我在一个循环中插入 100 个文件。对于此测试，我已禁用退避并重试，因此如果插入失败并出现 403，我将忽略它并继续下一个文件。在 100 个文件中，我得到 63 403 个速率限制异常。
但是，在检查 Drive 时，在这 63 次失败中，有 3 次实际上成功了，即。该文件是在驱动器上创建的。如果我完成了通常的退避并重试，我最终会得到重复的插入。这证实了我在启用退避重试时看到的行为，即。从我的 100 个文件测试中，我一直看到 3-4 个重复插入。
看起来 API 端点服务器和 Drive 存储服务器之间存在异步连接，这会导致不确定的结果，尤其是在大容量写入时。
由于这意味着我不能依靠“403 速率限制”来限制我的插入，我需要知道什么是安全的插入速率，以免触发这些计时错误。
运行下面的代码，给出...
Summary...
File insert attempts (a) = 100
rate limit errors (b) = 31
expected number of files (a-b) = 69
Actual number of files = 73
代码...
package com.cnw.test.servlets;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.google.api.client.auth.oauth2.Credential;
import com.google.api.client.googleapis.json.GoogleJsonError;
import com.google.api.client.googleapis.json.GoogleJsonResponseException;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.jackson.JacksonFactory;
import com.google.api.services.drive.Drive;
import com.google.api.services.drive.model.ChildList;
import com.google.api.services.drive.model.File;
import com.google.api.services.drive.model.File.Labels;
import com.google.api.services.drive.model.ParentReference;
import couk.cleverthinking.cnw.oauth.CredentialMediatorB;
import couk.cleverthinking.cnw.oauth.CredentialMediatorB.InvalidClientSecretsException;
@SuppressWarnings("serial")
/**
*
* AppEngine servlet to demonstrate that Drive IS performing an insert despite throwing a 403 rate limit exception.
*
* All it does is create a folder, then loop to create x files. Any 403 rate limit exceptions are counted.
* At the end, compare the expected number of file (attempted - 403) vs. the actual.
* In a run of 100 files, I consistently see between 1 and 3 more files than expected, ie. despite throwing a 403 rate limit,
* Drive *sometimes* creates the file anyway.
*
* To run this, you will need to ...
* 1) enter an APPNAME above
* 2) enter a google user id above
* 3) Have a valid stored credential for that user
*
* (2) and (3) can be replaced by a manually constructed Credential
*
* Your test must generate rate limit errors, so if you have a very slow connection, you might need to run 2 or 3 in parallel.
* I run the test on a medium speed connection and I see 403 rate limits after 30 or so inserts.
* Creating 100 files consistently exposes the problem.
*
*/
public class Hack extends HttpServlet {
private final String APPNAME = "MyApp"; // ENTER YOUR APP NAME
private final String GOOGLE_USER_ID_TO_FETCH_CREDENTIAL = "11222222222222222222222"; //ENTER YOUR GOOGLE USER ID
@Override
public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
/*
* set up the counters
*/
// I run this as a servlet, so I get the number of files from the request URL
int numFiles = Integer.parseInt(request.getParameter("numfiles"));
int fileCount = 0;
int ratelimitCount = 0;
/*
* Load the Credential
*/
CredentialMediatorB cmb = null;
try {
cmb = new CredentialMediatorB(request);
} catch (InvalidClientSecretsException e) {
e.printStackTrace();
}
// this fetches a stored credential, you might choose to construct one manually
Credential credential = cmb.getStoredCredential(GOOGLE_USER_ID_TO_FETCH_CREDENTIAL);
/*
* Use the credential to create a drive service
*/
Drive driveService = new Drive.Builder(new NetHttpTransport(), new JacksonFactory(), credential).setApplicationName(APPNAME).build();
/*
* make a parent folder to make it easier to count the files and delete them after the test
*/
File folderParent = new File();
folderParent.setTitle("403parentfolder-" + numFiles);
folderParent.setMimeType("application/vnd.google-apps.folder");
folderParent.setParents(Arrays.asList(new ParentReference().setId("root")));
folderParent.setLabels(new Labels().setHidden(false));
driveService.files().list().execute();
folderParent = driveService.files().insert(folderParent).execute();
System.out.println("folder made with id = " + folderParent.getId());
/*
* store the parent folder id in a parent array for use by each child file
*/
List<ParentReference> parents = new ArrayList<ParentReference>();
parents.add(new ParentReference().setId(folderParent.getId()));
/*
* loop for each file
*/
for (fileCount = 0; fileCount < numFiles; fileCount++) {
/*
* make a File object for the insert
*/
File file = new File();
file.setTitle("testfile-" + (fileCount+1));
file.setParents(parents);
file.setDescription("description");
file.setMimeType("text/html");
try {
System.out.println("making file "+fileCount + " of "+numFiles);
// call the drive service insert execute method
driveService.files().insert(file).setConvert(false).execute();
} catch (GoogleJsonResponseException e) {
GoogleJsonError error = e.getDetails();
// look for rate errors and count them. Normally one would expo-backoff here, but this is to demonstrate that despite
// the 403, the file DID get created
if (error.getCode() == 403 && error.getMessage().toLowerCase().contains("rate limit")) {
System.out.println("rate limit exception on file " + fileCount + " of "+numFiles);
// increment a count of rate limit errors
ratelimitCount++;
} else {
// just in case there is a different exception thrown
System.out.println("[DbSA465] Error message: " + error.getCode() + " " + error.getMessage());
}
}
}
/*
* all done. get the children of the folder to see how many files were actually created
*/
ChildList children = driveService.children().list(folderParent.getId()).execute();
/*
* and the winner is ...
*/
System.out.println("\nSummary...");
System.out.println("File insert attempts (a) = " + numFiles);
System.out.println("rate limit errors (b) = " + ratelimitCount);
System.out.println("expected number of files (a-b) = " + (numFiles - ratelimitCount));
System.out.println("Actual number of files = " + children.getItems().size() + " NB. There is a limit of 100 children in a single page, so if you're expecting more than 100, need to follow nextPageToken");
}
}