So, it was a complete additional system.

It is not very popular or used nowadays.

## OpenAPI { #openapi }

OpenAPI (previously known as Swagger) is the open specification for building APIs (now part of the Linux Foundation).

**FastAPI** is based on **OpenAPI**.

That's what makes it possible to have multiple automatic interactive documentation interfaces, code generation, etc.

Neste guia, você aprenderá como gerar um **SDK em TypeScript** para o seu backend FastAPI.

## Geradores de SDK de código aberto { #open-source-sdk-generators }

		iostats.DiscardSectors = stats[13]
		iostats.DiscardTicks = stats[14]
	}
	return iostats, err
}

func readStat(fileName string) (stats []uint64, err error) {
	file, err := os.Open(fileName)
	if err != nil {
		return nil, err
	}
	defer file.Close()

	s, err := bufio.NewReader(file).ReadString('\n')
	if err != nil && !errors.Is(err, io.EOF) {
		return nil, err
	}

```Python
with open("./somefile.txt") as f:
    contents = f.read()
    print(contents)
```

Под капотом вызов `open("./somefile.txt")` создаёт объект, называемый «контекстным менеджером».

Когда блок `with` завершается, он обязательно закрывает файл, даже если были исключения.

{* ../../docs_src/query_params/tutorial005_py39.py hl[6:7] *}

Here the query parameter `needy` is a required query parameter of type `str`.

If you open in your browser a URL like:

```
http://127.0.0.1:8000/items/foo-item
```

...without adding the required parameter `needy`, you will see an error like:

```JSON
{
  "detail": [
    {

            HttpURLConnection connection = null;
            try {
                logger.fine(() -> ">>> " + method + " " + finalUrl);
                final URL u = new URL(finalUrl);
                connection = open(u);
                connection.setRequestMethod(method.toString());
                if (headerList != null) {
                    for (final String[] values : headerList) {

	if err != nil {
		in.Error("unquoting include file name: ", err)
	}
	in.expectNewline("#include")
	// Push tokenizer for file onto stack.
	fd, err := os.Open(name)
	if err != nil {
		for _, dir := range in.includes {
			fd, err = os.Open(filepath.Join(dir, name))
			if err == nil {
				break
			}
		}
		if err != nil {
			in.Error("#include:", err)
		}
	}

                // It is more critical than other attributes because append mode depends on it.
                // We do only really care if we open for writing and not shared for writing
                // otherwise there are no guarantees anyway, but this stuff is legacy anyways.
                final SmbComSeek seekReq = new SmbComSeek(config, 0);

 * Caffeine}</a> class. Caffeine offers better performance, more features (including asynchronous
 * loading), and fewer <a
 * href="https://github.com/google/guava/issues?q=is%3Aopen+is%3Aissue+label%3Apackage%3Dcache+label%3Atype%3Ddefect">bugs</a>.
 *
 * <p>Caffeine defines its own interfaces (<a

      } else {
        pos++ // Consume '='.
        pos = value.indexOfNonWhitespace(pos)

        if (pos < value.length && value[pos] == '\"') {
          // Quoted string.
          pos++ // Consume '"' open quote.
          val parameterStart = pos
          pos = value.indexOf('"', pos)
          parameter = value.substring(parameterStart, pos)
          pos++ // Consume '"' close quote (if necessary).
        } else {