Add command docs

Author: bjori

docs/commands.md

@@ -0,0 +1,105 @@
+# Running Commands
+
+# Listing databases & collections
+
+```php
+<?php
+
+/* Construct the MongoDB Manager */
+$manager = new MongoDB\Manager("mongodb://localhost:27017");
+
+
+$listdatabases = new MongoDB\Command(array("listDatabases" => 1));
+$retval        = $manager->executeCommand("admin", $listdatabases);
+$databases     = $retval->getResponseDocument();
+
+foreach($databases["databases"] as $database) {
+	echo $database->name, "\n";
+
+	$listcollections = new MongoDB\Command(array("listCollections" => 1));
+	$retval          = $manager->executeCommand($database->name, $listcollections);
+	$collections     = $retval->getResponseDocument();
+	foreach($collections["collections"] as $collection) {
+		echo "\t- ", $collection->name, "\n";
+	}
+}
+
+?>
+```
+
+# Create a User
+
+```php
+<?php
+
+
+/* Construct the MongoDB Manager */
+$manager = new MongoDB\Manager("mongodb://localhost:27017");
+
+
+$command = array(
+	"createUser" => "USERNAME2",
+	"pwd"        => "PASSWORD",
+	"roles"      => array(
+		array("role" => "clusterAdmin",         "db" => "admin"),
+		array("role" => "readWriteAnyDatabase", "db" => "admin"),
+		array("role" => "userAdminAnyDatabase", "db" => "admin"),
+		"readWrite",
+	),
+	"writeConcern" => array("w" => "majority"),
+);
+$createuser = new MongoDB\Command($command);
+
+try {
+	$result     = $manager->executeCommand("admin", $createuser);
+	$response   = $result->getResponseDocument();
+	if ($reponse["ok"]) {
+		echo "User created\n";
+	}
+} catch(Exception $e) {
+	echo $e->getMessage(), "\n";
+}
+
+
+?>
+```
+
+## Commands and ReadPreferences
+
+```php
+<?php
+
+/* Some commands, like count, dbStats, aggregate, ... can be executed on secondaries.
+ * Just like with normal queries, an instance of MongoDB\ReadPreference needs to
+ * be constructed to prefer certain servers over others */
+$prefer = MongoDB\ReadPreference::RP_SECONDARY_PREFERRED;
+$tags = array(
+	/* Prefer the West Coast datacenter in Iceland */
+	array("country" => "iceland", "datacenter" => "west"),
+
+	/* Fallback to any datacenter in Iceland */
+	array("country" => "iceland"),
+
+	/* If Iceland is offline, read from whatever is online! */
+	array(),
+);
+
+/* Construct the ReadPreference object from our options */
+$rp = new MongoDB\ReadPreference($prefer, $tags);
+
+/* Construct the MongoDB Manager */
+$manager = new MongoDB\Manager("mongodb://localhost:27017");
+
+$query    = array("citizen" => "Iceland");
+$count    = new MongoDB\Command(array("count" => "collection", "query" => $query));
+$retval   = $manager->executeCommand("db", $count, $rp);
+$response = $retval->getResponseDocument();
+if ($response["ok"]) {
+	printf("db.collection has %d documents matching: %s\n",
+		$response["n"],
+		BSON\toJSON(BSON\fromArray($query))
+	);
+}
+
+?>
+```