How to access block fields programmatically?
I found the value by first grabbing the assignment value from the URL, then looking up the path to find the node id, then loading that node and using a wrapper to find the value of that specific field.


        $url = $_SERVER['REQUEST_URI'];
        $pos = strpos($url, '?') + 1;
        $assignment = substr($url, $pos, strlen($url)); //get the assignment from the URL

        $nodeID = drupal_lookup_path('source', "student-assignments-new/" . $assignment);//get the path from the assignment - e.g. node/145
        $pos = strpos($nodeID, '/') + 1;
        $nid = substr($nodeID, $pos, strlen($nodeID));//get the node id

        $node = node_load($nid);

        $wrapper = entity_metadata_wrapper('node', $node); 
        $fieldValue = $wrapper->field_file_type_text->value();

        $output = $node->field_file_type_text[LANGUAGE_NONE][0]['value']; //field_file_type_text is my own field name
        return $output;