(Unicode C++) REST Stream Multipart Body from File

Demonstrates how to send a multipart/form-data HTTP request, where one of the parts contains data streamed directly from a file. This is good for cases where the file to be uploaded is very large.

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#include <CkRestW.h>
#include <CkStringBuilderW.h>
#include <CkStreamW.h>

void ChilkatSample(void)
    {
    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkRestW rest;

    // Connect to the destination web server.
    bool bTls = true;
    int port = 443;
    bool bAutoReconnect = true;
    bool success = rest.Connect(L"www.somewebserver.com",port,bTls,bAutoReconnect);

    // This example will send the following multipart/form-data request.
    // The Content-Length is automatically computed and added by Chilkat.

    // 	POST /some_path HTTP/1.1
    // 	Content-Type: multipart/form-data; boundary=---------------------------735323031399963166993862150
    // 	Content-Length: 834
    // 
    // 	-----------------------------735323031399963166993862150
    // 	Content-Disposition: form-data; name="text1"
    // 
    // 	text 123 abc
    // 	-----------------------------735323031399963166993862150
    // 	Content-Disposition: form-data; name="text2"
    // 
    // 	xyz
    // 	-----------------------------735323031399963166993862150
    // 	Content-Disposition: form-data; name="file1"; filename="a.txt"
    // 	Content-Type: text/plain
    // 
    // 	Content of a.txt.
    // 
    // 	-----------------------------735323031399963166993862150
    // 	Content-Disposition: form-data; name="file2"; filename="a.html"
    // 	Content-Type: text/html
    // 
    // 	<!DOCTYPE html><title>Content of a.html.</title>
    // 
    // 	-----------------------------735323031399963166993862150
    // 	Content-Disposition: form-data; name="file3"; filename="starfish.jpg"
    // 	Content-Type: image/jpeg
    // 
    // 	binary data goes here
    // 	-----------------------------735323031399963166993862150--

    // Set the Content-Type for the topmost MIME part.
    rest.AddHeader(L"Content-Type",L"multipart/form-data");

    // Specify each part of the request.
    rest.put_PartSelector(L"1");
    rest.AddHeader(L"Content-Disposition",L"form-data; name=\"text1\"");
    rest.SetMultipartBodyString(L"text 123 abc");

    rest.put_PartSelector(L"2");
    rest.AddHeader(L"Content-Disposition",L"form-data; name=\"text2\"");
    rest.SetMultipartBodyString(L"xyz");

    rest.put_PartSelector(L"3");
    rest.AddHeader(L"Content-Disposition",L"form-data; name=\"file1\"; filename=\"a.txt\"");
    rest.AddHeader(L"Content-Type",L"text/plain");
    rest.SetMultipartBodyString(L"Content of a.txt.");

    rest.put_PartSelector(L"4");
    rest.AddHeader(L"Content-Disposition",L"form-data; name=\"file2\"; filename=\"a.html\"");
    rest.AddHeader(L"Content-Type",L"text/html");
    CkStringBuilderW sbHtml;
    sbHtml.LoadFile(L"qa_data/html/a.html",L"utf-8");
    rest.SetMultipartBodySb(sbHtml);

    rest.put_PartSelector(L"5");
    rest.AddHeader(L"Content-Disposition",L"form-data; name=\"file3\"; filename=\"starfish.jpg\"");
    rest.AddHeader(L"Content-Type",L"image/jpeg");

    // When the request is sent, stream this part directly from the file.
    // This avoids having to load the entire file into memory.
    CkStreamW fileStream;
    fileStream.put_SourceFile(L"qa_data/jpg/starfish.jpg");
    rest.SetMultipartBodyStream(fileStream);

    const wchar_t *responseBody = rest.fullRequestMultipart(L"POST",L"/some_path");
    if (rest.get_LastMethodSuccess() != true) {
        wprintf(L"%s\n",rest.lastErrorText());
        return;
    }

    // ...
    // ...

    // Clear the REST object for any subsequent requests..
    rest.ClearAllHeaders();
    rest.ClearAllParts();
    rest.put_PartSelector(L"");
    }