateTime());
if (!process)
continue;
/* print the data to the csv file */
if (link.getStatus() != null && link.getStatus().equals(LinkNodeStatus.OK)) {
synchronized(out) {
out.println(getOutputLine(link));
out.flush();
}
} else {
synchronized(err) {
err.println(getOutputLine(link));
err.flush();
}
}
}
}
};
/* run n_threads threads which perform dequeue and process */
LinkedList <Thread> threads = new LinkedList <> ();
for (int i = 0; i < n_threads; i++) {
threads.add(new Thread(r));
threads.getLast().start();
}
for (Thread thread : threads) {
try {
thread.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
/* returns true if link was actually processed */
private boolean processLink(LinkNode inputLink) {
String url = getUrlGeneralForm(inputLink);
boolean process = true;
synchronized (processed) {
if (processed.contains(url)) {
process = false;
synchronized (dub) {dub++;}
} else
processed.add(url);
}
/* start processing only if the url have not been processed yet or not being processed */
if (process) {
System.out.println("Processing url " + url);
List<LinkNodeLight> outputLinks = parseAndWieghtResults(inputLink);
for (LinkNodeLight outputLink : outputLinks) {
String getUrlGeneralForumOutput = getUrlGeneralForm(outputLink);
/* add the new link to the queue only if it has not been processed yet */
process = true;
synchronized (processed) {
if (processed.contains(getUrlGeneralForumOutput)) {
process = false;
synchronized (dub) {dub++;}
}
}
if (process) {
enque(outputLink);
}
}
return true;
}
return false;
}
void enque(LinkNodeLight link){
link.setEnqueTime(new DateTime());
/* the add method requires implicit priority */
synchronized (queue) {
if (link.interLinks)
synchronized (cntInter) {cntInter++;}
else
synchronized (cntIntra) {cntIntra++;}
//queue.add(link, 100 - (int)(link.getWeight() * 100.f));
queue.add(link);
}
}
/**
* Picks an element from the queue
* @return top element from the queue or null if the queue is empty
*/
LinkNode deque(){
/* link must be checked */
LinkNode link = null;
synchronized (queue) {
link = (LinkNode) queue.poll();
if (link != null) {
link.setDequeTime(new DateTime());
if (link.isInterLinks())
synchronized (cntInter) {cntInter--;}
else
synchronized (cntIntra) {cntIntra--;}
}
}
return link;
}
private void createFiles() {
/* create output file */
try {
out = new PrintWriter(new BufferedWriter(new FileWriter("CrawledURLS.csv", false)));
out.println(generateHeaderFile());
} catch (IOException e) {
System.err.println(e);
}
/* create error file */
try {
err = new PrintWriter(new BufferedWriter(new FileWriter("CrawledURLSERROR.csv", false)));
err.println(generateHeaderFile());
} catch (IOException e) {
System.err.println(e);
}
}
/**
* formats the string so it can be valid entry in csv file
* @param s
* @return
*/
private static String format(String s) {
// replace " by ""
String ret = s.replaceAll("\"", "\"\"");
// put string into quotes
return "\"" + ret + "\"";
}
/**
* Creates the line that needs to be written in the outputfile
* @param link
* @return
*/
public static String getOutputLine(LinkNode link){
StringBuilder builder = new StringBuilder();
builder.append(link.getParentLink()!=null ? format(link.getParentLink().getUrl()) : "");
builder.append(",");
builder.append(link.getParentLink()!=null ? link.getParentLink().getIpAdress() : "");
builder.append(",");
builder.append(link.getParentLink()!=null ? link.getParentLink().linkProcessingDuration() : "");
builder.append(",");
builder.append(format(link.getUrl()));
builder.append(",");
builder.append(link.getDomain());
builder.append(",");
builder.append(link.isInterLinks());
builder.append(",");
builder.append(Util.formatDate(link.getEnqueTime()));
builder.append(",");
builder.append(Util.formatDate(link.getDequeTime()));
builder.append(",");
builder.append(link.waitingInQueue());
builder.append(",");
builder.append(queue.size());
/* Inter and intra links in queue */
builder.append(",");
builder.append(cntIntra.toString());
builder.append(",");
builder.append(cntInter.toString());
builder.append(",");
builder.append(dub);
builder.append(",");
builder.append(new Date ());
/* URL size*/
builder.append(",");
builder.append(link.getSize());
/* HTML file
builder.append(",");
builder.append(link.getFileName());*/
/* add HTTP error */
builder.append(",");
if (link.getParseException() != null) {
if (link.getParseException() instanceof HttpStatusException)
