Error codes / 错误码

Error codes are 32-bit fields that are used in RST_STREAM and GOAWAY frames to convey the reasons for the stream or connection error.

错误码是 RST_STREAM 帧和 GOAWAY 帧中32-bit位的域，用于表达流或连接错误的原因。

Error codes share a common code space. Some error codes apply only to either streams or the entire connection and have no defined semantics in the other context.

错误码共享一个公共的码空间。一些错误码要么只适用于流，要么只适用于整个连接，并且在其他的上下文中没有语义定义。

The following error codes are defined:

• NO_ERROR (0x0): The associated condition is not a result of an error. For example, a GOAWAY might include this code to indicate graceful shutdown of a connection.
• PROTOCOL_ERROR (0x1): The endpoint detected an unspecific protocol error. This error is for use when a more specific error code is not available.
• INTERNAL_ERROR (0x2): The endpoint encountered an unexpected internal error.
• FLOW_CONTROL_ERROR (0x3): The endpoint detected that its peer violated the flow-control protocol.
• SETTINGS_TIMEOUT (0x4): The endpoint sent a SETTINGS frame but did not receive a response in a timely manner. See Section 6.5.3 ("Settings Synchronization").
• STREAM_CLOSED (0x5): The endpoint received a frame after a stream was half-closed.
• FRAME_SIZE_ERROR (0x6): The endpoint received a frame with an invalid size.
• REFUSED_STREAM (0x7): The endpoint refused the stream prior to performing any application processing (see Section 8.1.4 for details).
• CANCEL (0x8): Used by the endpoint to indicate that the stream is no longer needed.
• COMPRESSION_ERROR (0x9): The endpoint is unable to maintain the header compression context for the connection.
• CONNECT_ERROR (0xa): The connection established in response to a CONNECT request (Section 8.3) was reset or abnormally closed.
• ENHANCE_YOUR_CALM (0xb): The endpoint detected that its peer is exhibiting a behavior that might be generating excessive load.
• INADEQUATE_SECURITY (0xc): The underlying transport has properties that do not meet minimum security requirements (see Section 9.2).
• HTTP_1_1_REQUIRED (0xd): The endpoint requires that HTTP/1.1 be used instead of HTTP/2.

定义了以下错误码：

• NO_ERROR (0x0): 相关情况不是错误。例如，GOAWAY 帧可以包含该码，表示优雅地关闭连接。
• PROTOCOL_ERROR (0x1): 端点检测到一个不确定的协议错误。当没有更加具体的错误码可用时，可以使用该错误码。
• INTERNAL_ERROR (0x2): 端点遭遇到未知的内部错误。
• FLOW_CONTROL_ERROR (0x3): 端点检测到其对端违反了流量控制协议。
• SETTINGS_TIMEOUT (0x4): 端点发送了一个 SETTIGNS 帧，但是没有及时收到响应。参见 6.5.3节 ("同步设置")。
• STREAM_CLOSED (0x5): 流半关闭以后，端点收到一个帧。
• FRAME_SIZE_ERROR (0x6): 端点收到了一个大小无效的帧。
• REFUSED_STREAM (0x7): 在执行任何处理之前，端点拒绝了流(细节参见 8.4.1节 )。
• CANCEL (0x8): 被端点用于表示不再需要该流了。
• COMPRESSION_ERROR (0x9): 端点不能为连接维持首部压缩上下文。
• CONNECT_ERROR (0xa): 响应CONNECT请求( 8.3节 )而建立的连接被重置，或者被非正常关闭。
• ENHANCE_YOUR_CALM (0xb): 端点检测到对端正在展现出可能会产生极大负荷的行为。
• INADEQUATE_SECURITY (0xc): 下层的传输层具有不满足最低安全要求( 9.2节 )的属性。
• HTTP_1_1_REQUIRED (0xd): 端点要求使用HTTP/1.1代替HTTP/2。

Unknown or unsupported error codes MUST NOT trigger any special behavior. These MAY be treated by an implementation as being equivalent to INTERNAL_ERROR.

未知的或者不支持的错误码不能触发任何特别的行为。实现可以将这些错误看做等价于INTERNAL_ERROR。