From 53d99e46e6b34d4437f46266cb797a65c0736803 Mon Sep 17 00:00:00 2001
From: Torsten Grote <t@grobox.de>
Date: Thu, 27 Aug 2020 16:42:03 -0300
Subject: [cashier] don't crash on unexpected network input

---
 .../src/main/java/net/taler/cashier/Response.kt    | 86 ++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 cashier/src/main/java/net/taler/cashier/Response.kt

(limited to 'cashier/src/main/java/net/taler/cashier/Response.kt')

diff --git a/cashier/src/main/java/net/taler/cashier/Response.kt b/cashier/src/main/java/net/taler/cashier/Response.kt
new file mode 100644
index 0000000..0ad39d0
--- /dev/null
+++ b/cashier/src/main/java/net/taler/cashier/Response.kt
@@ -0,0 +1,86 @@
+/*
+ * This file is part of GNU Taler
+ * (C) 2020 Taler Systems S.A.
+ *
+ * GNU Taler is free software; you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation; either version 3, or (at your option) any later version.
+ *
+ * GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ * A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+package net.taler.cashier
+
+import android.content.Context
+import android.util.Log
+import io.ktor.client.call.receive
+import io.ktor.client.features.ResponseException
+import io.ktor.http.HttpStatusCode
+import kotlinx.serialization.Serializable
+import net.taler.common.isOnline
+import java.net.UnknownHostException
+
+class Response<out T> private constructor(
+    private val value: Any?
+) {
+    companion object {
+        suspend fun <T> response(request: suspend () -> T): Response<T> {
+            return try {
+                Response(request())
+            } catch (e: Throwable) {
+                Log.e("HttpClient", "Error getting request", e)
+                Response(getFailure(e))
+            }
+        }
+
+        private suspend fun getFailure(e: Throwable): Failure = when (e) {
+            is ResponseException -> Failure(e, getExceptionString(e), e.response?.status)
+            else -> Failure(e, e.toString())
+        }
+
+        private suspend fun getExceptionString(e: ResponseException): String {
+            val response = e.response ?: return e.toString()
+            return try {
+                Log.e("TEST", "TRY RECEIVE $response")
+                val error: Error = response.receive()
+                "Error ${error.code}: ${error.hint}"
+            } catch (ex: Exception) {
+                "Status code: ${response.status.value}"
+            }
+        }
+    }
+
+    private val isFailure: Boolean get() = value is Failure
+
+    suspend fun onSuccess(block: suspend (result: T) -> Unit): Response<T> {
+        @Suppress("UNCHECKED_CAST")
+        if (!isFailure) block(value as T)
+        return this
+    }
+
+    suspend fun onError(block: suspend (failure: Failure) -> Unit): Response<T> {
+        if (value is Failure) block(value)
+        return this
+    }
+
+    data class Failure(
+        val exception: Throwable,
+        val msg: String,
+        val statusCode: HttpStatusCode? = null
+    ) {
+        fun isOffline(context: Context): Boolean {
+            return exception is UnknownHostException && !context.isOnline()
+        }
+    }
+
+    @Serializable
+    private class Error(
+        val code: Int?,
+        val hint: String?
+    )
+}
-- 
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