BIT-765: Parse user information from JWT token (#127)

app/src/main/java/com/x8bit/bitwarden/data/auth/repository/model/JwtTokenDataJson.kt

@@ -0,0 +1,34 @@
+package com.x8bit.bitwarden.data.auth.repository.model
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+/**
+ * Contains data that can be parsed from a valid JWT token.
+ *
+ * @property userId The ID of the user.
+ * @property email The user's email address.
+ * @property isEmailVerified Whether or not the user's email is verified.
+ * @property name The user's name.
+ * @property expirationAsEpochTime The expiration time measured as an epoch time in seconds.
+ * @property hasPremium True if the user has a premium account.
+ * @property authenticationMethodsReference A list of the authentication methods used during
+ * authentication.
+ */
+@Serializable
+data class JwtTokenDataJson(
+    @SerialName("sub")
+    val userId: String,
+    @SerialName("email")
+    val email: String,
+    @SerialName("email_verified")
+    val isEmailVerified: Boolean,
+    @SerialName("name")
+    val name: String?,
+    @SerialName("exp")
+    val expirationAsEpochTime: Int,
+    @SerialName("premium")
+    val hasPremium: Boolean,
+    @SerialName("amr")
+    val authenticationMethodsReference: List<String>,
+)

app/src/main/java/com/x8bit/bitwarden/data/auth/repository/util/JwtTokenUtils.kt

@@ -0,0 +1,28 @@
+package com.x8bit.bitwarden.data.auth.repository.util
+
+import com.x8bit.bitwarden.data.auth.repository.model.JwtTokenDataJson
+import com.x8bit.bitwarden.data.platform.datasource.network.util.base64UrlDecodeOrNull
+import kotlinx.serialization.json.Json
+
+/**
+ * Internal, generally basic [Json] instance for JWT parsing purposes.
+ */
+private val json by lazy { Json { ignoreUnknownKeys = true } }
+
+/**
+ * Parses a [JwtTokenDataJson] from the given [jwtToken], or `null` if this parsing is not possible.
+ */
+@Suppress("MagicNumber", "ReturnCount")
+fun parseJwtTokenDataOrNull(jwtToken: String): JwtTokenDataJson? {
+    val parts = jwtToken.split(".")
+    if (parts.size != 3) return null
+
+    val dataJson = parts[1]
+    val decodedDataJson = dataJson.base64UrlDecodeOrNull() ?: return null
+
+    return try {
+        json.decodeFromString<JwtTokenDataJson>(decodedDataJson)
+    } catch (_: Throwable) {
+        null
+    }
+}

app/src/main/java/com/x8bit/bitwarden/data/platform/datasource/network/util/NetworkUtils.kt

@@ -1,5 +1,7 @@
 package com.x8bit.bitwarden.data.platform.datasource.network.util
 
+import okio.ByteString.Companion.decodeBase64
+import java.nio.charset.Charset
 import java.util.Base64
 
 /**
@@ -15,3 +17,18 @@ fun String.base64UrlEncode(): String =
         .replace("+", "-")
         .replace("/", "_")
         .replace("=", "")
+
+/**
+ * Base 64 decode the given string after making the following replacements:
+ *
+ * - replace all "-" with "+"
+ * - replace all "_" with "/"
+ *
+ * A value of `null` will be returned if the decoding fails.
+ */
+fun String.base64UrlDecodeOrNull(): String? =
+    this
+        .replace("-", "+")
+        .replace("_", "/")
+        .decodeBase64()
+        ?.string(Charset.defaultCharset())

app/src/test/java/com/x8bit/bitwarden/data/auth/repository/util/JwtTokenUtilsTest.kt

