usockets：打开套接字时如何指定外部格式 [英] usockets: How do I specify the external format when I open a socket

问题描述

我正在尝试连接到Mud客户端，因此我正在使用usockets通过TCP连接。但是写完之后，我得到了解码错误的阅读。我有理由相信编码应该是ascii，或者至少使用：clrf作为行尾指示符，因为在我读到的行中，在行尾之前有一个^ M

I'm trying to connect to a mud client, so I'm using usockets to connect over tcp. But After I write I get a decoding error reading. I have reason to believe the encoding should ascii ,or least use :clrf as the end of line designator, as on the lines I read there is a ^M before the end of line

(let* ((sock (socket-connect "angalon.net" 3011))
       (stream (slot-value sock 'stream)))
  (format stream "guest~%")
  (force-output stream)
  (dotimes (i 40)
    (read-line stream))
  stream)

:UTF-8 stream decoding error on
#<SB-SYS:FD-STREAM
  for "socket 192.168.1.39:65516, peer: 93.174.104.58:3011"
  {1004129903}>:

  the octet sequence #(255 251 1 80) cannot be decoded.
   [Condition of type SB-INT:STREAM-DECODING-ERROR]

我可以验证流的外部格式确实是：utf-8，但问题是我如何指定套接字给我的流的外部格式？

I can verify the external format of the stream is indeed :utf-8, but the question is how I specify the external-format of the stream the socket gives me?

(let* ((sock (socket-connect "angalon.net" 3011))
       (stream (slot-value sock 'stream)))
  (stream-external-format stream))
;; => :UTF-8

推荐答案

只需查看源在Clozure CL后端，外部格式被硬编码为 ccl：* default-external-format * ，在我的系统中是UTF-8。 SBCL后端未指定外部格式，但可能会使用SBCL默认值（同样是UTF-8）创建套接字。我不认为没有一种简便的方法可以更改外部格式，而无需修改usocket。

Just by looking at the source for the Clozure CL backend, the external format is hard coded to ccl:*default-external-format* which is UTF-8 in my system. The SBCL backend does not specify an external format, but it probably creates the socket with SBCL defaults, which is again UTF-8. I don't think there's a portable way to change the external format short of modifying usocket.

也就是说，您可以绑定 sb-impl： ：*默认外部格式* 在调用 socket-connect ：latin-1 c>：

That said, you could bind sb-impl::*default-external-format* to say :latin-1 before calling socket-connect:

(let* ((sb-impl::*default-external-format* :latin-1)
       (sock (socket-connect "angalon.net" 3011))
       (stream (slot-value sock 'stream)))
   (stream-external-format stream))

;; :LATIN-1

编辑：也可以看看 FLEXI-STREAMS 。我尚未对其进行测试，但是您可以将流转换为 FLEXI-STREAM 并指定外部格式。

also take a look at FLEXI-STREAMS. I haven't tested it, but you could convert the stream to a FLEXI-STREAMand specify an external format.

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