Tinode is an IM router and a store. Conceptually it loosely follows a publish-subscribe model.
Server connects sessions, users, and topics. Session is a network connection between a client application and the server. User represents a human being who connects to the server with a session. Topic is a named communication channel which routes content between sessions.
Users and topics are assigned unique IDs. User ID is a string with 'usr' prefix followed by base64-URL-encoded pseudo-random 64-bit number, e.g. usr2il9suCbuko. Topic IDs are described below.
Clients such as mobile or web applications create sessions by connecting to the server over a websocket or through long polling. Client authentication is optional (anonymous clients are technically supported but may not fully work as expected yet). Client authenticates the session by sending a {login} packet. Only basic authentication with user name and password is currently supported for initial authentication. Once authenticated with login and password, the client may use token authentication later. Multiple simultaneous sessions may be established by the same user. Logging out is not supported.
Once the session is established, the user can start interacting with other users through topics. The following topic types are available:
meis a topic for managing one's profile, receiving invites and requests for approval;metopic exists for every user.- Peer to peer topic is a communication channel strictly between two users. Each participant sees topic name as the ID of the other participant: 'usr' prefix followed by a base64-URL-encoded numeric part of user ID, e.g.
usr2il9suCbuko. - Group topic is a channel for multi-user communication. It's named as 'grp' followed by 12 pseudo-random characters, i.e.
grp1XUtEhjv6HND. Group topics must be explicitly created.
Session joins a topic by sending a {sub} packet. Packet {sub} serves three functions: creating a new topic, subscribing user to a topic, and attaching session to a topic. See {sub} section below for details.
Once the session has joined the topic, the user may start generating content by sending {pub} packets. The content is delivered to other attached sessions as {data} packets.
The user may query or update topic metadata by sending {get} and {set} packets.
Changes to topic metadata, such as changes in topic description, or when other users join or leave the topic, is reported to live sessions with {pres} (presence) packet.
When user's me topic comes online (i.e. an authenticated session attaches to me topic), a {pres} packet is sent to me topics of all other users, who have peer to peer subscriptions with the first user.
Timestamps are always represented as RFC 3339-formatted string with precision up to milliseconds and timezone always set to UTC, e.g. "2015-10-06T18:07:29.841Z".
Whenever base64 encoding is mentioned, it means base64 URL encoding with padding characters stripped, see RFC 4648.
Server-issued message IDs are base-10 sequential numbers starting at 1. They guaranteed to be unique per topic. Client-assigned message IDs are strings generated by the client. Client should make them unique at least per session. The client-assigned IDs are not interpreted by the server, they are returned to the client as is.
Client establishes a connection to the server over HTTP(S). Server offers two end points:
/v0/channelsfor websocket connections/v0/channels/lpfor long polling
v0 denotes API version (currently zero). Every HTTP(S) request must include the API key. It may be included in the URL as ...?apikey=<YOUR_API_KEY>, in the request body as apikey=<YOUR_API_KEY>, or in the HTTP header X-Tinode-APIKey: <YOUR_API_KEY>. A default key is included in every demo app for convenience. Generate your own key using keygen utility.
Once the connection is opened, the client must issue a {hi} message to the server. Server responds with a {ctrl} message which maybe an error message. The params field of the response contains server's protocol version "params":{"ver":"0.15"} and may include other values.
Messages are sent in text frames, one message per frame. Binary frames are reserved for future use. Server allows connections with any value in the Origin header.
Long polling works over HTTP POST (preferred) or GET. In response to client's very first request server sends a {ctrl} message containing sid (session ID) in params. Long polling client must include sid in every subsequent request either in URL or in request body.
Server allows connections from all origins, i.e. Access-Control-Allow-Origin: *
A message is a logically associated set of data. Messages are passed as JSON-formatted UTF-8 text.
All client to server messages may have an optional id field. It's set by the client as means to receive an aknowledgement from the server that the message was received and processed. The id is expected to be a session-unique string but it can be any string. The server does not attempt to interpret it other than to check JSON validity. It's returned unchanged by the server when it replies to client messages.
Server requires strictly valid JSON, including double quotes around field names. For brevity the notation below omits double quotes around field names as well as outer curly brackets.
For messages that update application-defined data, such as {set} private or public fields, when server-side
data needs to be cleared, use a string with a single Unicode DEL character "␡" "\u2421". I.e. sending "public": null will not clear the field, but sending "public": "\u2421" will.
Handshake message client uses to inform the server of its version and user agent. This message must be the first that
the client sends to the server. Server responds with a {ctrl} which contains server build build, wire protocol version ver, and
session ID sid in case of long polling, all in ctrl.params.
hi: {
id: "1a2b3", // string, client-provided message id, optional
ver: "0.14", // string, version of the wire protocol supported by the client, required
ua: "JS/1.0 (Windows 10)", // string, user agent identifying client software,
// optional
dev: "L1iC2dNtk2", // string, unique value which identifies this specific
// connected device for the purpose of push notifications; not
// interpreted by the server; optional
// see [Push notifications support](#push-notifications-support); optional
lang: "EN" // human language of the client device; optional
}The user agent ua is expected to follow RFC 7231 section 5.5.3 recommendation but the format is not enforced. The message can be sent more than once to update ua, dev and lang values. If sent more than once, the ver field of the second and subsequent messages must be either unchanged or not set.
