synapse/docs/client-server/howto.rst

TODO(kegan): Tweak joinalias API keys/path? Event stream historical > live needs a token (currently doesn't). im/sync responses include outdated event formats (room membership change messages). Room config (specifically: message history, public rooms). /register seems super simplistic compared to /login, maybe it would be better if /register used the same technique as /login? /register should be "user" not "user_id".

How to use the client-server API

This guide focuses on how the client-server APIs provided by the reference home server can be used. Since this is specific to a home server implementation, there may be variations in relation to registering/logging in which are not covered in extensive detail in this guide.

If you haven't already, get a home server up and running on http://localhost:8080.

Accounts

Before you can send and receive messages, you must register for an account. If you already have an account, you must login into it.

Try out the fiddle: http://jsfiddle.net/jrf1h02d/

Registration

The aim of registration is to get a user ID and access token which you will need when accessing other APIs:

curl -XPOST -d '{"user_id":"example", "password":"wordpass"}' "http://localhost:8080/_matrix/client/api/v1/register"

{
    "access_token": "QGV4YW1wbGU6bG9jYWxob3N0.AqdSzFmFYrLrTmteXc", 
    "home_server": "localhost", 
    "user_id": "@example:localhost"
}

NB: If a user_id is not specified, one will be randomly generated for you. If you do not specify a password, you will be unable to login to the account if you forget the access_token.

Implementation note: The matrix specification does not enforce how users register with a server. It just specifies the URL path and absolute minimum keys. The reference home server uses a username/password to authenticate user, but other home servers may use different methods.

Login

The aim when logging in is to get an access token for your existing user ID:

curl -XGET "http://localhost:8080/_matrix/client/api/v1/login"

{
    "type": "m.login.password"
}

curl -XPOST -d '{"type":"m.login.password", "user":"example", "password":"wordpass"}' "http://localhost:8080/_matrix/client/api/v1/login"

{
    "access_token": "QGV4YW1wbGU6bG9jYWxob3N0.vRDLTgxefmKWQEtgGd", 
    "home_server": "localhost", 
    "user_id": "@example:localhost"
}

Implementation note: Different home servers may implement different methods for logging in to an existing account. In order to check that you know how to login to this home server, you must perform a GET first and make sure you recognise the login type. If you do not know how to login, you can GET /login/fallback which will return a basic webpage which you can use to login. The reference home server implementation support username/password login, but other home servers may support different login methods (e.g. OAuth2).

Communicating

In order to communicate with another user, you must create a room with that user and send a message to that room.

Try out the fiddle: http://jsfiddle.net/jnwqcshc/

Creating a room

If you want to send a message to someone, you have to be in a room with them. To create a room:

curl -XPOST -d '{"room_alias_name":"tutorial"}' "http://localhost:8080/_matrix/client/api/v1/rooms?access_token=QGV4YW1wbGU6bG9jYWxob3N0.vRDLTgxefmKWQEtgGd"

{
    "room_alias": "#tutorial:localhost", 
    "room_id": "!CvcvRuDYDzTOzfKKgh:localhost"
}

The "room alias" is a human-readable string which can be shared with other users so they can join a room, rather than the room ID which is a randomly generated string. You can have multiple room aliases per room.

TODO(kegan): How to add/remove aliases from an existing room.

Sending messages

You can now send messages to this room:

curl -XPUT -d '{"msgtype":"m.text", "body":"hello"}' "http://localhost:8080/_matrix/client/api/v1/rooms/%21CvcvRuDYDzTOzfKKgh:localhost/messages/%40example%3Alocalhost/msgid1?access_token=QGV4YW1wbGU6bG9jYWxob3N0.vRDLTgxefmKWQEtgGd"

NB: There are no limitations to the types of messages which can be exchanged. The only requirement is that "msgtype" is specified.

NB: Depending on the room config, users who join the room may be able to see message history from before they joined.

Users and rooms

Each room can be configured to allow or disallow certain rules. In particular, these rules may specify if you require an invitation from someone already in the room in order to join the room. In addition, you may also be able to join a room via a room alias if one was set up.

Try out the fiddle: http://jsfiddle.net/og1xokcr/

Inviting a user to a room

You can directly invite a user to a room like so:

curl -XPUT -d '{"membership":"invite"}' "http://localhost:8080/_matrix/client/api/v1/rooms/%21CvcvRuDYDzTOzfKKgh:localhost/members/%40myfriend%3Alocalhost/state?access_token=QGV4YW1wbGU6bG9jYWxob3N0.vRDLTgxefmKWQEtgGd"

This informs @myfriend:localhost of the room ID !CvcvRuDYDzTOzfKKgh:localhost and allows them to join the room.

Joining a room via an invite

If you receive an invite, you can join the room by changing the membership to join:

curl -XPUT -d '{"membership":"join"}' "http://localhost:8080/_matrix/client/api/v1/rooms/%21CvcvRuDYDzTOzfKKgh:localhost/members/%40myfriend%3Alocalhost/state?access_token=QG15ZnJpZW5kOmxvY2FsaG9zdA...XKuGdVsovHmwMyDDvK"

NB: Only the person invited (@myfriend:localhost) can change the membership state to "join".

