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Start fleshing out architecture section. Moar .rst formatting! Reword some copypastaed sections to be terser.

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Kegan Dougal 2014-08-28 17:40:04 +01:00
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docs/specification.rst
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@ -5,16 +5,18 @@ TODO(Introduction) : Matthew
- Similar to intro paragraph from README.
- Explaining the overall mission, what this spec describes...
- "What is Matrix?"
- Draw parallels with email?
Architecture
============
- Basic structure: What are clients/home servers and what are their
responsibilities? What are events.
- Sending a message from A to B
::
{ Matrix clients } { Matrix clients }
How data flows between clients
==============================
{ Matrix client A } { Matrix client B }
^ | ^ |
| events | | events |
| V | V
@ -22,22 +24,87 @@ Architecture
| |---------( HTTP )---------->| |
| Home Server | | Home Server |
| |<--------( HTTP )-----------| |
+------------------+ +------------------+
+------------------+ Federation +------------------+
- How do identity servers fit in? 3PIDs? Users? Aliases
- Pattern of the APIs (HTTP/JSON, REST + txns)
- Standard error response format.
- C-S Event stream
- Client is an end-user (web app, mobile app) which uses C-S APIs to talk to the home server.
A given client is typically responsible for a single user.
- Home server provides C-S APIs and has the ability to federate with other HSes.
Typically responsible for N clients.
- Federation's purpose is to share content between interested HSes; no SPOF.
- Events are actions within the system. Typically each action (e.g. sending a message)
correlates with exactly one event. Each event has a ``type`` string.
- ``type`` values SHOULD be namespaced according to standard Java package naming conventions,
with a ``.`` delimiter e.g. ``com.example.myapp.event``
- Events are typically send in the context of a room.
Rooms
=====
Room structure
--------------
A room is a conceptual place where users can send and receive messages. Rooms
can be created, joined and left. Messages are sent to a room, and all
participants in that room will receive the message. Rooms are uniquely
identified via a room ID. There is exactly one room ID for each room.
identified via a room ID. There is exactly one room ID for each room. Each
room can also have an alias. Each room can have many aliases.
- Aliases
::
How events flow in rooms
========================
{ @alice:matrix.org } { @bob:domain.com }
| ^
| |
Room ID: !qporfwt:matrix.org Room ID: !qporfwt:matrix.org
Event type: m.room.message Event type: m.room.message
Content: { JSON object } Content: { JSON object }
| |
V |
+------------------+ +------------------+
| Home Server | | Home Server |
| matrix.org |<-------Federation--------->| domain.com |
+------------------+ +------------------+
Room ID: !qporfwt:matrix.org Room ID: !qporfwt:matrix.org
Servers: matrix.org, domain.com Servers: matrix.org, domain.com
Members: Members:
- @alice:matrix.org - @alice:matrix.org
- @bob:domain.com - @bob:domain.com
- Room IDs MUST have ! prefix; looks like !foo:domain - domain is simply for namespacing,
the room does NOT reside on domain. NOT human readable.
- Room Aliases MUST have # prefix; looks like #foo:domain - domain indicates where this
alias can be mapped to a room ID. Key point: human readable / friendly.
- User IDs MUST have @ prefix; looks like @foo:domain - domain indicates the user's home
server.
- Aliases can be queried on the domain they specify, which will return a room ID if a
mapping exists. These mappings can change.
Identity
--------
- Identity in relation to 3PIDs. Discovery of users based on 3PIDs.
- Identity servers; trusted clique of servers which replicate content.
- They govern the mapping of 3PIDs to user IDs and the creation of said mappings.
- Not strictly required in order to communicate.
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.
Receiving live updates on a client
----------------------------------
- C-S longpoll event stream
- Concept of start/end tokens.
- Mention /initialSync to get token.
Rooms
=====
- How are they created?
- Adding / removing aliases.
- Invite/join dance
- State and non-state data (+extensibility)
@ -46,10 +113,8 @@ TODO : Room permissions / config / power levels.
Messages
========
This specification outlines several standard message types, all of which are
prefixed with "m.".
- Namespacing?
This specification outlines several standard event types, all of which are
prefixed with ``m.``
State messages
--------------
@ -174,88 +239,59 @@ The following keys can be attached to any ``m.room.message``:
Presence
========
Each user has the concept of Presence information. This encodes a sense of the
"availability" of that user, suitable for display on other user's clients.
