Automatic generation of client code from flask server code -- Introduction to flask native stubs Library

flask-native-stubs Project inspiration swagger Of codegen Tools . It is used to automatically generate the corresponding client interface function from the server's routing function .

You will experience something like “ Local function call ” As fast and natural . As follows :

• Server code :

  from flask_native_stubs import app, auto_route
  
  @auto_route()
  def hello_world(a: int, b: bool, c: str) -> str:
      print('received from client side:', a, b, c)
      return 'hello from server side!'
  
  app.run(host='127.0.0.1', port=8080)
  

• Client code :

  # client side
  from flask_native_stubs import setup_client
  #  notes :  take  flask_native_stubs  Auto generated code  ( If called  "server_stubs.py")  Put it where it can 
  #  Enough place to import . 
  from my_lib.server_stubs import hello_world
  
  #  To configure  host  and  port  port .
  setup_client(host='127.0.0.1', port=8080)
  
  #  It's like calling a local function .  No matter how it is written ,  still  ide  Type tips ,  Code completion, etc 
  #  can ,  It can be implemented completely according to the habits of ordinary function calls !
  response = hello_world(a=123, b=True, c='hello from client!')
  print(response)  # -> 'hello from server side!'
  

  • Use flask_native_stubs Auto generated code ( Referenced in the above code block “server_stubs.py”) What does it look like :

    from flask_native_stubs.stubgen import magic_route
    
    #  This is one that doesn't have any function  " Pseudofunction "
    def hello_world(a: int, b: bool, c: str) -> str:
        ...  #  Here are three points .
    
    #  Last use  magic_route  Magic method of this module  hello_world  Function grafted to  request 
    #  Decorator .
    [magic_route(x) for x in ('hello_world',)]
    

Run a screenshot :

What is a stub file (stubs)

“stub” Quote from java j2ee Of stub Concept :

Invokes an object on a remote host for masking clients , You must provide some way to simulate local objects , Such local objects are called stubs (stub). The stub is responsible for receiving the local method call , And delegate them to their concrete implementation objects .

stay python in , Also have stub The concept of , Mainly used for the enhanced experience of type checking . ( With python The type annotation is becoming more and more perfect , Some people think that stub Its role in this regard has been weakened .)

We use the shell of the original function on the server side , The generated shapes are similar but do not have any real business logic “ Pseudo function ”, Call it stubs, In terms of concept and purpose of use, it is consistent with the above .

How to generate stub file (stubs)

Generate flask-native-stubs The stub file method of is very simple . Just put the app.run Change it to app.generate_stubs that will do :

# server side
from flask_native_stubs import app, auto_route

@auto_route()
def hello_world(a: int, b: bool, c: str) -> str:
    print('received from client side:', a, b, c)
    return 'hello from server side!'

# app.generate_stubs(output_dir: str, filenames_map: dict = None)
# args:
# output_dir:  In which directory will the generated stub file be placed .
# filenames_map: ( Optional )  Customize input and output file names .  Key is the input file path ,  Value is lose 
#  Out of the file path . 
#  Paths can use relative or absolute paths .
#  When using relative paths ,  The input is relative to the current working directory ;  The output is relative to  # output_dir  Parameters .
app.generate_stubs(
    output_dir='../lib',
    filenames_map={
    
        'server.py': 'server_stubs.py'
    }
)

Copy the generated stub file to the client project , Put it where the client can import . ( Like joining in sys.path, Or join PYTHONPATH In the environment variables .)