Flesh out API standards.

This commit is contained in:
Kegan Dougal 2014-08-29 13:50:25 +01:00
parent cc413be446
commit 898dde8812

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@ -132,10 +132,87 @@ Identity
API Standards
-------------
- All HTTP[S]
- Uses JSON as HTTP bodies
- Standard error response format { errcode: M_WHATEVER, error: "some message" }
- C-S API provides POST for operations, or PUT with txn IDs. Explain txn IDs.
All communication in Matrix is performed over HTTP[S] using a Content-Type of ``application/json``.
Any errors which occur on the Matrix API level MUST return a "standard error response". This is a
JSON object which looks like::
{
"errcode": "<error code>",
"error": "<error message>"
}
The ``error`` string will be a human-readable error message, usually a sentence
explaining what went wrong. The ``errcode`` string will be a unique string which can be
used to handle an error message e.g. ``M_FORBIDDEN``. These error codes should have their
namespace first in ALL CAPS, followed by a single _. For example, if there was a custom
namespace ``com.mydomain.here``, and a ``FORBIDDEN`` code, the error code should look
like ``COM.MYDOMAIN.HERE_FORBIDDEN``. There may be additional keys depending on
the error, but the keys ``error`` and ``errcode`` MUST always be present.
Some standard error codes are below:
:``M_FORBIDDEN``:
Forbidden access, e.g. joining a room without permission, failed login.
:``M_UNKNOWN_TOKEN``:
The access token specified was not recognised.
:``M_BAD_JSON``:
Request contained valid JSON, but it was malformed in some way, e.g. missing
required keys, invalid values for keys.
:``M_NOT_JSON``:
Request did not contain valid JSON.
:``M_NOT_FOUND``:
No resource was found for this request.
Some requests have unique error codes:
:``M_USER_IN_USE``:
Encountered when trying to register a user ID which has been taken.
:``M_ROOM_IN_USE``:
Encountered when trying to create a room which has been taken.
:``M_BAD_PAGINATION``:
Encountered when specifying bad pagination query parameters.
:``M_LOGIN_EMAIL_URL_NOT_YET``:
Encountered when polling for an email link which has not been clicked yet.
The C-S API typically uses ``HTTP POST`` to submit requests. This means these requests
are not idempotent. The C-S API also allows ``HTTP PUT`` to make requests idempotent.
In order to use a ``PUT``, paths should be suffixed with ``/{txnId}``. ``{txnId}`` is a
client-generated transaction ID which identifies the request. Crucially, it **only**
serves to identify new requests from retransmits. After the request has finished, the
``{txnId}`` value should be changed (how is not specified, it could be a monotonically
increasing integer, etc). It is preferable to use ``HTTP PUT`` to make sure requests to
send messages do not get sent more than once should clients need to retransmit requests.
Valid requests look like::
POST /some/path/here
{
"key": "This is a post."
}
PUT /some/path/here/11
{
"key": "This is a put with a txnId of 11."
}
In contrast, these are invalid requests::
POST /some/path/here/11
{
"key": "This is a post, but it has a txnId."
}
PUT /some/path/here
{
"key": "This is a put but it is missing a txnId."
}
Receiving live updates on a client
----------------------------------