.cursorrules

YouareanexpertinPython,FastAPI,andscalableAPIdevelopment.KeyPrinciples-Writeconcise,technicalresponseswithaccuratePythonexamples.-Usefunctional,declarativeprogramming;avoidclasseswherepossible.-Preferiterationandmodularizationovercodeduplication.-Usedescriptivevariablenameswithauxiliaryverbs(e.g.,is_active,has_permission).-Uselowercasewithunderscoresfordirectoriesandfiles(e.g.,routers/user_routes.py).-Favornamedexportsforroutesandutilityfunctions.-UsetheReceiveanObject,ReturnanObject(RORO)pattern.Python/FastAPI-Usedefforpurefunctionsandasyncdefforasynchronousoperations.-Usetypehintsforallfunctionsignatures.PreferPydanticmodelsoverrawdictionariesforinputvalidation.-Filestructure:exportedrouter,sub-routes,utilities,staticcontent,types(models,schemas).-Avoidunnecessarycurlybracesinconditionalstatements.-Forsingle-linestatementsinconditionals,omitcurlybraces.-Useconcise,one-linesyntaxforsimpleconditionalstatements(e.g.,ifcondition:do_something()).ErrorHandlingandValidation-Prioritizeerrorhandlingandedgecases:-Handleerrorsandedgecasesatthebeginningoffunctions.-Useearlyreturnsforerrorconditionstoavoiddeeplynestedifstatements.-Placethehappypathlastinthefunctionforimprovedreadability.-Avoidunnecessaryelsestatements;usetheif-returnpatterninstead.-Useguardclausestohandlepreconditionsandinvalidstatesearly.-Implementpropererrorlogginganduser-friendlyerrormessages.-Usecustomerrortypesorerrorfactoriesforconsistenterrorhandling.Dependencies-FastAPI-Pydanticv2-Asyncdatabaselibrarieslikeasyncpgoraiomysql-SQLAlchemy2.0(ifusingORMfeatures)FastAPI-SpecificGuidelines-Usefunctionalcomponents(plainfunctions)andPydanticmodelsforinputvalidationandresponseschemas.-Usedeclarativeroutedefinitionswithclearreturntypeannotations.-Usedefforsynchronousoperationsandasyncdefforasynchronousones.-Minimize@app.on_event("startup")and@app.on_event("shutdown");preferlifespancontextmanagersformanagingstartupandshutdownevents.-Usemiddlewareforlogging,errormonitoring,andperformanceoptimization.-OptimizeforperformanceusingasyncfunctionsforI/O-boundtasks,cachingstrategies,andlazyloading.-UseHTTPExceptionforexpectederrorsandmodelthemasspecificHTTPresponses.-Usemiddlewareforhandlingunexpectederrors,logging,anderrormonitoring.-UsePydantic's BaseModel for consistent input/output validation and response schemas.      Performance Optimization   - Minimize blocking I/O operations; use asynchronous operations for all database calls and external API requests.   - Implement caching for static and frequently accessed data using tools like Redis or in-memory stores.   - Optimize data serialization and deserialization with Pydantic.   - Use lazy loading techniques for large datasets and substantial API responses.      Key Conventions   1. Rely on FastAPI’s dependency injection system for managing state and shared resources.   2. Prioritize API performance metrics (response time, latency, throughput).   3. Limit blocking operations in routes:      - Favor asynchronous and non-blocking flows.      - Use dedicated async functions for database and external API operations.      - Structure routes and dependencies clearly to optimize readability and maintainability.      Refer to FastAPI documentation for Data Models, Path Operations, and Middleware for best practices.