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HTTP Basics

When writing an ISAPI application, you often examine and add to the information in HTTP header. Return codes indicate the success or failure of the requested event. Several common return codes are listed in the following table.

Return Code Meaning
200 URL located, transmission follows
400 Unintelligible request
404 Requested URL not found
405 Server does not support requested method
500 Unknown server error
503 Service unavailable

Additional return codes can be found in the AFXISAPI.H file. The HTTP responses are grouped as shown in the following table.

Group Meaning
200–299 Success
300–399 Information
400–499 Request error
500–599 Server error

The Hypertext Transfer Protocol (HTTP) is an application-level protocol for hypermedia information systems. For more information about HTTP, and how Web browsers and servers communicate, see the Hypertext Transfer Protocol (HTTP) specification:

See Also

MFC Internet Programming Basics