Account
Sign in to you account
Sign In Sign Up

How to Process Query Using Fastapi?

6 minutes read

FastAPI provides a way to process query parameters using request parameters in route functions. By defining the route function with parameters that match the query parameters in the URL, FastAPI automatically extracts and type checks the query parameters for you. This makes it easy to access and process query parameters in your application. You can define query parameters in the route path as {parameter_name} and FastAPI will extract the value for you. Additionally, you can define default values for query parameters by providing a default value in the route function parameters. Overall, processing query parameters using FastAPI is a simple and efficient process that allows you to easily work with query parameters in your web application.


How to handle query parameters with default values in FastAPI?

In FastAPI, you can handle query parameters with default values by using the Query parameter with a default value specified.


Here is an example of how to handle query parameters with default values in FastAPI:

1
2
3
4
5
6
7

from fastapi import FastAPI, Query

app = FastAPI()

@app.get("/items/")
async def read_items(skip: int = Query(default=0), limit: int = Query(default=10)):
    return {"skip": skip, "limit": limit}


In this example, we have defined a route /items/ with two query parameters skip and limit. Both parameters have default values specified using the Query parameter. If the client does not provide values for these parameters, the default values will be used.


When you make a request to /items/, you can include query parameters in the URL like http://127.0.0.1:8000/items/?skip=5&limit=15. If you do not provide any query parameters, the default values of skip=0 and limit=10 will be used.


How to access raw query parameters in FastAPI?

In FastAPI, you can access raw query parameters using the request variable. Here's an example code snippet to demonstrate how to access raw query parameters in FastAPI:

1
2
3
4
5
6
7
8
9

from fastapi import FastAPI, Request

app = FastAPI()

@app.get("/items")
async def read_item(request: Request):
    # Get all query parameters as a dict
    query_params = request.query_params._dict
    return {"query_params": query_params}


In this example, the read_item endpoint retrieves all query parameters from the request object and returns them as a dictionary. You can access specific query parameters by using the request.query_params.get() method and providing the parameter name as an argument.


Remember to import the Request class from fastapi in order to access the request object.


How to extract specific query parameters in FastAPI?

In FastAPI, you can extract specific query parameters using the Query class from the fastapi.params module. Here's an example of how to extract specific query parameters in FastAPI:

1
2
3
4
5
6
7

from fastapi import FastAPI, Query

app = FastAPI()

@app.get("/items/")
async def read_item(q: str = Query(..., min_length=3, max_length=50)):
    return {"q": q}


In this example, the Query class is used to extract the value of the q query parameter from the URL. The query parameter is required (indicated by ...) and must have a minimum length of 3 characters and a maximum length of 50 characters. The extracted query parameter value is then returned in the response.


You can also extract multiple query parameters by defining multiple parameters in the function signature, like this:

1
2
3

@app.get("/items/")
async def read_items(q: str = Query(...), limit: int = Query(10)):
    return {"q": q, "limit": limit}


In this example, the q and limit query parameters are extracted from the URL and their values are returned in the response. The limit parameter has a default value of 10 if not provided in the URL.


You can also use the params attribute of the Request object to access all query parameters as a dictionary:

1
2
3
4
5
6
7
8

from fastapi import FastAPI, Request

app = FastAPI()

@app.get("/items/")
async def read_item(request: Request):
    params = dict(request.query_params)
    return {"params": params}


In this example, the Request object is used to access all query parameters as a dictionary, which is then returned in the response.


How to handle query parameters for searching with wildcard characters in FastAPI?

