hipcms/thumbnailservice

HiP-ThumbnailService

Microservice (REST API) for generating thumbnails.

Development Environment Setup

• Clone the repository
• Configure the app: Create a file appsettings.Development.json in the same folder as HiP-ThumbnailService.csproj with the following content, replacing "YOUR URL PREFIX" with a valid URL according to the documentation for https://github.com/HiP-App/HiP-ThumbnailService/blob/develop/HiP-ThumbnailService/Utility/ThumbnailConfig.cs:

  {
      "Thumbnails": {
          "HostUrl": "YOUR URL PREFIX"
      }
  }
  

• Launch the app
  • via Visual Studio: Open the solution (*.sln) and run the app (F5)
  • via Terminal: Execute dotnet run from the project folder containing HiP-ThumbnailService.csproj

The app is preconfigured to run on dev machines with minimal manual configuration. See https://github.com/HiP-App/HiP-ThumbnailService/blob/develop/HiP-ThumbnailService/appsettings.json for a list of configuration fields and their default values.

Core Concepts

When requesting thumbnails via GET /api/Thumbnails?Url=..., the thumbnail service retrieves the original image from another server or service, resizes and crops the image, and then returns it. The URL to the original image is constructed from two parts:

1. The "HostUrl" configured in the thumbnail service
   (example: "[***]")
2. The relative URL given by the client via ?Url=
   (example: "datastore/Media/42/File")

Thumbnails of different sizes and formats are cached. When the original image changes, the service owning the image needs to clear the thumbnail cache for that image by calling DELETE /api/Thumbnails?Url=..., otherwise the thumbnail service will continue to return the outdated, cached thumbnails.