FTP WinInet APIs Report Error 12003

最新推荐文章于 2023-01-05 13:48:54 发布

kybd2006

最新推荐文章于 2023-01-05 13:48:54 发布

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文章标签： report internet server parsing behavior api

本文链接：https://blog.youkuaiyun.com/kybd2006/article/details/1700288

本文介绍了使用WinInet FTP APIs连接非Microsoft FTP服务器时可能出现的错误12003的问题及其原因。此错误可能由于服务器返回了意外的状态码导致，WinInet未能正确解析这些消息。文章还提供了解决方案，即通过避免使用INTERNET_FLAG_PASSIVE标志来防止此类错误的发生。

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Symptoms
Connection to a non-Microsoft FTP server with WinInet FTP APIs may fail with error 12003.

Cause
When connecting to a non-Microsoft FTP server with WinInet APIs, some WinInet FTP APIs may fail with error 12003 (ERROR_INTERNET_EXTENDED_ERROR). The InternetGetLastResponseInfo API may not retrieve any Internet specific information. This error may occur when the FTP server sends an unexpected status code to the WinInet client. Please note that this may not indicate an error, but rather the server's success message or confirmation (such as confirmation of getting a file, sending a directory listing, and so forth). In some cases the WinInet FTP APIs may not parse such messages correctly and erroneously report an error. This may happen when the WinInet FTP APIs are used to connect to certain VAX/VMS FTP servers.

Resolution
The above behavior may be avoided by not using the INTERNET_FLAG_PASSIVE flag in the InternetConnect or InternetOpenUrl API. When this flag is not used WinInet uses active semantics for the FTP connection, which avoids the return of the status code, which causes the parsing problem.