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< title > Patterns for Flask — Flask Documentation (3.2.x)< / title >
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< li class = "nav-item nav-item-this" > < a href = "" > Patterns for Flask< / a > < / li >
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< section id = "patterns-for-flask" >
< h1 > Patterns for Flask< a class = "headerlink" href = "#patterns-for-flask" title = "Link to this heading" > ¶< / a > < / h1 >
< p > Certain features and interactions are common enough that you will find
them in most web applications. For example, many applications use a
relational database and user authentication. They will open a database
connection at the beginning of the request and get the information for
the logged in user. At the end of the request, the database connection
is closed.< / p >
< p > These types of patterns may be a bit outside the scope of Flask itself,
but Flask makes it easy to implement them. Some common patterns are
collected in the following pages.< / p >
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< li class = "toctree-l1" > < a class = "reference internal" href = "packages.html" > Large Applications as Packages< / a > < ul >
< li class = "toctree-l2" > < a class = "reference internal" href = "packages.html#simple-packages" > Simple Packages< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "packages.html#working-with-blueprints" > Working with Blueprints< / a > < / li >
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< li class = "toctree-l1" > < a class = "reference internal" href = "appfactories.html" > Application Factories< / a > < ul >
< li class = "toctree-l2" > < a class = "reference internal" href = "appfactories.html#basic-factories" > Basic Factories< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "appfactories.html#factories-extensions" > Factories & Extensions< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "appfactories.html#using-applications" > Using Applications< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "appfactories.html#factory-improvements" > Factory Improvements< / a > < / li >
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< li class = "toctree-l1" > < a class = "reference internal" href = "appdispatch.html" > Application Dispatching< / a > < ul >
< li class = "toctree-l2" > < a class = "reference internal" href = "appdispatch.html#working-with-this-document" > Working with this Document< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "appdispatch.html#combining-applications" > Combining Applications< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "appdispatch.html#dispatch-by-subdomain" > Dispatch by Subdomain< / a > < / li >
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< li class = "toctree-l1" > < a class = "reference internal" href = "urlprocessors.html" > Using URL Processors< / a > < ul >
< li class = "toctree-l2" > < a class = "reference internal" href = "urlprocessors.html#internationalized-application-urls" > Internationalized Application URLs< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "urlprocessors.html#internationalized-blueprint-urls" > Internationalized Blueprint URLs< / a > < / li >
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< li class = "toctree-l1" > < a class = "reference internal" href = "sqlite3.html" > Using SQLite 3 with Flask< / a > < ul >
< li class = "toctree-l2" > < a class = "reference internal" href = "sqlite3.html#connect-on-demand" > Connect on Demand< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "sqlite3.html#easy-querying" > Easy Querying< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "sqlite3.html#initial-schemas" > Initial Schemas< / a > < / li >
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< li class = "toctree-l1" > < a class = "reference internal" href = "sqlalchemy.html" > SQLAlchemy in Flask< / a > < ul >
< li class = "toctree-l2" > < a class = "reference internal" href = "sqlalchemy.html#flask-sqlalchemy-extension" > Flask-SQLAlchemy Extension< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "sqlalchemy.html#declarative" > Declarative< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "sqlalchemy.html#manual-object-relational-mapping" > Manual Object Relational Mapping< / a > < / li >
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< li class = "toctree-l2" > < a class = "reference internal" href = "fileuploads.html#a-gentle-introduction" > A Gentle Introduction< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "fileuploads.html#improving-uploads" > Improving Uploads< / a > < / li >
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< li class = "toctree-l2" > < a class = "reference internal" href = "fileuploads.html#an-easier-solution" > An Easier Solution< / a > < / li >
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< li class = "toctree-l2" > < a class = "reference internal" href = "viewdecorators.html#login-required-decorator" > Login Required Decorator< / a > < / li >
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< li class = "toctree-l1" > < a class = "reference internal" href = "wtforms.html" > Form Validation with WTForms< / a > < ul >
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< li class = "toctree-l1" > < a class = "reference internal" href = "javascript.html" > JavaScript, < code class = "docutils literal notranslate" > < span class = "pre" > fetch< / span > < / code > , and JSON< / a > < ul >
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< li class = "toctree-l2" > < a class = "reference internal" href = "javascript.html#following-redirects" > Following Redirects< / a > < / li >
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< li class = "toctree-l2" > < a class = "reference internal" href = "javascript.html#return-json-from-views" > Return JSON from Views< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "javascript.html#receiving-json-in-views" > Receiving JSON in Views< / a > < / li >
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< li class = "toctree-l2" > < a class = "reference internal" href = "lazyloading.html#converting-to-centralized-url-map" > Converting to Centralized URL Map< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "lazyloading.html#loading-late" > Loading Late< / a > < / li >
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< li class = "toctree-l1" > < a class = "reference internal" href = "mongoengine.html" > MongoDB with MongoEngine< / a > < ul >
< li class = "toctree-l2" > < a class = "reference internal" href = "mongoengine.html#configuration" > Configuration< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "mongoengine.html#mapping-documents" > Mapping Documents< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "mongoengine.html#creating-data" > Creating Data< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "mongoengine.html#queries" > Queries< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "mongoengine.html#documentation" > Documentation< / a > < / li >
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< li class = "toctree-l1" > < a class = "reference internal" href = "favicon.html" > Adding a favicon< / a > < ul >
< li class = "toctree-l2" > < a class = "reference internal" href = "favicon.html#see-also" > See also< / a > < / li >
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< li class = "toctree-l1" > < a class = "reference internal" href = "streaming.html" > Streaming Contents< / a > < ul >
< li class = "toctree-l2" > < a class = "reference internal" href = "streaming.html#basic-usage" > Basic Usage< / a > < / li >
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< li class = "toctree-l1" > < a class = "reference internal" href = "celery.html" > Background Tasks with Celery< / a > < ul >
< li class = "toctree-l2" > < a class = "reference internal" href = "celery.html#install" > Install< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "celery.html#integrate-celery-with-flask" > Integrate Celery with Flask< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "celery.html#application-factory" > Application Factory< / a > < / li >
< li class = "toctree-l2" > < a class = "reference internal" href = "celery.html#defining-tasks" > Defining Tasks< / a > < / li >
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< li class = "toctree-l2" > < a class = "reference internal" href = "celery.html#passing-data-to-tasks" > Passing Data to Tasks< / a > < / li >
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< li class = "toctree-l1" > < a class = "reference internal" href = "subclassing.html" > Subclassing Flask< / a > < / li >
< li class = "toctree-l1" > < a class = "reference internal" href = "singlepageapplications.html" > Single-Page Applications< / a > < / li >
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