Joining a room via an alias

Alternatively, if you know the room alias for this room and the room config allows it, you can directly join a room via the alias:

curl -XPUT -d '{}' "http://localhost:8080/_matrix/client/api/v1/join/%23tutorial%3Alocalhost?access_token=QG15ZnJpZW5kOmxvY2FsaG9zdA...XKuGdVsovHmwMyDDvK"

{
    "room_id": "!CvcvRuDYDzTOzfKKgh:localhost"
}

You will need to use the room ID when sending messages, not the room alias.

NB: If the room is configured to be an invite-only room, you will still require an invite in order to join the room even though you know the room alias. As a result, it is more common to see a room alias in relation to a public room, which do not require invitations.

Getting events

An event is some interesting piece of data that a client may be interested in. It can be a message in a room, a room invite, etc. There are many different ways of getting events, depending on what the client already knows.

Try out the fiddle: http://jsfiddle.net/5uk4dqe2/

Getting all state

If the client doesn't know any information on the rooms the user is invited/joined on, they can get all the user's state for all rooms:

curl -XGET "http://localhost:8080/_matrix/client/api/v1/im/sync?access_token=QG15ZnJpZW5kOmxvY2FsaG9zdA...XKuGdVsovHmwMyDDvK"

[
    {
        "membership": "join", 
        "messages": {
            "chunk": [
                {
                    "content": {
                        "body": "@example:localhost joined the room.", 
                        "hsob_ts": 1408444664249, 
                        "membership": "join", 
                        "membership_source": "@example:localhost", 
                        "membership_target": "@example:localhost", 
                        "msgtype": "m.text"
                    }, 
                    "event_id": "lZjmmlrEvo", 
                    "msg_id": "m1408444664249", 
                    "room_id": "!CvcvRuDYDzTOzfKKgh:localhost", 
                    "type": "m.room.message", 
                    "user_id": "_homeserver_"
                }, 
                {
                    "content": {
                        "body": "hello", 
                        "hsob_ts": 1408445405672, 
                        "msgtype": "m.text"
                    }, 
                    "event_id": "BiBJqamISg", 
                    "msg_id": "msgid1", 
                    "room_id": "!CvcvRuDYDzTOzfKKgh:localhost", 
                    "type": "m.room.message", 
                    "user_id": "@example:localhost"
                }, 
                [...]
                {
                    "content": {
                        "body": "@myfriend:localhost joined the room.", 
                        "hsob_ts": 1408446501661, 
                        "membership": "join", 
                        "membership_source": "@myfriend:localhost", 
                        "membership_target": "@myfriend:localhost", 
                        "msgtype": "m.text"
                    }, 
                    "event_id": "IMmXbOzFAa", 
                    "msg_id": "m1408446501661", 
                    "room_id": "!CvcvRuDYDzTOzfKKgh:localhost", 
                    "type": "m.room.message", 
                    "user_id": "_homeserver_"
                }
            ], 
            "end": "20", 
            "start": "0"
        }, 
        "room_id": "!CvcvRuDYDzTOzfKKgh:localhost"
    }
]

This returns all the room IDs of rooms the user is invited/joined on, as well as all of the messages and feedback for these rooms. This can be a LOT of data. You may just want the most recent message for each room. This can be achieved by applying pagination stream parameters to this request:

curl -XGET "http://localhost:8080/_matrix/client/api/v1/im/sync?access_token=QG15ZnJpZW5kOmxvY2FsaG9zdA...XKuGdVsovHmwMyDDvK&from=END&to=START&limit=1"

[
    {
        "membership": "join", 
        "messages": {
            "chunk": [
                {
                    "content": {
                        "body": "@myfriend:localhost joined the room.", 
                        "hsob_ts": 1408446501661, 
                        "membership": "join", 
                        "membership_source": "@myfriend:localhost", 
                        "membership_target": "@myfriend:localhost", 
                        "msgtype": "m.text"
                    }, 
                    "event_id": "IMmXbOzFAa", 
                    "msg_id": "m1408446501661", 
                    "room_id": "!CvcvRuDYDzTOzfKKgh:localhost", 
                    "type": "m.room.message", 
                    "user_id": "_homeserver_"
                }
            ], 
            "end": "20", 
            "start": "21"
        }, 
        "room_id": "!CvcvRuDYDzTOzfKKgh:localhost"
    }
]

Getting live state

Once you know which rooms the client has previously interacted with, you need to listen for incoming events. This can be done like so:

curl -XGET "http://localhost:8080/_matrix/client/api/v1/events?access_token=QG15ZnJpZW5kOmxvY2FsaG9zdA...XKuGdVsovHmwMyDDvK&from=END"

{
    "chunk": [], 
    "end": "215", 
    "start": "215"
}

This will block waiting for an incoming event, timing out after several seconds. Even if there are no new events (as in the example above), there will be some pagination stream response keys. The client should make subsequent requests using the value of the "end" key (in this case 215) as the from query parameter. This value should be stored so when the client reopens your app after a period of inactivity, you can resume from where you got up to in the event stream. If it has been a long period of inactivity, there may be LOTS of events waiting for the user. In this case, you may wish to get all state instead and then resume getting live state from a newer end token.

NB: The timeout can be changed by adding a timeout query parameter, which is in milliseconds. A timeout of 0 will not block.

Example application

The following example demonstrates registration and login, live event streaming, creating and joining rooms, sending messages, getting member lists and getting historical messages for a room. This covers most functionality of a messaging application.

Try out the fiddle: http://jsfiddle.net/L8r3o1wr/