The content type. This a string giving the MIME type specified by the client with the upload. This is the full content-type string, including any attributes, such "charset" for a text type. This can be nil if the client doesn't specify a content-type at all.

It's important to recognize that this information is supplied by the client, and is NOT validated by the protocol server. At best you should consider it a suggestion, and at worst a malicious lie. The client could be innocently mistaken about the type, or could even be intentionally misrepresenting it. You should always validate the actual contents, rather than relying on the client's description of the format; in particular, be careful not to assume that expected data fields are present, in the valid range, etc.

The file data.

When you create the FileUpload object for use with sendNetRequest() to post form data, you must use a string or ByteArray value for this property.

When the FileUpload is created by HTTPRequest.getFormFields(), this property contains a File object with the uploaded content. This is open for read-only access. If the contentType parameter is a text type ("text/html", "text/plain", etc), and the interpreter recognizes the character set parameter in the contentType, the file is in Text mode (FileModeText) with the appropriate character mapper in effect. Otherwise, the file is in raw binary mode (FileModeRaw). If you need the file to be opened in a different mode, you can use setFileMode() on the file to change the mode.

The client-side filename, if specified. This is a string giving the name of the file on the client machine. This generally has no particular meaning to the server, since we can't infer anything about the directory structure or naming conventions on an arbitrary client. However, this might be useful for reference, such as showing information about the upload in a user interface. It's sometimes also marginally useful to know the suffix (extension) for making further guesses about the content type - although as with the content-type, you can't rely upon this, but can only use it as a suggestion from the client.

The client won't necessarily specify a filename at all, in which case this will be nil.