Building Blocks
Indexer
Responsibilities:
- Create and update a file index from a diretory to detect file changes quickly such as new, deleted files and moved files
- Create unique file identifier for each file (SHA1 sum)
For the first time the creation of a file index can be time consuming due the calculation of SHA1 checksum where each byte of a file needs to be processed. Depending on the total file size this process can take hours.
On file index update known files do not need to be updated. Known files are detected by file path and inode. Other strategies are supported, too.
The file index is used to have a filtered view on your files of your source directories. The gallery handles only files which are listed in the file index. To exclude files or folders in the gallery it is sufficient to add exclude patterns on the source directories.
Extractor
Responsibilities:
- Calculate preview images and videos based on the file index and the uniq file identifier
- Extract meta data original files, preview data or other meta data
- Store all data to the storage directory
The work of the extractor is explorative and the raw output data from extractors is stored.
The calculation of preview files and extracting meta data is time consuming. The calculation of preview videos takes also long. Depending on image and video count and used PC this process can take weeks for the intial run. Updates compute only new media (detected by the file index).
Database Builder
Responsibilities:
- Create a database from preview files extracted meta data for the WebApp
The database builder prepares the data for the (mobile) browser and collects the important data for the presentational WebApp
Events
User inputs such as add or remove tags are handled and stored as events. These events are applied on the database entries.
Server
Responsibilities:
- Serve the WebApp
- Serve the preview images and videos to the WebApp
- Handle user events like add or remove tags
Since the database is loaded into the browser, the server acts mainly as a static webserver. The main logic such as filtering and sorting is executed in the WebApp
Export Meta Data
Responsibilities:
- Export meta data to XMP sidecar files
Fetch
Responsibilities:
- Fetch a (subset) of a remote gallery and merge it into the local gallery
Export Static Gallery
Responsibilities:
- Export static web site from a subset
- Static export requires only an HTTP server such Apache2 or Nginx