builder.append(((HttpStatusException) link.getParseException()).getStatusCode());
if (link.getParseException() instanceof SocketTimeoutException)
builder.append("Time out");
if (link.getParseException() instanceof MalformedURLException)
builder.append("URL is not valid");
if (link.getParseException() instanceof UnsupportedMimeTypeException)
builder.append("Unsupported mime type: " + ((UnsupportedMimeTypeException)link.getParseException()).getMimeType());
}
return builder.toString();
}
/**
* generates the Header for the file
* @param link
* @return
*/
private String generateHeaderFile(){
StringBuilder builder = new StringBuilder();
builder.append("Seed URL");
builder.append(",");
builder.append("Seed IP");
builder.append(",");
builder.append("Process Duration");
builder.append(",");
builder.append("Link URL");
builder.append(",");
builder.append("Link domain");
builder.append(",");
builder.append("Link IP");
builder.append(",");
builder.append("Enque Time");
builder.append(",");
builder.append("Deque Time");
builder.append(",");
builder.append("Waiting in the Queue");
builder.append(",");
builder.append("QueueSize");
builder.append(",");
builder.append("Intra in queue");
builder.append(",");
builder.append("Inter in queue");
builder.append(",");
builder.append("Dublications skipped");
/* time was printed, but no header was */
builder.append(",");
builder.append("Time");
/* URL size*/
builder.append(",");
builder.append("Size bytes");
/* HTTP errors */
builder.append(",");
builder.append("HTTP error");
return builder.toString();
}
String getUrlGeneralForm(LinkNodeLight link){
String url = link.getUrl();
if (url.endsWith("/")){
url = url.substring(0, url.length() - 1);
}
return url;
}
private List<LinkNodeLight> parseAndWieghtResults(LinkNode inputLink) {
List<LinkNodeLight> outputLinks = HTMLParser.parse(inputLink);
if (inputLink.hasParseException()) {
return outputLinks;
} else {
return URLWeight.weight(inputLink, outputLinks);
}
}
}
HTMLParser.java
package pkg.crawler;
import org.jsoup.Connection;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.Writer;
import java.math.BigInteger;
import java.util.Formatter;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.TimeUnit;
import java.util.logging.Logger;
import java.security.*;
import java.nio.file.Path;
import java.nio.file.Paths;
public class HTMLParser {
private static final int READ_TIMEOUT_IN_MILLISSECS = (int) TimeUnit.MILLISECONDS.convert(30, TimeUnit.SECONDS);
private static HashMap <String, Integer> filecounter = new HashMap<> ();
public static List<LinkNodeLight> parse(LinkNode inputLink){
List<LinkNodeLight> outputLinks = new LinkedList<>();
try {
inputLink.setIpAdress(IpFromUrl.getIp(inputLink.getUrl()));
String url = inputLink.getUrl();
if (inputLink.getIpAdress() != null) {
url.replace(URLWeight.getHostName(url), inputLink.getIpAdress());
}
Document parsedResults = Jsoup
.connect(url)
.timeout(READ_TIMEOUT_IN_MILLISSECS)
.get();
inputLink.setSize(parsedResults.html().length());
/* IP address moved here in order to speed up the process */
inputLink.setStatus(LinkNodeStatus.OK);
inputLink.setDomain(URLWeight.getDomainName(inputLink.getUrl()));
if (true) {
/* save the file to the html */
String filename = parsedResults.title();//digestBig.toString(16) + ".html";
if (filename.length() > 24) {
filename = filename.substring(0, 24);
}
filename = filename.replaceAll("[^\\w\\d\\s]", "").trim();
filename = filename.replaceAll("\\s+", " ");
if (!filecounter.containsKey(filename)) {
filecounter.put(filename, 1);
} else {
Integer tmp = filecounter.remove(filename);
filecounter.put(filename, tmp + 1);
}
filename = filename + "-" + (filecounter.get(filename)).toString() + ".html";
filename = Paths.get("downloads", filename).toString();
inputLink.setFileName(filename);
/* use md5 of url as file name */
try (PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(filename)))) {
out.println("<!--" + inputLink.getUrl() + "-->");
out.print(parsedResults.html());
out.flush();
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
String tag;
Elements tagElements;
List<LinkNode> result;
tag = "a[href";
tagElements = parsedResults.select(tag);
result = toLinkNodeObject(inputLink, tagElements, tag);
outputLinks.addAll(result);
tag = "area[href";
tagElements = parsedResults.select(tag);
result = toLinkNodeObject(inputLink, tagElements, tag);
outputLinks.addAll(result);
} catch (IOException e) {
inputLink.setParseException(e);
inputLink.setStatus(LinkNodeStatus.ERROR);
