Design of REST interface to Couchbase NGINX module

This document describes the REST API exposed to access Couchbase
resources

What it doesn't describe:

* auth scheme, on this step you might only protect your API endpoint using nginx built-in means
* expiration handling. in Couchbase database it is possible to associate with the key expiration time. This feature will be exposed later

There are several terms we are using while describing this API.

|| Term || Definition||
| document | Arbitrary JSON or BLOB value. It could be referenced by its ID |
| bucket | The logical storage, which contains the documents. Like *database* in SQL world, or *collection* in mongodb |

Lets assume we have a bucket named {{wonderland}}.

h2. Document CRUD

This section shows how to perform simple Create, Retrieve, Update and Delete operations

Create document in the bucket
{code:none}
POST /wonderland
> Content-Type: application/json
{"name":"Alice","species":"human"}
< 201
< ETag: "f5b8da2cf1560000"
< Location: http://couchbasenginx.apiary.io/wonderland/0a4683e4b4b161f505d0c2ae0c3a1abf
{code}

You can also specify ID with POST request if you need to *create* the document with given ID.
{code:none}
POST /wonderland/alice
> Content-Type: application/json
{"name":"Alice","species":"human"}
< 201
< ETag: "f5b8da2cf1570000"
< Location: http://couchbasenginx.apiary.io/wonderland/alice
{code}

Note that when you are using POST request, the server is always supposed to create the new document. This means that you will get an error if the document already exists.
{code:none}
POST /wonderland/foobar
> Content-Type: application/json
{"foo":"bar"}
< 409
< Content-Type: application/json
< Content-Length: 74
{"error":"key_eexists","reason":"Key exists (with a different ETag value)"}
{code}

Update the document
{code:none}
PUT /wonderland/white-rabbit
> Content-Type: application/json
{"name":"Write Rabbit","species":"rabbit"}
< 204
< ETag: "3d24e52cf1570000"
< Location: http://couchbasenginx.apiary.io/wonderland/white-rabbit
{code}

You can also specify *If-Match* header and the server will perform optimistic lock before updating. This operation might fail *412 Precondition Failed*
{code:none}
PUT /wonderland/duchess
> Content-Type: application/json
> If-Match: "wrong_etag"
{"name":"Duchess","species":"human"}
< 412
< Content-Type: application/json
< Content-Length: 74
{"error":"key_eexists","reason":"Key exists (with a different ETag value)"}
{code}

If the document being updated doesn't exist, you will get *404 Not Found* error
{code:none}
PUT /wonderland/sheep
{"name":"Sheep","species":"sheep"}
< 404
< Content-Type: application/json
< Content-Length: 45
{"error":"key_enoent","reason":"No such key"}
{code}

Removing document from the bucket
{code:none}
DELETE /wonderland/caterpillar
< 204
< ETag: "7f463c2df1570000"
{code}


You can also specify *If-Match* header if you need to ensure you are removing know version of the document.
{code:none}
DELETE /wonderland/bill-the-lizard
> If-Match: "wrong_etag"
< 412
< Content-Type: application/json
< Content-Length: 74
{"error":"key_eexists","reason":"Key exists (with a different ETag value)"}
{code}


If the document being removed doesn't exist, you will get *404 Not Found* error
{code:none}
DELETE /wonderland/jabberwock
< 404
< Content-Type: application/json
< Content-Length: 45
{"error":"key_enoent","reason":"No such key"}
{code}

Getting the document by ID.
{code:none}
GET /wonderland/hatter
< 200
< Content-Type: application/json
< Content-Length: 36
< ETag: "5d45c301fc570000"
{"name":"Hatter","species":"human"}
{code}

In case when the given document ID isn't exist in the bucket you will get *404 Not Found*
{code:none}
GET /wonderland/red-queen
< 404
< Content-Type: application/json
< Content-Length: 45
{"error":"key_enoent","reason":"No such key"}

< ETag: "55c3a92df1570000"
{code}

Each operation is carry ETag, which internally is CAS value. The ETag value can be used in the conditional requests with *If-Match*, *If-None-Match*. See examples of *If-Match* above.

Check if the key has been modified (in this case the server responds that it wasn't modified):
{code:none}
HEAD /wonderland/dormouse
> If-None-Match: "3f5b792df1570000"
< 304
{code}


h2. Couchbase Views

This section shows more advanced server feature: View indexes

One of the features of the Couchbase is ability to build efficient indexes leveraging Map/Reduce. They are called Views and you can define them on Admin Console UI.

This module allows you to query your views proxying them to Couchbase. All arguments will be transparently passed to Couchbase and the result will be streamed back.

For example we have a view *all* defined in the design document *characters*. It is simple map which will just emit all known characters (without any reduce function):

