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Cannot fix http response 403 in Java

Just trying to use a files direct download link to download it but I keep getting this error around 1/3 times I run it, the other 2 times it runs properly like its supposed to.
java.io.IOException: Server returned HTTP response code: 403 for URL:
This is my code
public static void copyUrlToFile(URL url, File destination) throws IOException {
HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
connection.addRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:10.0.2) Gecko/20100101 Firefox/10.0.2");
connection.connect();
FileUtils.copyInputStreamToFile(connection.getInputStream(), destination);
}```

Getting 503 error with HttpUrlConnection but site loading on browser

url = "https://www.lmcu.org/?__cf_chl_jschl_tk__=9c114404052361017d9cfe1247981e24813649c7-1592389426-0-AfP07ha5TxZHf64q5tb5nJf9BJguC4U553-OJzJWivTqfgwYLqUODkXj-XsOjZTwpC71ROxHWx4Xhdp2S0LgAVlKgXpy7KWOex7lkoGBm8mNpBsCeJapdYNWty-X2oHE6gp_TtMfH0dcBabvWr_mXV1djsVR_IGlYJA-wCuZpPTGOozyzN9TFwjMPxU-3o6BIUxTh6DDcHmJ_Bw48EYKGpq6n57bVdeLezEs9PduataW1JUcF4GqLE2EHiUxWGubtS8YgcxkkGin4zitHXENMbFi1kMhxI77LsORzKyhkAD1OkG8fGmV--Cgd3EpxWHtHD5vpoIFFIwX0uGQywPnegs";
HttpURLConnection connection = pingHttpUrl(url);
responseCode = connection.getResponseCode();
public HttpURLConnection pingHttpUrl(String url) throws IOException {
HttpURLConnection conn = null;
try {
conn = (HttpURLConnection) new URL(url).openConnection();
conn.setRequestMethod("GET");
conn.addRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76 Safari/537.36");
conn.setConnectTimeout(2000);
conn.setInstanceFollowRedirects(false);
conn.setReadTimeout(10000);
conn.connect();
Thread.sleep(1000);
} catch (Exception e) {
logger.error("Caught exception : {}", e.getMessage());
throw new IOException();
}
return conn;
}
This gives response code as 503. But the site is properly loading on browser. What can be the issue with this ?

