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@python.decorators pynash · september 25, 2014

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No content

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@epochblue

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@epochblue

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def get_user_profile():
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 user = users.get(user_id)
 return jsonify(user=user.to_json())
 
 
 def create_user():
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 user = users.get(session.get('user_id'))
 if not user.has_role('admin'):
 abort(401)
 
 data = request.get_json()
 new_user = users.create(**data)
 return jsonify(user=new_user.to_json()), 201

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@login_required
 def get_user_profile():
 user = users.get(session.get(‘user_id')
 return jsonify(user=user.to_json())
 
 
 @login_required
 @role_required('admin')
 def create_user():
 data = request.get_json()
 new_user = users.create(**data)
 return jsonify(user=new_user.to_json()), 201

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A Quick Note

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def get_user_profile():
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 user = users.get(user_id)
 return jsonify(user=user.to_json())

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def get_user_profile():
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 user = users.get(user_id)
 return jsonify(user=user.to_json())

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But first...

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Let’s talk about functions

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def example():
 print("I'm a function!")

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>>> example() I'm a function! def example():
 print("I'm a function!")

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First-Class Functions

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Save functions into variables

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def example():
 print("I'm a function!")

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def example():
 print("I'm a function!") >>> f = example >>> f() I'm a function!

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Pass functions as arguments

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def example():
 print("I'm a function!")

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def example():
 print("I'm a function!") def first_class(func):
 func()

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def example():
 print("I'm a function!") >>> first_class(example) I'm a function! def first_class(func):
 func()

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Return functions from functions

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def example():
 print("I'm a function!")

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def example():
 print("I'm a function!") def first_class2():
 return example

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def example():
 print("I'm a function!") >>> f = first_class2() >>> f() I'm a function! def first_class2():
 return example

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Nest functions inside functions

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def fist_class3():
 msg = "I'm a function!"
 
 def example():
 print(msg)
 
 example()

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def fist_class3():
 msg = "I'm a function!"
 
 def example():
 print(msg)
 
 example() >>> first_class3() I'm a function!

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First-Class Functions

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Save functions into variables

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Return functions from functions Save functions into variables

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Pass functions as arguments Save functions into variables Return functions from functions

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Nest functions inside functions Save functions into variables Pass functions as arguments Return functions from functions

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Return functions from functions Pass functions as arguments Nest functions inside functions Save functions into variables

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Return functions from functions Pass functions as arguments Nest functions inside functions Save functions into variables Decorators

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def decorator(func):
 def wrapper():
 print("I'm a wrapper.")
 func()
 
 return wrapper
 
 def example():
 print("I'm a function!")

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def decorator(func):
 def wrapper():
 print("I'm a wrapper.")
 func()
 
 return wrapper
 
 def example():
 print("I'm a function!")

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>>> wrapped = decorator(example) >>> wrapped() I'm a wrapper. I'm a function! def decorator(func):
 def wrapper():
 print("I'm a wrapper.")
 func()
 
 return wrapper
 
 def example():
 print("I'm a function!")

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>>> wrapped = decorator(example) >>> wrapped() I'm a wrapper. I'm a function!

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>>> example = decorator(example) >>> example() I'm a wrapper. I'm a function! >>> wrapped = decorator(example) >>> wrapped() I'm a wrapper. I'm a function!

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def decorator(f):
 def wrapper():
 print("I'm a wrapper.")
 f()
 
 return wrapper
 
 def example():
 print("I'm a function!") ! example = decorator(example)

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def decorator(f):
 def wrapper():
 print("I'm a wrapper.")
 f()
 
 return wrapper
 
 def example():
 print("I'm a function!") ! example = decorator(example)

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PEP 318

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example = decorator(example)

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example = decorator(example) example = decorator(example) @decorator
 def example():
 print("I'm a function!")

