Display specific, user-friendly error message when upload categories search API call returns an error (#6540)

* Make OkHttpConnectionFactory raise MwIOException when a non-suppressed API call returns an error

* Add AlertDialog displaying specific error message when categories search API call returns an error

* Add test for error alert dialog to UploadCategoriesFragment unit tests

* Add error handling when API call fails to CategoriesPresenter.onAttachViewWithMedia

app/src/main/java/fr/free/nrw/commons/OkHttpConnectionFactory.kt

@@ -1,7 +1,11 @@
 package fr.free.nrw.commons
 
 import androidx.annotation.VisibleForTesting
+import fr.free.nrw.commons.wikidata.GsonUtil
 import fr.free.nrw.commons.wikidata.cookies.CommonsCookieJar
+import fr.free.nrw.commons.wikidata.mwapi.MwErrorResponse
+import fr.free.nrw.commons.wikidata.mwapi.MwIOException
+import fr.free.nrw.commons.wikidata.mwapi.MwLegacyServiceError
 import okhttp3.Cache
 import okhttp3.Interceptor
 import okhttp3.OkHttpClient
@@ -86,16 +90,25 @@ private class UnsuccessfulResponseInterceptor : Interceptor {
                 rsp.peekBody(ERRORS_PREFIX.length.toLong()).use { responseBody ->
                     if (ERRORS_PREFIX == responseBody.string()) {
                         rsp.body.use { body ->
-                            throw IOException(body!!.string())
+                            val bodyString = body!!.string()
+
+                            throw MwIOException(
+                                "MediaWiki API returned error: $bodyString",
+                                GsonUtil.defaultGson.fromJson(
+                                    bodyString,
+                                    MwErrorResponse::class.java
+                                ).error!!,
+                            )
                         }
                     }
                 }
-            } catch (e: IOException) {
+            } catch (e: MwIOException) {
                 // Log the error as debug (and therefore, "expected") or at error level
                 if (suppressErrors) {
                     Timber.d(e, "Suppressed (known / expected) error")
                 } else {
                     Timber.e(e)
+                    throw e
                 }
             }
             return rsp

app/src/main/java/fr/free/nrw/commons/upload/categories/CategoriesContract.kt

@@ -17,6 +17,11 @@ interface CategoriesContract {
 
         fun showError(stringResourceId: Int)
 
+        /**
+         * Show a cancelable AlertDialog with a given message.
+         */
+        fun showErrorDialog(message: String)
+
         fun setCategories(categories: List<CategoryItem>?)
 
         fun goToNextScreen()

app/src/main/java/fr/free/nrw/commons/upload/categories/CategoriesPresenter.kt

@@ -12,6 +12,7 @@ import fr.free.nrw.commons.di.CommonsApplicationModule.Companion.IO_THREAD
 import fr.free.nrw.commons.di.CommonsApplicationModule.Companion.MAIN_THREAD
 import fr.free.nrw.commons.repository.UploadRepository
 import fr.free.nrw.commons.upload.depicts.proxy
+import fr.free.nrw.commons.wikidata.mwapi.MwIOException
 import io.reactivex.Observable
 import io.reactivex.Scheduler
 import io.reactivex.android.schedulers.AndroidSchedulers
@@ -75,7 +76,12 @@ class CategoriesPresenter
                         },
                         { t: Throwable? ->
                             view.showProgress(false)
-                            view.showError(R.string.no_categories_found)
+                            view.showError(R.string.error_loading_categories)
+                            val mwException = t as? MwIOException
+                            view.showErrorDialog(
+                                if (mwException == null) ""
+                                else "\n${mwException.error.title} / ${mwException.error.details}"
+                            )
                             Timber.e(t)
                         },
                     ),
@@ -194,7 +200,12 @@ class CategoriesPresenter
                         },
                         { t: Throwable? ->
                             view.showProgress(false)
-                            view.showError(R.string.no_categories_found)
+                            view.showError(R.string.error_loading_categories)
+                            val mwException = t as? MwIOException
+                            view.showErrorDialog(
+                                if (mwException == null) ""
+                                else "\n${mwException.error.title} / ${mwException.error.details}"
+                            )
                             Timber.e(t)
                         },
                     ),

app/src/main/java/fr/free/nrw/commons/upload/categories/UploadCategoriesFragment.kt

@@ -10,6 +10,7 @@ import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import android.widget.Toast
+import androidx.appcompat.app.AlertDialog
 import androidx.appcompat.app.AppCompatActivity
 import androidx.recyclerview.widget.LinearLayoutManager
 import com.jakewharton.rxbinding2.view.RxView
@@ -32,7 +33,6 @@ import io.reactivex.Notification
 import io.reactivex.android.schedulers.AndroidSchedulers
 import io.reactivex.disposables.Disposable
 import timber.log.Timber
-import java.util.Objects
 import java.util.concurrent.TimeUnit
 import javax.inject.Inject
 
@@ -199,6 +199,15 @@ class UploadCategoriesFragment : UploadBaseFragment(), CategoriesContract.View {
         binding?.tilContainerSearch?.error = getString(stringResourceId)
     }
 
+    override fun showErrorDialog(message: String) {
+        AlertDialog
+            .Builder(requireContext())
+            .setMessage(getString(R.string.error_loading_categories) + "\n" + message)
+            .setCancelable(false)
+            .setNegativeButton(R.string.ok){_,_ -> }
+            .show()
+    }
+
     override fun setCategories(categories: List<CategoryItem>?) {
         if (adapter == null) {
             Timber.e("Adapter is null in setCategories")

app/src/main/java/fr/free/nrw/commons/wikidata/mwapi/MwErrorResponse.kt

@@ -0,0 +1,7 @@
+package fr.free.nrw.commons.wikidata.mwapi
+
+import fr.free.nrw.commons.wikidata.model.BaseModel
+
+class MwErrorResponse : BaseModel() {
+    val error: MwLegacyServiceError? = null
+}

app/src/main/java/fr/free/nrw/commons/wikidata/mwapi/MwIOException.kt

@@ -0,0 +1,5 @@
+package fr.free.nrw.commons.wikidata.mwapi
+
+import java.io.IOException
+
+class MwIOException(string: String, val error: MwLegacyServiceError) : IOException(string)

app/src/main/java/fr/free/nrw/commons/wikidata/mwapi/MwLegacyServiceError.kt

@@ -0,0 +1,14 @@
+package fr.free.nrw.commons.wikidata.mwapi
+
+import fr.free.nrw.commons.wikidata.model.BaseModel
+
+class MwLegacyServiceError : BaseModel() {
+    val code: String? = null
+    private val info: String? = null
+
+    val title: String
+        get() = code ?: ""
+
+    val details: String
+        get() = info ?: ""
+}

app/src/test/kotlin/fr/free/nrw/commons/upload/categories/UploadCategoriesFragmentUnitTests.kt

@@ -153,6 +153,13 @@ class UploadCategoriesFragmentUnitTests {
         fragment.showError(R.string.no_categories_found)
     }
 
+    @Test
+    @Throws(Exception::class)
+    fun testShowErrorDialog() {
+        Shadows.shadowOf(Looper.getMainLooper()).idle()
+        fragment.showErrorDialog("")
+    }
+
     @Test
     @Throws(Exception::class)
     fun testSetCategoriesCaseNull() {