Nexus x-libeufin-bank connection.

Introducing the operation to download transactions
from the bank.  More helpers were added, and some
CaMt specific code got moved from BankAccount.kt to
Iso20022.kt.

3 files changed, 102 insertions, 9 deletions

diff --git a/nexus/src/main/kotlin/tech/libeufin/nexus/server/Helpers.kt b/nexus/src/main/kotlin/tech/libeufin/nexus/server/Helpers.kt
new file mode 100644
index 00000000..8c01705a
--- /dev/null
+++ b/nexus/src/main/kotlin/tech/libeufin/nexus/server/Helpers.kt
@@ -0,0 +1,85 @@
+package tech.libeufin.nexus.server
+
+import org.jetbrains.exposed.sql.transactions.transaction
+import tech.libeufin.nexus.NexusBankConnectionEntity
+import tech.libeufin.nexus.NexusBankConnectionsTable
+import tech.libeufin.util.internalServerError
+import tech.libeufin.util.notFound
+
+/**
+ * FIXME:
+ * enum type names were introduced after 0.9.2 and need to
+ * be employed wherever now type names are passed as plain
+ * strings.
+ */
+
+// Valid connection types.
+enum class BankConnectionType(val typeName: String) {
+    EBICS("ebics"),
+    X_LIBEUFIN_BANK("x-taler-bank");
+    companion object {
+        /**
+         * This method takes legacy bank connection type names as input
+         * and _tries_ to return the correspondent enum type.  This
+         * fixes the cases where bank connection types are passed as
+         * easy-to-break arbitrary strings; eventually this method should
+         * be discarded and only enum types be passed as connection type names.
+         */
+        fun parseBankConnectionType(typeName: String): BankConnectionType {
+            return when(typeName) {
+                "ebics" -> EBICS
+                "x-libeufin-bank" -> X_LIBEUFIN_BANK
+                else -> throw internalServerError(
+                    "Cannot extract ${this::class.java.typeName}' instance from name: $typeName'"
+                )
+            }
+        }
+    }
+}
+// Valid facade types
+enum class NexusFacadeType(val facadeType: String) {
+    TALER("taler-wire-gateway"),
+    ANASTASIS("anastasis")
+}
+
+/**
+ * These types point at the _content_ brought by bank connections.
+ * The following stack depicts the layering of banking communication
+ * as modeled here in Nexus.  On top the most inner layer.
+ *
+ * --------------------
+ * Banking data type
+ * --------------------
+ * Bank connection type
+ * --------------------
+ * HTTP
+ * --------------------
+ *
+ * Once the banking data type arrives to the local database, facades
+ * types MAY apply further processing to it.
+ *
+ * For example, a Taler facade WILL look for Taler-meaningful wire
+ * subjects and act accordingly.  Even without a facade, the Nexus
+ * native HTTP API picks instances of banking data and extracts its
+ * details to serve to the client.
+ *
+ * NOTE: this type MAY help but is NOT essential, as each connection
+ * is USUALLY tied with the same banking data type.  For example, EBICS
+ * brings CaMt, and x-libeufin-bank bring its own (same-named x-libeufin-bank)
+ * banking data type.
+ */
+enum class BankingDataType {
+    X_LIBEUFIN_BANK,
+    CAMT
+}
+
+// Gets connection or throws.
+fun getBankConnection(connId: String): NexusBankConnectionEntity {
+    val maybeConn = transaction {
+        NexusBankConnectionEntity.find {
+            NexusBankConnectionsTable.connectionId eq connId
+        }.firstOrNull()
+    }
+    if (maybeConn == null) throw notFound("Bank connection $connId not found")
+    return maybeConn
+}
\ No newline at end of file
diff --git a/nexus/src/main/kotlin/tech/libeufin/nexus/server/JSON.kt b/nexus/src/main/kotlin/tech/libeufin/nexus/server/JSON.kt
index 38ab4236..7fdfd526 100644
--- a/nexus/src/main/kotlin/tech/libeufin/nexus/server/JSON.kt
+++ b/nexus/src/main/kotlin/tech/libeufin/nexus/server/JSON.kt
@@ -32,10 +32,9 @@ import com.fasterxml.jackson.databind.annotation.JsonDeserialize
 import com.fasterxml.jackson.databind.annotation.JsonSerialize
 import com.fasterxml.jackson.databind.deser.std.StdDeserializer
 import com.fasterxml.jackson.databind.ser.std.StdSerializer
+import tech.libeufin.nexus.EntryStatus
 import tech.libeufin.nexus.iso20022.CamtBankAccountEntry
-import tech.libeufin.nexus.iso20022.EntryStatus
 import tech.libeufin.util.*
-import java.math.BigDecimal
 import java.time.Instant
 import java.time.ZoneId
 import java.time.ZonedDateTime
@@ -251,6 +250,17 @@ data class EbicsNewTransport(
     val systemID: String?
 )
 
+/**
+ * Credentials and URL to access Sandbox and talk JSON to it.
+ * See https://docs.taler.net/design-documents/038-demobanks-protocol-suppliers.html#static-x-libeufin-bank-with-dynamic-demobank
+ * for an introduction on x-libeufin-bank.
+ */
+data class XLibeufinBankTransport(
+    val username: String,
+    val password: String,
+    val baseUrl: String
+)
+
 /** Response type of "GET /prepared-payments/{uuid}" */
 data class PaymentStatus(
     val paymentInitiationId: String,
@@ -262,10 +272,6 @@ data class PaymentStatus(
     val subject: String,
     val submissionDate: String?,
     val preparationDate: String,
-    // null when the payment was never acknowledged by
-    // the bank.  For example, it was submitted but never
-    // seen in any report; or only created and not even
-    // submitted.
     val status: EntryStatus?
 )
 
@@ -346,8 +352,9 @@ data class BankMessageList(
 )
 
 data class BankMessageInfo(
-    val messageId: String,
-    val code: String,
+    // x-libeufin-bank messages do not have any ID or code.
+    val messageId: String?,
+    val code: String?,
     val length: Long
 )
 
diff --git a/nexus/src/main/kotlin/tech/libeufin/nexus/server/NexusServer.kt b/nexus/src/main/kotlin/tech/libeufin/nexus/server/NexusServer.kt
index ebe002fc..fb864d3b 100644
--- a/nexus/src/main/kotlin/tech/libeufin/nexus/server/NexusServer.kt
+++ b/nexus/src/main/kotlin/tech/libeufin/nexus/server/NexusServer.kt
@@ -53,6 +53,7 @@ import tech.libeufin.nexus.*
 import tech.libeufin.nexus.bankaccount.*
 import tech.libeufin.nexus.ebics.*
 import tech.libeufin.nexus.iso20022.CamtBankAccountEntry
+import tech.libeufin.nexus.iso20022.processCamtMessage
 import tech.libeufin.util.*
 import java.net.BindException
 import java.net.URLEncoder
@@ -739,7 +740,7 @@ val nexusApp: Application.() -> Unit = {
             var statusCode = HttpStatusCode.OK
             /**
              * Client errors are unlikely here, because authentication
-             * and JSON validity fail earlier.  Hence either Nexus or the
+             * and JSON validity fail earlier.  Hence, either Nexus or the
              * bank had a problem.  NOTE: because this handler triggers multiple
              * fetches, it is ALSO possible that although one error is reported,
              * SOME transactions made it to the database!