`Header`は`Path`や`Query`、`Cookie`の「姉妹」クラスです。また、同じ共通の`Param`クラスを継承しています。

しかし、`fastapi`から`Query`や`Path`、`Header`などをインポートする場合、それらは実際には特殊なクラスを返す関数であることを覚えておいてください。

///

/// info | "情報"

ヘッダーを宣言するには、`Header`を使う必要があります。なぜなら、そうしないと、パラメータがクエリのパラメータとして解釈されてしまうからです。

///

## 自動変換

`Header`は`Path`や`Query`、`Cookie`が提供する機能に加え、少しだけ追加の機能を持っています。

ほとんどの標準ヘッダーは、「マイナス記号」（`-`）としても知られる「ハイフン」で区切られています。

しかし、`user-agent`のような変数はPythonでは無効です。

Nitish Tiwari <******@****.***> 1629498654 +0530

    internal val reader: Http2Reader,
  ) : Http2Reader.Handler, () -> Unit {
    override fun invoke() {
      var connectionErrorCode = ErrorCode.INTERNAL_ERROR
      var streamErrorCode = ErrorCode.INTERNAL_ERROR
      var errorException: IOException? = null
      try {
        reader.readConnectionPreface(this)
        while (reader.nextFrame(false, this)) {
        }

cc.ri.us cc.sc.us cc.sd.us cc.tn.us cc.tx.us cc.ua cc.ut.us cc.va.us cc.vi.us cc.vt.us cc.wa.us cc.wi.us cc.wv.us cc.wy.us cci.fr cd cd.eu.org cdn-edges.net cdn.prod.atlassian-dev.net cdn77-ssl.net ce.gov.br ce.it ce.leg.br cechire.com celtic.museum center center.museum centralus.azurestaticapps.net ceo cern certification.aero certmgr.org cesena-forli.it cesena-forlì.it cesenaforli.it cesenaforlì.it cf cf-ipfs.com cfa cfd cg ch ch.eu.org ch.it ch.tc ch.trendhosting.cloud chambagri.fr championship.aero...

   * independent reader each time it is called.
   *
   * <p>The caller is responsible for ensuring that the returned reader is closed.
   *
   * @throws IOException if an I/O error occurs while of opening the reader
   */
  public BufferedReader openBufferedStream() throws IOException {
    Reader reader = openStream();
    return (reader instanceof BufferedReader)
        ? (BufferedReader) reader

        while ((source = reader.read()) != null) {
            int current = Integer.parseInt(source.get("field2").toString());
            assertTrue(prev < current);
            prev = current;
            count++;
        }
        assertEquals(num, count);

        reader = new ESSourceReader(client, settings, indexName);
        reader.setScrollSize(1000);

# Header Parameter Models

If you have a group of related **header parameters**, you can create a **Pydantic model** to declare them.

This would allow you to **re-use the model** in **multiple places** and also to declare validations and metadata for all the parameters at once. 😎

/// note

This is supported since FastAPI version `0.115.0`. 🤓

///

## Header Parameters with a Pydantic Model

    // The most common case is that from is a Reader (like InputStreamReader or StringReader) so
    // take advantage of that.
    if (from instanceof Reader) {
      // optimize for common output types which are optimized to deal with char[]
      if (to instanceof StringBuilder) {
        return copyReaderToBuilder((Reader) from, (StringBuilder) to);
      } else {
        return copyReaderToWriter((Reader) from, asWriter(to));
      }
    }

    CharSequenceReader reader = new CharSequenceReader(string);
    assertTrue(reader.markSupported());

    assertEquals(string, readFully(reader));
    assertFullyRead(reader);

    // reset and read again
    reader.reset();
    assertEquals(string, readFully(reader));
    assertFullyRead(reader);

    // reset, skip, mark, then read the rest
    reader.reset();
    assertEquals(5, reader.skip(5));

        }
    }

    @Override
    public org.apache.maven.model.Model read(Reader reader, Map<String, ?> options) throws IOException {
        Objects.requireNonNull(reader, "reader cannot be null");
        try (Reader r = reader) {
            org.apache.maven.api.model.Model model = read(null, null, r, options);
            return new org.apache.maven.model.Model(model);