Message {acc} creates users or updates tags or authentication credentials scheme and secret of exiting users. To create a new user set user to the string new optionally followed by any character sequence, e.g. newr15gsr. Either authenticated or anonymous session can send an {acc} message to create a new user. To authentication data or validate a credential of the current user leave user unset.
acc: {
id: "1a2b3", // string, client-provided message id, optional
user: "new", // string, "new" to create a new user, default: current user, optional
scheme: "basic", // authentication scheme for this account, required;
// "basic" and "anonymous" are currently supported for account creation. The
// current implementation of the basic scheme does not allow changes to
// username.
secret: btoa("username:password"), // string, base64 encoded secret for the chosen
// authentication scheme; to delete a scheme use a string with a single DEL
// Unicode character "\u2421"; "token" and "basic" cannot be deleted
tags: ["alice johnson",... ], // array of tags for user discovery; see 'fnd' topic for
// details, optional (if missing, user will not be discoverable other than
// by login)
cred: [
{
meth: "email", // string, verification method, e.g. "email", "tel", "recaptcha", etc.
val: "alice@example.com", // string, credential to verify such as email or phone
resp: "178307", // string, verification response, optional
params: { ... } // parameters, specific to the verification method, optional
},
...
], // account credentials which require verifiction, such as email.
desc: { // object, user initialization data closely matching that of table
// initialization; optional
defacs: {
auth: "JRWS", // string, default access mode for peer to peer conversations
// between this user and other authenticated users
anon: "N" // string, default access mode for peer to peer conversations
// between this user and anonymous (un-authenticated) users
}, // Default access mode for user's peer to peer topics
public: { ... }, // application-defined payload to describe user,
// available to everyone
private: { ... } // private application-defined payload available only to user
// through 'me' topic
}
}Server responds with a {ctrl} message with params containing details of the new user. If desc.defacs is missing,
server will assign server-default access values.
The only supported authentication schemes for account creation are basic and anonymous.
Login is used to authenticate the current session.
login: {
id: "1a2b3", // string, client-provided message id, optional
scheme: "basic", // string, authentication scheme, optional; "basic" and "token"
// are currently supported
secret: btoa("username:password"), // string, base64-encoded secret for the chosen
// authentication scheme, required
cred: [
{
meth: "email", // string, verification method, e.g. "email", "tel", "captcha", etc, required
resp: "178307" // string, verification response, required
},
...
], // response to a request for credential verification, optional
}The basic authentication scheme expects secret to be a base64-encoded string of a string composed of a user name followed by a colon : followed by a plan text password. User name in the basic scheme must not contain colon character ':' (ASCII 0x3A). The token expects secret to be a previously obtained security token.
The only supported authentication schemes are basic and token. Although anonymous scheme can be used to create accounts, it cannot be used for logging in.
Server responds to a {login} packet with a {ctrl} message. The params of the message contains the id of the logged in user as user. The token contains an encrypted string which can be used for authentication. Expiration time of the token is passed as expires.
The {sub} packet serves the following functions:
- creating a topic
- subscribing user to a topic
- attaching session to a topic
- fetching topic data
User creates a new group topic by sending {sub} packet with the topic field set to "new". Server will create a topic and respond back to session with the name of the newly created topic.
User creates a new peer to peer topic by sending {sub} packet with topic set to peer's user ID.
The user is always subscribed to and the session is attached to the newly created topic.
If the user had no relationship with the topic, sending {sub} packet creates it. Subscribing means to establish a relationship between session's user and the topic where no relationship existed in the past.
Joining (attaching to) a topic means for the session to start consuming content from the topic. Server automatically differentiates between subscribing and joining/attaching based on context: if the user had no prior relationship with the topic, the server subscribes the user then attaches the current session to the topic. If relationship existed, the server only attaches the session to the topic. When subscribing, the server checks user's access permissions against topic's access control list. It may grant immediate access, deny access, may generate a request for approval from topic managers.
Server replies to the {sub} with a {ctrl}.
The {sub} message may include a get and browse fields which mirror what and browse fields of a {get} message. If included, server will treat them as a subsequent {get} message on the same topic. In that case the reply may also include {meta} and {data} messages.
