The Security class initializes the Flask-Security extension. Initializes the Flask-Security extension for the specified application and datastore implentation. If you decorate a view with this, it will ensure that the current user is logged in and authenticated before calling the actual view.
If they are not, it calls the LoginManager. For example:. If there are only certain times you need to require that your user is logged in, you can do so with:. It can be convenient to globally turn off authentication when unit testing. The current user must have both the admin role and editor role in order to view the page.
The current user must have either the editor role or author role in order to view the page. Decorator that protects endpoints using token authentication.
Returns True if the password matches the supplied hash. Returns True if the password is valid for the specified user. Additionally, the hashed password in the database is updated if the hashing algorithm happens to have changed.
Deprecated since version 2. See the Flask documentation on signals for information on how to use these signals in your code. See the documentation for the signals provided by the Flask-Login and Flask-Principal extensions. In addition to those signals, Flask-Security sends the following signals.
Sent when a user registers on the site. Sent when a user is confirmed. In addition to the app which is the senderit is passed a user argument.
Sent when a user requests confirmation instructions. Sent when passwordless login is used and user logs in. Sent when a user completes a password reset.
Sent when a user completes a password change. Sent when a user requests a password reset. In addition to the app which is the senderit is passed user and token arguments. Navigation index next previous Flask-Security 3. Parameters: app — The application. For example: app. Returns True if a change was made.
Always returns True. Parameters: user — The user to login remember — Flag specifying if the remember cookie should be set. This will also clean up the remember me cookie if it exists. It uses the configured encryption options. Quick search. Created using Sphinx 1. Defaults to False.Python decorators are functions that are used to transform other functions. When a decorated function is called, the decorator is called instead.
The decorator can then take action, modify the arguments, halt execution or call the original function. The Flask-Login extension makes it easy to implement a login system.
Read more about using Flask-Login in the official docs. Imagine that an article mentioning our application just appeared on CNN and some other news sites. Our homepage makes several trips to the database for each request, so all of this attention is slowing things down to a crawl. This extension provides us with a decorator that we can use on our index view to cache the response for some period of time.
Flask-Cache can be configured to work with a bunch of different caching backends. A popular choice is Rediswhich is easy to set-up and use. Assuming Flask-Cache is already configured, this code block shows what our decorated view would look like.
Now the function will only be run once every 60 seconds, when the cache expires. The response will be saved in our cache and pulled from there for any intervening requests. Flask-Cache also lets us memoize functions — or cache the result of a function being called with certain arguments. You can even cache computationally expensive Jinja2 template snippets. When we stack decorators, the topmost decorator will run first, then call the next function in line: either the view function or the next decorator.
The decorator syntax is just a little syntactic sugar. We can use multiple decorators by stacking them. Read more about what the wraps function does in the Python docs. When you define a route in Flask, you can specify parts of it that will be converted into Python variables and passed to the view function. This is because the part of the URL that is supposed to be an integer is actually a string. We could have a second view that looks for a string as well. We can also make custom converters to suit our needs.
On Reddit — a popular link sharing site — users create and moderate communities for theme-based discussion and link sharing.
An interesting feature of Reddit is that you can view the posts from multiple subreddits as one by seperating the names with a plus-sign in the URL, e. We can use a custom converter to implement this feature in our own Flask apps.
To use our ListConverterwe first have to tell Flask that it exists. This is another chance to run into some circular import problems if your util module has a from. Now we can use our converter just like one of the built-ins.
This same method can be used to make any URL converter we can dream of. Explore Flask latest. Warning app. Note Read more about using Flask-Login in the official docs. Note Flask-Cache also lets us memoize functions — or cache the result of a function being called with certain arguments.
I'm setting up a token auth system for my Flask server, and I want to be able to setup a decorator to look something like this:. Unfortunately, the 'token' parameter is not made available inside of args. The problem seems to be that Flask passes the req.
Since this is the first google result for "flask query parameters decorator", this is the solution I ended up with to add the query parameters, on top of path parameters in methods:.
Learn more. Pass query parameters to Flask decorator Ask Question. Asked 5 years, 6 months ago. Active 2 years, 6 months ago. Viewed 2k times. I'm setting up a token auth system for my Flask server, and I want to be able to setup a decorator to look something like this: app.
Where's your code that tries to access the token parameter? Active Oldest Votes. The names are the names that are mapped in the function.
Oh, I just realized that I can do it the same way as I normally would! Sign up or log in Sign up using Google.
Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Podcast Programming tutorials can be a real drag. Featured on Meta.This part of the documentation covers all the interfaces of Flask. For parts where Flask depends on external libraries, we document the most important right here and provide links to the canonical documentation.
The flask object implements a WSGI application and acts as the central object. It is passed the name of the module or package of the application.
Flask – Routing
Once it is created it will act as a central registry for the view functions, the URL rules, template configuration and much more.
