如何在mongo-go-driver中使用ParseExtJSONArray()在聚合管道中解析扩展的JSON日期 [英] How to parse extended JSON Date in aggregation pipeline using ParseExtJSONArray() in mongo-go-driver
问题描述
我有一个带有日期"字段的收藏集:
I've got a collection with a Date field:
{
"_id" : ObjectId("5b92b359ddceef5b24502834"),
"dateTimeGMT" : ISODate("2018-08-22T09:29:25.000Z"),
yada, yada, yada
}
我正在尝试使用mongo-go-driver的ParseExtJSONArray函数在$ match聚合阶段按日期查找. (我知道如何直接使用* bson.Array进行此操作.我要问的是,我知道用ParserExtJSONArray进行处理的正确方法,或者是否遇到了限制.)
I'm trying to find by date in a $match aggregation stage with the ParseExtJSONArray function of mongo-go-driver. (I am aware of how to do this with *bson.Array directly. I'm asking so I know the right way to do it with ParserExtJSONArray or if I've run up against a limitation.)
我已简化为该示例,并确认它与上述文档不匹配.
I've simplified to this example and confirmed it is failing to match the above document.
pipeline, err := bson.ParseExtJSONArray(`[
{ "$match": { "dateTimeGMT.$date":"2018-08-22T09:29:25.000Z" } }
]`)
cursor, err := receivedFromResponseQueue.Aggregate(ctx, pipeline)
以下内容在mongo shell中不起作用. (这并不奇怪,因为它会自动转换为ISODate()格式)
The following doesn't work in the mongo shell. ( Not surprising because it converts automatically to ISODate() format )
db.getCollection('received_from_response_queue').aggregate([
{ "$match": { "dateTimeGMT.$date":"2018-08-22T09:29:25.000Z" } }
])
但这确实在mongo shell中起作用.
But this does work in the mongo shell.
db.getCollection('received_from_response_queue').aggregate([
{ "$match": { "dateTimeGMT": ISODate("2018-08-22T09:29:25.000Z") } }
])
但是这会在管道"中返回一个空数组. (因为ParseExtJSONArray无法处理JavaScript)
But this returns an empty array in "pipeline". (Because ParseExtJSONArray doesn't handle JavaScript)
pipeline, err := bson.ParseExtJSONArray(`[
{ "$match": { "dateTimeGMT":ISODate("2018-08-22T09:29:25.000Z") } }
]`)
因为它随后使用了一个空数组,所以它将重新调整集合中的所有文档.有趣的是,日期在我们尝试匹配的文档中的格式不同.
Because it then uses an empty array it retuns all the documents in the collection. Interestingly, the date is formatted differently in the document we are trying to match.
{
"_id" : { "$oid" : "5b92b359ddceef5b24502834" },
"dateTimeGMT" : { "$date" : "2018-08-22T05:29:25-04:00" },
yada yada yada
}
但这也不匹配.
pipeline, err := bson.ParseExtJSONArray(`[
{ "$match": { "dateTimeGMT.$date":"2018-08-22T05:29:25-04:00" } }
]`)
cursor, err := receivedFromResponseQueue.Aggregate(ctx, pipeline)
这在mongo shell中不起作用.
And this doesn't work in the mongo shell.
db.getCollection('received_from_response_queue').aggregate([
{ "$match": { "dateTimeGMT.$date":"2018-08-22T05:29:25-04:00" } }
])
有见识吗?
推荐答案
BSON )类型以纯JSON表示.
The idea behind MongoDB Extended JSON is to represent Binary JSON (BSON) types in plain JSON.
一般语法是将对象表示为单个嵌入式文档.例如,BSON binary 对象表示为文档{"$binary": "<binary data>"}
.键字段中的$
前缀指示类型. BSON date 对象也是如此.
The general syntax is to represent an object as a single embedded document. For example, BSON binary object is represented as a document {"$binary": "<binary data>"}
. The $
prefix in the key field indicates the type. The same goes for BSON date object.
方法 bson.ParseExtJSONArray()期望扩展的JSON类型是文档,而不是MongoDB中的点符号表达式.例如,而不是下面:
The method bson.ParseExtJSONArray() expects extended JSON types to be documents, and not in MongoDB dot-notation expression. For example, instead of below:
{ "$match": { "dateTimeGMT.$date":"2018-08-22T09:29:25.000Z" } }
该方法预期:
{ "$match": { "dateTimeGMT": {"$date":"2018-08-22T09:29:25.000Z" } } }
您还可以在 Unix时代中提供日期值,例如:
You can also supply the date value in Unix Epoch, for example:
{ "$match": { "dateTimeGMT": {"$date": { "$numberLong": "1546300800"} } } }
使用 mongo-go-driver/bson ,一个例子是:
raw := `[ { "$match": {"dateTimeGMT": {"$date": {"$numberLong": "1530962624753" } } } } ]`
pipeline, err := bson.ParseExtJSONArray(raw)
cursor, err := collection.Aggregate(context.Background(), pipeline)
附加说明:
您可以在迭代ParseExtJSONArray()
之前将结果值传递给聚合之前进行调试.例如:
Extra Note:
you can debug ParseExtJSONArray()
before passing the resulting value to aggregation by iterating over it. For example:
toConvert := `[
{ "$lookup": {
"from": "anotherCollection",
"localField": "foreignKey",
"foreignField": "_id",
"as": "someField"
}},
{ "$match": {"dateTimeGMT":{"$lt": {"$date": "2019-01-10T09:29:25.000Z" } } } }
]`
pipeline, err := bson.ParseExtJSONArray(toConvert)
it, err := bson.NewArrayIterator(pipeline)
for it.Next() {
fmt.Println(it.Value().MutableDocument().ToExtJSON(true))
}
//Outputs :
// {"$lookup":{"from":"anotherCollection","localField":"foreignKey","foreignField":"_id","as":"someField"}}
// {"$match":{"dateTimeGMT":{"$lt":{"$date":{"$numberLong":"1547112565000"}}}}}
//
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