sub: {
id: "1a2b3", // string, client-provided message id, optional
topic: "me", // topic to be subscribed or attached to
// Object with topic initialization data, new topics & new
// subscriptions only, mirrors {set} message
set: {
// New topic parameters, mirrors {set desc}
desc: {
defacs: {
auth: "JRWS", // string, default access for new authenticated subscribers
anon: "N" // string, default access for new anonymous (un-authenticated)
// subscribers
}, // Default access mode for the new topic
public: { ... }, // application-defined payload to describe topic
private: { ... } // per-user private application-defined content
}, // object, optional
// Subscription parameters, mirrors {set sub}. 'sub.user' must be blank
sub: {
mode: "JRWS", // string, requested access mode, optional;
// default: server-defined
info: { ... } // application-defined payload to pass to the topic manager
}, // object, optional
// Optional update to tags (see fnd topic description)
tags: [ // array of strings
"email:alice@example.com", "tel:1234567890"
]
},
get: {
// Metadata to request from the topic; space-separated list, valid strings
// are "info", "sub", "data"; default: request nothing; unknown strings are
// ignored; see {get what} for details
what: "desc sub data", // string, optional
// Optional parameters for {get what="desc"}
desc: {
ims: "2015-10-06T18:07:30.038Z" // timestamp, "if modified since" - return
// public and private values only if at least one of them has been
// updated after the stated timestamp, optional
},
// Optional parameters for {get what="sub"}
sub: {
ims: "2015-10-06T18:07:30.038Z", // timestamp, "if modified since" - return
// public and private values only if at least one of them has been
// updated after the stated timestamp, optional
user: "usr2il9suCbuko", // string, return results for a single user,
// any topic other than 'me', optional
topic: "usr2il9suCbuko", // string, return results for a single topic,
// 'me' topic only, optional
limit: 20 // integer, limit the number of returned objects
},
// Optional parameters for {get what="data"}, see {get what="data"} for details
data: {
since: 123, // integer, load messages with server-issued IDs greater or equal
// to this (inclusive/closed), optional
before: 321, // integer, load messages with server-issued sequential IDs less
// than this (exclusive/open), optional
limit: 20, // integer, limit the number of returned objects,
// default: 32, optional
} // object, optional
}
}See Public and Private Fields for private and public format considerations.
This is a counterpart to {sub} message. It also serves two functions:
- leaving the topic without unsubscribing (
unsub=false) - unsubscribing (
unsub=true)
Server responds to {leave} with a {ctrl} packet. Leaving without unsubscribing affects just the current session. Leaving with unsubscribing will affect all user's sessions.
leave: {
id: "1a2b3", // string, client-provided message id, optional
topic: "grp1XUtEhjv6HND", // string, topic to leave, unsubscribe, or
// delete, required
unsub: true // boolean, leave and unsubscribe, optional, default: false
}The message is used to distribute content to topic subscribers.
pub: {
id: "1a2b3", // string, client-provided message id, optional
topic: "grp1XUtEhjv6HND", // string, topic to publish to, required
noecho: false, // boolean, suppress echo (see below), optional
head: { key: "value", ... }, // set of string key-value pairs,
// passed to {data} unchanged, optional
content: { ... } // object, application-defined content to publish
// to topic subscribers, required
}Topic subscribers receive the content in the {data} message. By default the originating session gets a copy of {data} like any other session currently attached to the topic. If for some reason the originating session does not want to receive the copy of the data it just published, set noecho to true.
See Format of Content for content format considerations.
`
Query topic for metadata, such as description or a list of subscribers, or query message history.
get: {
id: "1a2b3", // string, client-provided message id, optional
topic: "grp1XUtEhjv6HND", // string, name of topic to request data from
what: "sub desc data del", // string, space-separated list of parameters to query;
// unknown strings are ignored; required
// Optional parameters for {get what="desc"}
desc: {
ims: "2015-10-06T18:07:30.038Z" // timestamp, "if modified since" - return
// public and private values only if at least one of them has been
// updated after the stated timestamp, optional
},
// Optional parameters for {get what="sub"}
sub: {
ims: "2015-10-06T18:07:30.038Z", // timestamp, "if modified since" - return
// public and private values only if at least one of them has been
// updated after the stated timestamp, optional
user: "usr2il9suCbuko", // string, return results for a single user,
// any topic other than 'me', optional
topic: "usr2il9suCbuko", // string, return results for a single topic,
// 'me' topic only, optional
limit: 20 // integer, limit the number of returned objects
},
// Optional parameters for {get what="data"}
data: {
since: 123, // integer, load messages with server-issued IDs greater or equal
// to this (inclusive/closed), optional
before: 321, // integer, load messages with server-issed sequential IDs less
// than this (exclusive/open), optional
limit: 20, // integer, limit the number of returned objects, default: 32,
// optional
},
// Optional parameters for {get what="del"}
del: {
since: 5, // integer, load deleted ranges with the delete transaction IDs greater
// or equal to this (inclusive/closed), optional
before: 12, // integer, load deleted ranges with the delete transaction IDs less
// than this (exclusive/open), optional
limit: 25, // integer, limit the number of returned objects, default: 32,
// optional
}
}{get what="desc"}
Query topic description. Server responds with a {meta} message containing requested data. See {meta} for details.
If ims is specified and data has not been updated, the message will skip public and private fields.
{get what="sub"}
Get a list of subscribers. Server responds with a {meta} message containing a list of subscribers. See {meta} for details.
For me topic the request returns a list of user's subscriptions. If ims is specified and data has not been updated,
responds with a {ctrl} "not modified" message.
{get what="tags"}
Query indexed tags. Server responds with a {meta} message containing an array of string tags. See {meta} and fnd topic for details.
Supported only for me and group topics.
{get what="data"}
Query message history. Server sends {data} messages matching parameters provided in the data field of the query.
The id field of the data messages is not provided as it's common for data messages. When all {data} messages are transmitted, a {ctrl} message is sent.
{get what="del"}
Query message deletion history. Server responds with a {meta} message containing a list of deleted message ranges.
