Error: Invalid Json Object

I tried to run this query and keep having this error:

install.packages(“mongolite”)
library(mongolite)

m <- mongo(db = "ionmom")
m6 <- m$aggregate('[{"$unwind":"$cdr"}, {$lookup:{from: "inventory", localField: "_id", foreignField: "_id", as:"inventory"}},{$unwind: "$inventory"}, {"$project":{ "$project": {"cdr.duration": 1, "inventory.wearables.type":1, "inventory.wearables.status":1, "inventory.wearables.battery":1 }}}]')

# Error: Invalid JSON object: [{"$unwind":"$cdr"}, {$lookup:{from: "inventory", localField: "_id", foreignField: "_id", as:"inventory"}},{$unwind: "$inventory"}, {"$project":{ "$project": {"cdr.duration": 1, "inventory.wearables.type":1, "inventory.wearables.status":1, "inventory.wearables.battery":1 }}}]

2 Answers

mongolite uses jsonlite under the hood to do the JSON parsing. If you put your query through jsonlite::fromJSON() you'll see the issue

js <- '[{"$unwind":"$cdr"}, {$lookup:{from: "inventory", localField: "_id", foreignField: "_id", as:"inventory"}},{$unwind: "$inventory"}, {"$project":{ "$project": {"cdr.duration": 1, "inventory.wearables.type":1, "inventory.wearables.status":1, "inventory.wearables.battery":1 }}}]'

jsonlite::fromJSON(js)

# Error: lexical error: invalid char in json text.
#                  [{"$unwind":"$cdr"}, {$lookup:{from: "inventory", loc
#                      (right here) ------^

This is telling you the JSON structure is invalid, because it's expecting quotes " " around each string

js <- '[{"$unwind":"$cdr"}, {"$lookup":{"from": "inventory", "localField": "_id", "foreignField": "_id", "as":"inventory"}},{"$unwind": "$inventory"}, {"$project":{ "$project": {"cdr.duration": 1, "inventory.wearables.type":1, "inventory.wearables.status":1, "inventory.wearables.battery":1 }}}]'

m$aggregate(js)

## I don't have your data ...

# Imported 0 records. Simplifying into dataframe...
# data frame with 0 columns and 0 rows
2

Try to add:

js <- '[{"$unwind":"$cdr"}, {"$lookup":{"from": "inventory", localField:}]'

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James H. Sterling

James H. Sterling

Environmental Science & Climate Journalist

James Sterling reports on renewable energy developments, climate policy, ecological conservation, and green tech innovations around the globe.

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