OAuth 1.0a Twitter API example

ListsRealTest.groovy

import static java.lang.String.format
import static java.net.http.HttpRequest.BodyPublishers
import static java.net.http.HttpResponse.BodyHandlers

import com.github.driversti.twittygram.utils.PercentUtil
import com.github.driversti.twittygram.utils.SignatureUtil
import java.net.http.HttpRequest
import java.net.http.HttpResponse
import java.time.Instant
import org.apache.commons.lang3.RandomStringUtils

class ListsRealTest extends RealUnitTest {

    protected static final String MY_ID = "79765753"
    protected static final API_URL = "https://api.twitter.com"
    private static final OWNED_LISTS_URL = "$API_URL/2/users/%s/owned_lists"

    def "should return lists owned by the given user with optional query parameters"() {
        given:
        def url = format(OWNED_LISTS_URL, MY_ID)
        def urlParams = Map.of("expansions", "owner_id", "list.fields", "follower_count,member_count", "user.fields", "created_at")
        def header = createOauthHeader("GET", url, urlParams)
//        def header = "Bearer $BEARER_TOKEN"
        HttpRequest request = HttpRequest.newBuilder()
                .GET()
                .uri(new URI(url + "?expansions=owner_id&list.fields=follower_count,member_count&user.fields=created_at"))
                .header("Content-Type", "application/json")
                .header("Authorization", header)
                .build()
        println request

        when:
        HttpResponse<String> response = client.send(request, BodyHandlers.ofString())

        then:
        response.statusCode() == 200
        def body = response.body()
        println body
        body.contains("IT related")
    }

PercentUtil.java

import java.nio.charset.StandardCharsets;
import java.util.HexFormat;
import java.util.Map;
import java.util.Objects;
import java.util.TreeMap;
import java.util.stream.Collectors;

public class PercentUtil {

  private static final String ASCII = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-._~";
  private static final HexFormat HEX = HexFormat.of().withUpperCase();

  public static String encode(final String source) {
    Objects.requireNonNull(source, "The 'source' string should not be null!");
    final StringBuilder builder = new StringBuilder();

    for (byte b : source.getBytes(StandardCharsets.UTF_8)) {
      final String currentCharacter = new String(new byte[]{b}, StandardCharsets.US_ASCII);
      if (ASCII.contains(currentCharacter)) {
        builder.append(currentCharacter);
      } else {
        builder.append("%").append(HEX.formatHex(new byte[]{b}));
      }
    }
    return builder.toString();
  }

  public static String encode(final Map<String, String> parameters) {
    final Map<String, String> encoded = parameters.entrySet().stream()
        .collect(Collectors.toMap(it -> encode(it.getKey()), it -> encode(it.getValue())));
    final TreeMap<String, String> sorted = new TreeMap<>(encoded);

    return sorted.entrySet().stream()
        .map(entry -> entry.getKey().concat(encode("=")).concat(entry.getValue()))
        .collect(Collectors.joining(encode("&")));
  }
}

SignatureUtil.java

import java.util.Base64;
import java.util.Map;
import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Hex;
import org.apache.commons.codec.digest.HmacAlgorithms;
import org.apache.commons.codec.digest.HmacUtils;

public class SignatureUtil {

  private static final String DELIMITER = "&";

  public static String signature(final String method, final String url,
      final Map<String, String> parameters, final String consumerSecret, final String userSecret) {

    String signatureBaseString = method.toUpperCase().concat(DELIMITER)
        .concat(PercentUtil.encode(url));
    if (!parameters.isEmpty()) {
      signatureBaseString = signatureBaseString.concat(DELIMITER)
          .concat(PercentUtil.encode(parameters));
    }
    System.out.println(signatureBaseString);

    final String signingKey = PercentUtil.encode(consumerSecret).concat(DELIMITER)
        .concat(PercentUtil.encode(userSecret));

    final String binaryRepresentation = new HmacUtils(HmacAlgorithms.HMAC_SHA_1, signingKey)
        .hmacHex(signatureBaseString);

    try {
      return Base64.getEncoder().encodeToString(Hex.decodeHex(binaryRepresentation));
    } catch (DecoderException e) {
      // todo think to not catch the exception and do it later in the business logic
      throw new RuntimeException("Cannot decode the binary representation of the signature");
    }
  }
}