TODO.md

Query Validation

What we will cover? (Recap)

• Generic validations and metadata:
  1. alias -> Show as placeholder
  2. title -> Show as title
  3. description -> show as params description
  4. deprecated (ডেফরিকেটেট) -> make disable
• Strings Validations:
  1. min_length -> set min length of string
  2. max_length -> set max length of string
  3. pattern -> regular ex

Simple query validation

@app.get("/items", tags=["get items"])
async def get_items(q: str | None = None):
# async def get_items(q: Annotated[str] = None):
    results: dict[str, list[dict[str, str]]] = {
        "items": [
            {"item_id": "Foo"},
            {"item_id": "Bar"}
        ]
    }
    if q:
        results.update({"query": q})
    return results

Additional validation

• query Length validation
  • We can use 2 way our query validations (Without Annotated)

  q: str | None = None

  • With Annotated

  q: Annotated[str | None] = None

  • With Query fastapi method

  q: Annotated[str | None, Query(max_length=10)] = None

  • Note: Both of those versions mean the same thing

Add more validations

• We can also add min_length for validation

  q: Annotated[str | None, Query(min_length=3, max_length=50)] = None

Add regular expressions

We can also define a regular expression pattern that the parameter should match. We can also call this parameter parttern

Query(min_length=3, max_length=50, pattern="^sabbir$")

^: starts with the following characters, doesn't have characters before. sabbir: has the exact value sabbir. $: ends there, doesn't have any more characters after sabbir.

Query List/multiple value

query: Annotated[list[str] | None, Query()] = None