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--- wiki2:python:flask [2015/08/09 14:30]
alfred [Extend your application]
+++ wiki2:python:flask [2020/05/09 09:25] (actual)
@@ Línea 1: / Línea 1: @@
 ====== Flask ======
+===== Extensions =====
+  * [[wiki2:python:flask:sqlalchemy|Flask SQLAlchemy]]
+  * [[wiki2:python:flask:restful|Flask RESTful]]
+  * [[wiki2:python:flask:mongoalchemy|Flask MongoAlchemy]]
+  * [[wiki2:python:flask:flaskmongoengine|Flask Mongo Engine]]
+  * [[wiki2:python:flask:flasklogin|Flask Login]]
+  * [[wiki2:python:flask:testing|Flask Testing]]
+  * [[wiki2:python:flask:used_libraries|Flask used libraries]]
 ===== Some elements =====
@@ Línea 112: / Línea 121: @@
 ==== Pluggable views ====
+You need to subclass flask.views.View and implement dispatch_request(), then use  as_view() class method. The string you pass to that function is the name of the endpoint.
+<code python>
+from flask.views import View
+class ShowUsers(View):
+    def dispatch_request(self):
+        users = User.query.all()
+        return render_template('users.html', objects=users)
+app.add_url_rule('/users/', view_func=ShowUsers.as_view('show_users'))
+</code>
+''add_url_rule()'' is the function to register methods. To provide methods you use the ''methods'' property:
+<code python>
+class MyView(View):
+    methods = ['GET', 'POST']
+    def dispatch_request(self):
+        if request.method == 'POST':
+            ...
+        ...
+app.add_url_rule('/myview', view_func=MyView.as_view('myview'))
+</code>
+=== MethodViews ===
+Also you can use ''MethodView'' to implement methods:
+<code python>
+from flask.views import MethodView
+class UserAPI(MethodView):
+    def get(self):
+        users = User.query.all()
+        ...
+    def post(self):
+        user = User.from_form_data(request.form)
+        ...
+app.add_url_rule('/users/', view_func=UserAPI.as_view('users'))
+</code>
+So you can implement a REST API easily:
+^ URL ^ Method ^
+| /users/ | GET	|
+| /users/ | POST |
+| /users/<id> | GET |
+| /users/<id> | PUT |
+| /users/<id> | DELETE |
+<code python>
+class UserAPI(MethodView):
+    def get(self, user_id):
+        if user_id is None:
+            # return a list of users
+            pass
+        else:
+            # expose a single user
+            pass
+    def post(self):
+        # create a new user
+        pass
+    def delete(self, user_id):
+        # delete a single user
+        pass
+    def put(self, user_id):
+        # update a single user
+        pass
+</code>
+Explicitly mention the methods for each:
+<code python>
+user_view = UserAPI.as_view('user_api')
+app.add_url_rule('/users/', defaults={'user_id': None}, view_func=user_view, methods=['GET',])
+app.add_url_rule('/users/', view_func=user_view, methods=['POST',])
+app.add_url_rule('/users/<int:user_id>', view_func=user_view, methods=['GET', 'PUT', 'DELETE'])
+</code>
+If you have a lot of APIs that look similar you can refactor that registration code:
+<code python>
+def register_api(view, endpoint, url, pk='id', pk_type='int'):
+    view_func = view.as_view(endpoint)
+    app.add_url_rule(url, defaults={pk: None},
+                     view_func=view_func, methods=['GET',])
+    app.add_url_rule(url, view_func=view_func, methods=['POST',])
+    app.add_url_rule('%s<%s:%s>' % (url, pk_type, pk), view_func=view_func,
+                     methods=['GET', 'PUT', 'DELETE'])
+register_api(UserAPI, 'user_api', '/users/', pk='user_id')
+</code>
 ==== Blueprints ====
+A blueprint defines a collection of views, templates, static files and other elements that can be applied to an application. For example, let’s imagine that we have a blueprint for an admin panel. This blueprint would define the views for routes like /admin/login and /admin/dashboard. This lets us structure our app as several smaller “apps” that each do one thing.
+<code python>
+from flask import Blueprint, render_template
+profile = Blueprint('profile', __name__)
+@profile.route('/<user_url_slug>')
+def timeline(user_url_slug):
+    # Do some stuff
+    return render_template('profile/timeline.html')
+@profile.route('/<user_url_slug>/photos')
+def photos(user_url_slug):
+    # Do some stuff
+    return render_template('profile/photos.html')
+@profile.route('/<user_url_slug>/about')
+def about(user_url_slug):
+    # Do some stuff
+    return render_template('profile/about.html')
+</code>
+If we were using a divisional structure, we’d want to tell Flask that the blueprint has its own template and static directories.
+<code python>
+profile = Blueprint('profile', __name__,
+                    template_folder='templates',
+                    static_folder='static')
+</code>
+Now we only need to add it to our app:
+<code python>
+# facebook/__init__.py
+from flask import Flask
+from .views.profile import profile
+app = Flask(__name__)
+app.register_blueprint(profile)
+</code>
+We can define the prefix in one of two places: \\
+(1) when we instantiate the Blueprint()
+<code python>
+from flask import Blueprint, render_template
+profile = Blueprint('profile', __name__, url_prefix='/<user_url_slug>')
+# [...]
+</code>
+(2) when we register it with app.register_blueprint()
+<code python>
+from flask import Flask
+from .views.profile import profile
+app = Flask(__name__)
+app.register_blueprint(profile, url_prefix='/<user_url_slug>')
+</code>
+=== Build blueprints URLs ===
+If you want to link from one page to another you can use the url_for() function just like you normally would do just that you prefix the URL endpoint with the name of the blueprint and a dot (.):
+<code python>
+url_for('admin.index')
+</code>
+Additionally if you are in a view function of a blueprint or a rendered template and you want to link to another endpoint of the same blueprint, you can use relative redirects by prefixing the endpoint with a dot only:
+<code python>
+url_for('.index')
+</code>
+=== Notes ===
+To access the flask app from a blueprint:
+<code python>
+from flask import current_app
+...
+if current_app.debug:
+  ...
+</code>
+  * The url's will end with ''/''.
 ===== Notes =====
@@ Línea 126: / Línea 302: @@
     return redirect(url_for('static', filename='resume.html'))
 </code>
-''url_for(folder, file)'' will return the url for that file in that folder.
+==== url_for ====
+''url_for(folder, file)'' will return the url for that file in that folder. \\
+For static files:
+<code python>
+url_for('static', filename='path/to/file')
+# In blueprints
+url_for('admin.static', filename='style.css')
+</code>
+You also can use it in templates.
+<code>
+<link rel="stylesheet" type="text/css" href="{{ url_for('static', filename='bootstrap/bootstrap.min.css') }}">
+</code>
+In blueprints:
+<code python>
+# this blueprint -> printable function
+url_for('.printable')
+# blueprint: resume, resource FUNCTION: printable_resume
+url_for('resume.printable_resume')
+</code>
+You can get the absolute url:
+<code python>
+url_for('settings', _external=True)
+</code>

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