policy grants access to buckets with name starting with example. ## In addition, grants objects read permissions on buckets starting with example. # - name: readonlyexamplepolic # statements: # - resources: # - 'arn:aws:s3:::example*/*' # actions: # - "s3:GetObject" # - resources: # - 'arn:aws:s3:::example*' # actions: # - "s3:GetBucketLocation" # - "s3:ListBucket" # - "s3:ListBucketMultipartU" ## conditionsexample policy creates all access to example bucket with aws:username="johndoe" and source ip range...

# Query Parameters and String Validations

**FastAPI** allows you to declare additional information and validation for your parameters.

Let's take this application as example:

//// tab | Python 3.10+

```Python hl_lines="7"
{!> ../../docs_src/query_params_str_validations/tutorial001_py310.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="9"
{!> ../../docs_src/query_params_str_validations/tutorial001.py!}
```

    email: Union[str, None] = None
    full_name: Union[str, None] = None
    disabled: Union[bool, None] = None


def fake_decode_token(token):
    return User(
        username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
    )


async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
    user = fake_decode_token(token)
    return user


@app.get("/users/me")

policy grants access to buckets with name starting with example. ## In addition, grants objects read permissions on buckets starting with example. # - name: readonlyexamplepolic # statements: # - resources: # - 'arn:aws:s3:::example*/*' # actions: # - "s3:GetObject" # - resources: # - 'arn:aws:s3:::example*' # actions: # - "s3:GetBucketLocation" # - "s3:ListBucket" # - "s3:ListBucketMultipartU" ## conditionsexample policy creates all access to example bucket with aws:username="johndoe" and source ip range...

writeexamplepolicy policy grants creation or deletion of buckets with name ## starting with example. In addition, grants objects write permissions on buckets starting with ## example. # - name: writeexamplepolicy # statements: # - resources: # - 'arn:aws:s3:::example*/*' # actions: # - "s3:AbortMultipartUpload" # - "s3:GetObject" # - "s3:DeleteObject" # - "s3:PutObject" # - "s3:ListMultipartUploadP" # - resources: # - 'arn:aws:s3:::example*' # actions: # - "s3:CreateBucket" # - "s3:DeleteBucket" # - "s3:GetBucketLocation"...

writeexamplepolicy policy grants creation or deletion of buckets with name ## starting with example. In addition, grants objects write permissions on buckets starting with ## example. # - name: writeexamplepolicy # statements: # - resources: # - 'arn:aws:s3:::example*/*' # actions: # - "s3:AbortMultipartUpload" # - "s3:GetObject" # - "s3:DeleteObject" # - "s3:PutObject" # - "s3:ListMultipartUploadP" # - resources: # - 'arn:aws:s3:::example*' # actions: # - "s3:CreateBucket" # - "s3:DeleteBucket" # - "s3:GetBucketLocation"...

writeexamplepolicy policy grants creation or deletion of buckets with name ## starting with example. In addition, grants objects write permissions on buckets starting with ## example. # - name: writeexamplepolicy # statements: # - resources: # - 'arn:aws:s3:::example*/*' # actions: # - "s3:AbortMultipartUpload" # - "s3:GetObject" # - "s3:DeleteObject" # - "s3:PutObject" # - "s3:ListMultipartUploadP" # - resources: # - 'arn:aws:s3:::example*' # actions: # - "s3:CreateBucket" # - "s3:DeleteBucket" # - "s3:GetBucketLocation"...

writeexamplepolicy policy grants creation or deletion of buckets with name ## starting with example. In addition, grants objects write permissions on buckets starting with ## example. # - name: writeexamplepolicy # statements: # - resources: # - 'arn:aws:s3:::example*/*' # actions: # - "s3:AbortMultipartUpload" # - "s3:GetObject" # - "s3:DeleteObject" # - "s3:PutObject" # - "s3:ListMultipartUploadP" # - resources: # - 'arn:aws:s3:::example*' # actions: # - "s3:CreateBucket" # - "s3:DeleteBucket" # - "s3:GetBucketLocation"...

 * with {@link #where} and types are resolved using {@link #resolveType}.
 *
 * <p>Note that usually type mappings are already implied by the static type hierarchy (for example,
 * the {@code E} type variable declared by class {@code List} naturally maps to {@code String} in
 * the context of {@code class MyStringList implements List<String>}). In such case, prefer to use

You could also use it to generate code automatically, for clients that communicate with your API. For example, frontend, mobile or IoT applications.

## Recap, step by step

### Step 1: import `FastAPI`

{* ../../docs_src/first_steps/tutorial001.py hl[1] *}