Implement GetBalance client call and server endpoint

httpclient/src/main/kotlin/tbdex/sdk/httpclient/RequestToken.kt

@@ -44,7 +44,6 @@ object RequestToken {
         .didDocument?.findAssertionMethodById(assertionMethodId)
         ?: throw RequestTokenCreateException("Assertion method not found")
 
-    // TODO: ensure that publicKeyJwk is not null
     val publicKeyJwk = assertionMethod.publicKeyJwk
     check(publicKeyJwk != null) { "publicKeyJwk is null" }
     val keyAlias = did.keyManager.getDeterministicAlias(publicKeyJwk)

httpclient/src/main/kotlin/tbdex/sdk/httpclient/TbdexHttpClient.kt

@@ -15,6 +15,7 @@ import tbdex.sdk.httpclient.models.GetExchangesFilter
 import tbdex.sdk.httpclient.models.GetOfferingsFilter
 import tbdex.sdk.httpclient.models.TbdexResponseException
 import tbdex.sdk.protocol.Validator
+import tbdex.sdk.protocol.models.Balance
 import tbdex.sdk.protocol.models.Close
 import tbdex.sdk.protocol.models.Message
 import tbdex.sdk.protocol.models.Offering
@@ -29,6 +30,8 @@ import web5.sdk.dids.did.BearerDid
  */
 object TbdexHttpClient {
   private val client = OkHttpClient()
+  private const val CONTENT_TYPE = "Content-Type"
+  private const val AUTHORIZATION = "Authorization"
   private val jsonMediaType = "application/json; charset=utf-8".toMediaType()
   private const val JSON_HEADER = "application/json"
 
@@ -41,6 +44,7 @@ object TbdexHttpClient {
    * @return A list of [Offering] matching the request.
    * @throws TbdexResponseException for request or response errors.
    */
+  @Suppress("SwallowedException")
   fun getOfferings(pfiDid: String, filter: GetOfferingsFilter? = null): List<Offering> {
     val pfiServiceEndpoint = getPfiServiceEndpoint(pfiDid)
     val baseUrl = "$pfiServiceEndpoint/offerings/"
@@ -64,7 +68,70 @@ object TbdexHttpClient {
         val jsonNode = jsonMapper.readTree(responseString)
         return jsonNode.get("data").elements()
           .asSequence()
-          .map { Offering.parse(it.toString()) }
+          .map {
+            try {
+              Offering.parse(it.toString())
+            } catch (e: Exception) {
+              throw TbdexResponseException(
+                "response status: ${response.code}",
+                errors = listOf(
+                  ErrorDetail(
+                    detail = "Failed to parse offering ${e.message}"
+                  )
+                )
+              )
+            }
+          }
+          .toList()
+      }
+
+      else -> throw buildResponseException(response)
+    }
+  }
+
+  /**
+   * Fetches balances from a PFI.
+   *
+   * @param pfiDid The decentralized identifier of the PFI.
+   * @param requesterDid The decentralized identifier of the entity requesting the balances.
+   * @return A list of [Balance] matching the request.
+   * @throws TbdexResponseException for request or response errors.
+   */
+  @Suppress("SwallowedException")
+  fun getBalances(pfiDid: String, requesterDid: BearerDid): List<Balance> {
+    val pfiServiceEndpoint = getPfiServiceEndpoint(pfiDid)
+    val baseUrl = "$pfiServiceEndpoint/balances/"
+    val requestToken = RequestToken.generate(requesterDid, pfiDid)
+
+    val request = Request.Builder()
+      .url(baseUrl)
+      .addHeader(CONTENT_TYPE, JSON_HEADER)
+      .addHeader(AUTHORIZATION, "Bearer $requestToken")
+      .get()
+      .build()
+
+    val response: Response = client.newCall(request).execute()
+    when {
+      response.isSuccessful -> {
+        val responseString = response.body?.string()
+        // response body is an object with a data field
+        val jsonNode = jsonMapper.readTree(responseString)
+        return jsonNode.get("data").elements()
+          .asSequence()
+          .map {
+            try {
+              Balance.parse(it.toString())
+            } catch (e: Exception) {
+              throw TbdexResponseException(
+                "response status: ${response.code}",
+                errors = listOf(
+                  ErrorDetail(
+                    detail = "Failed to parse balance ${e.message}"
+                  )
+                )
+              )
+            }
+          }
           .toList()
       }
 
