VB.NET

Add Data to multipart/form-data Request

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Demonstrates how to add content (such as a JPG, PDF, XML, etc.) to multipart/form-data requests. VB.NET

Dim success As Boolean = False

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

Dim req As New Chilkat.HttpRequest
req.HttpVerb = "POST"
req.ContentType = "multipart/form-data"
req.Path = "/xyz/something"

req.AddParam("param1","value1")
req.AddParam("param2","value2")

' Add some small files to the request. (Small so we can see what the full request looks like without too much data..)
Dim bd As New Chilkat.BinData
success = bd.LoadFile("qa_data/jpg/starfish20.jpg")
req.AddBdForUpload("starfish20","starfish20.jpg",bd,"image/jpeg")

success = bd.LoadFile("qa_data/pdf/helloWorld.pdf")
req.AddBdForUpload("helloWorld","helloWorld.pdf",bd,"application/pdf")

success = bd.LoadFile("qa_data/xml/tinyA.xml")
req.AddBdForUpload("tinyA","tinyA.xml",bd,"text/xml")

' This HTTP request contains binary data, so we cannot call GenerateRequestText
' to examine it as a string.  We can instead call GenerateRequestFile
' to write the request to a file and then examine using a hex editor,
' or an editor that is capable of handling null bytes and non-printable chars (perhaps by displaying "?" chars instead).
req.GenerateRequestFile("qa_output/multipartFormDataRequest.bin")

Debug.WriteLine("OK.")

' This is the HTTP multipart/form-data request built by the above code:

' POST /xyz/something HTTP/1.1
' Host: domain
' Content-Type: multipart/form-data; boundary=------------090708030009010000030901
' Content-Length: 2220
' 
' --------------090708030009010000030901
' Content-Disposition: form-data; name="param1"
' 
' value1
' --------------090708030009010000030901
' Content-Disposition: form-data; name="param2"
' 
' value2
' --------------090708030009010000030901
' Content-Disposition: form-data; name="starfish20"; filename="starfish20.jpg"
' Content-Type: image/jpeg
' 
' JPEG DATA HERE...
' --------------090708030009010000030901
' Content-Disposition: form-data; name="helloWorld"; filename="helloWorld.pdf"
' Content-Type: application/pdf
' 
' PDF DATA HERE...
' --------------090708030009010000030901
' Content-Disposition: form-data; name="tinyA"; filename="tinyA.xml"
' Content-Type: text/xml
' 
' XML DATA HERE...
' --------------090708030009010000030901--
'