java - Get Metadata from Dropbox Link Without Auth -

i want check version changed/get metadata of text-file shared link on dropbox. not using dropbox api makes users use own accounts. want them link account , cannot manually since might change password later.

so: no auth token, metadata shared link of dropbox can check version changes , if version has changed download contents of new file.

also: i'm open other suggestions make work well. please explain in little detail solution.

updated e-tag issue:

public void getfromonlinetxtdatabase(){         try{             url url = new url("url-here");             httpurlconnection.setfollowredirects(true);             httpurlconnection con = (httpurlconnection) url.openconnection();             con.setdooutput(false);             con.setreadtimeout(20000);             con.setrequestproperty("connection", "keep-alive");             //get etag update check                 string etag = con.getheaderfield("etag");             //string etag= "";              con.setrequestproperty("user-agent", "mozilla/5.0 (windows nt 6.1; wow64; rv:16.0) gecko/20100101 firefox/16.0");             ((httpurlconnection) con).setrequestmethod("get");             //system.out.println(con.getcontentlength()) ;             con.setconnecttimeout(5000);             bufferedinputstream in = new bufferedinputstream(con.getinputstream());             int responsecode = con.getresponsecode();             if (responsecode == httpurlconnection.http_ok) {                 system.out.println(responsecode);             }             stringbuffer buffer = new stringbuffer();             int chars_read;             //int total = 0;             while ((chars_read = in.read()) != -1)              {                 char g = (char) chars_read;                 buffer.append(g);             }             final string page = buffer.tostring();             //create password_ems.txt internal             if (fileexistance("data.txt")){                 file dir = getfilesdir();                 file file = new file(dir, "data.txt");                 boolean deleted = file.delete();                 stringtotxt(page, "data.txt");               }else{                 stringtotxt(page, "data.txt");             }              if (fileexistance("data_etag.txt")){                 file dir = getfilesdir();                 file file = new file(dir, "etag.txt");                 boolean deleted = file.delete();                 stringtotxt(etag, "etag.txt");               }else{                 //create etag_file                 stringtotxt(etag, "data_etag.txt");             }              //  log.i("page", page);         }catch(exception e){             showdialog("database fetch failure","unable fetch password database, check internet" +                     " connection , try again later.",0);             log.i("page", "error");         }      } 

if http head request against public or shared dropbox url, you'll get, among other things, etag header. don't know behavior guaranteed, since don't think it's documented anywhere, @ least etag header can used determine when file has changed. (if etag different, file has changed.)

edit

in general when using etags, efficient thing issue get request header of if-none-match: <old etag>. if content hasn't changed, respond 304, if content has changed, download new content per normal get request (and response 200).