{code:javascript}
function (doc, meta) {
emit(meta.id, null);
}
{code}

The result will look like (note: when *id* isn't accessible like for reduced views, the *meta* will be missing too)
{code:none}
GET /wonderland/_design/characters/_view/all
< 200
< Transfer-Encoding: chunked
< Content-Type: application/json
{"total_rows":20,"rows":[
{"id":"alice","key":"alice","value":null,"meta":{"etag":"f5b8da2cf1570000"}},
{"id":"bill-the-lizard","key":"bill-the-lizard","value":null,"meta":{"etag":"accb302df1570000"}},
{"id":"caterpillar","key":"caterpillar","value":null,"meta":{"etag":"7f463c2df1570000"}},
{"id":"cheshire-cat","key":"cheshire-cat","value":null,"meta":{"etag":"5b99582df1570000"}},
{"id":"dodo","key":"dodo","value":null,"meta":{"etag":"2fe2ed2cf1570000"}},
{"id":"dormouse","key":"dormouse","value":null,"meta":{"etag":"3f5b792df1570000"}},
{"id":"duchess","key":"duchess","value":null,"meta":{"etag":"a8bc492df1570000"}},
{"id":"duck","key":"duck","value":null,"meta":{"etag":"e076132df1570000"}},
{"id":"eaglet","key":"eaglet","value":null,"meta":{"etag":"b9bd062df1570000"}},
{"id":"gryphon","key":"gryphon","value":null,"meta":{"etag":"55c3a92df1570000"}},
{"id":"hatter","key":"hatter","value":null,"meta":{"etag":"5d45c301fc570000"}},
{"id":"king-of-hearts","key":"king-of-hearts","value":null,"meta":{"etag":"4e1c9f2df1570000"}},
{"id":"knave-of-hearts","key":"knave-of-hearts","value":null,"meta":{"etag":"43fa922df1570000"}},
{"id":"lory","key":"lory","value":null,"meta":{"etag":"01f6fa2cf1570000"}},
{"id":"march-hare","key":"march-hare","value":null,"meta":{"etag":"08f6642df1570000"}},
{"id":"mock-turtle","key":"mock-turtle","value":null,"meta":{"etag":"11a8b52df1570000"}},
{"id":"mouse","key":"mouse","value":null,"meta":{"etag":"fa38ea2cf1570000"}},
{"id":"pat","key":"pat","value":null,"meta":{"etag":"8bd71f2df1570000"}},
{"id":"queen-of-hearts","key":"queen-of-hearts","value":null,"meta":{"etag":"f72c862df1570000"}},
{"id":"white-rabbit","key":"white-rabbit","value":null,"meta":{"etag":"3d24e52cf1570000"}},
]
}
{code}


You can pass the any of supported query parameters, like *include_docs=true* for example:
{code:none}
GET /wonderland/_design/characters/_view/all?include_docs=true
< 200
< Transfer-Encoding: chunked
< Content-Type: application/json
{"total_rows":20,"rows":[
{"id":"alice","key":"alice","value":null,"meta":{"etag":"f5b8da2cf1570000"},"json":{"name":"Alice","species":"human"}},
{"id":"bill-the-lizard","key":"bill-the-lizard","value":null,"meta":{"etag":"accb302df1570000"},"json":{"name":"Bill the Lizard","species":"lizard"}},
{"id":"caterpillar","key":"caterpillar","value":null,"meta":{"etag":"7f463c2df1570000"},"json":{"name":"Caterpillar","species":"caterpillar"}},
{"id":"cheshire-cat","key":"cheshire-cat","value":null,"meta":{"etag":"5b99582df1570000"},"json":{"name":"Cheshire Cat","species":"cat"}},
{"id":"dodo","key":"dodo","value":null,"meta":{"etag":"2fe2ed2cf1570000"},"json":{"name":"Dodo","species":"bird"}},
{"id":"dormouse","key":"dormouse","value":null,"meta":{"etag":"3f5b792df1570000"},"json":{"name":"Dormouse","species":"dormouse"}},
{"id":"duchess","key":"duchess","value":null,"meta":{"etag":"a8bc492df1570000"},"json":{"name":"Duchess","species":"human"}},
{"id":"duck","key":"duck","value":null,"meta":{"etag":"e076132df1570000"},"json":{"name":"Duck","species":"bird"}},
{"id":"eaglet","key":"eaglet","value":null,"meta":{"etag":"b9bd062df1570000"},"json":{"name":"Eaglet","species":"bird"}},
{"id":"gryphon","key":"gryphon","value":null,"meta":{"etag":"55c3a92df1570000"},"json":{"name":"Gryphon","species":"gryphon"}},
{"id":"hatter","key":"hatter","value":null,"meta":{"etag":"5d45c301fc570000"},"json":"foo"},
{"id":"king-of-hearts","key":"king-of-hearts","value":null,"meta":{"etag":"4e1c9f2df1570000"},"json":{"name":"King of Hearts","species":"card"}},
{"id":"knave-of-hearts","key":"knave-of-hearts","value":null,"meta":{"etag":"43fa922df1570000"},"json":{"name":"Knave of Hearts","species":"card"}},
{"id":"lory","key":"lory","value":null,"meta":{"etag":"01f6fa2cf1570000"},"json":{"name":"Lory","species":"bird"}},
{"id":"march-hare","key":"march-hare","value":null,"meta":{"etag":"08f6642df1570000"},"json":{"name":"March Hare","species":"hare"}},
{"id":"mock-turtle","key":"mock-turtle","value":null,"meta":{"etag":"11a8b52df1570000"},"json":{"name":"Mock Turtle","species":"turtle"}},
{"id":"mouse","key":"mouse","value":null,"meta":{"etag":"fa38ea2cf1570000"},"json":{"name":"Mouse","species":"mouse"}},
{"id":"pat","key":"pat","value":null,"meta":{"etag":"8bd71f2df1570000"},"json":{"name":"Pat","species":"pig"}},
{"id":"queen-of-hearts","key":"queen-of-hearts","value":null,"meta":{"etag":"f72c862df1570000"},"json":{"name":"Queen of Hearts","species":"card"}},
{"id":"white-rabbit","key":"white-rabbit","value":null,"meta":{"etag":"3d24e52cf1570000"},"json":{"name":"White Rabbit","species":"rabbit"}}
]
}
{code}

h2. Misc

You can find executable spec here: http://docs.couchbasenginx.apiary.io/