Use EXIF data of image to prefill image description

During attachment upload Pleroma returns a "description" field. Pleroma-fe has an MR to use that to pre-fill the image description field, <https://git.pleroma.social/pleroma/pleroma-fe/-/merge_requests/1399>

* This MR allows Pleroma to read the EXIF data during upload and return the description to the FE
    * If a description is already present (e.g. because a previous module added it), it will use that
    * Otherwise it will read from the EXIF data. First it will check -ImageDescription, if that's empty, it will check -iptc:Caption-Abstract
    * If no description is found, it will simply return nil, just like before
* When people set up a new instance, they will be asked if they want to read metadata and this module will be activated if so

This was taken from an MR i did on Pleroma and isn't finished yet.

2 files changed, 14 insertions, 7 deletions

diff --git a/docs/configuration/cheatsheet.md b/docs/configuration/cheatsheet.md
index 1e74d40e6..f1624b651 100644
--- a/docs/configuration/cheatsheet.md
+++ b/docs/configuration/cheatsheet.md
@@ -633,6 +633,12 @@ This filter only strips the GPS and location metadata with Exiftool leaving colo
 
 No specific configuration.
 
+#### Pleroma.Upload.Filter.ExiftoolReadData
+
+This filter only reads metadata with Exiftool so clients can prefill the media description field.
+
+No specific configuration.
+
 #### Pleroma.Upload.Filter.Mogrify
 
 * `args`: List of actions for the `mogrify` command like `"strip"` or `["strip", "auto-orient", {"implode", "1"}]`.
diff --git a/docs/installation/optional/media_graphics_packages.md b/docs/installation/optional/media_graphics_packages.md
index cb3d71188..47e2ef3fb 100644
--- a/docs/installation/optional/media_graphics_packages.md
+++ b/docs/installation/optional/media_graphics_packages.md
@@ -1,9 +1,9 @@
 # Optional software packages needed for specific functionality
 
 For specific Pleroma functionality (which is disabled by default) some or all of the below packages are required:
-  * `ImageMagic`
-  * `ffmpeg`
-  * `exiftool`
+    * `ImageMagic`
+    * `ffmpeg`
+    * `exiftool`
   
 Please refer to documentation in `docs/installation` on how to install them on specific OS.
   
@@ -14,19 +14,20 @@ Note: the packages are not required with the current default settings of Pleroma
 `ImageMagick` is a set of tools to create, edit, compose, or convert bitmap images.
 
 It is required for the following Pleroma features:
-  * `Pleroma.Upload.Filters.Mogrify`, `Pleroma.Upload.Filters.Mogrifun` upload filters (related config: `Plaroma.Upload/filters` in `config/config.exs`)
-  * Media preview proxy for still images (related config: `media_preview_proxy/enabled` in `config/config.exs`)
+    * `Pleroma.Upload.Filters.Mogrify`, `Pleroma.Upload.Filters.Mogrifun` upload filters (related config: `Plaroma.Upload/filters` in `config/config.exs`)
+    * Media preview proxy for still images (related config: `media_preview_proxy/enabled` in `config/config.exs`)
   
 ## `ffmpeg`
 
 `ffmpeg` is software to record, convert and stream audio and video.
 
 It is required for the following Pleroma features:
-  * Media preview proxy for videos (related config: `media_preview_proxy/enabled` in `config/config.exs`)
+    * Media preview proxy for videos (related config: `media_preview_proxy/enabled` in `config/config.exs`)
 
 ## `exiftool`
 
 `exiftool` is media files metadata reader/writer.
 
 It is required for the following Pleroma features:
-  * `Pleroma.Upload.Filters.Exiftool` upload filter (related config: `Plaroma.Upload/filters` in `config/config.exs`)
+    * `Pleroma.Upload.Filters.Exiftool` upload filter (related config: `Plaroma.Upload/filters` in `config/config.exs`)
+    * `Pleroma.Upload.Filters.ExiftoolReadData` upload filter (related config: `Plaroma.Upload/filters` in `config/config.exs`)