(DataFlex) 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.

Chilkat ActiveX Downloads

ActiveX for 32-bit and 64-bit Windows

Use ChilkatAx-win32.pkg

Procedure Test
    Handle hoRest
    Boolean iBTls
    Integer iPort
    Boolean iBAutoReconnect
    Boolean iSuccess
    Variant vSbHtml
    Handle hoSbHtml
    Variant vFileStream
    Handle hoFileStream
    String sResponseBody
    String sTemp1
    Boolean bTemp1

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

    Get Create (RefClass(cComChilkatRest)) To hoRest
    If (Not(IsComObjectCreated(hoRest))) Begin
        Send CreateComObject of hoRest
    End

    // Connect to the destination web server.
    Move True To iBTls
    Move 443 To iPort
    Move True To iBAutoReconnect
    Get ComConnect Of hoRest "www.somewebserver.com" iPort iBTls iBAutoReconnect To iSuccess

    // 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.
    Get ComAddHeader Of hoRest "Content-Type" "multipart/form-data" To iSuccess

    // Specify each part of the request.
    Set ComPartSelector Of hoRest To "1"
    Get ComAddHeader Of hoRest "Content-Disposition" 'form-data; name="text1"' To iSuccess
    Get ComSetMultipartBodyString Of hoRest "text 123 abc" To iSuccess

    Set ComPartSelector Of hoRest To "2"
    Get ComAddHeader Of hoRest "Content-Disposition" 'form-data; name="text2"' To iSuccess
    Get ComSetMultipartBodyString Of hoRest "xyz" To iSuccess

    Set ComPartSelector Of hoRest To "3"
    Get ComAddHeader Of hoRest "Content-Disposition" 'form-data; name="file1"; filename="a.txt"' To iSuccess
    Get ComAddHeader Of hoRest "Content-Type" "text/plain" To iSuccess
    Get ComSetMultipartBodyString Of hoRest "Content of a.txt." To iSuccess

    Set ComPartSelector Of hoRest To "4"
    Get ComAddHeader Of hoRest "Content-Disposition" 'form-data; name="file2"; filename="a.html"' To iSuccess
    Get ComAddHeader Of hoRest "Content-Type" "text/html" To iSuccess
    Get Create (RefClass(cComChilkatStringBuilder)) To hoSbHtml
    If (Not(IsComObjectCreated(hoSbHtml))) Begin
        Send CreateComObject of hoSbHtml
    End
    Get ComLoadFile Of hoSbHtml "qa_data/html/a.html" "utf-8" To iSuccess
    Get pvComObject of hoSbHtml to vSbHtml
    Get ComSetMultipartBodySb Of hoRest vSbHtml To iSuccess

    Set ComPartSelector Of hoRest To "5"
    Get ComAddHeader Of hoRest "Content-Disposition" 'form-data; name="file3"; filename="starfish.jpg"' To iSuccess
    Get ComAddHeader Of hoRest "Content-Type" "image/jpeg" To iSuccess

    // When the request is sent, stream this part directly from the file.
    // This avoids having to load the entire file into memory.
    Get Create (RefClass(cComChilkatStream)) To hoFileStream
    If (Not(IsComObjectCreated(hoFileStream))) Begin
        Send CreateComObject of hoFileStream
    End
    Set ComSourceFile Of hoFileStream To "qa_data/jpg/starfish.jpg"
    Get pvComObject of hoFileStream to vFileStream
    Get ComSetMultipartBodyStream Of hoRest vFileStream To iSuccess

    Get ComFullRequestMultipart Of hoRest "POST" "/some_path" To sResponseBody
    Get ComLastMethodSuccess Of hoRest To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoRest To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // ...
    // ...

    // Clear the REST object for any subsequent requests..
    Get ComClearAllHeaders Of hoRest To iSuccess
    Get ComClearAllParts Of hoRest To iSuccess
    Set ComPartSelector Of hoRest To ""


End_Procedure