title: Ruby On Rails multipart request unable to read using param[:name]
body: <p>When our client side application posts (Json and csv file) data to our rest API (Ruby on Rails Controller) the data gets changed as seen below (prefix with WebKitFormBoundaryBgpEuNnwhpVHhk5s).</p>
  
  <pre><code>Parameters: {"------WebKitFormBoundaryBgpEuNnwhpVHhk5s\r\nContent-Disposition: form-data; name"=&gt;"\"file\"; filename=\"client_trades20170313.csv\"\r\nContent-Type: application/vnd.ms-excel\r\n\r\nTr_DATE,TRAC_CLASS,PSTATUS,RWS,STR1,SWIT2\r\n3/13/2017,test,D,0,0,22\r\n3/13/2017,FX,D,4949,6615,2379\r\n3/13/2017,test2,D,17,17,0\r\n3/13/2017,ORN,D,22,22,0\r\n3/13/2017,RFE,D,127,127,0\r\n3/13/2017,FCOME,D,191,244,1425\r\n3/13/2017,EWS,D,0,0,356\r\n3/13/2017,REPO,D,40,40,0\r\n3/13/2017,DUND,D,0,0,38\r\n3/13/2017,QAS,D,24,33,21\r\n3/13/2017,TEURE,D,13,24,24\r\n3/13/2017,WQ,D,461,478,62\r\n3/13/2017,FUT,D,24624,32279,2685\r\n\r\n------WebKitFormBoundaryBgpEuNnwhpVHhk5s\r\nContent-Disposition: form-data; name=\"metadata\"\r\n\r\n{\"title\":\"Document Uploaded by nexen UI\",\"description\":\"Upload document\",\"name\":\"BTS1492089784675_bmd@red\",\"client\":\"test23\",\"rrea\":\"Trane\",\"sourceSystem\":\"CLIENT-CSV\",\"tradeDate\":\"2017-04-11\",\"timeOfDay\":\"intraDay\"}\r\n------WebKitFormBoundaryBgpEuNnwhpVHhk5s--\r\n"}
  </code></pre>
  
  <p>As as a result unable to retrieve parameter (on rest controller) 'metadata' like params[:metadata] .  </p>
  
  <p>I am new to ruby on rails and don't know how to retrieve parameter surrounded by WebKitFormBoundary.</p>
  
  <p>Please help.</p>
  
  <p>Code is written using ruby 2.x and rails 5.x.  </p>