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def get_user_profile():
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 user = users.get(user_id)
 return jsonify(user=user.to_json())

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def get_user_profile():
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 user = users.get(user_id)
 return jsonify(user=user.to_json())

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def login_required(func):
 def wrapper(*args, **kwargs):
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 return func(*args, **kwargs)
 
 return wrapper

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@login_required
 def get_user_profile():
 user = users.get(session.get('user_id'))
 return jsonify(user=user.to_json()) def login_required(func):
 def wrapper(*args, **kwargs):
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 return func(*args, **kwargs)
 
 return wrapper

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@login_required
 def get_user_profile():
 user = users.get(session.get('user_id'))
 return jsonify(user=user.to_json()) def login_required(func):
 def wrapper(*args, **kwargs):
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 return func(*args, **kwargs)
 
 return wrapper

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def create_new_user():
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 user = users.get(session.get('user_id'))
 if not user.has_role('admin'):
 abort(401)
 
 data = request.get_json()
 newbie = users.create(**data)
 return jsonify(user=newbie.to_json()), 201

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def create_new_user():
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 user = users.get(session.get('user_id'))
 if not user.has_role('admin'):
 abort(401)
 
 data = request.get_json()
 newbie = users.create(**data)
 return jsonify(user=newbie.to_json()), 201

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@login_required def create_new_user(): user = users.get(session.get('user_id'))
 if not user.has_role('admin'):
 abort(401)
 
 data = request.get_json()
 newbie = users.create(**data)
 return jsonify(user=newbie.to_json()), 201

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@login_required
 def create_new_user():
 user = users.get(session.get('user_id'))
 if not user.has_role('admin'):
 abort(401)
 
 data = request.get_json()
 newbie = users.create(**data)
 return jsonify(user=newbie.to_json()), 201

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Remember...

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@login_required
 def get_user_profile():
 # ... ...is the same as...

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get_user_profile = login_required(get_user_profile) @login_required
 def get_user_profile():
 # ... ...is the same as...

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@role_required('admin')
 def create_user():
 # ...

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@role_required('admin')
 def create_user():
 # ... ...is the same as...

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create_user = role_required('admin')(create_user) @role_required('admin')
 def create_user():
 # ... ...is the same as...

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create_user = role_required('admin')(create_user) @role_required('admin')
 def create_user():
 # ... OR ...is the same as...

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create_user = role_required('admin')(create_user) @role_required('admin')
 def create_user():
 # ... OR decorator = role_required('admin')
 create_user = decorator(create_user) ...is the same as...

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def admin_required(func): 
 def wrapper(*args, **kwargs):
 user = users.get(session.get('user_id'))
 if not user.has_role('admin'):
 abort(401) 
 return func(*args, **kwargs)
 
 return wrapper

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def admin_required():
 def decorator(func): 
 def wrapper(*args, **kwargs):
 user = users.get(session.get('user_id'))
 if not user.has_role('admin'):
 abort(401) return func(*args, **kwargs) 
 return wrapper
 return decorator

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def role_required(role):
 def decorator(func): 
 def wrapper(*args, **kwargs):
 user = users.get(session.get('user_id'))
 if not user.has_role(role):
 abort(401)
 return func(*args, **kwargs) 
 return wrapper
 return decorator

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@role_required('admin')
 def create_user():
 data = request.get_json()
 new_user = users.create(**data)
 return jsonify(user=new_user.to_json()), 201 def role_required(role):
 def decorator(func): 
 def wrapper(*args, **kwargs):
 user = users.get(session.get('user_id'))
 if not user.has_role(role):
 abort(401)
 return func(*args, **kwargs) 
 return wrapper
 return decorator

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@login_required
 @role_required('admin')
 def create_user():
 data = request.get_json()
 new_user = users.create(**data)
 return jsonify(user=new_user.to_json()), 201

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@login_required
 @role_required('admin')
 def create_user(): # ... ...is the same as...

