python - Mengenai pembolehubah global dalam Flask
S: Saya menonton tutorial ringkas tentang Flask, tetapi ada soalan yang saya tidak faham. Adakah pembolehubah global apl dalam Flask tidak akan menjadi salah apabila berbilang pelanggan mengaksesnya Sebagai contoh, adakah senarai tugasan dalam kod di bawah tidak akan menjadi salah apabila berbilang pelanggan mengaksesnya pada masa yang sama? Apabila saya menggunakan dua pelanggan untuk melakukan operasi pemadaman, saya tidak menemui masalah, tetapi adakah masalah akan berlaku apabila konkurensinya lebih tinggi, dan saya mahukan penjelasan?
task = filter(lambda t: t['id'] == task_id, tasks)
if len(task) == 0:
tugas = penapis(lambda t: t['id'] == task_id, tasks)
task = senarai(tugas)
if len(task) == 0:#!flask/bin/python
from flask import Flask, jsonify, abort, request, make_response, url_for
from flask.ext.httpauth import HTTPBasicAuth
app = Flask(__name__, static_url_path = "")
auth = HTTPBasicAuth()
@auth.get_password
def get_password(username):
if username == 'miguel':
return 'python'
return None
@auth.error_handler
def unauthorized():
return make_response(jsonify( { 'error': 'Unauthorized access' } ), 403)
# return 403 instead of 401 to prevent browsers from displaying the default auth dialog
@app.errorhandler(400)
def not_found(error):
return make_response(jsonify( { 'error': 'Bad request' } ), 400)
@app.errorhandler(404)
def not_found(error):
return make_response(jsonify( { 'error': 'Not found' } ), 404)
tasks = [
{
'id': 1,
'title': u'Buy groceries',
'description': u'Milk, Cheese, Pizza, Fruit, Tylenol',
'done': False
},
{
'id': 2,
'title': u'Learn Python',
'description': u'Need to find a good Python tutorial on the web',
'done': False
}
]
def make_public_task(task):
new_task = {}
for field in task:
if field == 'id':
new_task['uri'] = url_for('get_task', task_id = task['id'], _external = True)
else:
new_task[field] = task[field]
return new_task
@app.route('/todo/api/v1.0/tasks', methods = ['GET'])
@auth.login_required
def get_tasks():
return jsonify( { 'tasks': map(make_public_task, tasks) } )
@app.route('/todo/api/v1.0/tasks/<int:task_id>', methods = ['GET'])
@auth.login_required
def get_task(task_id):
task = filter(lambda t: t['id'] == task_id, tasks)
if len(task) == 0:
abort(404)
return jsonify( { 'task': make_public_task(task[0]) } )
@app.route('/todo/api/v1.0/tasks', methods = ['POST'])
@auth.login_required
def create_task():
if not request.json or not 'title' in request.json:
abort(400)
task = {
'id': tasks[-1]['id'] + 1,
'title': request.json['title'],
'description': request.json.get('description', ""),
'done': False
}
tasks.append(task)
return jsonify( { 'task': make_public_task(task) } ), 201
@app.route('/todo/api/v1.0/tasks/<int:task_id>', methods = ['PUT'])
@auth.login_required
def update_task(task_id):
task = filter(lambda t: t['id'] == task_id, tasks)
if len(task) == 0:
abort(404)
if not request.json:
abort(400)
if 'title' in request.json and type(request.json['title']) != unicode:
abort(400)
if 'description' in request.json and type(request.json['description']) is not unicode:
abort(400)
if 'done' in request.json and type(request.json['done']) is not bool:
abort(400)
task[0]['title'] = request.json.get('title', task[0]['title'])
task[0]['description'] = request.json.get('description', task[0]['description'])
task[0]['done'] = request.json.get('done', task[0]['done'])
return jsonify( { 'task': make_public_task(task[0]) } )
@app.route('/todo/api/v1.0/tasks/<int:task_id>', methods = ['DELETE'])
@auth.login_required
def delete_task(task_id):
task = filter(lambda t: t['id'] == task_id, tasks)
if len(task) == 0:
abort(404)
tasks.remove(task[0])
return jsonify( { 'result': True } )
if __name__ == '__main__':
app.run(debug = True)
