Files
directus/docs/guides/files.md
2020-12-01 18:01:00 -05:00

5.3 KiB

Files & Thumbnails

Directus offers a full-featured Digital Asset Management (DAM) system, multiple storage adapters, private file permissions, and on-demand image thumbnail generation.

Uploading a File

@TODO

Accessing an Original File

The location of your actual file originals is based on the project's configuration, but you can consistently access them via the API using the following URL.

example.com/assets/<file-id>
example.com/assets/1ac73658-8b62-4dea-b6da-529fbc9d01a4

Original File Original File Used Below — 602KB and 1800x1200

::: warning Direct File Access While you may technically be able to access your original files within their actual filesystem directory (eg: /uploads/<filename_disk> for the default local storage configuration), it is recommended that you always use the Directus API. This is the only way that you can take advantage of file permissions and other built-in features. :::

Creating Thumbnail Presets

  1. Navigate to Settings > Project Settings
  2. Scroll to the Storage Asset Presets field
  3. Click Add a New Item
  4. Enter a unique Key for the preset
  5. Enter the Fit, Width, Height, and Quality for the preset
  6. Click the Save action button in the header

::: tip Storage Asset Transform The Storage Asset Transform can be used in conjunction with the presets to force an allow-list or completely disable the thumbnailing system. The options for this are:

  • All — Any valid thumbnail request will be returned
  • None — No thumbnails will be returned, not even presets
  • Presets Only — Only valid Storage Asset Presets will be returned :::

Requesting a Thumbnail

Fetching thumbnails is as easy as adding query parameters to the original file's URL. If a requested thumbnail doesn't yet exist, it is dynamically generated and immediately returned. When requesting a thumbnail, the following parameters are all required.

  • fit — The fit of the thumbnail while always preserving the aspect ratio, can be any of the following options:
    • cover — Covers both width/height by cropping/clipping to fit
    • contain — Contain within both width/height using "letterboxing" as needed
    • inside — Resize to be as large as possible, ensuring dimensions are less than or equal to the requested width and height
    • outside — Resize to be as small as possible, ensuring dimensions are greater than or equal to the requested width and height
  • width — The width of the thumbnail in pixels
  • height — The height of the thumbnail in pixels
  • quality — The quality of the thumbnail (0 to 100)
  • withoutEnlargement — Disable image up-scaling
  • download — Add Content-Disposition header and force browser to download file
example.com/assets/<file-id>?fit=<fit>&width=<width>&height=<height>&quality=<quality>
example.com/assets/1ac73658-8b62-4dea-b6da-529fbc9d01a4?fit=cover&width=200&height=200&quality=80

Alternatively, you can reference a specific thumbnail by its preset key.

example.com/assets/<file-id>?key=<preset-key>
example.com/assets/1ac73658-8b62-4dea-b6da-529fbc9d01a4?key=card

Cover vs Contain

For easier comparison, both of the examples below were requested at 200 width, 200 height, and 75 quality. The cover thumbnail forces the dimensions, trimming the outside edges as needed. The contain thumbnail always maintains its aspect ratio, shrinking the image to fit within the dimensions and adding "letterboxing" as needed.

Cover Contain
Cover
8KB • 200x200
Contain
6KB • 200x133

::: Aspect Ratio Images are never stretched or distorted even when changing the aspect ratio. :::

Quality vs Filesize

The quality parameter can be any integer from 0-100. Qualities closer to 0 have lower filesizes, but also poor image quality due to compression artifacts. Values closer to 100 have larger filesizes, but better image quality. Below are four possible qualities (200x200 cover) to visually compare the balance between compression and filesize.

25% 50% 75% 100%
25%
4KB
50%
6KB
75%
8KB
100%
38KB