使用Google Drive API进行递归搜索 [英] Recursive search with Google Drive API

问题描述

我正在使用Google Drive API v2。

我试图使用API​​中包含的搜索功能实现搜索功能。

似乎children.list不是递归的，这意味着它不会查看所有的子文件夹。
对于每个文件夹子引用，我是否必须通过多次调用API来实现它？或者我在这里丢失了什么？

感谢您的帮助。 当你得到一个ChildReference的列表，你不能确定它们是否是一个文件夹，除非你真的检索文件。所以如果你正在做一个大的递归搜索，你应该使用批处理来实现这一点。我创建了一个递归地更改文件夹中所有文件的所有者的方法，这可能有帮助：

  private void updateFolderOwner （String folderId，final String newOwnerEmail）throws IOException {
 String permissionId = service.permissions（）。getIdForEmail（newOwnerEmail）.execute（）。getId（）; 
 
 Children.List request = service.children（）。list（folderId）; 
 
 JsonBatchCallback< Permission> callback = new JsonBatchCallback< Permission>（）{
 @Override 
 public void onSuccess（Permission permission，HttpHeaders responseHeaders）{} 
 $ b @Override 
 public void onFailure GoogleJsonError e，HttpHeaders responseHeaders）{
 System.out.println（Error Message：+ e.getMessage（））; 
} 
}; 
 
 JsonBatchCallback< File> findFolderCallback = new JsonBatchCallback< File>（）{
 @Override $ b $ public void onSuccess（File file，HttpHeaders responseHeaders）throws IOException {
 if（file！= null）{
 String fileExtension = file.getFileExtension（）; 
 String mimeType = file.getMimeType（）; 
 if（mimeType！= null&& mimeType.equals（application / vnd.google-apps.folder）&&（fileExtension == null || fileExtension.equals（））） {
 //递归搜索此文件夹... 
 updateFolderOwner（file.getId（），newOwnerEmail）; 
 
 
 $ b @Override 
 public void onFailure（GoogleJsonError e，HttpHeaders responseHeaders）{
 System.out.println（错误信息： + e.getMessage（））; 
} 
}; 
 
 do {
 try {
 ChildList children = request.execute（）; 
 
 BatchRequest changeOwnerBatch = service.batch（）; 
 BatchRequest findFolderBatch = service.batch（）; 
 
权限许可= new Permission（）; 
 permission.setEmailAddress（newOwnerEmail）; 
 permission.setValue（newOwnerEmail）; 
 permission.setType（user）; 
 permission.setRole（owner）; （ChildReference child：children.getItems（））{
 service.files（）。get（child.getId（））。queue（findFolderBatch，findFolderCallback）; 
 
。 
 service.permissions（）。update（child.getId（），permissionId，permission）.setTransferOwnership（true）.queue（changeOwnerBatch，callback）; 
} 
 changeOwnerBatch.execute（）; 
 findFolderBatch.execute（）; 
 
 request.setPageToken（children.getNextPageToken（））; 
 catch（IOException e）{
 System.out.println（发生错误：+ e）; 
 request.setPageToken（null）; （request.getPageToken（）！= null&&&& amp; request.getPageToken（）。length（）> 0）; 
} 
} 
 
} 
  

I'm working with the Google Drive API v2.

I trying to implement a search feature using the one included in the API.

It seems that the "children.list" is not recursive, meaning it doesn't look through all the subfolders. Do I have to implement it via multiple calls to the API, for each folder child reference? Or am I missing something here?

Thanks for your help.

解决方案

When you get a list of ChildReferences, you cannot determine if they are a folder or not unless you actually retrieve the file. So if you are doing a large recursive search you should use batching to achieve this. I created a method to recursively change the owner of all the files in a folder, this might be of help:

private void updateFolderOwner(String folderId, final String newOwnerEmail) throws IOException{
    String permissionId = service.permissions().getIdForEmail(newOwnerEmail).execute().getId();

    Children.List request = service.children().list(folderId);

    JsonBatchCallback<Permission> callback = new JsonBatchCallback<Permission>() {
        @Override
        public void onSuccess(Permission permission, HttpHeaders responseHeaders) {}

        @Override
        public void onFailure(GoogleJsonError e, HttpHeaders responseHeaders) {
            System.out.println("Error Message: " + e.getMessage());
        }
    };

    JsonBatchCallback<File> findFolderCallback = new JsonBatchCallback<File>() {
        @Override
        public void onSuccess(File file, HttpHeaders responseHeaders) throws IOException {
            if (file != null) {
                String fileExtension = file.getFileExtension();
                String mimeType = file.getMimeType();
                if (mimeType != null && mimeType.equals("application/vnd.google-apps.folder") && (fileExtension == null || fileExtension.equals(""))) {
                    //Recursively search this folder...
                    updateFolderOwner(file.getId(),newOwnerEmail);
                }
            }
        }
        @Override
        public void onFailure(GoogleJsonError e, HttpHeaders responseHeaders) {
            System.out.println("Error Message: " + e.getMessage());
        }
    };

    do {
        try {
            ChildList children = request.execute();

            BatchRequest changeOwnerBatch = service.batch();
            BatchRequest findFolderBatch = service.batch();

            Permission permission = new Permission();
            permission.setEmailAddress(newOwnerEmail);
            permission.setValue(newOwnerEmail);
            permission.setType("user");
            permission.setRole("owner");

            for (ChildReference child : children.getItems()) {
                service.files().get(child.getId()).queue(findFolderBatch, findFolderCallback);
                service.permissions().update(child.getId(), permissionId, permission).setTransferOwnership(true).queue(changeOwnerBatch, callback);
            }
            changeOwnerBatch.execute();
            findFolderBatch.execute();

            request.setPageToken(children.getNextPageToken());
        } catch (IOException e) {
            System.out.println("An error occurred: " + e);
            request.setPageToken(null);
        }
    } while (request.getPageToken() != null && request.getPageToken().length() > 0);

}

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