![](/img/trans.png)
[英]How to add description to Image collection in meteor.js ( client side & server side)
[英]How to setup a mongo projection AFTER a server side transform function in Meteor.js?
在应用需要访问原始文档的转换后,我需要限制从发布功能发送给客户端的字段数。
我基本上是在尝试避免向客户端发送潜在的巨大数组,并运行一堆检查以返回一个很好的整洁对象以供使用。
这是我现在拥有的功能-它可以正常工作,但并不是我想要的那样,基本上限制了要观察功能的字段。 有没有办法在观察/变换之后添加投影。
Meteor.publish('network', function() {
var self = this;
// get the user values initially
var user = Meteor.users.findOne(self.userId);
var followingUsers = user.following ? user.following.users || [] : [];
var followingChannels = user.following ? user.following.channels || [] : [];
var transformMedia = function(doc) {
// get the user each time to keep this publication reactive
votesUp = doc.votes ? doc.votes.up || [] : [];
votesDown = doc.votes ? doc.votes.down || [] : [];
favourites = doc.votes ? doc.votes.favourites || [] : [];
doc.userActions = {
votedUp: _.contains(votesUp, doc._id) ? 1 : 0,
votedDown: _.contains(votesDown, doc._id) ? 1 : 0,
isFavourite: _.contains(favourites, doc._id) ? 1 : 0,
played: _.contains(doc.played, self.userId) ? 1 : 0,
};
return doc;
};
var networkQuery = Media.find({
$and: [
{
$and: [
{processedAt: { $exists: true} },
{processedStatus: 'successful'},
{publishStatus: 'published'}
]
},
{
// if created by this user, user they follow or channels they subscribe to
$or: [
{createdBy: self.userId },
{createdBy: { $in: followingUsers} },
{channels: { $in: followingChannels} },
]
}
// TODO : add not banned or trashed once implemented
]
}, mediaModifiers).observe({
added: function(doc) {
self.added('media', doc._id, transformMedia(doc));
},
changed: function(doc, oldDoc) {
self.changed('media', doc._id, transformMedia(doc));
},
removed: function(doc) {
self.removed('media', doc._id, transformMedia(doc));
},
});
self.onStop(function() {
networkQuery.stop();
});
self.ready();
});
我曾经有过类似的问题 。 我使用cursor.observe()
+一个自定义函数来处理它(就像您所做的那样),我只是添加了一个_.pick()
来过滤不必要的字段。 请看下面的发布代码示例(尤其是白名单docToPublish
部分):
var self = this;
// Modify the document we are sending to the client.
function filter(doc) {
var length = doc.item.length;
// White list the fields you want to publish.
var docToPublish = _.pick(doc, [
'someOtherField'
]);
// Add your custom fields.
docToPublish.itemLength = length;
return docToPublish;
}
var handle = myCollection.find({}, {fields: {item:1, someOtherField:1}})
// Use observe since it gives us the the old and new document when something is changing.
// If this becomes a performance issue then consider using observeChanges,
// but its usually a lot simpler to use observe in cases like this.
.observe({
added: function(doc) {
self.added("myCollection", doc._id, filter(doc));
},
changed: function(newDocument, oldDocument)
// When the item count is changing, send update to client.
if (newDocument.item.length !== oldDocument.item.length)
self.changed("myCollection", newDocument._id, filter(newDocument));
},
removed: function(doc) {
self.removed("myCollection", doc._id);
});
self.ready();
self.onStop(function () {
handle.stop();
});
这段代码是从@datacarl答案借来的,上面提到了我的主题。
请注意,如果您最多可以扩展到多个服务器,则此方法的缺点是每个服务器都必须运行cursor.observe()
函数。
您还忘记准备发布,并在发布结束时将观察员丢弃(这可能是因为您没有粘贴所有发布)。 它看起来像这样:
self.ready();
self.onStop(function () {
networkQuery.stop();
});
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.