@@ -0,0 +1,43 @@
+package com.x8bit.bitwarden.data.auth.repository.util
+
+import com.x8bit.bitwarden.data.auth.repository.model.JwtTokenDataJson
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertNull
+import org.junit.jupiter.api.Test
+
+class JwtTokenUtilsTest {
+    @Test
+    fun `parseJwtTokenDataOrNull for a valid token input should return a JwtTokenData`() {
+        val testJwtToken =
+            "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJuYmYiOjE2OTc0OTIxMTQsImV4cCI6MTY5NzQ5NTcxN" +
+                "CwiaXNzIjoiaHR0cHM6Ly9pZGVudGl0eS5iaXR3YXJkZW4uY29tIiwiY2xpZW50X2lkIjoibW9iaWxl" +
+                "Iiwic3ViIjoiMmExMzViMjMtZTFmYi00MmM5LWJlYzMtNTczODU3YmM4MTgxIiwiYXV0aF90aW1lIjo" +
+                "xNjk3NDkyMTE0LCJpZHAiOiJiaXR3YXJkZW4iLCJwcmVtaXVtIjpmYWxzZSwiZW1haWwiOiJ0ZXN0QG" +
+                "JpdHdhcmRlbi5jb20iLCJlbWFpbF92ZXJpZmllZCI6dHJ1ZSwic3N0YW1wIjoiSkRIUzRSTUxFNEtGV" +
+                "EI0TFRIMjVTNkVLRktGTlhOQ0IiLCJuYW1lIjoiQml0d2FyZGVuIFRlc3RlciIsImRldmljZSI6IjNk" +
+                "ODYxNTU3LWI0Y2MtNDQxZi05YjE4LWM0NTAyYTcxN2UwYiIsImp0aSI6IjA1M0U5NUEzNjFBNEI4QUY" +
+                "yREEyRDIyNzNDREUxRDVFIiwiaWF0IjoxNjk3NDkyMTE0LCJzY29wZSI6WyJhcGkiLCJvZmZsaW5lX2" +
+                "FjY2VzcyJdLCJhbXIiOlsiQXBwbGljYXRpb24iXX0.RP2-wABK63Osu-tJY6KJjqVRSJ3-JR_OOdc3N" +
+                "nm4C5U"
+
+        assertEquals(
+            JwtTokenDataJson(
+                userId = "2a135b23-e1fb-42c9-bec3-573857bc8181",
+                email = "test@bitwarden.com",
+                isEmailVerified = true,
+                name = "Bitwarden Tester",
+                expirationAsEpochTime = 1697495714,
+                hasPremium = false,
+                authenticationMethodsReference = listOf("Application"),
+            ),
+            parseJwtTokenDataOrNull(jwtToken = testJwtToken),
+        )
+    }
+
+    @Test
+    fun `parseJwtTokenDataOrNull for an invalid token input should return null`() {
+        assertNull(
+            parseJwtTokenDataOrNull(jwtToken = "invalid JWT token"),
+        )
+    }
+}

app/src/test/java/com/x8bit/bitwarden/data/platform/datasource/network/util/NetworkUtilsTest.kt

@@ -0,0 +1,43 @@
+package com.x8bit.bitwarden.data.platform.datasource.network.util
+
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertNull
+import org.junit.jupiter.api.Test
+
+class NetworkUtilsTest {
+    @Test
+    fun `base64UrlEncode should Base64 encode the string and make the relevant replacements`() {
+        // Checks replacement of + to - and removal of =
+        assertEquals(
+            "dis-ZA",
+            "v+>d".base64UrlEncode(),
+        )
+        // Checks replacement of \ to _
+        assertEquals(
+            "NmI_ImE4",
+            "6b?\"a8".base64UrlEncode(),
+        )
+    }
+
+    @Suppress("MaxLineLength")
+    @Test
+    fun `base64UrlDecodeOrNull should Base64 decode the string and make the relevant replacements`() {
+        // Checks replacement of - to +
+        assertEquals(
+            "v+>d",
+            "dis-ZA==".base64UrlDecodeOrNull(),
+        )
+        // Checks replacement of _ to \
+        assertEquals(
+            "6b?\"a8",
+            "NmI_ImE4".base64UrlDecodeOrNull(),
+        )
+    }
+
+    @Test
+    fun `base64UrlDecodeOrNull should return null value a non-encoded String`() {
+        assertNull(
+            "*.*".base64UrlDecodeOrNull(),
+        )
+    }
+}