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@login_required
 @role_required('admin')
 def create_user(): # ... ...is the same as... create_user = login_required(role_required(‘admin’)(create_user))

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@login_required
 @role_required('admin')
 def create_user():
 data = request.get_json()
 new_user = users.create(**data)
 return jsonify(user=new_user.to_json()), 201

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No content

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@login_required
 def get_user_profile():
 # ... def login_required(func):
 def wrapper(*args, **kwargs):
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 return func(*args, **kwargs)
 
 return wrapper

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@login_required
 def get_user_profile():
 # ... >>> get_user_profile.__name__ def login_required(func):
 def wrapper(*args, **kwargs):
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 return func(*args, **kwargs)
 
 return wrapper

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@login_required
 def get_user_profile():
 # ... >>> get_user_profile.__name__ 'wrapper' def login_required(func):
 def wrapper(*args, **kwargs):
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 return func(*args, **kwargs)
 
 return wrapper

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from functools import wraps

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def login_required(func):
 def wrapper(*args, **kwargs):
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 return func(*args, **kwargs)
 
 return wrapper

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from functools import wraps
 
 def login_required(func):
 @wraps(func)
 def wrapper(*args, **kwargs):
 user_id = session.get(user_id)
 if user_id is None:
 return redirect('/login', code=302)
 
 return func(*args, **kwargs)
 return wrapper

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from functools import wraps
 
 def login_required(func):
 @wraps(func)
 def wrapper(*args, **kwargs):
 user_id = session.get(user_id)
 if user_id is None:
 return redirect('/login', code=302)
 
 return func(*args, **kwargs)
 return wrapper @login_required
 def get_user_profile():
 # ...

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from functools import wraps
 
 def login_required(func):
 @wraps(func)
 def wrapper(*args, **kwargs):
 user_id = session.get(user_id)
 if user_id is None:
 return redirect('/login', code=302)
 
 return func(*args, **kwargs)
 return wrapper @login_required
 def get_user_profile():
 # ... >>> get_user_profile.__name__

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from functools import wraps
 
 def login_required(func):
 @wraps(func)
 def wrapper(*args, **kwargs):
 user_id = session.get(user_id)
 if user_id is None:
 return redirect('/login', code=302)
 
 return func(*args, **kwargs)
 return wrapper @login_required
 def get_user_profile():
 # ... >>> get_user_profile.__name__ ‘get_user_profile’

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Recap

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def get_user_profile():
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 user = users.get(user_id)
 return jsonify(user=user.to_json())
 
 
 def create_user():
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 user = users.get(session.get('user_id'))
 if not user.has_role('admin'):
 abort(401)
 
 data = request.get_json()
 new_user = users.create(**data)
 return jsonify(user=new_user.to_json()), 201

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def get_user_profile():
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 user = users.get(user_id)
 return jsonify(user=user.to_json())
 
 
 def create_user():
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 user = users.get(g.get('user_id'))
 if not user.has_role('admin'):
 abort(401)
 
 data = request.get_json()
 new_user = users.create(**data)
 return jsonify(user=new_user.to_json()), 201

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def login_required(func):
 def wrapper(*args, **kwargs):
 user_id = session.get('user_id')
 if user_id is None:
 return redirect('/login', code=302)
 
 return func(*args, **kwargs)
 
 return wrapper def role_required(role):
 def decorator(func): 
 def wrapper(*args, **kwargs):
 user = users.get(session.get('user_id'))
 if not user.has_role(role):
 abort(401)
 return func(*args, **kwargs) 
 return wrapper
 return decorator

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@login_required
 def get_user_profile():
 user = users.get(session.get(‘user_id'))
 return jsonify(user=user.to_json())
 
 
 @login_required
 @role_required('admin')
 def create_user():
 data = request.get_json()
 new_user = users.create(**data)
 return jsonify(user=new_user.to_json()), 201

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No content

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Decorators

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Questions? @epochblue Thank you.