Use Python & amp; Flask to implement RESTful Web APIs. Use python

Use Python & Flask to implement RESTful Web APIs, and use python

Environment installation:

sudo pip install flask

Flask is a Python microservice framework, based on Werkzeug, a wsgi class library.

Advantages of Flask:

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

RESOURCES

An API service that responds to/articles and/articles/: id:

from flask import Flask, url_forapp = 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 ' + articleidif __name__ == '__main__':    app.run()

Request:

curl http://127.0.0.1:5000/

Response:

GET /WelcomeGET /articlesList of /articlesGET /articles/123You are reading 123

REQUESTSGET 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'

Request:

GET /helloHello John DoeGET /hello?name=LuisHello 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"

Request type specified by the request:

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

GET /echoECHO: GETPOST /ECHOECHO: 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 ;)"

Request specified 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

View response HTTP headers:

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

Optimization code:

from flask import jsonify

Use

resp = jsonify(data)resp.status_code = 200

Replace

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()

Request:

GET /users/2HTTP/1.0 200 OK{    "2": "steve"}GET /users/4HTTP/1.0 404 NOT FOUND{"status": 404, "message": "Not Found: http://127.0.0.1:5000/users/4"}

AUTHORIZATION

from functools import wrapsdef 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 respdef 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

Replacingcheck_authFunction and usingrequires_authDecorator:

@app.route('/secrets')@requires_authdef 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 loggingfile_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"

 

Refer:

Flask documentation

Flask snippets

Werkzeug documentation

Curl manual