The idea of the first parameter is to give Flask an idea of what belongs to your application. This name is used to find resources on the filesystem, can be used by extensions to improve debugging information and a lot more. Why is that? However it will make debugging more painful. Certain extensions can make assumptions based on the import name of your application.
If the import name is not properly set up, that debugging information is lost. For example it would only pick up SQL queries in yourapplication. New in version 1. Subdomain matching needs to be enabled manually now. New in version 0. Defaults to 'static'. Defaults to None. Defaults to False. Defaults to 'templates' folder in the root path of the application.
By default the folder 'instance' next to the package or module is assumed to be the instance path. In certain situations this cannot be achieved for instance if the package is a Python 3 namespace package and needs to be manually defined. Register a custom template filter. Register a custom template global function. Register a custom template test. Connects a URL rule. Works exactly like the route decorator.
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Changed in version 0. Flask itself assumes the name of the view function as endpoint. A change to Werkzeug is handling of method options. Starting with Flask 0. As of Flask 0. A dictionary with lists of functions that should be called after each request. The key of the dictionary is the name of the blueprint this function is active for, None for all requests. This can for example be used to close database connections.
Create an AppContext. An application context is automatically pushed by RequestContext.
Python – http Get and Post methods in Flask
Use this to manually create a context outside of these situations. See The Application Context. Tries to locate the instance path if it was not provided to the constructor of the application class.Now that we can have users register and log in, we're also allowing them to log out. It makes a little sense to not let users log out, unless they are logged in! You may also find you want to protect various pages, like maybe an admin page, or maybe you have subscriber content or otherwise protected or paywal content.
You can use wrapper functions for this. People tend to shy away from wrapper functions and decorators, because they can be confusing. But, look at you, you've been using them this whole time! Flask uses them for the URL routing. Let's show how we can make our own! It's actually pretty simple! Here, we define the function, where the parameter is f, which is convention for the fact that it wraps a function. Then, we define the wrapper. If so, great. If not, they get a flash message and a redirect to the login page.
Now that we have the wrapper function, we're ready to apply it to whatever we want to have a login required for. For example, we can apply it to our logout page, like so:. Simple enough, underneath the app. Now, in order to even get to the logout function, a user must first attempt to access the URL in the top wrapper, then they also need to satisfy the conditions of the next wrapper, and then they can finally reach the logout function!
Pretty neat! What's more is that we can actually use this sort of dynamic treatment of our users in our templates too! We'll head there next. The next tutorial: Dynamic user-based content Flask Tutorial.Routes in Flask can be defined using the route decorator of the Flask application instance:.
The route decorator takes a string which is the URL to match. When a request for a URL that matches this string is received by the application, the function decorated also called a view function will be invoked. So for an about route we would have:. It's important to note that these routes are not regular expressions like they are in Django.
Here the variable rule is in the last segment of the URL. It is also common to reuse URLs. So we could have two routes for the same view function:. When the first route is matched, there will be no value to pass to the view function. Also note that by default the type of a variable rule is a string. However, you can specify several different types such as int and float by prefixing the variable:. Finally, routes can be configured to accept HTTP methods as well.
The route decorator takes a methods keyword argument which is a list of string representing the acceptable HTTP methods for this route. As you might have assumed, the default is GET only.
The request is found in the flask package. Note that when using the methods keyword argument, we must be explicit about the HTTP methods to accept. Flask Basic Routes.
So for an about route we would have: app. You can also define variable rules to extract URL segment values into variables: app.
So we could have two routes for the same view function: app. However, you can specify several different types such as int and float by prefixing the variable: app. PDF - Download Flask for free. Previous Next. This website is not affiliated with Stack Overflow.Python has a really interesting feature called function decorators.
This allows some really neat things for web applications. Because each view in Flask is a function, decorators can be used to inject additional functionality to one or more functions. The route decorator is the one you probably used already. But there are use cases for implementing your own decorator. For instance, imagine you have a view that should only be used by people that are logged in. If a user goes to the site and is not logged in, they should be redirected to the login page.
This is a good example of a use case where a decorator is an excellent solution. A decorator is a function that wraps and replaces another function. Use functools.
This example assumes that the login page is called 'login' and that the current user is stored in g.
To use the decorator, apply it as innermost decorator to a view function. When applying further decorators, always remember that the route decorator is the outermost. The next value will exist in request. You can do this with a hidden input tag, then retrieve it from request. Imagine you have a view function that does an expensive calculation and because of that you would like to cache the generated results for a certain amount of time.
A decorator would be nice for that. Here is an example cache function. It generates the cache key from a specific prefix actually a format string and the current path of the request. Notice that we are using a function that first creates the decorator that then decorates the function. Sounds awful? Unfortunately it is a little bit more complex, but the code should still be straightforward to read. If the cache returned something we will return that value. Notice that this assumes an instantiated cache object is available, see Caching for more information.
A common pattern invented by the TurboGears guys a while back is a templating decorator. The idea of that decorator is that you return a dictionary with the values passed to the template from the view function and the template is automatically rendered.