Each user has the concept of presence information. This encodes the
"availability" of that user, suitable for display on other user's clients. This
is transmitted as an ``m.presence`` event and is one of the few events which
are sent *outside the context of a room*. The basic piece of presence information
is represented by the ``state`` key, which is an enum of one of the following:
The basic piece of presence information is an enumeration of a small set of
state; such as "free to chat", "online", "busy", or "offline". The default state
unless the user changes it is "online". Lower states suggest some amount of
decreased availability from normal, which might have some client-side effect
like muting notification sounds and suggests to other users not to bother them
unless it is urgent. Equally, the "free to chat" state exists to let the user
announce their general willingness to receive messages moreso than default.
- ``online`` : The default state when the user is connected to an event stream.
- ``unavailable`` : The user is not reachable at this time.
- ``offline`` : The user is not connected to an event stream.
- ``free_for_chat`` : The user is generally willing to receive messages
moreso than default.
- ``hidden`` : TODO. Behaves as offline, but allows the user to see the client
state anyway and generally interact with client features.
Home servers should also allow a user to set their state as "hidden" - a state
which behaves as offline, but allows the user to see the client state anyway and
generally interact with client features such as reading message history or
accessing contacts in the address book.
This basic state field applies to the user as a whole, regardless of how many
This basic ``state`` field applies to the user as a whole, regardless of how many
client devices they have connected. The home server should synchronise this
status choice among multiple devices to ensure the user gets a consistent
experience.
Idle Time
---------
As well as the basic state field, the presence information can also show a sense
As well as the basic ``state`` field, the presence information can also show a sense
of an "idle timer". This should be maintained individually by the user's
clients, and the homeserver can take the highest reported time as that to
report. Likely this should be presented in fairly coarse granularity; possibly
being limited to letting the home server automatically switch from a "free to
chat" or "online" mode into "idle".
clients, and the home server can take the highest reported time as that to
report. When a user is offline, the home server can still report when the user was last
seen online.
When a user is offline, the Home Server can still report when the user was last
seen online, again perhaps in a somewhat coarse manner.
Device Type
-----------
Client devices that may limit the user experience somewhat (such as "mobile"
devices with limited ability to type on a real keyboard or read large amounts of
text) should report this to the home server, as this is also useful information
to report as "presence" if the user cannot be expected to provide a good typed
response to messages.
- m.presence and enums (when should they be used)
Transmission
------------
- Transmitted as an EDU.
- Presence lists determine who to send to.
Presence List
-------------
Each user's home server stores a "presence list" for that user. This stores a
list of other user IDs the user has chosen to add to it (remembering any ACL
Pointer if appropriate).
To be added to a contact list, the user being added must grant permission. Once
granted, both user's HS(es) store this information, as it allows the user who
has added the contact some more abilities; see below. Since such subscriptions
list of other user IDs the user has chosen to add to it. To be added to this
list, the user being added must receive permission from the list owner. Once
granted, both user's HS(es) store this information. Since such subscriptions
are likely to be bidirectional, HSes may wish to automatically accept requests
when a reverse subscription already exists.
As a convenience, presence lists should support the ability to collect users
into groups, which could allow things like inviting the entire group to a new
("ad-hoc") chat room, or easy interaction with the profile information ACL
implementation of the HS.
Presence and Permissions
------------------------
For a viewing user to be allowed to see the presence information of a target
user, either
user, either:
* The target user has allowed the viewing user to add them to their presence
- The target user has allowed the viewing user to add them to their presence
list, or
* The two users share at least one room in common
- The two users share at least one room in common
In the latter case, this allows for clients to display some minimal sense of
presence information in a user list for a room.
Home servers can also use the user's choice of presence state as a signal for
how to handle new private one-to-one chat message requests. For example, it
might decide:
- "free to chat": accept anything
- "online": accept from anyone in my address book list
- "busy": accept from anyone in this "important people" group in my address
book list
Typing notifications
====================
@ -274,18 +310,14 @@ human-friendly string. Profiles grant users the ability to see human-readable
names for other users that are in some way meaningful to them. Additionally,
profiles can publish additional information, such as the user's age or location.
It is also conceivable that since we are attempting to provide a
worldwide-applicable messaging system, that users may wish to present different
subsets of information in their profile to different other people, from a
privacy and permissions perspective.
A Profile consists of a display name, an avatar picture, and a set of other
metadata fields that the user may wish to publish (email address, phone
numbers, website URLs, etc...). This specification puts no requirements on the
display name other than it being a valid Unicode string.
display name other than it being a valid unicode string.
