从Dropbox的链接获取元数据无需身份验证 [英] Get Metadata from Dropbox Link Without Auth
问题描述
我要检查一个版本的改变/获得一个文本文件的元数据与Dropbox的共享链接。我不会使用Dropbox的API,它使用户能够使用他们自己的帐户。我希望他们能够链接到我的帐户,我不能这样做手工,因为我以后可能会改变我的密码。
这样:没有身份验证令牌,刚刚获得元数据从Dropbox的共享链接,这样我可以检查版本的变化,如果版本已更改下载新文件的内容
。也:我接受其他的建议,使这项工作为好。请稍后详细说明您的解决方案。
更新电子标签问题:
公共无效getFromOnlineTxtDatabase(){
尝试{
网址URL =新的URL(URL-这里);
HttpURLConnection.setFollowRedirects(真正的);
HttpURLConnection的CON =(HttpURLConnection类)url.openConnection();
con.setDoOutput(假);
con.setReadTimeout(20000);
con.setRequestProperty(连接,保持活动);
//获取ETAG进行更新检查
串的etag = con.getHeaderField(ETAG);
//字符串ETAG =;
con.setRequestProperty(用户代理,Mozilla的/ 5.0(Windows NT的6.1; WOW64; RV:16.0)的Gecko / 20100101火狐/ 16.0);
((HttpURLConnection类)CON).setRequestMethod(GET);
//System.out.println(con.getContentLength());
con.setConnectTimeout(5000);
的BufferedInputStream在=新的BufferedInputStream(con.getInputStream());
INT响应code = con.getResponse code();
如果(响应code == HttpURLConnection.HTTP_OK){
的System.out.println(响应code);
}
StringBuffer的缓冲区=新的StringBuffer();
INT chars_read;
// INT总= 0;
而((chars_read = in.read())!= - 1)
{
焦炭G =(焦炭)chars_read;
buffer.append(G);
}
最后弦乐页= buffer.toString();
//创建password_ems.txt内部
如果(fileExistance(data.txt中)){
文件DIR = getFilesDir();
档案文件=新的文件(目录的data.txt);
布尔删除= file.delete();
stringToTxt(页,data.txt中);
}其他{
stringToTxt(页,data.txt中);
}
如果(fileExistance(data_etag.txt)){
文件DIR = getFilesDir();
档案文件=新的文件(目录,etag.txt);
布尔删除= file.delete();
stringToTxt(ETAGetag.txt);
}其他{
//创建etag_file
stringToTxt(ETAGdata_etag.txt);
}
// Log.i(页,页面);
}赶上(例外五){
的ShowDialog(数据库获取失败,无法获取密码数据库,检查您的互联网+
连接,并稍后重试。,0);
Log.i(页,错误);
}
}
如果你做一个HTTP 的头在公共或共享Dropbox的网址
的要求,你会得到,除其他事项外,一个 ETAG
头。我不知道这种行为是有保障的,因为我不认为这是记录任何地方,但至少现在 ETAG
头可以用来确定当一个文件已经改变。 (如果 ETAG
不同的是,该文件已经修改。)
修改
在一般使用ETag的时候,最有效的做法是发行与如果无 - 匹配标头中的
。如果内容没有改变,这将有304回应,但如果含量发生了变化,这将下载新的内容,每一个正常的 GET
要求:其中;老ETAG> GET
请求(和响应将是200)。
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.
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.
also: I'm open to other suggestions to make this work as well. Please explain in a little detail your 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 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");
}
}
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.)
EDIT
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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