To handle query parameters for searching with wildcard characters in FastAPI, you can use query parameters in the path operation function and then apply the wildcard characters to the search query. Here's an example of how you can do this:

  1. Define a path operation function in your FastAPI application that accepts query parameters for searching:
 1
 2
 3
 4
 5
 6
 7
 8
 9
10

from fastapi import FastAPI

app = FastAPI()

@app.get("/search/")
async def search_items(query: str):
    # Perform search with wildcard characters
    search_results = search_with_wildcards(query)
    
    return search_results


  1. Create a function to perform the search with wildcard characters:
1
2
3
4
5

def search_with_wildcards(query: str):
    # Apply wildcard characters to search query
    search_results = [item for item in items if query.lower() in item.lower()]
    
    return search_results


  1. When making a request to the /search/ endpoint, include the query parameter with wildcard characters as needed:
1

GET /search/?query=test*


This will search for items that contain the string "test" followed by any characters using the wildcard character "*". You can adjust the wildcard characters as needed based on your specific search requirements.


By following these steps, you can handle query parameters for searching with wildcard characters in FastAPI.


How to pass query parameters in the request body in FastAPI?

In FastAPI, query parameters are typically passed in the URL rather than in the request body. However, if you really need to pass query parameters in the request body, you can do so by creating a Pydantic model that represents the query parameters and including it in the request body.


Here's an example of how to pass query parameters in the request body in FastAPI:

  1. Define a Pydantic model that represents the query parameters:
1
2
3
4
5

from pydantic import BaseModel

class QueryParams(BaseModel):
    param1: str
    param2: int


  1. In your FastAPI route, include the Pydantic model in the request body:
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()

class QueryParams(BaseModel):
    param1: str
    param2: int

@app.post("/query_params")
async def get_query_params(query_params: QueryParams):
    return {"param1": query_params.param1, "param2": query_params.param2}


  1. Now you can send a POST request to the /query_params endpoint with the query parameters included in the request body like this:
1
2
3
4

{
    "param1": "value1",
    "param2": 123
}


Note that passing query parameters in the request body goes against the RESTful principles, so it's recommended to use URL parameters for passing query parameters in FastAPI.


How to handle query parameters in FastAPI?

In FastAPI, query parameters can be handled by defining them as parameters in the request handler function. Here's an example of how to handle query parameters in FastAPI:

1
2
3
4
5
6
7

from fastapi import FastAPI

app = FastAPI()

@app.get("/items/")
async def read_items(skip: int = 0, limit: int = 10):
    return {"skip": skip, "limit": limit}


In this example, the read_items function takes two query parameters skip and limit. By default, the skip parameter is set to 0 and the limit parameter is set to 10. These parameters can be passed in the URL as query parameters like so: http://127.0.0.1:8000/items/?skip=20&limit=50.


FastAPI will automatically parse the query parameters from the URL and pass them as arguments to the read_items function. The function can then process the parameters and return a response based on them.

Facebook Twitter LinkedIn Telegram Whatsapp

Related Posts:

How to Enable Cors In Fastapi?
To enable CORS in FastAPI, you can use the fastapi.middleware.cors library. You need to import it and add it to your FastAPI app as a middleware. Here's an example of how you can enable CORS in your FastAPI app: from fastapi import FastAPI from fastapi.mid...
How to Load Index.html In Fastapi?
To load an index.html file in FastAPI, you can use the FileResponse class provided by the FastAPI framework. First, you need to import the FileResponse class from the fastapi.responses module. Then, you can create a FastAPI route that returns a FileResponse ob...
How to Run Fastapi From Terminal?
To run FastAPI from the terminal, you first need to install FastAPI and Uvicorn using pip. Once installed, you can start your FastAPI application by running the following command in the terminal: uvicorn main:app --reload Replace main with the name of your mai...
How to Call Another Path on Fastapi?
To call another path on FastAPI, you can use the client object from the TestClient module provided by FastAPI. First, you need to create an instance of TestClient with your FastAPI application as a parameter. Then, use the get, post, put, delete, etc. methods ...
How to Send an Image File Through Xhr Request to Fastapi?
To send an image file through an XHR request to FastAPI, you can use JavaScript to read the file as a data URL and send it as a string in the XHR request. First, use the File API in JavaScript to read the image file as a data URL. Then, create a new XHR reques...