myFirstAPI.py

import fastapi
import uvicorn
from fastapi import FastAPI, Path
from typing import Optional, List
from pydantic import BaseModel #提供基本校验和特定数据类型

# 当前路径加入系统变量 ------------------------------------
import os
import sys
root_path = os.getcwd()
print(root_path)
sys.path.append(root_path)

app=FastAPI()

# write a basic python dictionary to store info in key-value pair
students={
  1: {
    "name":"john",
    "age":"22",
    "year":"year 12"
  }
} 
# we want to return the student specific information with the student ID
# for web address in the web server, we need to type in `http://127.0.0.1:8000/get/1`

class Student(BaseModel): #设置固定的datatype
  name: str
  age: int
  year: str

class UpdateStudent(BaseModel):
  name: Optional[str]=None
  age: Optional[int]=None 
  year: Optional[str]=None

@app.get("/") #slash is simply the homepage
def index():
  return {"name": "First Data"} 
# later...written in python dictionary and automatically convert to json format 

## Path Parameter
@app.get("/get-student/{student_id}") #put a dynamic variable here
def get_student(student_id: int): #= Path(None, description="The ID of the student you want to view", gt=0, lt=3)): #None：catch the error
  return students[student_id] 
##对key的数值进行限制：
# gt: greater than
# lt: less than
# ge: greater than or equal to
# le: less than or equal to

## Query Parameter
@app.get('/get-by-name/{student_id}') #@app.get('/get-by-name?john')
def get_student(*, name: Optional[str]=None, test: int): #the star symbol represent the default or other we need 
  for student_id in students:
    if students[student_id]["name"]==name: #get the information by name
      return students[student_id]
  return {"Data":"Not Found"}
## in some situations, we can combine the query and path parameter together

@app.post("/create_student/{student_id}")
def create_student(student_id: int, student : Student):
  if student_id in students:
    return {"Error": "Student Exists"} #without store twice
  students[student_id]=student
  return students[student_id]
#BUT, the input generated by this function only exists in the memory. Namely, if we refresh the webpage, the new generated information will be lost.

@app.put('/update-student/{student_id}')
def update_student(student_id: int, student : Student):
  if student_id not in students:
    return {"Error": "Student does not exist"}
  if student.name != None:
    students[student_id].name=student.name
  if student.age != None:
    student[student_id].age=student.age
  if student.year != None:
    student[student_id].year=student.year
  return students[students_id]

@app.delete("/delete-student/{student_id}")
def delete_student(student_id: int):
  if student_id not in students:
    return {"Error": "Student does not exist"}
  del students[student_id]
  return {"Message" : "Delete Successfully"}


if __name__=='__main__':
  uvicorn.run(app='myFirstAPI:app', host="127.0.0.1", port=8000, reload=True, debug=True)


# Shell command:
# uvicorn Desktop.myFirstAPI:app --reload