通过猫鼬更新多个子文档?

问题描述

例如，我们使用以下模式定义注释树；

Say for example, we're using the following schema to define a comments tree;

{
    "_id" : ObjectId("id_here"),
    "parentComment" : "This is my opinion",
    "isHidden" : false,
    "comments" : [
        {
            "comment" : "I disagree with your opinion",
            "isHidden" : false
        },
        {
            "comment" : "Test Post",
            "isHidden" : false
        },
        ....
}

因此，如果我们要更新父注释，以将禁止使用的短语的isHidden标志设置为true，我们会这样做；

So, if we were to update the parent comment to set the isHidden flag to true for banned phrases, we'd do so like this;

        var userComments = require('mongoose').model("UserComments");
        for (let i = 0; i < bannedPhrases.length; i++) {
            var conditions = { parentComment: bannedPhrases[i] }
                , update = { isHidden: true}
                , options = { multi: true };

            userComments.update(conditions, update, options, callback);
        }

现在，考虑子文档注释"(线程注释，多个条目)-我们将如何更新这些注释?

Now, consider the subdocument "comments" (threaded comments, multiple entries) - how would we be able to go about updating these?

推荐答案

我能想到的解决方案是逐个更新嵌套文档.

The solution I can think of is to update the nested document one by one.

假设我们掌握了被禁止的短语，它是一个字符串数组:

Assume we've got hold of the banned phrases, which is an array of strings:

var bannedPhrases = ["censorship", "evil"]; // and more ...

然后我们执行查询以查找具有comments且包含任何bannedPhrases的所有UserComments.

Then we perform a query to find all UserComments which has comments that contain any of the bannedPhrases.

UserComments.find({"comments.comment": {$in: bannedPhrases }});

通过使用promises，我们可以一起异步执行更新:

By using promises, we can perform update asynchronously together:

UserComments.find({"comments.comment": {$in: bannedPhrases }}, {"comments.comment": 1})
  .then(function(results){
    return results.map(function(userComment){

       userComment.comments.forEach(function(commentContainer){
         // Check if this comment contains banned phrases
         if(bannedPhrases.indexOf(commentContainer.comment) >= 0) {
           commentContainer.isHidden = true;
         }
       });

       return userComment.save();
    });
  }).then(function(promises){
     // This step may vary depending on which promise library you are using
     return Promise.all(promises);
  });

如果您使用 Bluebird JS 是Mongoose的promise库，则可以简化代码:

If you use Bluebird JS is Mongoose's promise library, the code could be simplified:

UserComments.find({"comments.comment": {$in: bannedPhrases}}, {"comments.comment": 1})
    .exec()
    .map(function (userComment) {

        userComment.comments.forEach(function (commentContainer) {
            // Check if this comment contains banned phrases
            if (bannedPhrases.indexOf(commentContainer.comment) >= 0) {
                commentContainer.isHidden = true;
            }
        });

        return userComment.save();
    }).then(function () {
    // Done saving
});

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