使用Python & Flask 实现RESTful Web API的实例_Python

环境安装：

sudo pip install flask

Flask 是一个Python的微服务的框架，基于Werkzeug, 一个 WSGI 类库。

Flask 优点:

Written in Python (that can be an advantage);
Simple to use;
Flexible;
Multiple good deployment options;
RESTful request dispatching

RESOURCES

一个响应 /articles 和 /articles/:id的 API 服务：

									from flask import Flask, url_for

									app = Flask(__name__)

									@app.route('/')

									def api_root():

									 return 'Welcome'

									@app.route('/articles')

									def api_articles():

									 return 'List of ' + url_for('api_articles')

									@app.route('/articles/<articleid>')

									def api_article(articleid):

									 return 'You are reading ' + articleid

									if __name__ == '__main__':

									 app.run()

请求：

curl http://127.0.0.1:5000/

响应：

GET /
Welcome

GET /articles
List of /articles

GET /articles/123
You are reading 123

REQUESTS

GET Parameters

									from flask import request

									@app.route('/hello')

									def api_hello():

									 if 'name' in request.args:

									  return 'Hello ' + request.args['name']

									 else:

									  return 'Hello John Doe'

请求：

GET /hello
Hello John Doe

GET /hello?name=Luis
Hello Luis

Request Methods (HTTP Verbs)

									@app.route('/echo', methods = ['GET', 'POST', 'PATCH', 'PUT', 'DELETE'])

									def api_echo():

									 if request.method == 'GET':

									  return "ECHO: GET\n"

									 elif request.method == 'POST':

									  return "ECHO: POST\n"

									 elif request.method == 'PATCH':

									  return "ECHO: PACTH\n"

									 elif request.method == 'PUT':

									  return "ECHO: PUT\n"

									 elif request.method == 'DELETE':

									  return "ECHO: DELETE"

请求指定request type：

curl -X PATCH http://127.0.0.1:5000/echo
GET /echo
ECHO: GET

POST /ECHO
ECHO: POST

Request Data & Headers

									from flask import json

									@app.route('/messages', methods = ['POST'])

									def api_message():

									 if request.headers['Content-Type'] == 'text/plain':

									  return "Text Message: " + request.data

									 elif request.headers['Content-Type'] == 'application/json':

									  return "JSON Message: " + json.dumps(request.json)

									 elif request.headers['Content-Type'] == 'application/octet-stream':

									  f = open('./binary', 'wb')

									  f.write(request.data)

									    f.close()

									  return "Binary message written!"

									 else:

									  return "415 Unsupported Media Type ;)"

请求指定content type：

curl -H "Content-type: application/json" \
-X POST http://127.0.0.1:5000/messages -d '{"message":"Hello Data"}'

curl -H "Content-type: application/octet-stream" \
-X POST http://127.0.0.1:5000/messages --data-binary @message.bin

RESPONSES

									from flask import Response

									@app.route('/hello', methods = ['GET'])

									def api_hello():

									 data = {

									  'hello' : 'world',

									  'number' : 3

									 }

									 js = json.dumps(data)

									 resp = Response(js, status=200, mimetype='application/json')

									 resp.headers['Link'] = 'http://luisrei.com'

									 return resp

查看response HTTP headers：

curl -i http://127.0.0.1:5000/hello

优化代码：

from flask import jsonify

使用

1 2	`resp = jsonify(data)` `resp.status_code = 200`

替换

1	`resp = Response(js, status=200, mimetype='application/json')`

Status Codes & Errors

									@app.errorhandler(404)

									def not_found(error=None):

									 message = {

									   'status': 404,

									   'message': 'Not Found: ' + request.url,

									 }

									 resp = jsonify(message)

									 resp.status_code = 404

									 return resp

									@app.route('/users/<userid>', methods = ['GET'])

									def api_users(userid):

									 users = {'1':'john', '2':'steve', '3':'bill'}

									 if userid in users:

									  return jsonify({userid:users[userid]})

									 else:

									  return not_found()

请求：

GET /users/2
HTTP/1.0 200 OK
{
"2": "steve"
}

GET /users/4
HTTP/1.0 404 NOT FOUND
{
"status": 404,
"message": "Not Found: http://127.0.0.1:5000/users/4"
}

AUTHORIZATION

									from functools import wraps

									def check_auth(username, password):

									 return username == 'admin' and password == 'secret'

									def authenticate():

									 message = {'message': "Authenticate."}

									 resp = jsonify(message)

									 resp.status_code = 401

									 resp.headers['WWW-Authenticate'] = 'Basic realm="Example"'

									 return resp

									def requires_auth(f):

									 @wraps(f)

									 def decorated(*args, **kwargs):

									  auth = request.authorization

									  if not auth: 

									   return authenticate()

									  elif not check_auth(auth.username, auth.password):

									   return authenticate()

									  return f(*args, **kwargs)

									 return decorated

replacing the check_auth function and using the requires_auth decorator:

@app.route('/secrets')
@requires_auth
def api_hello():
return "Shhh this is top secret spy stuff!"
HTTP basic authentication：

curl -v -u "admin:secret" http://127.0.0.1:5000/secrets

SIMPLE DEBUG & LOGGING

Debug:

app.run(debug=True)
Logging：

									import logging

									file_handler = logging.FileHandler('app.log')

									app.logger.addHandler(file_handler)

									app.logger.setLevel(logging.INFO)

									@app.route('/hello', methods = ['GET'])

									def api_hello():

									 app.logger.info('informing')

									 app.logger.warning('warning')

									 app.logger.error('screaming bloody murder!')

									 return "check your logs\n"