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Using MongoDB in Powershell

Readers of this blog know that I’ve been using MongoDB for a while, and I’ve recently become very excited about Powershell. Well recently I’ve been able to combine the two together for pure dynamically typed, schema-less, non-relational awesomeness. Such awesomeness is begging to be shared.

To get started you will need version 1.1 of the official 10gen CSharp driver for Mongodb. At the time of this writing 1.1 has not been released, so your going to have to pull the latest version from github and compile it yourself. The minimal revision of the trunk you will need is this one. First download and install the MSI (or download the source, build the MSI and install it). Then open up your favorite text editor or Powershell IDE. Personally I am a fan of Powershell ISE or plain old vim, with some configuration modifications. Now we will load the bson and driver DLLs via the Add-Type cmdlet.

# Check to see if we are running the 64 bit version of Powershell.
# See http://stackoverflow.com/questions/2897569/visual-studio-deployment-project-error-when-writing-to-registry
if ([intptr]::size -eq  {
    $mongoDriverPath = (Get-ItemProperty "HKLM:\SOFTWARE\Wow6432Node\Microsoft\.NETFramework\v3.5\AssemblyFoldersEx\MongoDB CSharpDriver 1.0").'(default)';
}
else {
    $mongoDriverPath = (Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\.NETFramework\v3.5\AssemblyFoldersEx\MongoDB CSharpDriver 1.0").'(default)';
}
Add-Type -Path "$($mongoDriverPath)\MongoDB.Bson.dll";
Add-Type -Path "$($mongoDriverPath)\MongoDB.Driver.dll";

Since the Csharp Driver MSI is 32 bits, it creates the registry entries in the Wow6432Node. Therefore, we have to check to see if we are running in the 32 or 64 bit version of Powershell . Credit to an anonymous commenter on the msgoodies blog for providing this size of a pointer trick to determine if you are running a 32 or 64 bit system.

The next thing we want to do is to create a BSON document. This is surprisingly easy.

[MongoDB.Bson.BsonDocument] $doc = @{
    "_id"= [MongoDB.Bson.ObjectId]::GenerateNewId();
    "FirstName"= "Justin";
    "LastName"= "Dearing";
    "PhoneNumbers"= [MongoDB.Bson.BsonDocument] @{
        'Home'= '718-555-1212';
        'Mobile'= '646-555-1212';
    };
};

As you can see Powershell can convert a HashTable to a BsonDocument. This is because of the public constructor BsonDocument(IDictionary hashTable). Powershell can use these one parameter constructors to cast an object. You can use the same Hashtable trick for the QueryDocument and UpdateDocument classes.

Now that we have our BsonDocument, its time to perform basic crud operations.

$db = [MongoDB.Driver.MongoDatabase]::Create('mongodb://localhost/powershell');
$collection = $db['example1'];
Write-Host "Insert";
$collection.Insert($doc);
$collection.FindOneById($doc['_id']);

$updates = @{'$set' = @{'email'= 'justin@mongodb.org'}};
$query = @{"_id"= $doc['_id']}

Write-Host "Update";
$collection.Update([MongoDB.Driver.QueryDocument]$query, [MongoDb.Driver.UpdateDocument]$updates);
$collection.FindOneById($doc['_id']);

Write-Host "Delete";
$collection.Remove([MongoDB.Driver.QueryDocument]$query);
$collection.FindOneById($doc['_id']);

This gives us the output below.

_id                                                         4dc5e5a43b42bd41d0154679
LastName                                                    Dearing
PhoneNumbers                                                {Mobile=646-555-1212, Home=718-555-1212}
FirstName                                                   Justin
Delete

PS E:\src\gist\gist-854911> powershell.exe -file .\MongoTest.ps1

Insert

Name                                                        Value
----                                                        -----
_id                                                         4dc636c33b42bd3d7c8dc3a4
LastName                                                    Dearing
PhoneNumbers                                                {Mobile=646-555-1212, Home=718-555-1212}
FirstName                                                   Justin
Update
FirstName                                                   Justin
LastName                                                    Dearing
PhoneNumbers                                                {Mobile=646-555-1212, Home=718-555-1212}
_id                                                         4dc636c33b42bd3d7c8dc3a4
email                                                       justin@mongodb.org
Delete

As you can see, its not very hard to use the 10Gen MongoDB Csharp driver from within Powershell. Using Powershell with the MongoDb C-Sharp driver has many possibilities. First of all, adhoc mongodb queries from inside of powershell. Secondly,  The code for this example is available in its entirety here.