Adding Files to FormData isnt working with solutions provided

Question

I was having trouble adding Files to a formdata and my question (How to add a file to a formdata for an api in apex) was closed because there were other solutions that should work. I've tried Compose a multipart/form-data request from apex without base64 encode and How can I compose a multipart/form-data request? (though I had to edit the class a bit) I still get the 422 error.

//I used
.writeFile( 'Files', 'Lease.pdf', EncodingUtil.base64Encode(file)) //From the pdf.getContentAsPdf() 

//then
.getFormAsBlob();
req.setHeader( 'Connection', 'keep-alive' );
req.setHeader( 'Content-Length', String.valueOf(formData.size()) );
req.setHeader( 'Content-Type', HttpHexFormBuilder.GetContentType() );
req.setBodyAsBlob(formData);

//And even the manual way
body += 'name=\"Files\"; filename=\"Lease.pdf\"; Content-Type=\"application/pdf\"\r\n\r\n'+EncodingUtil.base64Encode(file)+'\r\n';

//Then 
req.setBody(body);

I even tried using the VersionData of a file that I already have

ContentVersion cv = [Select VersionData from ContentVersion where id = '068Do000002J0ArIAK'];

.writeFile( 'Files', 'lease2.pdf', EncodingUtil.base64Encode(cv.VersionData))

And still nothing. It looks like it should work but I keep getting the same 422 error.

Answer 1

You can't just drop base-64 into the content area without declaring it as such:

--boundary
Content-Disposition: form-data; name="Files" filename="Lease.pdf"
Content-Type: application/pdf;base64

<<base64 encoded data here>>
--boundary--

Not all servers support this kind of content, however. You will likely need to encode the entire payload to hexadecimal, then convert it to a blob before sending it. You'll have a limit of approximately 3MB of file data if you use hexadecimal, which is easier to work with (no padding to figure out), but takes twice the extra space of the original file, instead of base64's 33% space increase.