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(Unicode C) REST Follow RedirectsDemonstrates how to follow a 302/303 redirect response.
#include <C_CkRestW.h> #include <C_CkUrlW.h> void ChilkatSample(void) { HCkRestW rest; BOOL bTls; int port; BOOL bAutoReconnect; BOOL success; const wchar_t *responseText; int statusCode; HCkUrlW redirectUrl; // This example requires the Chilkat API to have been previously unlocked. // See Global Unlock Sample for sample code. rest = CkRestW_Create(); bTls = TRUE; port = 443; bAutoReconnect = TRUE; success = CkRestW_Connect(rest,L"chilkatsoft.com",port,bTls,bAutoReconnect); if (success != TRUE) { wprintf(L"%s\n",CkRestW_lastErrorText(rest)); CkRestW_Dispose(rest); return; } // Send a POST to a URL that will respond with a 302 redirect.. CkRestW_AddQueryParam(rest,L"firstName",L"John"); CkRestW_AddQueryParam(rest,L"lastName",L"Doe"); responseText = CkRestW_fullRequestFormUrlEncoded(rest,L"POST",L"/echoPost302.asp"); if (CkRestW_getLastMethodSuccess(rest) != TRUE) { wprintf(L"%s\n",CkRestW_lastErrorText(rest)); CkRestW_Dispose(rest); return; } statusCode = CkRestW_getResponseStatusCode(rest); // Examine the response status code if (statusCode < 300) { wprintf(L"Not a redirect.\n"); wprintf(L"%s\n",responseText); CkRestW_Dispose(rest); return; } if (statusCode > 399) { wprintf(L"Error response: Status code = %d\n",statusCode); wprintf(L"%s\n",responseText); CkRestW_Dispose(rest); return; } wprintf(L"Redirect status code = %d\n",statusCode); // The response header will contain a Location field with the redirect URL, such as this: // Location: http://www.chilkatsoft.com/echoPostFinal.asp // The response status code determines how the client should behave. // Here are some common possibilities: // 301: Moved Permanently // This and all future requests should be directed to the given URI. (Keep the original HTTP method for the redirect. In this case, the // original request was a POST, so we POST to the redirect URL.) // 302: Found (aka Object Moved aka Moved Temporarily) // This is the most popular redirect code, but also an example of industrial practice contradicting the standard. HTTP/1.0 specification (RFC 1945 ) required the client // to perform a temporary redirect (the original describing phrase was Moved Temporarily), but popular browsers implemented it as a 303 See Other. Therefore, HTTP/1.1 // added status codes 303 and 307 to disambiguate between the two behaviors. However, the majority of Web applications and frameworks still use the 302 status code // as if it were the 303. // 303: See Other // The response to the request can be found under another URI using a GET method. When received in response to a PUT, it should be assumed that the server has // received the data and the redirect should be issued with a separate GET message. // 307: Temporary Redirect // In this occasion, the request should be repeated with another URI, but future requests can still use the original URI. In contrast to 303, the request method // should not be changed when reissuing the original request. For instance, a POST request must be repeated using another POST request. wprintf(L"%s\n",CkRestW_responseHeader(rest)); redirectUrl = CkRestW_RedirectUrl(rest); if (CkRestW_getLastMethodSuccess(rest) == FALSE) { wprintf(L"No Location header found for redirect.\n"); CkRestW_Dispose(rest); return; } // Prep for the redirect.. CkRestW_ClearAllParts(rest); // Disconnect and re-connect. // (This can be skipped if both the host and SSL/TLS conditions are the same.) CkRestW_Disconnect(rest,100); success = CkRestW_Connect(rest,CkUrlW_host(redirectUrl),CkUrlW_getPort(redirectUrl),CkUrlW_getSsl(redirectUrl),bAutoReconnect); if (success != TRUE) { wprintf(L"%s\n",CkRestW_lastErrorText(rest)); CkRestW_Dispose(rest); return; } if ((statusCode == 301) || (statusCode == 307)) { // Redirect using a POST, sending the same params to the new destination CkRestW_AddQueryParam(rest,L"firstName",L"John"); CkRestW_AddQueryParam(rest,L"lastName",L"Doe"); responseText = CkRestW_fullRequestFormUrlEncoded(rest,L"POST",CkUrlW_path(redirectUrl)); if (CkRestW_getLastMethodSuccess(rest) != TRUE) { wprintf(L"%s\n",CkRestW_lastErrorText(rest)); CkRestW_Dispose(rest); return; } } if ((statusCode == 302) || (statusCode == 303)) { // Redirect using a GET, sending the query params found in the redirect URL. responseText = CkRestW_fullRequestFormUrlEncoded(rest,L"GET",CkUrlW_pathWithQueryParams(redirectUrl)); if (CkRestW_getLastMethodSuccess(rest) != TRUE) { wprintf(L"%s\n",CkRestW_lastErrorText(rest)); CkRestW_Dispose(rest); return; } } // Show the final status code and the response text. wprintf(L"Final status code = %d\n",CkRestW_getResponseStatusCode(rest)); wprintf(L"Final response text (HTML, XML, JSON, or whatever..)\n"); wprintf(L"%s\n",responseText); CkRestW_Dispose(rest); } |
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