(PureBasic) Building a multipart/form-data Request for HTTP Upload

Uploading files to a web server typically requires building a multipart/form-data request where the files are contained in the sub-parts of the MIME request.

Note: HTTP uploads require code on the server-side to receive the upload. For example, see Complete C# ASP.NET HTTP Upload Example

This example produces the following HTTP multipart/form-data request:

POST /something HTTP/1.1
Content-Type: multipart/form-data; boundary=------------070002080409050901090203
Host: domain
Content-Length: 546

--------------070002080409050901090203
Content-Disposition: form-data; name="fileA"; filename="fileA.txt"
Content-Type: text/plain

This is the contents of file A
--------------070002080409050901090203
Content-Disposition: form-data; name="fileB"; filename="fileB.txt"
Content-Type: text/plain

This is the contents of file B
--------------070002080409050901090203
Content-Disposition: form-data; name="fileC"; filename="fileC.txt"
Content-Type: text/plain

This is the contents of file C
--------------070002080409050901090203--

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkHttpRequest.pb"

Procedure ChilkatExample()

    ; This example demonstrates building a multipart/form-data request.

    req.i = CkHttpRequest::ckCreate()
    If req.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; The ContentType, HttpVerb, and Path properties should
    ; always be explicitly set.
    CkHttpRequest::setCkHttpVerb(req, "POST")
    CkHttpRequest::setCkPath(req, "/something")
    CkHttpRequest::setCkContentType(req, "multipart/form-data")

    ; The contents and name of each file to be uploaded is provided
    ; by calling any of the following methods:
    ; AddBytesForUpload
    ; AddBytesForUpload2
    ; AddFileForUpload
    ; AddFileForUpload2
    ; AddStringForUpload
    ; AddStringForUpload2

    ; For this example, we'll provide the contents of the files to be uploaded
    ; directly as in-memory strings.
    CkHttpRequest::ckAddStringForUpload(req,"fileA","fileA.txt","This is the contents of file A","utf-8")
    CkHttpRequest::ckAddStringForUpload(req,"fileB","fileB.txt","This is the contents of file B","utf-8")
    CkHttpRequest::ckAddStringForUpload(req,"fileC","fileC.txt","This is the contents of file C","utf-8")

    ; View the request that would be sent if SynchronousRequest was called:
    requestMime.s = CkHttpRequest::ckGenerateRequestText(req)
    Debug requestMime

    ; A few important comments about the HTTP request that is generated:
    ; 
    ; 1) Chilkat automatically generates a random boundary string.   In 99.999% of cases, this should 
    ;    be sufficient.
    ; 2) The Content-Length header is automatically generated based on the actual length of the MIME message
    ;    that follows the intial (topmost) MIME header.
    ; 3) The HOST header will automatically get filled in with the actual domain when SynchronousRequest
    ;    is called


    CkHttpRequest::ckDispose(req)


    ProcedureReturn
EndProcedure