Jun 2024
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Jun 2024
Mar 25
harry_potter3Harry Potter
Jun 2024

help me with this problem:

I using pymongo to update my mongoDB database using this code:

updates = {"$inc":{}}
user_ip = "127.0.0.1"

updates["$inc"][f"ips.{user_ip}"] = 1

creates something like this in the mongoDB document:

  "ips": {
    "127": {
      "0": {
        "0": {
          "1": 1
        }
      }
    }
  }

but I want it to be like:

"ips": {
  "127.0.0.1": 1
}

I cannot replace the . of the ip-address to any other characters in the DB because of some compatibility issues.

but if I do this it works fine:

url_data["ips"][user_ip] = url_data["ips"].get(user_ip, 0) + 1
updates["$set"]["ips"] = url_data["ips"]

url_data is the full document and querying it and updating it whole is not efficient for me
9 months later
aneroidAnirudh Dutt
Mar 25

Assuming you’re on MongoDB 5 or above, to avoid issues with the dots in the IP address being treated as a path expression, you will need to use $getField and $setField.

Put that in an update aggregation pipeline to first get the current value, add 1, then set that as the value. In Python, you could do:

user_ip = "127.0.0.1"
update_pipeline = [
    {
        "$set": {
            "ips": {
                "$setField": {
                    "field": user_ip,
                    "input": "$ips",
                    "value": {
                        "$add": [
                            {
                                "$getField": {
                                    "field": user_ip,
                                    "input": "$ips",
                                }
                            },
                            1
                        ]
                    }
                }
            }
        }
    }
]
collection.update_many({ <user filter here> }, update_pipeline)

Mongo Playground example with more docs. Note that non-matching IP addresses are un-changed.

aneroidAnirudh Dutt
Mar 25

The real anti-pattern here is the usage of the IP address as the key. Instead having the IP addresses as the keys like this:

ips: {
  "127.0.0.1": 100,
  "192.168.0.1": 50
}

You should be using known keys/names as the field and value. That is the Attribute Pattern:

ips: [
  {addr: "127.0.0.1", count: 100},
  {addr: "192.168.0.1", count: 50},
]

Then you could use a standard operation to Update Documents in an Array:

db.collection.update({
  _id: 1,  // userID
  "ips.addr": "127.0.0.1"  // IP address
},
{
  $inc: {
    "ips.$.count": 1
  }
})

Mongo Playground update query with Attribute Pattern


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