从没有身份验证的 Dropbox 链接获取元数据 [英] Get Metadata from Dropbox Link Without Auth
问题描述
我想通过 Dropbox 上的共享链接检查版本更改/获取文本文件的元数据.我不会使用 dropbox api，因为它让用户使用自己的帐户.我希望他们链接到我的帐户，但我不能手动这样做，因为我以后可能会更改我的密码.
I want to check for a version changed/get metadata of a text-file with a shared link on dropbox. I will not be using dropbox api as it makes users use their own accounts. I want them to link to my account and I cannot do that manually since I might change my password later.
所以:没有身份验证令牌，只需从保管箱的共享链接获取元数据，以便我可以检查版本更改，如果版本已更改，请下载新文件的内容.
so: no auth token, just get metadata from shared link of dropbox so that I can check for version changes and if the version has changed download the contents of the new file.
另外:我愿意接受其他建议以使这项工作也有效.请详细说明您的解决方案.
also: I'm open to other suggestions to make this work as well. Please explain in a little detail your solution.
更新的电子标签问题:
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 for 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 to 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 to Fetch Password Database, check your internet" +
" connection and try again later.",0);
Log.i("Page", "Error");
}
}
推荐答案
如果您对公共或共享的 Dropbox URL 执行 HTTP HEAD 请求，除其他外，您将获得一个 etag 标头.我不知道这种行为是否得到保证，因为我认为它没有记录在任何地方，但至少现在 etag 标头可用于确定文件何时更改.(如果 etag 不同，则文件已更改.)
If you do an HTTP HEAD request against a public or shared Dropbox URL, you'll get, among other things, an etag header. I don't know that this behavior is guaranteed, since I don't think it's documented anywhere, but at least for now the etag header can be used to determine when a file has changed. (If the etag is different, the file has changed.)
编辑
通常在使用 ETags 时，最有效的做法是发出一个 GET 请求，其标头为 If-None-Match: <old etag>.如果内容没有改变，这将响应一个 304，但如果内容改变了，这将按照正常的 GET 请求下载新的内容(响应将是 200).
In general when using ETags, the most efficient thing to do is issue a GET request with a header of If-None-Match: <old etag>. If the content hasn't changed, this will respond with a 304, but if the content has changed, this will download the new content as per a normal GET request (and the response will be 200).
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