Implement file type validation to prevent unsupported uploads

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

@@ -156,4 +156,20 @@ object FileUtils {
         }
         return true
     }
+    // list of supported MIME types
+    private val imageAllowList = listOf(
+        "image/jpeg",
+        "image/jpg",
+        "image/png",
+        "image/svg+xml"
+    )
+
+    fun isSupportedFileType(context: Context, uri: Uri): Boolean {
+        val mimeType = getMimeType(context, uri)
+        return if (mimeType == null) {
+            false
+        } else {
+            imageAllowList.contains(mimeType.lowercase(Locale.getDefault()))
+        }
+    }
 }

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

@@ -511,10 +511,20 @@ class UploadActivity : BaseActivity(), UploadContract.View, UploadBaseFragment.C
             receiveInternalSharedItems()
         }
 
-        if (uploadableFiles.isEmpty()) {
-            handleNullMedia()
-        } else {
-            //Show thumbnails
+        // Filter the files using the correct property
+        val originalSize = uploadableFiles.size
+        uploadableFiles = uploadableFiles.filter { file ->
+            file.contentUri?.let { uri ->
+                FileUtils.isSupportedFileType(this, uri)
+            } ?: false
+        }.toMutableList()
+
+        fun proceedWithSetup() {
+            if (uploadableFiles.isEmpty()) {
+                handleNullMedia()
+                return
+            }
+
             if (uploadableFiles.size > 1) {
                 if (!defaultKvStore.getBoolean("hasAlreadyLaunchedCategoriesDialog")) {
                     // If there is only file, no need to show the image thumbnails
@@ -700,7 +710,7 @@ class UploadActivity : BaseActivity(), UploadContract.View, UploadBaseFragment.C
 
             uploadImagesAdapter!!.fragments = fragments!!
             binding.vpUpload.offscreenPageLimit = fragments!!.size
-        }
+
         // Saving size of uploadableFiles
         store!!.putInt(KEY_FOR_CURRENT_UPLOAD_IMAGE_SIZE, uploadableFiles.size)
     }
@@ -713,6 +723,35 @@ class UploadActivity : BaseActivity(), UploadContract.View, UploadBaseFragment.C
      * @param index Index of image to be removed
      * @param maxSize Max size of the `uploadableFiles`
      */
+
+
+        if (uploadableFiles.isEmpty() && originalSize > 0) {
+            showAlertDialog(
+                this,
+                getString(R.string.unsupported_format_title),
+                getString(R.string.unsupported_format_desc),
+                getString(R.string.ok)
+            ) {
+                finish()
+            }
+            return
+        }
+
+        if (uploadableFiles.size < originalSize) {
+            showAlertDialog(
+                this,
+                getString(R.string.unsupported_files_skipped_title),
+                getString(R.string.unsupported_files_skipped_desc),
+                getString(R.string.ok)
+            ) {
+                proceedWithSetup()
+            }
+            return
+        }
+
+        proceedWithSetup()
+    }
+
     override fun highlightNextImageOnCancelledImage(index: Int, maxSize: Int) {
         if (index < maxSize) {
             binding.vpUpload.setCurrentItem(index + 1, false)

app/src/main/res/values/strings.xml

@@ -904,4 +904,9 @@ Upload your first media by tapping on the add button.</string>
   <string name="license_cc0_long_description">This license allows reusers to distribute, remix, adapt, and build upon the material in any medium or format, with no conditions.</string>
   <string name="license_cc_by_long_description">This license allows reusers to distribute, remix, adapt, and build upon the material in any medium or format, even for commercial purposes, as long as attribution is given to the creator.</string>
   <string name="license_cc_by_sa_long_description">This license allows reusers to distribute, remix, adapt, and build upon the material in any medium or format, even for commercial purposes, as long as attribution is given to the creator and the new work is licensed under identical terms.</string>
+
+  <string name="unsupported_format_title">Unsupported Format</string>
+  <string name="unsupported_format_desc">The selected files could not be opened. Wikimedia Commons strictly requires JPEG, PNG, or SVG formats.</string>
+  <string name="unsupported_files_skipped_title">Unsupported Files Skipped</string>
+  <string name="unsupported_files_skipped_desc">Some files were skipped due to an unsupported format. The app will continue uploading your remaining JPEG, PNG, or SVG files.</string>
 </resources>