AWS documentdb documentation change

Service: documentdb · 2026-03-31 · Documentation low

File: documentdb/latest/developerguide/strLenBytes.md

Summary

Added new documentation page for the $strLenBytes operator in Amazon DocumentDB, including parameters, MongoDB shell example, and code examples in Node.js and Python with TLS connection details.

Security assessment

This change adds routine documentation for a MongoDB operator ($strLenBytes) that calculates string length in bytes. The code examples include standard TLS connection parameters (tls=true, tlsCAFile) for secure connections, but this is part of normal secure connection practices and not a new security feature or response to a security vulnerability. There is no evidence in the diff of addressing a specific security issue, weakness, or incident.

Diff

diff --git a/documentdb/latest/developerguide/strLenBytes.md b/documentdb/latest/developerguide/strLenBytes.md
index 8b1378917..9ca286726 100644
--- a//documentdb/latest/developerguide/strLenBytes.md
+++ b//documentdb/latest/developerguide/strLenBytes.md
@@ -0,0 +1 @@
+[](/pdfs/documentdb/latest/developerguide/developerguide.pdf#strLenBytes "Open PDF")
@@ -1,0 +3,127 @@
+[Documentation](/index.html)[Amazon DocumentDB](/documentdb/index.html)[Developer Guide](what-is.html)
+
+Example (MongoDB Shell)Code examples
+
+# $strLenBytes
+
+The `$strLenBytes` operator in Amazon DocumentDB is used to determine the length of a string in bytes. This is useful when you need to understand the storage size of a string field, especially when dealing with Unicode characters that may use more than one byte per character.
+
+**Parameters**
+
+  * `expression`: The string expression to calculate the length of.
+
+
+
+
+## Example (MongoDB Shell)
+
+This example demonstrates how to use the `$strLenBytes` operator to calculate the length of string fields in bytes.
+
+**Create sample documents**
+    
+    
+    db.people.insertMany([
+      { "_id": 1, "Desk": "Düsseldorf-BVV-021" },
+      { "_id": 2, "Desk": "Munich-HGG-32a" },
+      { "_id": 3, "Desk": "Cologne-ayu-892.50" },
+      { "_id": 4, "Desk": "Dortmund-Hop-78" }
+    ]);
+
+**Query example**
+    
+    
+    db.people.aggregate([
+      {
+        $project: {
+          "Desk": 1,
+          "length": { $strLenBytes: "$Desk" }
+        }
+      }
+    ])
+
+**Output**
+    
+    
+    { "_id" : 1, "Desk" : "Düsseldorf-BVV-021", "length" : 19 }
+    { "_id" : 2, "Desk" : "Munich-HGG-32a", "length" : 14 }
+    { "_id" : 3, "Desk" : "Cologne-ayu-892.50", "length" : 18 }
+    { "_id" : 4, "Desk" : "Dortmund-Hop-78", "length" : 15 }
+
+Note that the length of the "Düsseldorf-BVV-021" string is 19 bytes, which is different from the number of code points (18) due to the Unicode character "Ü" occupying 2 bytes.
+
+## Code examples
+
+To view a code example for using the `$strLenBytes` command, choose the tab for the language that you want to use:
+
+Node.js
+    
+    
+    
+    const { MongoClient } = require('mongodb');
+    
+    async function example() {
+      const client = await MongoClient.connect('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false');
+      const db = client.db('test');
+      const collection = db.collection('people');
+    
+      const result = await collection.aggregate([
+        {
+          $project: {
+            "Desk": 1,
+            "length": { $strLenBytes: "$Desk" }
+          }
+        }
+      ]).toArray();
+    
+      console.log(result);
+      client.close();
+    }
+    
+    example();
+
+Python
+    
+    
+    
+    from pymongo import MongoClient
+    
+    def example():
+        client = MongoClient('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false')
+        db = client.test
+        collection = db.people
+    
+        result = list(collection.aggregate([
+            {
+                '$project': {
+                    "Desk": 1,
+                    "length": { "$strLenBytes": "$Desk" }
+                }
+            }
+        ]))
+    
+        print(result)
+        client.close()
+    
+    example()
+
+![Warning](https://d1ge0kk1l5kms0.cloudfront.net/images/G/01/webservices/console/warning.png) **Javascript is disabled or is unavailable in your browser.**
+
+To use the Amazon Web Services Documentation, Javascript must be enabled. Please refer to your browser's Help pages for instructions.
+
+[Document Conventions](/general/latest/gr/docconventions.html)
+
+$sqrt
+
+$strLenCP
+
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