@@ -115,7 +182,7 @@ object TbdexHttpClient {
 
     val request = Request.Builder()
       .url(url)
-      .addHeader("Content-Type", JSON_HEADER)
+      .addHeader(CONTENT_TYPE, JSON_HEADER)
       .post(requestBody)
       .build()
 
@@ -170,7 +237,7 @@ object TbdexHttpClient {
 
     val request = Request.Builder()
       .url(url)
-      .addHeader("Content-Type", JSON_HEADER)
+      .addHeader(CONTENT_TYPE, JSON_HEADER)
       .put(requestBody)
       .build()
 
@@ -195,8 +262,8 @@ object TbdexHttpClient {
 
     val request = Request.Builder()
       .url(baseUrl)
-      .addHeader("Content-Type", JSON_HEADER)
-      .addHeader("Authorization", "Bearer $requestToken")
+      .addHeader(CONTENT_TYPE, JSON_HEADER)
+      .addHeader(AUTHORIZATION, "Bearer $requestToken")
       .get()
       .build()
 
@@ -237,8 +304,8 @@ object TbdexHttpClient {
 
     val request = Request.Builder()
       .url(httpUrlBuilder.build())
-      .addHeader("Content-Type", JSON_HEADER)
-      .addHeader("Authorization", "Bearer $requestToken")
+      .addHeader(CONTENT_TYPE, JSON_HEADER)
+      .addHeader(AUTHORIZATION, "Bearer $requestToken")
       .get()
       .build()
 

httpclient/src/test/kotlin/tbdex/sdk/httpclient/TbdexHttpClientTest.kt

@@ -86,6 +86,42 @@ class TbdexHttpClientTest {
     assertThrows<TbdexResponseException> { TbdexHttpClient.getOfferings(pfiDid.uri, null) }
   }
 
+  @Test
+  fun `get balances success via mockwebserver`() {
+    val balance = TestData.getBalance()
+    balance.sign(TestData.PFI_DID)
+    val mockBalance = listOf(balance)
+    val mockResponseString = Json.jsonMapper.writeValueAsString(mapOf("data" to mockBalance))
+    server.enqueue(MockResponse().setBody(mockResponseString).setResponseCode(HttpURLConnection.HTTP_OK))
+
+    val requesterDid = DidDht.create(InMemoryKeyManager())
+    val response = TbdexHttpClient.getBalances(pfiDid.uri, requesterDid)
+
+    assertEquals(1, response.size)
+  }
+
+  @Test
+  fun `get balances fail via mockwebserver`() {
+    val errorDetails = mapOf(
+      "errors" to listOf(
+        ErrorDetail(
+          id = "1",
+          status = "401",
+          code = "Unauthorized",
+          title = "Unauthorized",
+          detail = "The request is unauthorized.",
+          source = null,
+          meta = null
+        )
+      )
+    )
+
+    val mockResponseString = Json.jsonMapper.writeValueAsString(errorDetails)
+    server.enqueue(MockResponse().setBody(mockResponseString).setResponseCode(HttpURLConnection.HTTP_BAD_REQUEST))
+    val requesterDid = DidDht.create(InMemoryKeyManager())
+    assertThrows<TbdexResponseException> { TbdexHttpClient.getBalances(pfiDid.uri, requesterDid) }
+  }
+
   @Test
   fun `createExchange(Rfq) submits RFQ`() {
 

httpclient/src/test/kotlin/tbdex/sdk/httpclient/TestData.kt

@@ -2,6 +2,8 @@ package tbdex.sdk.httpclient
 
 import com.danubetech.verifiablecredentials.CredentialSubject
 import de.fxlae.typeid.TypeId
+import tbdex.sdk.protocol.models.Balance
+import tbdex.sdk.protocol.models.BalanceData
 import tbdex.sdk.protocol.models.MessageKind
 import tbdex.sdk.protocol.models.Offering
 import tbdex.sdk.protocol.models.OfferingData
@@ -74,6 +76,16 @@ object TestData {
     return offering
   }
 
