diff --git a/feeds.module b/feeds.module
index f0dd48c..dbdd74f 100644
--- a/feeds.module
+++ b/feeds.module
@@ -645,7 +645,7 @@ function feeds_node_insert($node) {
   if (isset($node->feeds) && $importer_id = feeds_get_importer_id($node->type)) {
     $source = feeds_source($importer_id, $node->nid);
     // Start import if requested.
-    if (feeds_importer($importer_id)->config['import_on_create'] && !isset($node->feeds['suppress_import'])) {
+    if ($source->hasFetcherSource() && feeds_importer($importer_id)->config['import_on_create'] && !isset($node->feeds['suppress_import'])) {
       $source->startImport();
     }
     // Schedule the source.
@@ -660,8 +660,13 @@ function feeds_node_update($node) {
   // Source attached to node.
   if (isset($node->feeds) && $importer_id = feeds_get_importer_id($node->type)) {
     $source = feeds_source($importer_id, $node->nid);
+    $had_fetcher_source = $source->hasFetcherSource();
     $source->addConfig($node->feeds);
     $source->save();
+    // Fetcher source was emptied or filled.
+    if ($had_fetcher_source != $source->hasFetcherSource()) {
+      $source->schedule();
+    }
   }
 }
 
diff --git a/includes/FeedsSource.inc b/includes/FeedsSource.inc
index 1fc5209..308bd07 100644
--- a/includes/FeedsSource.inc
+++ b/includes/FeedsSource.inc
@@ -305,17 +305,20 @@ class FeedsSource extends FeedsConfigurable {
       'period' => $period,
       'periodic' => TRUE,
     );
-    if ($period == FEEDS_SCHEDULE_NEVER && $this->progressImporting() === FEEDS_BATCH_COMPLETE) {
+
+    if (!$this->hasFetcherSource() || $period == FEEDS_SCHEDULE_NEVER && $this->progressImporting() === FEEDS_BATCH_COMPLETE) {
       JobScheduler::get('feeds_source_import')->remove($job);
     }
-    elseif ($this->progressImporting() === FEEDS_BATCH_COMPLETE) {
-      JobScheduler::get('feeds_source_import')->set($job);
-    }
-    else {
-      // Feed is not fully imported yet, so we put this job back in the queue
-      // immediately for further processing.
-      $queue = DrupalQueue::get('feeds_source_import');
-      $queue->createItem($job);
+    elseif ($this->hasFetcherSource()) {
+      if ($this->progressImporting() === FEEDS_BATCH_COMPLETE) {
+        JobScheduler::get('feeds_source_import')->set($job);
+      }
+      else {
+        // Feed is not fully imported yet, so we put this job back in the queue
+        // immediately for further processing.
+        $queue = DrupalQueue::get('feeds_source_import');
+        $queue->createItem($job);
+      }
     }
   }
 