The problem is with the headers of the request. I found that this solution hosted on cloudflare requires two headers to be just so, otherwise you will receive the 503 response:
User-Agent - Your header specified chrome version 76, apparently the server has a problem with this. I had success with this User-Agent value: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36
cookie - I found that the cookie value cf_clearance needs to be set, and possibly the other set-cookie values that are returned on the first request. This value has to do with the cloudflare support for privacy pass (https://blog.cloudflare.com/cloudflare-supports-privacy-pass/). It appears to be a means of verifying that a user is human, and not a machine. Which in turn is bad news for your efforts here.
I have a working solution below, but it will be hard to automate - since it will require you to establish a browser session, and use the cookie set there in the code. Upon expiration of the cf_clearance cookie, you will have visit the site again and reset the cookie value in the code.
I would also speculate that the User-Agent header of the request, is used in generating the cf_clearance cookie that is required. Making it more difficult to hijack the cookie, as you would have to use a matching User-Agent of the browser used for the request when the cf_clearance cookie was generated by cloudflare.
I have journaled my investigation here:
When visiting the URL in my browser:
https://www.lmcu.org/?cf_chl_jschl_tk=9c114404052361017d9cfe1247981e24813649c7-1592389426-0-AfP07ha5TxZHf64q5tb5nJf9BJguC4U553-OJzJWivTqfgwYLqUODkXj-XsOjZTwpC71ROxHWx4Xhdp2S0LgAVlKgXpy7KWOex7lkoGBm8mNpBsCeJapdYNWty-X2oHE6gp_TtMfH0dcBabvWr_mXV1djsVR_IGlYJA-wCuZpPTGOozyzN9TFwjMPxU-3o6BIUxTh6DDcHmJ_Bw48EYKGpq6n57bVdeLezEs9PduataW1JUcF4GqLE2EHiUxWGubtS8YgcxkkGin4zitHXENMbFi1kMhxI77LsORzKyhkAD1OkG8fGmV--Cgd3EpxWHtHD5vpoIFFIwX0uGQywPnegs
And inspecting the response that the server is giving, it turns out that it is infact giving back a 503 as well:
For some reson that I can't make out, the browser is redirected to the below URL instead. I cannot see that the location header is passed back in the response, or find this URL anywhere in the response.
https://www.lmcu.org/?cf_chl_jschl_tk=fe835fdc1e7e2f5b2857ab5eb4be84e67d0e8c42-1592506549-0-AQ3E1piNGHg7O7lxgRyItR1U5BzB52q7GmCHe_HPJBsUHv8RcZCgqLPPtyngPmDjvy7pZDprPNK6ihKVEgQ7HqmbDSPXZ1aHPkBDs9re49u_Q_jI04etmtK7E0GIdxhKWCd-p4TR7b_b0JdnwzJOF6z4XaJQOgNU8kazJr5Mo96zxQpUlsKWPSumEmSfynkGeMDgkM-O1mN59LKp0p4kt-2O2IIFrlc8289ZbCSO6JghtvDsLsFDA3VxLV3Irn2W3KQ8sHg_TdwB-0g0WX9J-WTwedVYzj2a7uNtH377ZIritTXKqRw1qeQ6mkpxQ0h_OVMIl8XUiEC0Zj1KP50tUK8
I checked with Postman, and sure enough - I got the 503 error there as well. As far as I could tell, the server (or reverse proxy in front of it) was inspecting the headers of the request, and invalidating the request based on them. I fooled around a little, moving headers from the browser request into Postman, and finally figured out that it is a combination of the cookie and User-Agent headers being set that allows the request to be served.
The User-Agent header is not allowed to have the specified chrome version, I have it working with version 83 here.
The cookkie header is something that the browser will populate from my first visit to the site in the browser. So that is a bit harder to handle in your code. I tried to fetch it in code with connection.getHeaderField("set-cookie") but that cookie does not seem to cut it.
But! I was able to make the code work, when taking the cookie from my browser, and setting it manually in code, along with the User-Agent:
public HttpURLConnection pingHttpUrl(String url) throws IOException {
HttpURLConnection conn = null;
try {
conn = (HttpURLConnection) new URL(url).openConnection();
conn.setRequestMethod("GET");
// This one does not work for the reason of the chrome version apparently
// conn.addRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76 Safari/537.36");
conn.addRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36");
conn.addRequestProperty("cookie", "<cookie value from the browser, from the header on a successful request>");
conn.setConnectTimeout(2000);
conn.setInstanceFollowRedirects(false);
conn.setReadTimeout(10000);
conn.connect();
Thread.sleep(1000);
} catch (Exception e) {
System.out.println(String.format("Caught exception : %s", e.getMessage()));
throw new IOException();
}
return conn;
}
I later found out that is is the cookie value from the cf_clearance key in the cookie that makes the difference.

copyURLToFile() throwing java.net.SocketException

When I run the following code:
try {
URL url = new URL("https://www1.nseindia.com/live_market/dynaContent/live_watch/get_quote/GetQuote.jsp?symbol=HUDCO&series=N2");
File f = new File("/Users/Vaibhav/Desktop/nseurltest.txt");
FileUtils.copyURLToFile(url, f);
} catch (Exception e) {
e.printStackTrace();
}
I get a java.net.SocketException: Operation timed out after about 30 seconds. Up to about a month ago, the same code was running without error. What could be the reason for this exception suddenly, and how can I fix it?
The objective of this code is to ultimately extract the latest market price of the HUDCO N2 bond from the .txt file the URL is copied into. If there is another simple way to extract the market price from the URL, I would love to hear.

