OAuth 1.0 Authorization Issues with X API v2 in Scala via STTP

Resolving OAuth 1.0 Authorization with Scala and STTP for the Twitter API

This script shows how to sign OAuth 1.0 requests in Scala using HMAC-SHA1. It ensures modularity and error handling, resulting in reusable, maintainable code.

import java.net.URLEncoder
import javax.crypto.Mac
import javax.crypto.spec.SecretKeySpec
import org.joda.time.DateTime
import sttp.client4._
import sttp.model.Header
import scala.util.Random
object Auth {
  def urlEncode(text: String): String =
    URLEncoder.encode(text, java.nio.charset.Charset.defaultCharset())
  def generateNonce: String = Random.alphanumeric.take(15).mkString
  def sha1sign(text: String, key: String): String = {
    val mac = Mac.getInstance("HmacSHA1")
    val signingKey = new SecretKeySpec(key.getBytes, "HmacSHA1")
    mac.init(signingKey)
    val signature = mac.doFinal(text.getBytes("UTF-8"))
    java.util.Base64.getEncoder.encodeToString(signature)
  }
  def createHeader(authData: Map[String, String]): Header = {
    val signatureBaseString = "POST&" + urlEncode("https://api.twitter.com/2/tweets") + "&" +
      urlEncode(authData.toSeq.sorted.map(x => s"${x._1}=${x._2}").mkString("&"))
    val signature = sha1sign(signatureBaseString, "consumerSecret&tokenSecret")
    val authHeader = "OAuth " + authData.map { case (k, v) => s"""$k="${urlEncode(v)}"""" }.mkString(", ") +
      s""", oauth_signature="${urlEncode(signature)}""""
    Header("Authorization", authHeader)
  }
}
object TwitterApi {
  val postEndpoint = "https://api.twitter.com/2/tweets"
  def createPost(text: String): Response = {
    val authData = Map(
      "oauth_consumer_key" -> "yourConsumerKey",
      "oauth_nonce" -> Auth.generateNonce,
      "oauth_signature_method" -> "HMAC-SHA1",
      "oauth_timestamp" -> DateTime.now().getMillis.toString,
      "oauth_token" -> "yourToken",
      "oauth_version" -> "1.0"
    )
    val header = Auth.createHeader(authData)
    basicRequest
      .header(header)
      .contentType("application/json")
      .body(s"""{"text":"$text"}""")
      .post(uri"$postEndpoint")
      .send(backend)
  }
}

Alternative Approach: OAuth 1.0 with Custom Nonce and Timestamp Handling

This method streamlines the signature process by focusing on generating bespoke nonces and timestamps with minimal dependencies.

import java.net.URLEncoder
import javax.crypto.Mac
import javax.crypto.spec.SecretKeySpec
import sttp.client4._
import sttp.model.Header
object OAuthHelper {
  def generateTimestamp: String = (System.currentTimeMillis / 1000).toString
  def generateNonce: String = java.util.UUID.randomUUID().toString.replace("-", "")
  def urlEncode(value: String): String = URLEncoder.encode(value, "UTF-8")
  def hmacSha1(baseString: String, key: String): String = {
    val mac = Mac.getInstance("HmacSHA1")
    val signingKey = new SecretKeySpec(key.getBytes("UTF-8"), "HmacSHA1")
    mac.init(signingKey)
    val rawHmac = mac.doFinal(baseString.getBytes("UTF-8"))
    java.util.Base64.getEncoder.encodeToString(rawHmac)
  }
}
object TwitterClient {
  def createAuthorizationHeader(params: Map[String, String], signature: String): Header = {
    val headerParams = params.map { case (k, v) => s"""$k="${OAuthHelper.urlEncode(v)}"""" }.mkString(", ")
    Header("Authorization", s"""OAuth $headerParams, oauth_signature="$signature"""")
  }
  def postTweet(text: String): Response = {
    val params = Map(
      "oauth_consumer_key" -> "consumerKey",
      "oauth_nonce" -> OAuthHelper.generateNonce,
      "oauth_signature_method" -> "HMAC-SHA1",
      "oauth_timestamp" -> OAuthHelper.generateTimestamp,
      "oauth_token" -> "accessToken",
      "oauth_version" -> "1.0"
    )
    val baseString = "POST&" + OAuthHelper.urlEncode("https://api.twitter.com/2/tweets") + "&" +
      OAuthHelper.urlEncode(params.toSeq.sorted.map { case (k, v) => s"$k=$v" }.mkString("&"))
    val signature = OAuthHelper.hmacSha1(baseString, "consumerSecret&tokenSecret")
    val authHeader = createAuthorizationHeader(params, signature)
    basicRequest
      .header(authHeader)
      .contentType("application/json")
      .body(s"""{"text":"$text"}""")
      .post(uri"https://api.twitter.com/2/tweets")
      .send(backend)
  }
}

Frequently Asked Questions About OAuth 1.0 and Twitter API Authentication

1. How does OAuth 1.0 differ from OAuth 2.0?
2. OAuth 1.0 uses signatures and HMAC-SHA1 encryption for security, whereas OAuth 2.0 uses token-based authorization, which simplifies the process but necessitates secure HTTPS connections.
3. What is the purpose of a nonce in OAuth 1.0?
4. To prevent replay attacks, each request generates a unique string known as a nonce. It ensures that each request is only executed once. Scala allows you to construct a nonce using Random.alphanumeric.take().
5. Why is URL encoding necessary in OAuth requests?
6. URL encoding is crucial because certain characters, like ampersands (&) or spaces, must be encoded to avoid misinterpretation. Use URLEncoder.encode() to safely encode these characters.
7. How do I generate an OAuth signature?
8. To establish an OAuth signature, first create a base string from the request data and then sign it with the HMAC-SHA1 technique. Use Mac.getInstance("HmacSHA1") to start the hashing process.
9. What can cause a 401 Unauthorized error in OAuth?
10. A 401 error can be caused by a variety of errors, including an invalid signature, mismatched consumer keys, or inappropriate parameter encoding. Always ensure that the signature matches the request data and that the encoding is accurate.

Final Thoughts on Solving Twitter OAuth Issues

To properly authorize an OAuth 1.0 request for Twitter's API, developers must carefully manage signatures and headers. Many problems are caused by encoding issues or using the incorrect base string format. Errors such as "401 Unauthorized" can be prevented by addressing these issues appropriately.

Furthermore, rechecking nonce creation, timestamp accuracy, and header formatting greatly increases authorization success. Optimizing the sha1sign method, assuring accurate signature calculation, and adhering to OAuth requirements are critical stages toward developing a functional and automated X publishing application.