Walkthrough using Python & Flask to implement restful Web APIs

Here is an example of using Python & Flask to implement a restful Web API. Small series feel very good, now share to everyone, also for everyone to make a reference. Let's take a look at it with a little knitting.

Environment Installation:

sudo pip install flask

Flask is a Python microservices framework based on Werkzeug, a WSGI class library.

Flask Advantages:

Written in Python (that can is 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/
Welcome

Get/articles
List Of/articles

Get/articles/123
Reading 123

Requests

GET Parameters

From flask import request@app.route ('/hello ') def api_hello (): If ' name ' in Request.args:  return ' Hello ' + request.arg s[' name '] Else:  return ' Hello John Doe '

Request:

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 ':  re Turn "echo:get\n" elif request.method = = ' POST ':  return "echo:post\n" elif request.method = = ' PATCH ':  return "EC ho:pacth\n "elif Request.method = = ' PUT ':  return" echo:put\n "elif request.method = = ' DELETE ':  return" Echo:del ETE "

Request specifies the requested 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 ': C3/>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 to specify 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 ',  ' num ' ber ': 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

Optimized 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 = [' G ET ']) 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/2
http/1.0 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 wrapsdef check_auth (username, password): return username = = ' admin ' and password = = ' secret ' def Auth Enticate (): message = {' message ': ' Authenticate. '} RESP = jsonify (message) Resp.status_code = 401 resp.headers[' www-authe  Nticate '] = ' 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

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 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"