I guess the website you try to reach, blocks unknown connections. But you can overcome this problem with jsoup library. With the following code, I've managed to download the content of the link.
Response response = Jsoup.connect(
"https://www1.nseindia.com/live_market/dynaContent/live_watch/get_quote/GetQuote.jsp?symbol=HUDCO&series=N2")
.ignoreContentType(true)
.userAgent(
"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36")
.referrer("http://www.google.com").timeout(30000).followRedirects(true).execute();
Document doc = response.parse();
JSOUP dependecy :
<!-- https://mvnrepository.com/artifact/org.jsoup/jsoup -->
<dependency>
<groupId>org.jsoup</groupId>
<artifactId>jsoup</artifactId>
<version>1.11.3</version>
</dependency>
You can change useragent. I put chrome 70 version's useragent string There are many options in the following link.
http://www.useragentstring.com/pages/useragentstring.php

Java ImageIO.read() crashes if url contains special characters

In my Java app, I want to download an image using the following:
ImageIO.read(new URL("https://www.example.com/example.png"))
It works fine most of the time, except for this url: https://cdn-images-1.medium.com/max/1200/1*XSCC_nLOSp1VJ6wXeANgCQ.png
The problem in the url is that there is an * in it. So I try the following workarounds, without any success:
replacing the * by \*
replacing the * by %2A
I always have the following error:
javax.imageio.IIOException: Can't get input stream from URL!
at javax.imageio.ImageIO.read(ImageIO.java:1395)
How can I download the image, then?
Thanks for your help.

The problem seems to be related to Java 8 and is fixed in Java 11. The problem with Java 8 is that a HTTP 403 code is returned.
Caused by: java.io.IOException: Server returned HTTP response code: 403 for URL: https://cdn-images-1.medium.com/max/1200/1*XSCC_nLOSp1VJ6wXeANgCQ.png
at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1894)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1492)
at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:263)
at java.net.URL.openStream(URL.java:1045)
at javax.imageio.ImageIO.read(ImageIO.java:1393)
To fix this we need to set the user agent header.
URL url = new URL("https://cdn-images-1.medium.com/max/1200/1*XSCC_nLOSp1VJ6wXeANgCQ.png");
URLConnection connection = url.openConnection();
connection.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.95 Safari/537.11");
connection.connect();
BufferedImage bufferedImage = ImageIO.read(connection.getInputStream());

How to handle 419 http response in Java

I am trying to parse through a particular website and am getting an HTTP response code of 419 when my java code calls it. I need to parse through the response to find content and I am stuck on the response code.
I have tried putting together a Java program using apache http client(version 4.5.6) to call a website that I need to parse. The http response code I get back is 419.
try (CloseableHttpClient httpclient = HttpClients.createDefault()) {
HttpGet httpGet = new HttpGet("http://www.website.com");
try (CloseableHttpResponse response1 = httpclient.execute(httpGet)) {
System.out.println(response1.getStatusLine());
HttpEntity entity1 = response1.getEntity();
EntityUtils.consume(entity1);
}
}
The result that it prints out is this:
HTTP/1.1 419 status code 419
I am expecting a 200
HTTP/1.1 200 OK
I get that when I change the website to google or other sites.

I was making a get request through HttpClient library as well as from POSTMAN and facing same 419 error. To solve this 419 error we need to add csrf token while making form submission.
However, In-case if you are still wondering how to find csrf token even when you are making a GET request and facing status 419. In my case I solved the problem by adding the user-agent: xxxx token in header.
Example:
user-agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/77.0.3865.90 Safari/537.36
HttpClient Code:
connectionManager = new PoolingHttpClientConnectionManager();
...
...
...
httpClient = HttpClients.custom()
.setConnectionManager(connectionManager)
.setRedirectStrategy(new LaxRedirectStrategy())
.setUserAgent("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/77.0.3865.90 Safari/537.36")
.build();