sharing: Set appropriate filename of shared content.

Previously filename was the last element of sharedFileUrl.split('/') or
sharedImageUrl.split('/'). This did not always correspond to the actual
filename, sometimes this element did not contain a file extension making
the uploaded data to be stored as a binary file. This made shared images
fail to render and on downloading the shared content it was downloaded
as a binary file.

This commit uses ContentResolver to find the actual name of file being
shared and uses that to identify the shared file.

Author: AkashDhiman

android/app/src/main/java/com/zulipmobile/MainActivity.kt

@@ -1,10 +1,13 @@
 package com.zulipmobile
 
 import android.content.Intent
+import android.provider.MediaStore
+import android.content.ContentResolver
 import android.net.Uri
 import android.os.Bundle
 import android.util.Log
 import android.webkit.WebView
+import android.database.Cursor
 import com.facebook.react.ReactActivity
 import com.facebook.react.ReactActivityDelegate;
 import com.facebook.react.ReactRootView;
@@ -94,6 +97,26 @@ open class MainActivity : ReactActivity() {
         }
     }
 
+    private fun getFileName(uri: Uri, cr: ContentResolver): String? {
+        var fileName: String? = null;
+        if (uri.scheme.equals("file")) {
+            fileName = uri.lastPathSegment;
+        } else {
+            var cursor: Cursor? = null;
+            try {
+                cursor = cr.query(uri, null, null, null, null)
+                if (cursor != null && cursor.moveToFirst()) {
+                    fileName = cursor.getString(cursor.getColumnIndex(MediaStore.Images.ImageColumns.DISPLAY_NAME))
+                }
+            } finally {
+                if (cursor != null) {
+                    cursor.close();
+                }
+            }
+        }
+        return fileName;
+    }
+
     private fun getParamsFromIntent(intent: Intent): WritableMap {
         // For documentation of what fields to expect here, see:
         //   https://developer.android.com/reference/android/content/Intent#ACTION_SEND
@@ -109,12 +132,14 @@ open class MainActivity : ReactActivity() {
                     ?: throw ShareParamsParseException("Could not extract URL from Image Intent")
                 params.putString("type", "image")
                 params.putString("sharedImageUrl", url.toString())
+                params.putString("fileName", getFileName(url, this.contentResolver))
             }
             else -> {
                 val url = intent.getParcelableExtra<Uri>(Intent.EXTRA_STREAM)
                     ?: throw ShareParamsParseException("Could not extract URL from File Intent")
                 params.putString("type", "file")
                 params.putString("sharedFileUrl", url.toString())
+                params.putString("fileName", getFileName(url, this.contentResolver))
             }
         }
         return params

src/sharing/send.js

@@ -34,7 +34,7 @@ export const handleSend = async (data: SendStream | SendPm, auth: Auth, _: GetTe
 
   if (sharedData.type === 'image' || sharedData.type === 'file') {
     const url = sharedData.type === 'image' ? sharedData.sharedImageUrl : sharedData.sharedFileUrl;
-    const fileName = url.split('/').pop();
+    const fileName = sharedData.fileName;
     const response = await uploadFile(auth, url, fileName);
     messageToSend += `\n[${fileName}](${response.uri})`;
   }

src/types.js

@@ -346,11 +346,13 @@ export type SharedText = {|
 export type SharedImage = {|
   type: 'image',
   sharedImageUrl: string,
+  fileName: string,
 |};
 
 export type SharedFile = {|
   type: 'file',
   sharedFileUrl: string,
+  fileName: string,
 |};
 
 /**