CONTINUATION / CONTINUATION帧

The CONTINUATION frame (type=0x9) is used to continue a sequence of header block fragments (Section 4.3). Any number of CONTINUATION frames can be sent, as long as the preceding frame is on the same stream and is a HEADERS, PUSH_PROMISE, or CONTINUATION frame without the END_HEADERS flag set.

+---------------------------------------------------------------+
|                   Header Block Fragment (*)                 ...
+---------------------------------------------------------------+
                Figure 15: CONTINUATION Frame Payload

CONTINUATION帧(type=0x9)用于继续传送首部块片段序列( 4.3节 )。只要前面的帧在同一个流上，而且是一个没有设置END_HEADERS标志的 HEADERS 帧，PUSH_PROMISE帧，或者CONTINUATION帧，就可以发送任意数量的CONTINUATION帧。

+---------------------------------------------------------------+
|                   Header Block Fragment (*)                 ...
+---------------------------------------------------------------+
                      图 15: CONTINUATION帧负载

The CONTINUATION frame payload contains a header block fragment (Section 4.3).

CONTINUATION帧的负载包含一个首部块片段( 4.3节 )。

The CONTINUATION frame defines the following flag:

• END_HEADERS (0x4): When set, bit 2 indicates that this frame ends a header block (Section 4.3).

  If the END_HEADERS bit is not set, this frame MUST be followed by another CONTINUATION frame. A receiver MUST treat the receipt of any other type of frame or a frame on a different stream as a connection error (Section 5.4.1) of type PROTOCOL_ERROR.

CONTINUATION帧定义了如下标志：

• END_HEADERS (0x4): 当设置了该标志，第2个bit位表示该帧是一个首部块的结束( 4.3节 )。

  如果没有设置 END_HEADERS bit位，该帧的后面必须跟有其他的CONTINUATION帧。如果接收端收到了任何其他类型的帧，或者另外一条流上的帧，必须将其当做类型为 PROTOCOL_ERROR 的连接错误( 5.4.1节 )。

The CONTINUATION frame changes the connection state as defined in Section 4.3.

CONTINUATION帧改变了 4.3节 定义的连接状态。

CONTINUATION frames MUST be associated with a stream. If a CONTINUATION frame is received whose stream identifier field is 0x0, the recipient MUST respond with a connection error (Section 5.4.1) of type PROTOCOL_ERROR.

CONTINUATION帧必须和一个流相关联。如果收到了流标识符域的值为0x0的CONTINUATION帧，接收端必须响应一个类型为PROTOCOL_ERROR的连接错误( 5.4.1节 )。

A CONTINUATION frame MUST be preceded by a HEADERS, PUSH_PROMISE or CONTINUATION frame without the END_HEADERS flag set. A recipient that observes violation of this rule MUST respond with a connection error (Section 5.4.1) of type PROTOCOL_ERROR.

CONTINUATION帧之前必须是一个没有设置END_HEADERS标志的 HEADERS 帧，PUSH_PROMISE 帧，或者CONTINUATION帧。如果接收端发现违反该规则了，必须响应一个类型为 PROTOCOL_ERROR 的连接错误( 5.4.1节 )。