}
return outputLinks;
}
static List<LinkNode> toLinkNodeObject(LinkNode parentLink, Elements tagElements, String tag) {
List<LinkNode> links = new LinkedList<>();
for (Element element : tagElements) {
if(isFragmentRef(element)){
continue;
}
String absoluteRef = String.format("abs:%s", tag.contains("[") ? tag.substring(tag.indexOf("[") + 1, tag.length()) : "href");
String url = element.attr(absoluteRef);
if(url!=null && url.trim().length()>0) {
LinkNode link = new LinkNode(url);
link.setTag(element.tagName());
link.setParentLink(parentLink);
links.add(link);
}
}
return links;
}
static boolean isFragmentRef(Element element){
String href = element.attr("href");
return href!=null && (href.trim().startsWith("#") || href.startsWith("mailto:"));
}
}
Util.java
package pkg.crawler;
import java.util.Date;
import org.joda.time.DateTime;
import org.joda.time.format.DateTimeFormat;
import org.joda.time.format.DateTimeFormatter;
public class Util {
private static DateTimeFormatter formatter;
static {
formatter = DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ss:SSS");
}
public static String linkToString(LinkNode inputLink){
return String.format("%s\t%s\t%s\t%s\t%s\t%s",
inputLink.getUrl(),
inputLink.getWeight(),
formatDate(inputLink.getEnqueTime()),
formatDate(inputLink.getDequeTime()),
differenceInMilliSeconds(inputLink.getEnqueTime(), inputLink.getDequeTime()),
inputLink.getParentLink()==null?"":inputLink.getParentLink().getUrl()
);
}
public static String linkToErrorString(LinkNode inputLink){
return String.format("%s\t%s\t%s\t%s\t%s\t%s",
inputLink.getUrl(),
inputLink.getWeight(),
formatDate(inputLink.getEnqueTime()),
formatDate(inputLink.getDequeTime()),
inputLink.getParentLink()==null?"":inputLink.getParentLink().getUrl(),
inputLink.getParseException().getMessage()
);
}
public static String formatDate(DateTime date){
return formatter.print(date);
}
public static long differenceInMilliSeconds(DateTime dequeTime, DateTime enqueTime){
return (dequeTime.getMillis()- enqueTime.getMillis());
}
public static int differenceInSeconds(Date enqueTime, Date dequeTime){
return (int)((dequeTime.getTime()/1000) - (enqueTime.getTime()/1000));
}
public static int differenceInMinutes(Date enqueTime, Date dequeTime){
return (int)((dequeTime.getTime()/60000) - (enqueTime.getTime()/60000));
}
}
URLWeight.java
package pkg.crawler;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.regex.Pattern;
public class URLWeight {
public static List<LinkNodeLight> weight(LinkNode sourceLink, List<LinkNodeLight> links) {
List<LinkNodeLight> interLinks = new LinkedList<>();
List<LinkNodeLight> intraLinks = new LinkedList<>();
for (LinkNodeLight link : links) {
if (isIntraLink(sourceLink, link)) {
intraLinks.add(link);
link.setInterLinks(false);
} else {
interLinks.add(link);
link.setInterLinks(true);
}
}
static boolean isIntraLink(LinkNodeLight sourceLink, LinkNodeLight link){
String parentDomainName = getHostName(sourceLink.getUrl());
String childDomainName = getHostName(link.getUrl());
return parentDomainName.equalsIgnoreCase(childDomainName);
}
public static String getHostName(String url) {
if(url == null){
// System.out.println("Deneme");
return "";
}
String domainName = new String(url);
int index = domainName.indexOf("://");
if (index != -1) {
domainName = domainName.substring(index + 3);
}
for (int i = 0; i < domainName.length(); i++)
if (domainName.charAt(i) == '?' || domainName.charAt(i) == '/') {
domainName = domainName.substring(0, i);
break;
}
/*if (index != -1) {
domainName = domainName.substring(0, index);
}*/
/* have to keep www in order to do replacements with IP */
//domainName = domainName.replaceFirst("^www.*?\\.", "");
return domainName;
}
public static String getDomainName(String url) {
String [] tmp= getHostName(url).split("\\.");
if (tmp.length == 0)
return "";
return tmp[tmp.length - 1];
}
}
PingTaskManager.java
package pkg.crawler;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class PingTaskManager {
private static ExecutorService executor = Executors.newFixedThreadPool(100);
public static void ping (LinkNode e) {
executor.submit(new PingTaks(e));
}
}
class PingTaks implements Runnable {
private LinkNode link;
public PingTaks( LinkNode link ) {
}
@Override
public void run() {
/* link.ping(); */
}
}
LinkNodeStatus.java
package pkg.crawler;
public enum LinkNodeStatus {
OK,
ERROR
}
LinkNodeLight.java
package pkg.crawler;
import org.joda.time.DateTime;
