Indexing attachments with Apache Solr Search module

In addition to Drupal nodes, Acquia Search results presented to your users can include files that contain matches to the search query. File formats that can be indexed include HTML, XML, Microsoft Office documents, OpenDocument, PDF, RTF, .zip, and other compression formats, text formats, audio formats, video formats, and more. For a complete list of supported document formats, see the Apache Tika documentation.

Search results for attached files display a direct link to the attached file and the node to which it is attached:

Search results with attachments

Searching file attachments requires the Apache Solr Attachments module. The Apache Solr Attachments module uses the Apache Tika Content Analysis Toolkit to detect and extract meta data and structured text content from a wide variety of file formats. After extraction, this information is indexed and available to your users with Acquia Search.


EOL notice! Drupal 9 reached end-of-life on November 1, 2023 and Drupal 8 reached end-of-life on November 2, 2021. Therefore, Acquia will not be performing any testing related to Drupal 9 or Drupal 8 to ensure compatibility. Acquia recommends upgrading to Drupal 10 or later. For more information, see Frequently Asked Questions.


  • Ensure that the most recent versions of your modules are in use. If you use older versions, you may experience problems with extracting attachments.

  • Earlier versions before Drupal 8.6 require that you install a patch, available from the following posting.

Installing the Apache Solr Attachments module

To index attachments:

  1. Install and enable the Apache Solr Attachments 7.x-1.x-dev module on your website. You must use this version since this is currently compatible with the Acquia Search Platform and other versions are incompatible.

  2. Go to the Apache Solr search > Configuration > Default Index page.

  3. In the Configuration section, select the File checkbox as an entity to be indexed.

  4. Click Save.

Search index configuration

The Apache Solr Search configuration page now displays the Attachments tab. Use the settings on this tab to configure the file attachment indexing settings.


The Apache Solr Attachments module is compatible only with Apache Solr Search. If you are using the Search API module, you can use the Search API attachments module instead. Configure it to work with Acquia Search. Be sure to use version 7.x-1.4 or later; earlier versions of the Search API attachments module are not compatible with Acquia Search.

Configuring file attachment index settings

The Attachments tab of the Apache Solr Search configuration page contains the following configuration options for indexing attachments in Apache Solr Search:

Apache Solr Search attachments configuration

S. No.




Excluded file extensions

A space-separated list of file extensions that are excluded from indexing. Modify this list to suit the needs of your site. Extensions are internally mapped to a MIME type, so it is not necessary to include variations that map to the same type. For example, tif is sufficient to exclude both the tif and tiff file extensions.


Extract using

Acquia Search includes Apache Tika for indexing documents. For best performance, select Solr (remote server).


File Size Limit

If a file is larger than this limit, do not index it. Default is 41943040 bytes (40MB).


Tika directory

Leave this blank.


Tika jar file

Leave this set to the default value.


Tika extracting servlet path



Tika extracting servlet parameters


Index and cache controls

File attachments get indexed at the same time as their parent entities. Under Actions, you can:



Clear the attachment text extraction cache

Clears all extracted data.

Delete the attachments from index

Deletes all the attached files on your site from the Acquia Search index. You need to do this if you change what types of files should be indexed, if your search index becomes corrupted, or if you install a new schema.xml.

Test your tika extraction

Tests if your Tika configuration settings work.