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 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

resp = jsonify(data)

resp.status_code = 200

  替换

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"