public class LinkNodeLight implements Comparable<LinkNodeLight> {
protected String url;
protected float weight;
protected DateTime enqueTime;
protected boolean interLinks;
public String getUrl() {
return url;
}
public float getWeight() {
return weight;
}
public void setWeight(float weight) {
this.weight = weight;
}
public DateTime getEnqueTime() {
return enqueTime;
}
public LinkNodeLight(String url) {
this.url = url;
}
public void setEnqueTime(DateTime enqueTime) {
this.enqueTime = enqueTime;
}
@Override
public int compareTo(LinkNodeLight link) {
if (this.weight < link.weight) return 1;
else if (this.weight > link.weight) return -1;
return 0;
}
}
LinkNode.java
package pkg.crawler;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.Socket;
import java.net.URL;
import java.net.UnknownHostException;
import java.util.Date;
import org.joda.time.DateTime;
public class LinkNode extends LinkNodeLight{
public LinkNode(String url) {
super(url);
}
private String tag;
private LinkNode parentLink;
private IOException parseException = null; // initialize parse Exception with null
private float weight;
private DateTime dequeTime;
private DateTime startTime;
private DateTime endTime;
private LinkNodeStatus status;
private String ipAdress;
private int size;
private String filename;
private String domain;
public DateTime getStartTime() {
return startTime;
}
public void setStartTime(DateTime startTime) {
this.startTime = startTime;
}
public DateTime getEndTime() {
return endTime;
}
public void setEndTime(DateTime endTime) {
this.endTime = endTime;
}
public DateTime getDequeTime() {
return dequeTime;
}
public String getTag() {
return tag;
}
public LinkNode getParentLink() {
return parentLink;
}
public Exception getParseException() {
return parseException;
}
public boolean hasParseException(){
return parseException!=null;
}
public void setDequeTime(DateTime dequeTime) {
this.dequeTime = dequeTime;
}
public void setTag(String tag) {
this.tag = tag;
}
public void setParentLink(LinkNode parentLink) {
this.parentLink = parentLink;
}
public void setParseException(IOException parseException) {
this.parseException = parseException;
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
LinkNode link = (LinkNode) o;
if (url != null ? !url.equals(link.url) : link.url != null) {
return false;
}
return true;
}
@Override
public int hashCode() {
return url != null ? url.hashCode() : 0;
}
public long waitingInQueue(){
return Util.differenceInMilliSeconds( dequeTime,enqueTime );
}
public long linkProcessingDuration(){
return Util.differenceInMilliSeconds( endTime,startTime );
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder("LinkNode{");
sb.append("url='").append(url).append('\'');
sb.append(", score=").append(weight);
sb.append(", enqueTime=").append(enqueTime);
sb.append(", dequeTime=").append(dequeTime);
sb.append(", tag=").append(tag);
if(parentLink!=null) {
sb.append(", parentLink=").append(parentLink.getUrl());
}
sb.append('}');
return sb.toString();
}
public void setStatus(LinkNodeStatus status) {
this.status = status;
}
public LinkNodeStatus getStatus(){
if (status == null) {
status = LinkNodeStatus.ERROR;
}
return status;
}
// check server link is it exist or not
/* this method gives fake errors
public LinkNodeStatus ping () {
boolean reachable = false;
String sanitizeUrl = url.replaceFirst("^https", "http");
try {
HttpURLConnection connection = (HttpURLConnection) new URL(sanitizeUrl).openConnection();
connection.setConnectTimeout(1000);
connection.setRequestMethod("HEAD");
int responseCode = connection.getResponseCode();
System.err.println(url + " " + responseCode);
reachable = (200 <= responseCode && responseCode <= 399);
} catch (IOException exception) {
}
return reachable?LinkNodeStatus.OK: LinkNodeStatus.ERROR;
}*/
public String getIpAdress() {
return ipAdress;
}
public void setIpAdress(String ipAdress) {
this.ipAdress = ipAdress;
}
/* methods for controlling url size */
public void setSize(int size) {
this.size = size;
}
public int getSize() {
return this.size;
}
public void setFileName(String filename) {
this.filename = filename;
}
public String getFileName() {
return this.filename;
}
public String getDomain() {
return domain;
}
public void setDomain(String domain) {
this.domain = domain;
}
}
最佳答案
I tried to allocate memory by changing eclipse.ini setting to 2048 MB of ram as it was answered in this topic but still get the same errors after 3 hours or less.
