Query view with multiple keys with OR logic

[Simeon F. Willbanks]

Hello,

I'm trying to fetch a set of documents with OR logic. For example,
fetch all documents with type="post" OR tag="tag1". Here are a few
example documents with rev omitted for brevity:

{
    "_id": 1,
    "type": "post",
    "tags": [
        "tag1",
        "tag2"
    ]
}

{
    "_id": 2,
    "type": "photo",
    "tags": [
        "tag1",
        "tag3"
    ]
}

{
    "_id": 3,
    "type": "photo",
    "tags": [
        "tag4",
        "tag5"
    ]
}

I'd like to fetch documents with the ids 1 and 2.

It seems this method will be my starting point:
"A JSON structure of {"keys": ["key1", "key2", ...]} can be posted to
any user defined view or _all_docs to retrieve just the view rows
matching that set of keys. Rows are returned in the order of the keys
specified. Combining this feature with include_docs=true results in
the so-called multi-document-fetch feature."
http://wiki.apache.org/couchdb/HTTP_view_API

Am I correct so far? If yes, how would I define my map function? Would
I call emit multiple times and possibly use a group=true parameter?

Thanks,
Simeon