See Public and Private Fields for private and public format considerations.
Update topic metadata, delete messages or topic.
set: {
id: "1a2b3", // string, client-provided message id, optional
topic: "grp1XUtEhjv6HND", // string, name of topic to update, required
// Optional payload to update topic description
desc: {
defacs: { // new default access mode
auth: "JRWP", // access permissions for authenticated users
anon: "JRW" // access permissions for anonymous users
},
public: { ... }, // application-defined payload to describe topic
private: { ... } // per-user private application-defined content
},
// Optional payload to update subscription(s)
sub: {
user: "usr2il9suCbuko", // string, user affected by this request;
// default (empty) means current user
mode: "JRWP", // string, access mode change, either given ('user'
// is defined) or requested ('user' undefined)
info: { ... } // object, application-defined payload to pass to
// the invited user or to the topic manager in {data}
// message on 'me' topic
}, // object, payload for what == "sub"
// Optional update to tags (see fnd topic description)
tags: [ // array of strings
"email:alice@example.com", "tel:1234567890"
]
}Delete messages or topic.
del: {
id: "1a2b3", // string, client-provided message id, optional
topic: "grp1XUtEhjv6HND", // string, topic affect, required
what: "msg", // string, either "topic" or "sub" or "msg"; what to delete - the
// entire topic or subscription or just the messages;
// optional, default: "msg"
hard: false, // boolean, request to delete messages for all users, default: false
delseq: [{low: 123, hi: 125}, {low: 156}], // array of ranges of message IDs
// to delete, inclusive-exclusive, i.e. [low, hi), optional
user: "usr2il9suCbuko" // string, user whose subscription is being deleted
// (what="sub"), optional
}User can soft-delete or hard-delete messages what="msg". Soft-deleting messages hides them from the requesting user but does not delete them from storage. An R permission is required to soft-delete messages hard=false (default). Messages can be deleted in bulk by sepcifying one or more message ID ranges in delseq parameter. Hard-deleting messages deletes them from storage affecting all users. The D permission is needed to hard-delete messages.
Deleting a subscription what="sub" removes specified user from topic subscribers. It requires an A permission. A user cannot delete own subscription. A {leave} should be used instead.
Deleting a topic what="topic" deletes the topic including all subscriptions, and all messages. The hard parameter has no effect on topic deletion: all topic deletions are hard-deletions. Only the owner can delete a topic. The greatest deleted ID is reported back in the clear of the {meta} message.
Client-generated ephemeral notification for forwarding to other clients currently attached to the topic, such as typing notifications or delivery receipts. The message is "fire and forget": not stored to disk per se and not acknowledged by the server. Messages deemed invalid are silently dropped.
The {note.recv} and {note.read} do alter persistent state on the server. The value is stored and reported back in the corresponding fields of the {meta.sub} message.
note: {
topic: "grp1XUtEhjv6HND", // string, topic to notify, required
what: "kp", // string, one of "kp" (key press), "read" (read notification),
// "rcpt" (received notification), any other string will cause
// message to be silently ignored, required
seq: 123, // integer, ID of the message being acknowledged, required for
// rcpt & read
}The following actions are currently recognized:
- kp: key press, i.e. a typing notification. The client should use it to indicate that the user is composing a new message.
- recv: a
{data}message is received by the client software but not yet seen by user. - read: a
{data}message is seen by the user. It impliesrecvas well.
Messages to a session generated in response to a specific request contain an id field equal to the id of the
originating message. The id is not interpreted by the server.
Most server to client messages have a ts field which is a timestamp when the message was generated by the server.
Content published in the topic. These messages are the only messages persisted in database; {data} messages are
broadcast to all topic subscribers with an R permission.
data: {
topic: "grp1XUtEhjv6HND", // string, topic which distributed this message,
// always present
from: "usr2il9suCbuko", // string, id of the user who published the
// message; could be missing if the message was
// generated by the server
head: { key: "value", ... }, // set of string key-value pairs, passed
// unchanged from {pub}, optional
ts: "2015-10-06T18:07:30.038Z", // string, timestamp
seq: 123, // integer, server-issued sequential ID
content: { ... } // object, application-defined content exactly as published
// by the user in the {pub} message
}Data messages have a seq field which holds a sequential numeric ID generated by the server. The IDs are guaranteed to be unique within a topic. IDs start from 1 and sequentially increment with every successful {pub} message received by the topic. See Format of Content for content format considerations.
Generic response indicating an error or a success condition. The message is sent to the originating session.
ctrl: {
id: "1a2b3", // string, client-provided message id, optional
topic: "grp1XUtEhjv6HND", // string, topic name, if this is a response in context
// of a topic, optional
code: 200, // integer, code indicating success or failure of the request, follows
// the HTTP status codes model, always present
text: "OK", // string, text with more details about the result, always present
params: { ... }, // object, generic response parameters, context-dependent,
// optional
ts: "2015-10-06T18:07:30.038Z", // string, timestamp
}Information about topic metadata or subscribers, sent in response to {set} or {sub} message to the originating session.
