Node/Mongoose-从Array[重复]中删除ObjectId

Question

我正在建设的网站上有一个带有评论功能的页面。该网站类似于Yelp for campsites，mongo db集合中的每个露营地都有一个字段-comments-用于存储该露营地上发布的每条评论的id，该id引用另一个名为comments的集合中的对象。添加、编辑、查看和删除评论除了删除评论外，该评论的id不会从其关联营地的评论数组中删除。

以下是一个目前营地记录的例子：

{ 
     "_id" : ObjectId("5b18331953b9811c54ddc4cd"),
          "contact" : { 
          "phone" : "403-748-4066", 
          "email" : "", 
          "website" : "https://www.albertaparks.ca/parks/central/aspen-beach-pp/information-facilities/camping/lakeview/" 
     }, 
     "author" : { 
          "id" : ObjectId("5a998953342cbc7fe8521ef5"), 
          "username" : "Adam" 
     }, 
     "createdAt" : ISODate("2018-06-06T19:04:25.418Z"), 
     "comments" : [ 
          ObjectId("5b1bf59f8f21e152cce41b49") 
     ], 
     "name" : "Lakeview", 
     "cost" : "40", 
     "location" : "Range Rd 284, Bentley, AB T0C 0J0, Canada", 
     "image" : "https://c1.staticflickr.com/9/8620/16612167676_6418f1b470_b.jpg",
      "description" : "Open, pull-through sites are well-suited to RVs. There are unserviced, power, and power/water options. Trees provide some shade from the summer sun. There are many amenities available including a boat launch, playground, sewage disposal, flush toilets and showers. Camp along Gull Lake and enjoy swimming, boating, and the beach. Explore the trails and boardwalks for walking, biking, bird and wildlife watching. ", 
     "lat" : 52.4357744, 
     "__v" : 1, 
     "long" : -113.9873582 
}

如您所见，营地对象当前引用了一条注释，但如果我通过UI删除该注释，它将停止显示该注释，因为它将从注释集合中删除，但营地对象中对注释的引用将保留。以下是我当前删除评论的代码：

app.delete("/campgrounds/:id/comments/:comment_id", middleware.checkCommentOwnership, function(req, res){
    // RESTful - DESTROY
    Comment.findByIdAndRemove(req.params.comment_id, function(err){
        if(err){
            req.flash("error", "Uh Oh! Something went wrong.");
            res.redirect("/campgrounds");
        }
        Campground.findById(req.params.id, function(err, campground){
            if(err){
                req.flash("error", "Uh Oh! Something went wrong.");
                res.redirect("/campgrounds");
            }
            campground.comments.remove(req.params.comment_id);
            req.flash("success", "Comment has been deleted!");
            res.redirect("back");
        });
    });
});

然而这条线

campground.comments.remove(req.params.comment_id); 

似乎不起作用。我也（粗略地）尝试过

campground.comments.remove("ObjectId(\"" + req.params.comment_id + "\")")

要尝试镜像ID存储的格式，请在注释数组中，但这会引发以下错误：

CastError: Cast to ObjectId failed for value "ObjectId("5b1bf4215f319752ab28ba49")" at path "comments"

我使用Mongoose主要是为了与db接口。

抱歉，如果这是冗长的或重复的，我试图研究解决方案，但什么也找不到——至少没有我能理解的！

谢谢。

Answer 1

尝试从数组中删除，标记为已更改并保存，如下所示

app.delete("/campgrounds/:id/comments/:comment_id", middleware.checkCommentOwnership, function(req, res){
// RESTful - DESTROY
Comment.findByIdAndRemove(req.params.comment_id, function(err){
    if(err){
        req.flash("error", "Uh Oh! Something went wrong.");
        res.redirect("/campgrounds");
    }
    Campground.findById(req.params.id, function(err, campground){
        if(err){
            req.flash("error", "Uh Oh! Something went wrong.");
            res.redirect("/campgrounds");
        }
            campground.comments.filter(comment => comment.toString() === 
                req.params.comment_id);
            campground.markModified('comments');
            campground.save(function(err){
            if(err){
                 req.flash("error", "Uh Oh! Something went wrong.");
                 res.redirect("/campgrounds");
                 return;
            }
            req.flash("success", "Comment has been deleted!");
            res.redirect("back");
                })
        });
    });
});

Answer 2

你需要使用mongodb$拉运算符删除comment_id从数组...

Campground.update({ _id: req.params.id }, { $pull: { comments: req.params.comment_id } }, function(err, campground){
    if(err){
        req.flash("error", "Uh Oh! Something went wrong.");
        return res.redirect("/campgrounds");
    }
    req.flash("success", "Comment has been deleted!");
    return res.redirect("back");
});