@@ -802,6 +805,14 @@ class FeedsSource extends FeedsConfigurable {
   }
 
   /**
+   * Checks if the fetch source is empty.
+   */
+  public function hasFetcherSource() {
+    $fetcher_source_config = $this->getConfigFor($this->importer->fetcher);
+    return !empty($fetcher_source_config['source']);
+  }
+
+  /**
    * Implements FeedsConfigurable::dependencies().
    */
   public function dependencies() {
diff --git a/plugins/FeedsFetcher.inc b/plugins/FeedsFetcher.inc
index 33457de..d54084e 100644
--- a/plugins/FeedsFetcher.inc
+++ b/plugins/FeedsFetcher.inc
@@ -222,4 +222,29 @@ abstract class FeedsFetcher extends FeedsPlugin {
    *   $source, NULL otherwise.
    */
   public function importPeriod(FeedsSource $source) {}
+
+  /**
+   * Override parent::configDefaults().
+   */
+  public function configDefaults() {
+    return array(
+      'source_required' => TRUE,
+    );
+  }
+
+  /**
+   * Override parent::configForm().
+   */
+  public function configForm(&$form_state) {
+    $form = array();
+    // @todo Disable this option on stand-alone importers importer.
+    $form['source_required'] = array(
+      '#type' => 'checkbox',
+      '#title' => t('Require feed'),
+      '#description' => t('Ensure a feed source is provided during form submission.'),
+      '#default_value' => $this->config['source_required'],
+    );
+    return $form;
+  }
+
 }
diff --git a/plugins/FeedsFileFetcher.inc b/plugins/FeedsFileFetcher.inc
index 6f1b310..eed58d4 100644
--- a/plugins/FeedsFileFetcher.inc
+++ b/plugins/FeedsFileFetcher.inc
@@ -152,13 +152,19 @@ class FeedsFileFetcher extends FeedsFetcher {
         $values['file'] = $file;
       }
       elseif (empty($values['source'])) {
-        form_set_error('feeds][FeedsFileFetcher][source', t('Please upload a file.'));
+        if ($this->config['source_required']) {
+          form_set_error('feeds][FeedsFileFetcher][source', t('Please upload a file.'));
+        }
       }
       else {
         // File present from previous upload. Nothing to validate.
       }
     }
     else {
+      // Skip validating empty source if not required.
+      if (!$values['source'] && !$this->config['source_required']) {
+        return;
+      }
       // Check if chosen url scheme is allowed.
       $scheme = file_uri_scheme($values['source']);
       if (!$scheme || !in_array($scheme, $this->config['allowed_schemes'])) {
@@ -216,14 +222,14 @@ class FeedsFileFetcher extends FeedsFetcher {
       'direct' => FALSE,
       'directory' => $scheme . '://feeds',
       'allowed_schemes' => $schemes,
-    );
+    ) + parent::configDefaults();
   }
 
   /**
    * Overrides parent::configForm().
    */
   public function configForm(&$form_state) {
-    $form = array();
+    $form = parent::configForm($form_state);
     $form['allowed_extensions'] = array(
       '#type' => 'textfield',
       '#title' => t('Allowed file extensions'),
diff --git a/plugins/FeedsHTTPFetcher.inc b/plugins/FeedsHTTPFetcher.inc
index cd91b63..aacd662 100644
--- a/plugins/FeedsHTTPFetcher.inc
+++ b/plugins/FeedsHTTPFetcher.inc
@@ -90,6 +90,9 @@ class FeedsHTTPFetcher extends FeedsFetcher {
     if ($this->config['use_pubsubhubbub'] && ($raw = $this->subscriber($source->feed_nid)->receive())) {
       return new FeedsFetcherResult($raw);
     }
+    if (!$source_config['source']) {
+      throw new Exception(t('Source URL is empty.'));
+    }
     $fetcher_result = new FeedsHTTPFetcherResult($source_config['source']);
     // When request_timeout is empty, the global value is used.
     $fetcher_result->setTimeout($this->config['request_timeout']);
@@ -144,14 +147,14 @@ class FeedsHTTPFetcher extends FeedsFetcher {
       'request_timeout' => NULL,
       'auto_scheme' => 'http',
       'accept_invalid_cert' => FALSE,
-    );
+    ) + parent::configDefaults();
   }
 
   /**
    * Override parent::configForm().
    */
   public function configForm(&$form_state) {
-    $form = array();
+    $form = parent::configForm($form_state);
     $form['auto_detect_feeds'] = array(
       '#type' => 'checkbox',
       '#title' => t('Auto detect feeds'),
@@ -218,7 +221,7 @@ class FeedsHTTPFetcher extends FeedsFetcher {
       '#description' => t('Enter a feed URL.'),
       '#default_value' => isset($source_config['source']) ? $source_config['source'] : '',
       '#maxlength' => NULL,
-      '#required' => TRUE,
+      '#required' => $this->config['source_required'],
     );
     return $form;
   }
@@ -228,6 +231,10 @@ class FeedsHTTPFetcher extends FeedsFetcher {
    */
   public function sourceFormValidate(&$values) {
     $values['source'] = trim($values['source']);
+    // Skip validating empty source if not required.
+    if (!$values['source'] && !$this->config['source_required']) {
+      return;
+    }
 
     // Keep a copy for error messages.
     $original_url = $values['source'];