Added ExistingFileAsync.java

app/src/main/java/fr/free/nrw/commons/upload/ExistingFileAsync.java

@@ -0,0 +1,70 @@
+package fr.free.nrw.commons.upload;
+
+
+import android.os.AsyncTask;
+import android.util.Log;
+
+import org.mediawiki.api.ApiResult;
+import org.mediawiki.api.MWApi;
+
+import java.io.IOException;
+import java.util.ArrayList;
+
+import fr.free.nrw.commons.CommonsApplication;
+
+/**
+ * Sends asynchronous queries to the Commons MediaWiki API to check that file doesn't already exist
+ */
+public class ExistingFileAsync extends AsyncTask<Void, Void, ArrayList<String>> {
+
+    private final static int SEARCH_CATS_LIMIT = 25;
+    private static final String TAG = fr.free.nrw.commons.category.TitleCategories.class.getName();
+    private String title;
+
+    public ExistingFileAsync(String title) {
+        super();
+        this.title = title;
+    }
+
+    @Override
+    protected void onPreExecute() {
+        super.onPreExecute();
+    }
+
+    @Override
+    protected ArrayList<String> doInBackground(Void... voids) {
+
+        MWApi api = CommonsApplication.createMWApi();
+        ApiResult result;
+        ArrayList<String> items = new ArrayList<>();
+
+        //URL https://commons.wikimedia.org/w/api.php?action=query&format=xml&list=search&srwhat=text&srenablerewrites=1&srnamespace=14&srlimit=10&srsearch=
+        try {
+            result = api.action("query")
+                    .param("format", "xml")
+                    .param("list", "search")
+                    .param("srwhat", "text")
+                    .param("srnamespace", "14")
+                    .param("srlimit", SEARCH_CATS_LIMIT)
+                    .param("srsearch", title)
+                    .get();
+            Log.d(TAG, "Searching for cats for title: " + result.toString());
+        } catch (IOException e) {
+            Log.e(TAG, "IO Exception: ", e);
+            //Return empty arraylist
+            return items;
+        }
+
+        ArrayList<ApiResult> categoryNodes = result.getNodes("/api/query/search/p/@title");
+        for(ApiResult categoryNode: categoryNodes) {
+            String cat = categoryNode.getDocument().getTextContent();
+            String catString = cat.replace("Category:", "");
+            items.add(catString);
+        }
+
+        Log.d(TAG, "Title cat query results: " + items);
+
+        return items;
+    }
+
+}