meta: {
id: "1a2b3", // string, client-provided message id, optional
topic: "grp1XUtEhjv6HND", // string, topic name, if this is a response in
// context of a topic, optional
ts: "2015-10-06T18:07:30.038Z", // string, timestamp
desc: {
created: "2015-10-24T10:26:09.716Z",
updated: "2015-10-24T10:26:09.716Z",
defacs: { // topic's default access permissions; present only if the current
//user has 'S' permission
auth: "JRWP", // default access for authenticated users
anon: "N" // default access for anonymous users
},
acs: { // user's actual access permissions
want: "JRWP", // string, requested access permission
given: "JRWP", // string, granted access permission
mode: "JRWP" // string, combination of want and given
},
seq: 123, // integer, server-issued id of the last {data} message
read: 112, // integer, ID of the message user claims through {note} message
// to have read, optional
recv: 115, // integer, like 'read', but received, optional
clear: 12, // integer, in case some messages were deleted, the greatest ID
// of a deleted message, optional
public: { ... }, // application-defined data that's available to all topic
// subscribers
private: { ...} // application-deinfed data that's available to the current
// user only
}, // object, topic description, optional
sub: [ // array of objects, topic subscribers or user's subscriptions, optional
{
user: "usr2il9suCbuko", // string, ID of the user this subscription
// describes, absent when querying 'me'.
updated: "2015-10-24T10:26:09.716Z", // timestamp of the last change in the
// subscription, present only for
// requester's own subscriptions
touched: "2017-11-02T09:13:55.530Z", // timestamp of the last message in the
// topic (may also include other events
// in the future, such as new subscribers)
acs: { // user's access permissions
want: "JRWP", // string, requested access permission, present for user's own
// subscriptions and when the requester is topic's manager or owner
given: "JRWP", // string, granted access permission, optional exactly as 'want'
mode: "JRWP" // string, combination of want and given
},
read: 112, // integer, ID of the message user claims through {note} message
// to have read, optional
recv: 315, // integer, like 'read', but received, optional
clear: 12, // integer, in case some messages were deleted, the greatest ID
// of a deleted message, optional
private: { ... } // application-defined user's 'private' object, present only
// for the requester's own subscriptions.
online: true, // boolean, current online status of the user; if this is a
// group or a p2p topic, it's user's online status in the topic,
// i.e. if the user is attached and listening to messages; if this
// is a response to a 'me' query, it tells if the topic is
// online; p2p is considered online if the other party is
// online, not necessarily attached to topic; a group topic
// is considered online if it has at least one active
// subscriber.
// The following fields are present only when querying 'me' topic
topic: "grp1XUtEhjv6HND", // string, topic this subscription describes
seq: 321, // integer, server-issued id of the last {data} message
// The following fields are present only when querying 'me' topic and the
// topic described is a P2P topic
public: { ... }, // application-defined user's 'public' object, present for
// P2P topics only
seen: { // object, if this is a P2P topic, info on when the peer was last
//online
when: "2015-10-24T10:26:09.716Z", // timestamp
ua: "Tinode/1.0 (Android 5.1)" // string, user agent of peer's client
}
},
...
],
tags: [ // array of tags that the topic or user (in case of "me" topic) is indexed by
"email:alice@example.com", "tel:1234567890"
],
del: {
clear: 3, // ID of the latest applicable 'delete' transaction
delseq: [{low: 15}, {low: 22, hi: 28}, ...], // ranges of IDs of deleted messages
}
}Tinode uses {pres} message to inform clients of important events. A separate document explains all possible use cases.
pres: {
topic: "me", // string, topic which receives the notification, always present
src: "grp1XUtEhjv6HND", // string, topic or user affected by the change, always present
what: "on", // string, what's changed, always present
seq: 123, // integer, "what" is "msg", a server-issued ID of the message,
// optional
clear: 15, // integer, "what" is "del", an update to the delete transaction ID.
delseq: [{low: 123}, {low: 126, hi: 136}], // array of ranges, "what" is "del",
// ranges of IDs of deleted messages, optional
ua: "Tinode/1.0 (Android 2.2)", // string, a User Agent string identifying client
// software if "what" is "on" or "ua", optional
act: "usr2il9suCbuko", // string, user who performed the action, optional
tgt: "usrRkDVe0PYDOo", // string, user affected by the action, optional
acs: {want: "+AS-D", given: "+S"} // object, changes to access mode, "what" is "acs",
// optional
}The {pres} messages are purely transient: they are not stored and no attempt is made to deliver them later if the destination is temporarily unavailable.
Timestamp is not present in {pres} messages.
Forwarded client-generated notification {note}. Server guarantees that the message complies with this specification and that content of topic and from fields are valid. The other content is copied from the {note} message verbatim.
info: {
topic: "grp1XUtEhjv6HND", // string, topic affected, always present
from: "usr2il9suCbuko", // string, id of the user who published the
// message, always present
what: "read", // string, one of "kp", "recv", "read", see client-side {note},
// always present
seq: 123, // integer, ID of the message that client has acknowledged,
// guaranteed 0 < read <= recv <= {ctrl.info.seq}; present for rcpt &
// read
}User is meant to represent a person, an end-user: producer and consumer of messages.
There are two types of users: authenticated and anonymous. When a connection is first established, the client application can only send either an {acc} or a {login} message. Sending a {login} message will authenticate user or allow him to continue as an anonymous.
