Caracal

Caracal is a light multimedia server designed as a service.

It provides a simple HTTP REST API and a HTML5 user interface.

Installation

npm install caracal

GraphicsMagick or ImageMagick is required. FFmpeg (not libav) is necessary for video resizing and converting.

Docker

docker pull yellowiscool/caracal
 
docker volume create --name caracal-data
 
docker run -d --restart=always \
  --name caracal \
  -v caracal-data:/usr/src/app/data \
  -e DELETIONS_KEY=secretkey \
  yellowiscool/caracal

Features

• File uploads
• File suppressions
• Picture and video thumbnails
• Picture resizing
• Video resizing and converting
• Convert videos to H264 or Webm
• Can fetch distant HTTP files
• Multimedia reverse proxy with a cache
• Transparent resizing
• Transparent video converting
• Basic HTTP authentification support
• Light HTML5 user interface
• Drag and drop support
• Progression bar for slow connexions
• Thumbnails and pagination
• Configurable generation of identifiers
• human readable
• adjective-adjective-animal
• shortid
• sha256

Notes about the scalability

Caracal is designed to run as a single node on a single server. It does not support horizontal scaling. It is suitable for prototyping or simple non-critical multimedia applications, but it cannot be used to compete with Youtube or Imgur (yet). In case of a high load, a processing queue is used.

Configuration

Caracal can be configured using environment variables.

Environment Variable	Description	Default value
DELETIONS_KEY	The required password/key to delete files.	needs to be configured
ALLOWED_DOMAINS	Optionnal JSON array of allowed domains, for CORS	* (all domains are allowed)
HTTP_PORT	Listening HTTP port	8075
DATAPATH	Location of the storage folder	./data
CACHE	HTTP Cache-Control header	max-age=29030400, public
CONCURRENCY	Number of allowed concurrent image processing tasks	8
VIDEO_CONCURRENCY	Number of allowed concurrent video processing tasks	2
ALLOWED_SIZES	Array of allowed resizing sizes. If a requested size is not found, the closest size from this array is used instead. Set to * to allow every size, but it's not recommended since users can saturate the server by resizing the same image many times. The default configuration allows many sizes, you might want to use fewer sizes.	[32, 64, 128, 256, 1024, 2048, 4096, 8192, 16384, 50, 100, 200, 400, 500, 600, 800, 1000, 1050, 1200, 1600, 120, 160, 240, 320, 480, 576, 640, 768, 854, 960, 1050, 1080, 1152, 1280, 1440, 1536, 1716, 1920, 2160, 2560, 3200, 3840, 3996, 4320, 4800, 5120, 6400, 6144, 7680, 12288]
ALLOWED_VIDEO_SIZES	Array of allowed resizing sizes, for videos. Similar to ALLOWED_SIZES.	[144, 240, 360, 480, 720, 1080, 3840]
AUTHS	JSON association table (object) used for HTTP basic access authentications, when fetching distant files. keys are the host-names, values are the passwords.	{}
UA	The HTTP client user agent, to fetch distant files	~Firefox28-Win64
IDS_GENERATION	The algorithm used to generate identifiers. See the generation of identifiers section. Accepted values are sillyid, shortid, human-readable, bronze, and hash.	sillyid

API

GET /

HTML5 user interface.

GET /files

JSON list of files stored in the server

[
 {
    "url": "http://upload.wikimedia.org/wikipedia/commons/d/d3/Veymont-aiguille_mg-k.jpg",
    "name": "Veymont-aiguille_mg-k.jpg",
    "id": "ElementaryPertinentWalleye",
    "size": 168454,
    "hash": "698baa587aef2a26bddd8461d6a4e132ae1dcbd5f58aa6e47c20bc703356a8ec",
    "extension": "jpeg",
    "type": "image/jpeg",    
    "mtime": "2014-04-09T11:36:05.145Z"
  },...
]

POST /upload

Save on the server the provided file

{
  "name": "208T16-05E.jpg",
  "id": "HauntingWholeEsok",
  "size": 4700,
  "status": "ok",
  "hash": "7d15d97340aaf30e08baf92e9e3aa57b969f12540805be265dee44496f4b099f",
  "extension": "png",
  "type": "image/png",
  "mtime": "2017-02-25T11:49:29.002Z",
  "status": "ok"
}

GET /{URL}

If the URL is not in the cache, fetch, save and return the content of the url.

