Static File Host

The static file host server hosting the static files of courses built roman. It provides API allowing users to upload/update static files of courses to it.

It is built with the help of aplus-file-transfer package.

Architecture

• Authentication

  It applies JWT authentication with RS256 algorithm. A JWT token is encoded by a private key in the service shepherd. The token is sent in the Authorization header when making requests to the API, and this server provides a public key in PEM format to decode and authenticate it.

  An example of a public key:

  JWT_PUBLIC_KEY = """
  -----BEGIN PUBLIC KEY-----
  MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA0QIB6wP5rGpT7pcKM0uQ
  bn3FbQI2Xp58vLW+eLISgPvh0EMNuVWMazRfTBGnSxYI2P2F+Yf+O8Ck3JWOpuCD
  +i0a+RlC7gZdspULHpRYSccOqvRdcMn93nuPxiHJ+zAFuVR6mmDQmkHR3ruFvbQt
  FWABpbZpqVOlaOUqoyQcp7JGOrrGZZhifS8EE56azvhIm8n2qf+KhKkTq0P71j+4
  3h2sZtHM9nrsm/wtyb26xPBwGS1v1d5bWw0D2vhPSCP4HV2DuI6WD6pEN9Axjf5j
  dG7tGa6GnyPchdDAvlnA1FQiFfkz4NQtL5upmGiz6gBslFlPhZmejlr2RUYd4mbQ
  3QIDAQAB
  -----END PUBLIC KEY-----
  """ 

  The payload of a JWT token generated by shepherd includes the fields Subject, Issuer and Issued at. The Subject field is the name of the course folder, and the Issuer field is restricted, JWT_ISSUER = shepherd. An example of the payload component of a JWT token:

  {
  'sub': 'def_course', 
  'iss': 'shepherd',  
  'iat': 1562828304
  }

  The client also needs to provide a parameter course_name in the url, and whether the course_name and the sub field are the same will also be checked.

• Method:

  POST /<course_name>/select-files - Select files of the course to upload

  POST /<course_name>/upload-files - Upload the files to a temporary course directory

  POST /<course_name>/publish-files - Upload the files to a temporary course directory

  To deploy static files of a course, first calling the endpoint /<course_name>/select-files to decide which files to upload, and then calling the endpoint /<course_name>/upload-files to upload selected files. Finally calling /<course_name>/publish-files to publish the uploaded files to the server. The docker container of deploying a course to the server is available in aplus-file-transfer.

Set up the server

# to the root of repo
cd static-file-host

# build the images
docker-compose build

# start up the server
docker-compose up

Visit http://localhost:7000/ (or replace localhost with the docker0 IP address). Currently only the name list of uploaded courses in the server is showed.

Visit http://localhost:7000/courses/ to see the uploaded files (it lists the directory /server_app/courses/ that hosting static files in the nginx container).

For develop and test the Flask app alone

# to the root of repo    
cd static-file-host/server_app      
                         
# in your vitrualenv       
pip install -r requirements.txt
# or
# pip3 install -r requirements.txt

# development mode
export FLASK_ENV=development

# run the app
python app.py
# or
# python3 app.py    

Visit http://localhost:5000/