Upload files to webservers using Matlab's webread/webwrite or urlread2, urlreadpost

Hi, I am trying to upload a file to a webserver using an api. I can read the contents of the file to a string (using fileread) and then pass that to the api (see expected api payload below). I have used Matlab's in-built functions (webread, webwrite for accessing APIs), urlread2 and urlreadpost but havent been successful. I modified the code in urlreadpost.m:

            urlConnection.setDoOutput(true);
            boundary = '---------------------------';%'BoUnDaRyStRiNg';%'***********************';
            urlConnection.setRequestProperty( ...
                'Content-Type',['multipart/form-data; boundary=',boundary]);        
            printStream = java.io.PrintStream(urlConnection.getOutputStream);
            % also create a binary stream
    %         dataOutputStream = java.io.DataOutputStream(urlConnection.getOutputStream);
            eol = [char(13),char(10)];
            for i=1:2:length(params)
              printStream.print(['--',boundary,eol]);
              printStream.print(['Content-Disposition: form-data; name="',params{i},'"']);
              if ischar(params{i+1})
                % binary data is uploaded as an octet stream
                % Echo Nest API demands a filename in this case
                printStream.print(['; filename="file.wrg"',eol]);
                printStream.print(['Content-Type: application/octet-stream',eol]);
                printStream.print(params(i+1))
                printStream.print([eol]);
                %dataOutputStream.write(params{i+1},0,length(params{i+1}));
                printStream.print([eol]);
              else
                disp('Hello')
                printStream.print([eol]);
                printStream.print([eol]);
                printStream.print([params{i+1},eol]);
              end
            end
    %         printStream.print(['--',boundary,'--',eol]);
            printStream.close;

The expected the request payload for the API should look like this.

-----------------------------147542583027268
Content-Disposition: form-data; name="wrg_file"; filename="Breivikfjellet_windoku.wrg"
Content-Type: application/octet-stream

    14           11      606338      7140563     373
  GridPoint     606338   7140563     200   80 4.51 2.000              0 12  80  45  200  80  45  200  80  45  200  80  45  200  80  45  200  80  45  200  80  45  200  80  45  200  80  45  200  80  45  200  80  45  200  80  45  200

....

GridPoint     611187   7144293     200   80 9.03 2.000              0 12  80  90  200  80  90  200  80  90  200  80  90  200  80  90  200  80  90  200  80  90  200  80  90  200  80  90  200  80  90  200  80  90  200  80  90  200

-----------------------------147542583027268--

[Eugene]

Did you find and answer to your question? I've got the same problem and had to use urlreadpost instead of the native webwrite.

[Alex]

Please upvote this question!

Answer 1

[Vinod]

Here's an example that uploads any file from MATLAB to DropBox programmatically:

http://www.mathworks.com/matlabcentral/fileexchange/59673