Each user is assigned a unique ID. The IDs are composed as usr followed by base64-encoded 64-bit numeric value, e.g. usr2il9suCbuko. Users also have the following properties:
- created: timestamp when the user record was created
- updated: timestamp of when user's
publicwas last updated - username: unique string used in
basicauthentication; username is not accessible to other users - defacs: object describing user's default access mode for peer to peer conversations with authenticated and anonymous users; see Access control for details
- auth: default access mode for authenticated users
- anon: default access for anonymous users
- public: an application-defined object that describes the user. Anyone who can query user for
publicdata. - private: an application-defined object that is unique to the current user and accessible only by the user.
A user may maintain multiple simultaneous connections (sessions) with the server. Each session is tagged with a client-provided User Agent string intended to differentiate client software.
Logging out is not supported by design. If an application needs to change the user, it should open a new connection and authenticate it with the new user credentials.
Access control manages user's access to topics through access control lists (ACLs) or bearer tokens (bearer tokens are not implemented as of version 0.14).
Access control is mostly usable for group topics. Its usability for me and P2P topics is limited to managing presence notifications and banning uses from initiating or continuing P2P conversations.
User's access to a topic is defined by two sets of permissions: user's desired permissions "want", and permissions granted to user by topic's manager(s) "given". Each permission is represented by a bit in a bitmap. It can be either present or absent. The actual access is determined as a bitwise AND of wanted and given permissions. The permissions are communicated in messages as a set of ASCII characters, where presence of a character means a set permission bit:
- No access:
Nis not a permission per se but an indicator that permissions are explicitly cleared/not set. It usually indicates that the default permissions should not be applied. - Join:
J, permission to subscribe to a topic - Read:
R, permission to receive{data}packets - Write:
W, permission to{pub}to topic - Presence:
P, permission to receive presence updates{pres} - Approve:
A, permission to approve requests to join a topic; a user with such permission is topic's manager - Sharing:
S, permission to invite other people to join the topic - Delete:
D, permission to hard-delete messages; only owners can completely delete topics - Owner:
O, user is the topic owner; topic may have a single owner only; some topics have no owner
Topic's default access is established at the topic creation time by {sub.init.defacs} and can be subsequently modified by {set} messages. Default access is defined for two categories of users: authenticated and anonymous. This value is applied as a default "given" permission to all new subscriptions.
Client may replace explicit permissions in {sub} and {set} messages with an empty string to tell Tinode to use default permissions. If client specifies no default access permissions at topic creation time, authenticated users will receive a RWP permission, anonymous users will receive and empty permission which means every subscription request must be explicitly approved by the topic manager.
Access permissions can be assigned on a per-user basis by {set} messages.
Topic is a named communication channel for one or more people. Topics have persistent properties. These following topic properties can be queried by {get what="info"} message.
Topic properties independent of the user making the query:
- created: timestamp of topic creation time
- updated: timestamp of when topic's
publicorprivatewas last updated - defacs: object describing topic's default access mode for authenticated and anonymous users; see Access control for details
- auth: default access mode for authenticated users
- anon: default access for anonymous users
- seq: integer server-issued sequential ID of the latest
{data}message sent through the topic - public: an application-defined object that describes the topic. Anyone who can subscribe to topic can receive topic's
publicdata.
User-dependent topic properties:
- acs: object describing given user's current access permissions; see Access control for details
- want: access permission requested by this user
- given: access permissions given to this user
- private: an application-defined object that is unique to the current user.
Topic usually have subscribers. One the the subscribers may be designated as topic owner (O access permission) with full access permissions. The list of subscribers can be queries with a {get what="sub"} message. The list of subscribers is returned in a sub section of a {meta} message.
Topic me is automatically created for every user at the account creation time. It serves as means for account updates, receiving presence notification from people and topics of interest, invites to join topics, requests to approve subscription for topics where this user is a manager (has S permission). Topic me has no owner. The topic cannot be deleted or unsubscribed from. One can leave the topic which will stop all relevant communication and indicate that the user is offline (although the user may still be logged in and may continue to use other topics).
Joining or leaving me generates a {pres} presence update sent to all users who have peer to peer topics with the given user and P permissions set.
Topic me is read-only. {pub} messages to me are rejected.
The {data} message represents invites and requests to confirm a subscription. The from field of the message contains ID of the user who originated the request, for instance, the user who asked current user to join a topic or the user who requested an approval for subscription. The content field of the message contains the following information:
- act: request action as string; possible actions are:
- "info" to notify the user that user's request to subscribe was approved; in case of peer to peer topics this could be a notification that the peer has subscribed to the topic
- "join" is an invitation to subscribe to a topic
- "appr" is a request to approve a subscription
- topic: the name of the topic, in case of an invite the current user is invited to this topic; in case of a request to approve, another user wants to subscribe to this topic where the current user is a manager (has
Spermission) - user: user ID as a string of the user who is the target of this request. In case of an invite this is the ID of the current user; in case of an approval request this is the ID of the user who is being subscribed.
- acs: object describing access permissions of the subscription, see Access control for details
- info: object with a free-form payload. It's passed unchanged from the originating
{sub}or{set}message.
