// MD5 checksum of everything it reads as ETag.
//
// It also computes the SHA256 checksum of everything it reads
// if sha256Hex is not the empty string.
//
// If size resp. actualSize is unknown at the time of calling
// NewReader then it should be set to -1.
// When size is >=0 it *must* match the amount of data provided by r.
//
// NewReader may try merge the given size, MD5 and SHA256 values

const (
	// Deliberately hide the meaning of constants from public API.
	_ Format = (1 << iota) / 4 // Sequence of 0, 0, 1, 2, 4, 8, etc...

	// FormatUnknown indicates that the format is unknown.
	FormatUnknown

	// The format of the original Unix V7 tar tool prior to standardization.
	formatV7

	// FormatUSTAR represents the USTAR header format defined in POSIX.1-1988.
	//

import static com.google.common.collect.Multisets.difference;
import static com.google.common.collect.Multisets.intersection;
import static com.google.common.collect.Multisets.sum;
import static com.google.common.collect.Multisets.union;
import static com.google.common.collect.Multisets.unmodifiableMultiset;
import static java.util.Arrays.asList;
import static java.util.Collections.sort;

import com.google.common.annotations.GwtIncompatible;

/// check | "확인"

**FastAPI**는 `item_id`가 경로 매개변수이고 `q`는 경로 매개변수가 아닌 쿼리 매개변수라는 것을 알 정도로 충분히 똑똑합니다.

///

/// note | "참고"

FastAPI는 `q`가 `= None`이므로 선택적이라는 것을 인지합니다.

`Union[str, None]`에 있는 `Union`은 FastAPI(FastAPI는 `str` 부분만 사용합니다)가 사용하는게 아니지만, `Union[str, None]`은 편집기에게 코드에서 오류를 찾아낼 수 있게 도와줍니다.

///

## 쿼리 매개변수 형변환

`bool` 형으로 선언할 수도 있고, 아래처럼 변환됩니다:

```Python hl_lines="9"
{!../../docs_src/query_params/tutorial003.py!}

~ export MINIO_IDENTITY_OPENID_CLAIM_NAME=name
~ export MINIO_IDENTITY_OPENID_CONFIG_URL=http://127.0.0.1:5556/dex/.well-known/openid-configuration
~ minio server ~/test
```

### Run the `web-identity.go`

```
~ go run web-identity.go -cid example-app -csec ZXhhbXBsZS1hcHAtc2VjcmV0 \
     -config-ep http://127.0.0.1:5556/dex/.well-known/openid-configuration \
     -cscopes groups,openid,email,profile
```

```

		Version         = 1
	)

	var header [5]byte
	if _, err := io.ReadFull(ciphertext, header[:]); err != nil {
		return nil, err
	}
	if header[0] != Version {
		return nil, fmt.Errorf("config: unknown ciphertext version %d", header[0])
	}
	size := binary.LittleEndian.Uint32(header[1:])
	if size > MaxMetadataSize {
		return nil, errors.New("config: encryption metadata is too large")
	}

	var (

### Erstellung

* Erstellen Sie eine Datei `main.py` mit:

```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">

			}
			return errMalformedEncoding
		}
		key := strings.ToLower(line[:idx])
		value := line[idx+1:]
		if _, ok := wantTrailers[key]; !ok {
			if cr.debug {
				fmt.Printf("Unknown key %q - expected on of %v\n", key, cr.trailers)
			}
			return errMalformedEncoding
		}
		cr.trailers.Set(key, value)
		delete(wantTrailers, key)
	}

	// Check if we got all we want.

## דוגמא

### צרו אותה

-   צרו קובץ בשם `main.py` עם:

```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">

	default:
		return nil, fmt.Errorf("tierConfigInit: unknown format: %d", format)
	}

	cfg := NewTierConfigMgr()
	switch version := binary.LittleEndian.Uint16(data[2:4]); version {
	case tierConfigV1, tierConfigVersion:
		if _, decErr := cfg.UnmarshalMsg(data[4:]); decErr != nil {
			return nil, decErr
		}
	default:
		return nil, fmt.Errorf("tierConfigInit: unknown version: %d", version)
	}

	return cfg, nil
}