Flask is a lightweight python framework that provides a simple yet powerful and extensible structure it is Python after all. For its presentation layer, Flask leverages the Jinga2 engine.
Flask allows for the creation of templates using strings of HTML in the Python source code or laid out in static files in a templates directory local to your project. The template engine provided within the Flask framework may allow developers to introduce Server-Side Template Injection vulnerabilities. Execution of this input occurs within the context of the server. Depending on the context of the application this could allow for arbitrary remote code execution RCE. Consider the following snippet of code:.
Great success! What about a named guest? Oh no! Our code just shared the secret! Maybe we can use it. This is bad.
How do we fix it? The issue arises due to the use of string concatenation or substitution. By placing our output inside of these braces we will prevent user entered data containing template syntax from executing within the context of our server. As stated above, Flask provides an autoescape feature on certain file types.
While this is excellent there are some caveats:. Well there we have it. To fix the issue, we can pipe our output through the manual escape filter e to ensure proper output escaping before reflection to the user. So our final template string will appear as:. Now, not every application is going to use on-the-fly templates.
So what about more traditional Cross-Site Scripting attacks in the static templates? Consider the following function:. Depending on the code in the template, hello. Interesting, the autoescaped block works as expected; we appropriately escaped the output.
However, the second section allowed for the injected payload to execute in the browser. Using the following code as an example:. Uh oh, the payload executed. First, the problem: our injected payload executed due to the name parameter appearing in the context of an HTML attribute. The updated link tag:.
Remember, always escape your output but also validate your input! Application Assessments Static and dynamic analysis of web applications. Cloud Assessments Comprehensive anaylsis of cloud architecture security.
The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. But the newer version of injector 0. Learn more. How to Inject Interface as a parameter to function using flask-injector Ask Question.
Asked 2 years ago. Active 2 years ago. Viewed 1k times. I am working on an API app using flask-injector and connexion. Note - This function is in api. Navi Navi 13 13 bronze badges. Active Oldest Votes. Benedikt Naessens Benedikt Naessens 26 2 2 bronze badges.
Thanks a lot. Once it's out there, I feel a lot stupid to not be able to figure this out myself. 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.
Featured on Meta. Feedback on Q2 Community Roadmap.
Question Close Updates: Phase 1. Technical site integration observational experiment live on Stack Overflow. Related Hot Network Questions.
I'm new to python, actually I don't know if this usage of Flask-Injector is correct, so I'm getting this error when calling the api myapi with get method using the browser:. CallError: Call to MyApi. I was able to solve this with the help of an issue I opened on githubhere's the updated working version of the code:. Learn more. Asked 7 months ago. Active 7 months ago.
Viewed times. I'm trying to build an api using Flask-restplus and Flask-Flask-Injector. I searched and couldn't find an example on these two together. All examples are on Flask, not the restplus one. Dabbas Dabbas 2, 5 5 gold badges 31 31 silver badges 62 62 bronze badges. Active Oldest Votes. 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. Featured on Meta. Feedback on Q2 Community Roadmap. Question Close Updates: Phase 1. Technical site integration observational experiment live on Stack Overflow. Related 3.
You still have to consider several scenarios where you should be careful:. In order to secure your application against CSRF is to use a random string and to verify it against a hidden field. The complete code snippet can be found here. SQL Injection is an attack where users can inject SQL commands via user input form and have them executed on the server. This SQL commands could do everything: read sensitive data, modify the database data, perform administrative tasks against the database server.
By default SQL Alchemy quotes special characters — semicolons or apostrophes.
Authorization process verifies whether the authenticated user has access to a given resource. Flask-Security is a very helpful extensions that integrates several other Flask extensions and Python libraries:.Flask Tutorial #5 - Sessions
Note: I am using an older version of Flask-Login — 0. You could add any aditional information to both User and Role classes if you need to. Note: I have modified the seed. It is common to be able to access the current user in your Flask application within the Jinja templates and introduce some logic based on that data. In order to achieve that goal you could use context processors:.
As I mentioned earlier: authorization is a process verifies whether the authenticated user has access to a given resource.Create your free Platform account to download ActivePython or customize Python with the packages you require and get automatic updates.
Adds Injector support to Flask. Update the Flask app configuration as normal, additionally passing in any configuration for modules:. In the Injector world, all dependency configuration and initialization is performed in modules. The same is true with Flask-Injector. You can see some examples of configuring Flask extensions through modules below. Accordingly, the next step is to create modules for any objects we want made available to the application.
Note that in this example we also use the injector to gain access to the flask. Config :. Now perform Injector Flask application integration initialization. This needs to be run before any views, handlers, etc. Run the post-initialization step. This needs to be run only after you attached all views, handlers etc. See example. Typically, Flask extensions are initialized at the global scope using a pattern similar to the following.
As we don't have these globals with Flask-Injector we have to configure the extension the Injector way - through modules. Modules can either be subclasses of injector. Module or a callable taking an injector. Binder instance. ActivePython Enterprise Edition guarantees priority access to technical support, indemnification, expert consulting and quality-assured language builds.
Since I still have some handy knowledge I decided to make this note on how to set up things. However, I'd not advise starting a new project in using this technology. IMHO, it's aging and losing the traction. Python is booming and Flask is a pretty popular web-framework nowadays. Probably, quite some new projects are being started in Flask. But people should be aware, it's synchronous by design and ASGI is not a thing yet.
In the tutorial we will see:. It's a pretty common situation nowadays due to the enormous spread of microservice architectures and various 3rd-party APIs. The description is rather obscure for those who are unfamiliar with the mentioned dependencies like greenletlibevor libuv.
The patching introduces what's called cooperative multitasking into the Python standard library and some 3rd-party modules but the change stays almost completely hidden from the application and the existing code keeps its synchronous-alike outlook while gains the ability to serve requests asynchronously.
There is an obvious downside of this approach - the patching doesn't change the way every single HTTP request is being served, i. Well, we can start using something similar to asyncio.
However, now we can easily scale up the limit of concurrent HTTP requests for our application. After the patching, we don't need a dedicated thread or process per request anymore. Instead, each request handling now happens in a lightweight green thread. Thus, the application can serve tens of thousands of concurrent requests, probably increasing this number by orders of magnitude from the previous limit.
However, while the description sounds extremely promising at least to methe project and the surrounding eco-system is steadily losing traction in favor of asyncio and aiohttp?
The standard tutorial format always seemed boring to me. Instead, we will try to make a tiny playground here. We will try to create a simple Flask application dependant on a sleepy 3rd party API endpoint. The only route of our application will be responding with some hard-coded string concatenated with the API response text.Homepage PyPI Python.
Adds Injector support to Flask, this way there's no need to use global Flask objects, which makes testing simpler. Injector is a dependency-injection framework for Python, inspired by Guice. Flask-Injector is compatible with CPython 3. As of version 0. Creating an instance of FlaskInjector performs side-effectful configuration of the Flask application passed to it.
The following bindings are applied if you want to modify them you need to do it in one of the modules passed to the FlaskInjector constructor :. See example. Typically, Flask extensions are initialized at the global scope using a pattern similar to the following. As we don't have these globals with Flask-Injector we have to configure the extension the Injector way - through modules. Modules can either be subclasses of injector.
Module or a callable taking an injector. Binder instance.
How to Serve a React-app With a Flask-Server
Something wrong with this page? Make a suggestion. ABOUT file for this package. Login to resync this project. Toggle navigation. Search Packages Repositories.
Enterprise-ready open source software—managed for you. Sign up for a free trial. Flask-Injector Release 0. Release 0.