Sleepy Mongoose supports regex queries. Check out the tutorial:
If I insert a document in the MongoDB shell:
> db.test.insert({"a": "foo"})
... then I can find it from the shell like:
> db.test.find({"a": /fo+/})
{ "_id" : ObjectId("505cda7b71f3759c62076b13"), "a" : "foo" }
or:
> db.test.find({"a": {"$regex": "fo+", "$options": ""}})
{ "_id" : ObjectId("505cda7b71f3759c62076b13"), "a" : "foo" }
So to format a query for Sleepy Mongoose, first URL-escape the query using Javascript's built-in escape() function. Note the single-quotes around the query:
escape('{"a":{"$regex":"fo.*","$options":""}}')
%7B%22a%22%3A%7B%22%24regex%22%3A%22fo.*%22%2C%22%24options%22%3A%22%22%7D%7D
Then plug that into Sleepy Mongoose:
{"ok": 1, "results": [{"a": "foo", "_id": {"$oid": "505cda7b71f3759c62076b13"}}], "id": 8}