fastapi.exceptions.FastAPIError: Invalid args for response field! Hint: check that is a valid pydantic field type

We Are Going To Discuss About fastapi.exceptions.FastAPIError: Invalid args for response field! Hint: check that is a valid pydantic field type. So lets Start this Python Article.

<h2 id="h-fastapi.exceptions.fastapierror:-invalid-args-for-response-field!-hint:-check-that–is-a-valid-pydantic-field-type”>fastapi.exceptions.FastAPIError: Invalid args for response field! Hint: check that is a valid pydantic field type
  1. How to solve fastapi.exceptions.FastAPIError: Invalid args for response field! Hint: check that is a valid pydantic field type

    The error says your type you pass to predict must be pydantic BaseModel (or dataclass from 0.67.0 version of FastApi). However it won't work that way (at least on get request), if you want to pass query params (suggested solution) list them in function:
    @app.get('/predict') def predict(solute: str, solvent: str): print(solute, solvent)
    And use model for post request (which expects data in body):
    from pydantic import BaseModel class SoluteSolvent(BaseModel): solvent: str solute: str @app.post('/predict') def predict(sol:SoluteSolvent): print(sol.solute)
    Or you can use underlying starlette Request directly
    from fastapi import Request async def predict(r: Request): print(r.query_params["solute"])

  2. fastapi.exceptions.FastAPIError: Invalid args for response field! Hint: check that is a valid pydantic field type

    The error says your type you pass to predict must be pydantic BaseModel (or dataclass from 0.67.0 version of FastApi). However it won't work that way (at least on get request), if you want to pass query params (suggested solution) list them in function:
    @app.get('/predict') def predict(solute: str, solvent: str): print(solute, solvent)
    And use model for post request (which expects data in body):
    from pydantic import BaseModel class SoluteSolvent(BaseModel): solvent: str solute: str @app.post('/predict') def predict(sol:SoluteSolvent): print(sol.solute)
    Or you can use underlying starlette Request directly
    from fastapi import Request async def predict(r: Request): print(r.query_params["solute"])

Solution 1

The error says your type you pass to predict must be pydantic BaseModel (or dataclass from 0.67.0 version of FastApi). However it won’t work that way (at least on get request), if you want to pass query params (suggested solution) list them in function:

@app.get('/predict')
def predict(solute: str, solvent: str):
   print(solute, solvent)

And use model for post request (which expects data in body):

from pydantic import BaseModel
class SoluteSolvent(BaseModel):
    solvent: str
    solute: str

@app.post('/predict')
def predict(sol:SoluteSolvent):
    print(sol.solute)

Or you can use underlying starlette Request directly

from fastapi import Request

async def predict(r: Request):
    print(r.query_params["solute"])

Original Author kosciej16 Of This Content

Conclusion

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I am an Information Technology Engineer. I have Completed my MCA And I have 4 Year Plus Experience, I am a web developer with knowledge of multiple back-end platforms Like PHP, Node.js, Python and frontend JavaScript frameworks Like Angular, React, and Vue.

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