Message {get what="info"} to me is automatically replied with a {meta} message containing info section with the topic parameters (see intro to Topics section). The public parameter of me topic is data that the user wants to show to his/her connections. Changing it changes public not just for the me topic, but also everywhere where user's public is shown, such as 'public' of all user's peer to peer topics.
Message {get what="sub"} to me is different from any other topic as it returns the list of topics that the current user is subscribed to as opposite to the expected user's subscription to me.
- seq: server-issued numeric id of the last message in the topic
- read: seq value self-reported by the current user as received
- recv: seq value self-reported by the current user as read
- seen: for P2P subscriptions, timestamp of user's last presence and User Agent string are reported
- when: timestamp when the user was last online
- ua: user agent string of the user's client software last used
Message {get what="data"} to me queries the history of invites/notifications. It's handled the same way as to any other topic.
Topic fnd is automatically created for every user at the account creation time. It serves as an endpoint for discovering other users and group topics.
Users and group topics can be discovered by optional tags. Tags are optionally assigned at the topic or user creation time then can be updated by using {set what="tags"} against a fnd or a group topic.
A tag is an arbitrary case-insensitive Unicode string (forced to lowercase) starting with a Unicode letter or digit. Tags must not contain the double quote ", \u0022 but may contain spaces. Tags may have a prefix which serves as a namespace. The prefix is a string followed by a colon :, ex. prefixed phone tag tel:14155551212 or prefixed email tag email:alice@example.com. Some prefixed tags are optionally enforced to be unique. In that case only one user or topic may have such a tag. Certain tags may be forced to be immutable to the user, i.e. user's attemps to add or remove an immutable tag will be rejected by the server.
The tags are indexed server-side and used in user and topic discovery. Seach returns users and topics sorted by the number of matched tags in descending order.
In order to find users or topics, a user sets either public or private parameter of the fnd topic to a search query (see Query language) then issues a {get topic="fnd" what="sub"} request. If both public and private are set, the public query is used. The private query is persisted accress sessions and devices, i.e. all user's sessions see the same private query. The value of the public query is ephemeral, i.e. it's not saved to database and not shared between user's sessions. The private query is intended for large queries which do not change often, such as finding matches for everyone in user's contact list on a mobile phone. The public query is intended to be short and specific, such as finding some topic or a user who is not in the contact list.
The system responds with a {meta} message with the sub section listing details of the found users or topics formatted as subscriptions.
Topic fnd is read-only. {pub} messages to fnd are rejected.
(The following functionality is not implemented yet) When a new user registers with tags matching the given query, the fnd topic will receive {pres} notification for the new user.
Plugins support Find service which can be used to replace default search with a custom one.
Tinode query language is used to define search queries for finding users and topics. The query is a string containing tags separated by spaces or commas. Tags are strings - individual query terms which are matched against user's or topic's tags. The tags can be written in an RTL language but the query as a whole is parsed left to right. Spaces are treated as the AND operator, commas (as well commas preceeded and/or followed by a space) as the OR operator. The order of operators is ignored: all AND operators are grouped together, all OR operators are grouped together. OR takes precedence over AND.
Tags containing spaces or commas must be enclosed in double quotes (", \u0022): i.e. "abc, def" is treated as a single token. Tags must start with a Unicode letter or digit. Tags must not contain the double quote (", \u0022).
Some examples:
flowers travel: find topics or users which contain both tagsflowersandtravel.flowers, travel: find topics or users which contain either tagflowersortravel(or both).flowers travel, puppies: find topics or users which containflowersand eithertravelorpuppies, i.e.flowers AND (travel OR puppies).
-
Restricting users to organizations. An immutable tag(s) may be assigned to the user which denotes the organization the user belons to. When the user searches for other users or topics, the search can be restricted to always contain the tag. This approach can be used to segment users into organizations with limited visiblity into each other.
-
Search by geographical location. Client software may periodically assign a geohash tag to the user based on current location. Searching for users in a given area would mean matching on geohash tags.
-
Search by numerical range, such as age range. The approach is similar to geohashing. The entire range of numbers is covered by the smallest possible power of 2, for instance the range of human ages is covered by 27=128 years. The entire range is split in two halves: the range 0-63 is denoted by 0, 64-127 by 1. The operation is repeated with each subrange, i.e. 0-31 is 00, 32-63 is 01, 0-15 is 000, 32-47 is 010. Once completed, the age 30 will belong to the following ranges: 0 (0-63), 00 (0-31), 001 (16-31), 0011 (24-31), 00111 (28-31), 001111 (30-31), 0011110 (30). A 30 y.o. user is assigned a few tags to indicate the age, i.e.
age:00111,age:001111, andage:0011110. Technically, all 7 tags may be assigned but usually it's impractical. To query for anyone in the age range 28-35 convert the range into a minimal number of tags:age:00111(28-31),age:01000(32-35). This query will match the 30 y.o. user by tagage:00111.
Peer to peer (P2P) topics represent communication channels between strictly two users. The name of the topic is different for each of the two participants. Each of them sees the name of the topic as the user ID of the other participant: usr followed by base64 URL-encoded ID of the user. For example, if two users usrOj0B3-gSBSs and usrIU_LOVwRNsc start a P2P topic, the first one will see it as usrIU_LOVwRNsc, the second as usrOj0B3-gSBSs. The P2P topic has no owner.