我讨厌repeat myself (*),但是在eclipse.ini中你设置了Eclipse的内存,与你的爬虫的内存无关。
使用命令行时,需要通过java -Xmx2G pkg.crawler.WebCrawler
启动。
从 Eclipse 启动时,需要将 -Xmx2G
添加到运行配置(“VM 参数”而不是“程序参数”)。
(*) 链接到已删除的问题;需要一定的声誉才能查看。
关于java - 尝试在我的网络爬虫中运行几天时出现许多内存错误,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/30947742/
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我现在正在做一个元素。当您单击一个元素时,会出现以下信息,我想知道如何在您单击下一个元素而不重新单击同一元素时使其消失....例如,我的元素中有披萨,我想单击肉披萨看到浇头然后点击奶酪披萨看到浇头和肉
我有一个路由器模块,它将主题与正则表达式进行比较,并将出现的事件与一致的键掩码链接起来。 (它是一个简单的 url 路由过滤,如 symfony http://symfony.com/doc/curr
这个问题在这里已经有了答案: 9年前关闭。 Possible Duplicate: mysql_fetch_array() expects parameter 1 to be resource, bo
我在底部有一个带有工具栏的 View ,我正在使用 NavigationLink 导航到该 View 。但是当 View 出现时,工具栏显示得有点太低了。大约半秒钟后,它突然跳到位。它只会在应用程序启
我试图在我的应用程序上为背景音乐添加一个 AVAudioPlayer,我正在主屏幕上启动播放器,尝试在应用程序打开时开始播放但出现意外行为... 它播放并立即不断创建新玩家并播放这些玩家,因此同时播放
这是获取一个数字,获取其阶乘并将其加倍,但是由于基本情况,如果您输入 0,它会给出 2 作为答案,因此为了绕过它,我使用了 if 语句,但收到错误输入“if”时解析错误。如果你们能提供帮助,我真的很感
暂停期间抛出异常 android.os.DeadObjectException 在 android.os.BinderProxy.transactNative( native 方法) 在 androi
我已经为猜词游戏编写了一些代码。它从用户输入中读取字符并在单词中搜索该字符;根据字符是否在单词中,程序返回并控制一些变量。 代码如下: import java.util.Random; import
我是自动化领域的新手。这是我的简单 TestNG 登录代码,当我以 TestNG 身份运行该代码时,它会出现 java.lang.NullPointerException,双击它会突出显示我导航到 U
我是c#程序员,我习惯了c#的封装语法和其他东西。但是现在,由于某些原因,我应该用java写一些东西,我现在正在练习java一天!我要创建一个为我自己创建一个虚拟项目,以便让自己更熟悉 Java 的
我正在使用 Intellij,我的源类是 main.com.coding,我的资源文件是 main.com.testing。我将 spring.xml 文件放入资源文件中。 我的测试类位于 test.
我想要我的tests folder separate到我的应用程序代码。我的项目结构是这样的 myproject/ myproject/ myproject.py moduleon
这个问题已经有答案了: What is a NullPointerException, and how do I fix it? (12 个回答) 已关闭 6 年前。 因此,我尝试比较 2 个值,一个
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