Example : GET /http://perdu.com

GET /fetch/{URL}

If the URL is not in the cache fetch and save the content of the url. Then return information about the URL.

Response example :

{
  "url":"http://perdu.com",
  "name":"perdu.com",
  "id":"UnacceptableJoyfulLacewing",
  "size":204,
  "hash":"208e330c75ffd93949be0258660973bef8223917f036325020f3a4c51b4ca430",
  "extension":"html",
  "type":"text/html",
  "mtime":"2017-02-25T11:52:58.522Z",
  "status":"ok"
}

GET /remove/{hash}.{extension}

GET /remove/{id}

Remove the related files to the hash and the extension from the server.

Examples :

• GET /remove/698baa587aef2a26bddd8461d6a4e132ae1dcbd5f58aa6e47c20bc703356a8ec.jpeg
• GET /remove/ElementaryPertinentWalleye

GET /thumbnail/{hash}.{extension}

GET /thumbnail/{id}

Create and return a 128x128 thumbnail of the given file. If the format is not supported by GraphicsMagic, an error is returned.

Examples :

• GET /thumbnail/698baa587aef2a26bddd8461d6a4e132ae1dcbd5f58aa6e47c20bc703356a8ec.jpeg
• GET /thumbnail/ElementaryPertinentWalleye

GET /resize/{max_width}/{max_height}/{hash}.{extension}

GET /resize/{max_width}/{max_height}/{id}

Resize the given image. The image aspect ratio is conserved.

The image format must be compatible with GraphicsMagick.

Examples :

• GET /resize/1280/720/698baa587aef2a26bddd8461d6a4e132ae1dcbd5f58aa6e47c20bc703356a8ec.jpeg
• GET /resize/1280/720/ElementaryPertinentWalleye

GET /resize/deform/{max_width}/{max_height}/{hash}.{extension}

GET /resize/deform/{max_width}/{max_height}/{id}

Same as resize but the ratio is not conserved.

GET /convert/{format}/{height}/{hash}.{extension}

GET /convert/{format}/{height}/{id}

Resize the given video. The video aspect ratio is conserved.

The input video format must be compatible with your FFmpeg installation.

Supported output formats : mp4 or webm Supported output sizes : 240, 480, 720, 1080

Examples :

• GET /convert/mp4/720/e7c7c984066753d5cc52e97f26f4f7892df67bacb.wmv
• GET /convert/mp4/720/WiryRosyQueensnake

GET /thumbnail/{URL}

Create and return a 128x128 thumbnail of the distant image.

Example : GET /thumbnail/http://upload.wikimedia.org/wikipedia/commons/d/d3/Veymont-aiguille_mg-k.jpg

GET /resize/{max_width}/{max_height}/{URL}

Resize the distant image. The image aspect ratio is conserved.

Example : GET /resize/1280/720/http://upload.wikimedia.org/wikipedia/commons/d/d3/Veymont-aiguille_mg-k.jpg

GET /resize/deform/{max_width}/{max_height}/{URL}

Same as resize but the ratio is not conserved.

GET /convert/{format}/{height}/{URL}

Resize the distant video. The video ratio is conserved.

The input video format must be compatible with your FFmpeg installation.

Supported output formats : mp4 or webm Supported output sizes : 240, 480, 720, 1080

Example : GET /convert/webm/480/http://example.net/video.flv

GET /{hash}.{extension}

GET /{id}

Return the file :-)

Behind

• NodeJs
• GraphicsMagick with gm
• FFmpeg with node-fluent-ffmpeg
• Express
• Bootstrap
• jQuery
• jQuery File Upload
• NeDB

Generation of Identifiers

Name	Description	Example
sillyid (default)	Generation of fun gfycat like identifiers, following the AdjectiveAdjectiveAnimal pattern.	HairyOrangeGeckos
shortid	Short url-friendly identifiers.	PPBqWA9
human-readable	Easy to spell identifiers, following the adjective-noun-# pattern.	tricky-chicken-23
bronze	Collision-resistant ids for distributed systems.	1482810226160-0-14210-example-1a
hash	Use the sha256 checksum as id.	698baa587aef2a26bddd8461d6a4e132ae1dcbd5f58aa6e47c20bc703356a8ec

Screenshot (work in progress)

Acknowledgements

Caracal is developed in context of the BRIDGE and HUMANE European research projects.

Licence

The source code of this library is licenced under the MIT License.