A P2P topic is created by one user subscribing to topic with the name equal to the ID of the other user. For instance, user usrOj0B3-gSBSs can establish a P2P topic with user usrIU_LOVwRNsc by sending a {sub topic="usrIU_LOVwRNsc"}. Tinode will respond with a {ctrl} packet with the name of the newly created topic as described above. The other user will receive a {data} message on me topic with either a request to confirm the subscription or a notification of a successful subscription, depending on user's default permissions.
The 'public' parameter of P2P topics is user-dependent. For instance a P2P topic between users A and B would show user A's 'public' to user B and vice versa. If a user updates 'public', all user's P2P topics will automatically update 'public' too.
The 'private' parameter of a P2P topic is defined by each participant individually as with any other topic type.
Group topics represent communication channels between multiple users. The name of a group topic is grp followed by a string of characters from base64 URL-encoding set. No other assumptions can be made about internal structure or length of the group name.
A group topic is created by sending a {sub} message with the topic field set to string new optionally followed by any characters, e.g. new or newAbC123 are equivalent. Tinode will respond with a {ctrl} message with the name of the newly created topic, i.e. {sub topic="new"} is replied with {ctrl topic="grpmiKBkQVXnm3P"}. If topic creation fails, the error is reported on the original topic name, i.e. new or newAbC123. The user who created the topic becomes topic owner. Ownership can be transferred to another user with a {set} message but at least one user must remain the owner.
A user joining or leaving the topic generates a {pres} message to all other users who are currently in the joined state with the topic.
Tinode provides basic support for client-side caching of {data} messages in the form of server-issued message IDs. The client may request the last message id from the topic by issuing a {get what="info"} message. If the returned ID is greater than the ID of the latest received message, the client knows that the topic has unread messages and their count. The client may fetch these messages using {get what="data"} message. The client may also paginate history retrieval by using message IDs.
A user is reported as being online when one or more of user's sessions are attached to the me topic. Client-side software identifies itself to the server using ua (user agent) field of the {login} message. The user agent is published in {meta} and {pres} messages in the following way:
- When user's first session attaches to
me, the user agent from that session is broadcast in the{pres what="on" ua="..."}message. - When multiple user sessions are attached to
me, the user agent of the session where the most recent action has happened is reported in{pres what="ua" ua="..."}; the 'action' in this context means any message sent by the client. To avoid potentially excessive traffic, user agent changes are broadcast no more frequently than once a minute. - When user's last session detaches from
me, the user agent from that session is recorded together with the timestamp; the user agent is broadcast in the{pres what="off" ua="..."}message and subsequently reported as the last online timestamp and user agent.
An empty ua="" user agent is not reported. I.e. if user attaches to me with non-empty user agent then does so with an empty one, the change is not reported. An empty user agent may be disallowed in the future.
Tinode supports mobile push notifications though compile-time plugins. The channel published by the plugin receives a copy of every data message which was attempted to be delivered. The server supports Google FCM out of the box.
Topics and subscriptions have public and private fields. Generally, the fields are application-defined. The server does not enforce any particular structure of these fields except for fnd topic. At the same time, client software should use the same format for interoperability reasons.
The format of the public field is expected to be a vCard:
vcard: {
fn: "John Doe", // string, formatted name
n: {
surname: "Miner", // last of family name
given: "Coal", // first or given name
additional: "Diamond", // additional name, such as middle name or patronymic or nickname.
prefix: "Dr.", // prefix, such as homnorary title or gender designation.
suffix: "Jr.", // suffix, such as 'Jr' or 'II'
}, // object, user's structured name
org: "Most Evil Corp", // string, name of the organization the user belongs to.
title: "CEO", // string, job title
tel: [
{
type: "HOME", // string, optional designation
uri: "tel:+17025551234" // string, phone number
}, ...
], // array of objects, list of phone numbers associated with the user
email: [
{
type: "WORK", // string, optional designation
uri: "email:alice@example.com", // string, email address
}, ...
], // array of objects, list of user's email addresses
impp: [
{
type: "OTHER",
uri: "tinode:usrRkDVe0PYDOo", // string, email address
}, ...
], // array of objects, list of user's IM handles
photo: {
type: "jpeg", // image type
data: "..." // base64-encoded binary image data
} // object, avatar photo. Java does not have a useful bitmap class, so keeping it as bits here.
}The format of the private field is expected to be a dictionary. The following fields are currently defined:
private: {
comment: "some comment", // string, optional user comment about a topic or other user
arch: true // boolean value indicating that the topic is archived by the user, i.e. should not be shown in the UI with other non-archived topics.
}Although it's not yet enforced, custom fields should start with x-, e.g. x-example: "abc". The fields should contain primitive types only, i.e. string, boolean, number, null.
Format of {pub} and {data} content field is application-defined and as such the server does not enforce any particular structure of the field. At the same time, client software should use the same format for interoperability reasons. Currently the following two types of content are supported:
- Plain text
- Drafty
If Drafty is used, message header "head":{"mime":"text/x-drafty"} must be set.