Twitter oauth Request Token Response code 401 - twitter

Question

I am working on a twitter oauth login. However, when I do the request_token, the very first step, the response code always return 401 Unauthorized.
I have searched a lot for a week, but I cannot find the solution, please help.
Here is my connection:
URL url = new URL("https://api.twitter.com/oauth/request_token");
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
conn.setRequestProperty("Host","api.twitter.com");
conn.setRequestProperty("Authorization", data);
conn.setRequestMethod("POST");
conn.connect();
For my data:
String data = "OAuth oauth_nonce=\"" + oauth_nonce
+ "\", oauth_callback=\"" + oauth_callback
+ "\", oauth_signature_method=\"" + oauth_signature_method
+ "\", oauth_timestamp=\"" + oauth_timestamp
+ "\", oauth_consumer_key=\"" + oauth_consumer_key
+ "\", oauth_signature=\"" + oauth_signature
+ "\", oauth_version=\"" + oauth_version + "\"";
Also, I am sure that my signature is right, because I used the parameter of twitter example, I can calculate the same result as its example, so I think my method is right.
Here is my calculation:
String oauth_para = "oauth_callback=" + oauth_callback
+ "&oauth_consumer_key=" + oauth_consumer_key
+ "&oauth_nonce=" + oauth_nonce
+ "&oauth_signature_method=" + oauth_signature_method
+ "&oauth_timestamp=" + oauth_timestamp
+ "&oauth_version=" + oauth_version;
String signingRequests = "POST&" + requestToken + "&" + URLEncoder.encode(oauth_para, "UTF-8");
String key = oauth_consumer_secret + "&";
SecretKeySpec signingKey = new SecretKeySpec(key.getBytes(), "HmacSHA1");
Mac mac = null;
try {
mac = Mac.getInstance("HmacSHA1");
mac.init(signingKey);
}
catch(Exception e) {
System.err.println("Error: " + e);
}
byte[] rawHmac = mac.doFinal(signingRequests.getBytes());
String oauth_signature = Base64.encodeBytes(rawHmac);
oauth_signature = URLEncoder.encode(oauth_signature);
I understand that the nonce and timestamp should be random and unique. So, my method is like that:
StringBuffer buffer = new StringBuffer("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ");
StringBuffer sb = new StringBuffer();
Random r = new Random();
int range = buffer.length();
for (int i = 0; i < 43;i ++) {
sb.append(buffer.charAt(r.nextInt(range)));
}
long epoch = System.currentTimeMillis() / 1000;
String oauth_nonce = sb.toString();
Can somebody help me?
P.S: I have also removed my apps, and then create a new one. The result also is the same. Also, the apps is write and read already.

Answer 1

hey,,, I was getting the same problem 1 min ago, but I figured this out. My problem, at least, was that in the configuration of the application(inside twitter), my application type was Client, when should be Browser! So I changed to Browser, put a callback URL and worked fine!!