- Metadata extensibility
- Bundled with which events? e.g. m.room.member
- Generate own events? What type?
Registration and login
======================
@ -312,8 +344,8 @@ The login process breaks down into the following:
step 2.
As each home server may have different ways of logging in, the client needs to know how
they should login. All distinct login stages MUST have a corresponding ``'type'``.
A ``'type'`` is a namespaced string which details the mechanism for logging in.
they should login. All distinct login stages MUST have a corresponding ``type``.
A ``type`` is a namespaced string which details the mechanism for logging in.
A client may be able to login via multiple valid login flows, and should choose a single
flow when logging in. A flow is a series of login stages. The home server MUST respond
@ -359,17 +391,17 @@ subsequent requests until the login is completed::
}
This specification defines the following login types:
- m.login.password
- m.login.oauth2
- m.login.email.code
- m.login.email.url
- ``m.login.password``
- ``m.login.oauth2``
- ``m.login.email.code``
- ``m.login.email.url``
Password-based
--------------
Type:
"m.login.password"
Description:
:Type:
m.login.password
:Description:
Login is supported via a username and password.
To respond to this type, reply with::
@ -385,9 +417,9 @@ process, or a standard error response.
OAuth2-based
------------
Type:
"m.login.oauth2"
Description:
:Type:
m.login.oauth2
:Description:
Login is supported via OAuth2 URLs. This login consists of multiple requests.
To respond to this type, reply with::
@ -438,9 +470,9 @@ visits the REDIRECT_URI with the auth code= query parameter which returns::
Email-based (code)
------------------
Type:
"m.login.email.code"
Description:
:Type:
m.login.email.code
:Description:
Login is supported by typing in a code which is sent in an email. This login
consists of multiple requests.
@ -473,9 +505,9 @@ the login process, or a standard error response.
Email-based (url)
-----------------
Type:
"m.login.email.url"
Description:
:Type:
m.login.email.url
:Description:
Login is supported by clicking on a URL in an email. This login consists of
multiple requests.
@ -515,7 +547,7 @@ N-Factor Authentication
-----------------------
Multiple login stages can be combined to create N-factor authentication during login.
This can be achieved by responding with the ``'next'`` login type on completion of a
This can be achieved by responding with the ``next`` login type on completion of a
previous login stage::
{
@ -523,7 +555,7 @@ previous login stage::
}
If a home server implements N-factor authentication, it MUST respond with all
``'stages'`` when initially queried for their login requirements::
``stages`` when initially queried for their login requirements::
{
"type": "<1st login type>",
@ -592,19 +624,19 @@ can also be performed.
There are three main kinds of communication that occur between home servers:
* Queries
- Queries
These are single request/response interactions between a given pair of
servers, initiated by one side sending an HTTP request to obtain some
information, and responded by the other. They are not persisted and contain
no long-term significant history. They simply request a snapshot state at the
instant the query is made.
* EDUs - Ephemeral Data Units
- EDUs - Ephemeral Data Units
These are notifications of events that are pushed from one home server to
another. They are not persisted and contain no long-term significant history,
nor does the receiving home server have to reply to them.
* PDUs - Persisted Data Units
- PDUs - Persisted Data Units
These are notifications of events that are broadcast from one home server to
any others that are interested in the same "context" (namely, a Room ID).
They are persisted to long-term storage and form the record of history for
@ -629,6 +661,8 @@ milliseconds) generated by its origin server, an origin and destination server
name, a list of "previous IDs", and a list of PDUs - the actual message payload
that the Transaction carries.
::
{"transaction_id":"916d630ea616342b42e98a3be0b74113",
"ts":1404835423000,
"origin":"red",
@ -660,6 +694,8 @@ sent them), and a nested content field containing the actual event content.
[[TODO(paul): Update this structure so that 'pdu_id' is a two-element
[origin,ref] pair like the prev_pdus are]]
::
{"pdu_id":"a4ecee13e2accdadf56c1025af232176",
"context":"#example.green",
"origin":"green",
@ -686,6 +722,8 @@ PDUs fall into two main categories: those that deliver Events, and those that
synchronise State. For PDUs that relate to State synchronisation, additional
keys exist to support this:
::
{...,
"is_state":true,
"state_key":TODO
@ -704,6 +742,8 @@ EDUs, by comparison to PDUs, do not have an ID, a context, or a list of
"previous" IDs. The only mandatory fields for these are the type, origin and
destination home server names, and the actual nested content.
::
{"edu_type":"m.presence",
"origin":"blue",
"destination":"orange",