This document covers important considerations for naming files and working with metadata like thumbnails and indexable text. To get started inserting and retrieving files, see Files reference.
Specify file names & extensions
Apps should specify a file extension in the title property when inserting files
with the API. For example, an operation to insert a JPEG file should specify
"name": "cat.jpg" in the metadata.
GET responses can include the read-only
populated with the extension originally specified in the
name property. When a Google Drive user requests to download
a file, or when the file is downloaded through the sync client, Drive builds a
full filename (with extension) based on the title. In cases where the extension
is missing, Drive attempts to determine the extension based on the file's MIME
Save indexable text
Drive automatically indexes documents for search when it recognizes the file
type, including text documents, PDFs, images with text, and other common types.
If your app saves other types of files (such as drawings, video, and shortcuts),
you can improve the discoverability by supplying indexable text in the
contentHints.indexableText field of the file.
Indexable text is indexed as HTML. If you save the indexable text string
<section attribute="value1">Here's some text</section>, then "Here's some
text" is indexed, but "value1" is not. Because of this, saving XML as indexable
text isn't as useful as saving HTML.
indexableText, also keep in mind:
- The size limit for
contentHints.indexableTextis 128 KB.
- Capture the key terms and concepts that you expect a user to search for.
- Don't try to sort text in order of importance because the indexer does that efficiently for you.
- Your application should update the indexable text with each save.
- Make sure the text is related to the content or metadata of the file.
This last point might seem obvious, but it's important. It's not a good idea to add commonly searched terms to force a file to appear in search results. This can frustrate users, and might even motivate them to delete the file.
Drive automatically generates thumbnails for many common file types. For
shortcuts and other file types that Drive can't render, you can provide a
thumbnail image generated by your application. Upload a thumbnail by setting the
contentHints.thumbnail property on the
Files resource during an
contentHints.thumbnail.imageto the URL-safe Base64-encoded image (see RFC 4648 section 5).
contentHints.thumbnail.mimeTypeto the appropriate type for the image format.
If Drive can generate a thumbnail from the file, then it uses the generated one and ignores any you have uploaded. If it can't generate a thumbnail, it always uses yours if you provided one. Items to keep in mind:
- Thumbnails can be uploaded in PNG, GIF, or JPG formats.
- The recommended width is 1600 pixels.
- The maximum file size for a thumbnail is 2 MB.
- The minimum width for thumbnails is 220 pixels.
- Your application should update the thumbnails with each save.
For more information, see the Files reference.