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

    rest := chilkat.NewRest()

    // Connect to the destination web server.
    bTls := true
    port := 443
    bAutoReconnect := true
    success := rest.Connect("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("Content-Type","multipart/form-data")

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

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

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

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

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

    // When the request is sent, stream this part directly from the file.
    // This avoids having to load the entire file into memory.
    fileStream := chilkat.NewStream()
    fileStream.SetSourceFile("qa_data/jpg/starfish.jpg")
    rest.SetMultipartBodyStream(fileStream)

    responseBody := rest.FullRequestMultipart("POST","/some_path")
    if rest.LastMethodSuccess() != true {
        fmt.Println(rest.LastErrorText())
        rest.DisposeRest()
        sbHtml.DisposeStringBuilder()
        fileStream.DisposeStream()
        return
    }

    // ...
    // ...

    // Clear the REST object for any subsequent requests..
    rest.ClearAllHeaders()
    rest.ClearAllParts()
    rest.SetPartSelector("")

    rest.DisposeRest()
    sbHtml.DisposeStringBuilder()
    fileStream.DisposeStream()