Java

Building a multipart/form-data Request for HTTP Upload

See more HTTP Examples

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--

Chilkat2 Java

import com.chilkatsoft.chilkat2.HttpRequest;

public class ChilkatExample {

    public static void main(String[] args) {
        // This example demonstrates building a multipart/form-data request.

        HttpRequest req = new HttpRequest();

        // The ContentType, HttpVerb, and Path properties should
        // always be explicitly set.
        req.setHttpVerb("POST");
        req.setPath("/something");
        req.setContentType("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.
        req.addStringForUpload("fileA", "fileA.txt", "This is the contents of file A", "utf-8");
        req.addStringForUpload("fileB", "fileB.txt", "This is the contents of file B", "utf-8");
        req.addStringForUpload("fileC", "fileC.txt", "This is the contents of file C", "utf-8");

        // View the request that would be sent if HttpSReq was called:
        String requestMime = req.generateRequestText();
        System.out.println(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 HttpSReq
        //    is called.
    }
}