+  fun getBalance() =
+    Balance.create(
+      from = PFI_DID.uri,
+      data = BalanceData(
+        currencyCode = "BTC",
+        available = "0.001",
+      )
+    )
+
+
   fun getRfq(
     to: String = PFI_DID.uri,
     offeringId: String = TypeId.generate(ResourceKind.offering.name).toString(),

httpserver/src/main/kotlin/tbdex/sdk/httpserver/TbdexHttpServer.kt

@@ -18,13 +18,16 @@ import io.ktor.server.routing.put
 import io.ktor.server.routing.route
 import io.ktor.server.routing.routing
 import tbdex.sdk.httpserver.handlers.createExchange
+import tbdex.sdk.httpserver.handlers.getBalances
 import tbdex.sdk.httpserver.handlers.getExchange
 import tbdex.sdk.httpserver.handlers.getExchanges
 import tbdex.sdk.httpserver.handlers.getOfferings
 import tbdex.sdk.httpserver.handlers.submitMessage
+import tbdex.sdk.httpserver.models.BalancesApi
 import tbdex.sdk.httpserver.models.Callbacks
 import tbdex.sdk.httpserver.models.CreateExchangeCallback
 import tbdex.sdk.httpserver.models.ExchangesApi
+import tbdex.sdk.httpserver.models.FakeBalancesApi
 import tbdex.sdk.httpserver.models.FakeExchangesApi
 import tbdex.sdk.httpserver.models.FakeOfferingsApi
 import tbdex.sdk.httpserver.models.GetExchangeCallback
@@ -34,32 +37,21 @@ import tbdex.sdk.httpserver.models.OfferingsApi
 import tbdex.sdk.httpserver.models.SubmitCloseCallback
 import tbdex.sdk.httpserver.models.SubmitOrderCallback
 
-/**
- * Main function to start the TBDex HTTP server.
- */
-fun main() {
-
-  embeddedServer(Netty, port = 8080) {
-    val serverConfig = TbdexHttpServerConfig(
-      port = 8080,
-    )
-    val tbdexServer = TbdexHttpServer(serverConfig)
-    tbdexServer.configure(this)
-  }.start(wait = true)
-}
-
 /**
  * Configuration data for TBDex HTTP server.
  *
  * @property port The port on which the server will listen.
- * @property offeringsApi An optional [OfferingsApi] implementation to use.
- * @property exchangesApi An optional [ExchangesApi] implementation to use.
+ * @property offeringsApi A [OfferingsApi] implementation to use. If not provided, a [FakeOfferingsApi] will be used.
+ * @property exchangesApi A [ExchangesApi] implementation to use. If not provided, a [FakeExchangesApi] will be used.
+ * @property balancesApi A [BalancesApi] implementation to use. If not provided, Balances API will be disabled.
+ *           For testing, consumers must explicitly pass in [FakeBalancesApi].
  */
 class TbdexHttpServerConfig(
   val port: Int,
   val pfiDid: String? = null,
   val offeringsApi: OfferingsApi? = null,
-  val exchangesApi: ExchangesApi? = null
+  val exchangesApi: ExchangesApi? = null,
+  val balancesApi: BalancesApi? = null
 )
 
 
@@ -77,6 +69,7 @@ class TbdexHttpServer(private val config: TbdexHttpServerConfig) {
   internal val pfiDid = config.pfiDid ?: "did:ex:pfi"
   internal val offeringsApi = config.offeringsApi ?: FakeOfferingsApi()
   internal val exchangesApi = config.exchangesApi ?: FakeExchangesApi()
+  internal val balancesApi = config.balancesApi
 
   /**
    * Configures the Ktor application with necessary settings, including content negotiation.
@@ -102,6 +95,28 @@ class TbdexHttpServer(private val config: TbdexHttpServerConfig) {
         )
       }
 
+      get("/offerings") {
+        getOfferings(
+          call,
+          offeringsApi,
+          callbacks.getOfferings
+        )
+      }
+
+      if (config.balancesApi != null) {
+        if (balancesApi is FakeBalancesApi) {
+          println("Warning: Balances API is enabled, with FakeBalancesApi test implementation.")
+        }
+        get("/balances") {
+          getBalances(
+            call,
+            balancesApi!!,
+            callbacks.getBalances,
+            pfiDid
+          )
+        }
+      }
+
       route("/exchanges") {
         post {
           createExchange(
@@ -139,13 +154,6 @@ class TbdexHttpServer(private val config: TbdexHttpServerConfig) {
         }
       }
 
-      get("/offerings") {
-        getOfferings(
-          call,
-          offeringsApi,
-          callbacks.getOfferings
-        )
-      }
     }
   }