For Twitter oAuth: In case anyone needs to generate oAuth signature and header to connect to Twitter API, here is the code. This requires minimum of Java 8 and NO 3rd party library.
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;
import java.util.Date;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Random;
import java.util.stream.Collectors;
import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
/**
* Class to generate Oauth 1.0a header for Twitter
*
*/
public class TwitterOauthHeaderGenerator {
private String consumerKey;
private String consumerSecret;
private String signatureMethod;
private String token;
private String tokenSecret;
private String version;
public TwitterOauthHeaderGenerator(String consumerKey, String consumerSecret, String token, String tokenSecret) {
this.consumerKey = consumerKey;
this.consumerSecret = consumerSecret;
this.token = token;
this.tokenSecret = tokenSecret;
this.signatureMethod = "HMAC-SHA1";
this.version = "1.0";
}
private static final String oauth_consumer_key = "oauth_consumer_key";
private static final String oauth_token = "oauth_token";
private static final String oauth_signature_method = "oauth_signature_method";
private static final String oauth_timestamp = "oauth_timestamp";
private static final String oauth_nonce = "oauth_nonce";
private static final String oauth_version = "oauth_version";
private static final String oauth_signature = "oauth_signature";
private static final String HMAC_SHA1 = "HmacSHA1";
/**
* Generates oAuth 1.0a header which can be passed as Authorization header
*
* @param httpMethod
* @param url
* @param requestParams
* @return
*/
public String generateHeader(String httpMethod, String url, Map<String, String> requestParams) {
StringBuilder base = new StringBuilder();
String nonce = getNonce();
String timestamp = getTimestamp();
String baseSignatureString = generateSignatureBaseString(httpMethod, url, requestParams, nonce, timestamp);
String signature = encryptUsingHmacSHA1(baseSignatureString);
base.append("OAuth ");
append(base, oauth_consumer_key, consumerKey);
append(base, oauth_token, token);
append(base, oauth_signature_method, signatureMethod);
append(base, oauth_timestamp, timestamp);
append(base, oauth_nonce, nonce);
append(base, oauth_version, version);
append(base, oauth_signature, signature);
base.deleteCharAt(base.length() - 1);
System.out.println("header : " + base.toString());
return base.toString();
}
/**
* Generate base string to generate the oauth_signature
*
* @param httpMethod
* @param url
* @param requestParams
* @return
*/
private String generateSignatureBaseString(String httpMethod, String url, Map<String, String> requestParams, String nonce, String timestamp) {
Map<String, String> params = new HashMap<>();
requestParams.entrySet().forEach(entry -> {
put(params, entry.getKey(), entry.getValue());
});
put(params, oauth_consumer_key, consumerKey);
put(params, oauth_nonce, nonce);
put(params, oauth_signature_method, signatureMethod);
put(params, oauth_timestamp, timestamp);
put(params, oauth_token, token);
put(params, oauth_version, version);
Map<String, String> sortedParams = params.entrySet().stream().sorted(Map.Entry.comparingByKey())
.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (oldValue, newValue) -> oldValue, LinkedHashMap::new));
StringBuilder base = new StringBuilder();
sortedParams.entrySet().forEach(entry -> {
base.append(entry.getKey()).append("=").append(entry.getValue()).append("&");
});
base.deleteCharAt(base.length() - 1);
String baseString = httpMethod.toUpperCase() + "&" + encode(url) + "&" + encode(base.toString());
return baseString;
}
private String encryptUsingHmacSHA1(String input) {
String secret = new StringBuilder().append(encode(consumerSecret)).append("&").append(encode(tokenSecret)).toString();
byte[] keyBytes = secret.getBytes(StandardCharsets.UTF_8);
SecretKey key = new SecretKeySpec(keyBytes, HMAC_SHA1);
Mac mac;
try {
mac = Mac.getInstance(HMAC_SHA1);
mac.init(key);
} catch (NoSuchAlgorithmException | InvalidKeyException e) {
e.printStackTrace();
return null;
}
byte[] signatureBytes = mac.doFinal(input.getBytes(StandardCharsets.UTF_8));
return new String(Base64.getEncoder().encode(signatureBytes));
}
/**
* Percentage encode String as per RFC 3986, Section 2.1
*
* @param value
* @return
*/
private String encode(String value) {
String encoded = "";
try {
encoded = URLEncoder.encode(value, "UTF-8");
} catch (Exception e) {
e.printStackTrace();
}
String sb = "";
char focus;
for (int i = 0; i < encoded.length(); i++) {
focus = encoded.charAt(i);
if (focus == '*') {
sb += "%2A";
} else if (focus == '+') {
sb += "%20";
} else if (focus == '%' && i + 1 < encoded.length() && encoded.charAt(i + 1) == '7' && encoded.charAt(i + 2) == 'E') {
sb += '~';
i += 2;
} else {
sb += focus;
}
}
return sb.toString();
}
private void put(Map<String, String> map, String key, String value) {
map.put(encode(key), encode(value));
}
private void append(StringBuilder builder, String key, String value) {
builder.append(encode(key)).append("=\"").append(encode(value)).append("\",");
}
private String getNonce() {
int leftLimit = 48; // numeral '0'
int rightLimit = 122; // letter 'z'
int targetStringLength = 10;
Random random = new Random();
String generatedString = random.ints(leftLimit, rightLimit + 1).filter(i -> (i <= 57 || i >= 65) && (i <= 90 || i >= 97)).limit(targetStringLength)
.collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append).toString();
return generatedString;
}
private String getTimestamp() {
return Math.round((new Date()).getTime() / 1000.0) + "";
}
}
Sample usage using Spring RestTemplate to get details of a Twitter user:
TwitterOauthHeaderGenerator generator = new TwitterOauthHeaderGenerator("consumerKey", "consumerSecret", "token", "tokenSecret");
Map<String, String> requestParams = new HashMap<>();
requestParams.put("usernames", "some_handle");
String header = generator.generateHeader("GET", "https://api.twitter.com/labs/1/users", requestParams);
HttpHeaders headers = new HttpHeaders();
headers.add("Authorization", header);
HttpEntity<String> httpEntity = new HttpEntity<String>("body", headers);
ResponseEntity<SomeModel> someModelEntity= restTemplate.exchange("https://api.twitter.com/labs/1/users?usernames=some_handle",
HttpMethod.GET, httpEntity, SomeModel.class);
System.out.println(someModelEntity.getBody());
Complete code and working demo available at Twitter-Play
