cadmium-docs-legacy/CPEs/proposed/CPE4 - Basic chats.md

CPE#4 - Basic chats

1. Introduction

This extension is intended for organizing chats between some entities.

2. Requirements

• Exchanging text messages
• Typing status
• Message reading
• Sharing files/media
• Forwards and replies to messages
• Stickers/GIF
• Message reactions

3. Message type identifiers

• urn:cadmium:chats:message - regular message
• urn:cadmium:chats:read - read message system
• urn:cadmium:chats:typing - typing message system

4. Errors

• Ratelimit system: disabled
• Authorization: enabled

4.1. Error types

• urn:cadmium:chats:private:banned - Sending messages to user is prohibited, because he banned the sender of current message - in case if we send the message to user entity.

5. Chat message types

• urn:cadmium:chats:message:types:general - message with text and optional media
• urn:cadmium:chats:message:types:geolocation - message with geolocation (coordinates)

5.1. Media types

• urn:cadmium:chats:media:photo - a photo
• urn:cadmium:chats:media:audio - an audio or voice message
• urn:cadmium:chats:media:video - a video or rounded video message
• urn:cadmium:chats:media:file - any other file type
• urn:cadmium:chats:media:sticker - a sticker
• urn:cadmium:chats:media:gif - an animated GIF

6. Use cases

6.1. Exchanging messages

1. Sending message:

   {
       "id": "abcd",
       "type": "urn:cadmium:chats:message",
       "to": ["@user2@cadmium.org"],
       "payload": {
           "type": "urn:cadmium:chats:message:types:general",
           "content": {
               "text": "hello world",
           }
       }
   }
   

   Successful response:

   {
       "id": "abcd",
       "type": "urn:cadmium:chats:message",
       "from": "cadmium.org",
       "ok": true,
       "payload": {
           "messageID": "3b5135a5-aff5-4396-a629-a254f383e82f",
           "originServerTimestamp": 1599327584
       }
   }
   

   Error response:

   {
       "id": "abcd",
       "type": "urn:cadmium:chats:message",
       "from": "cadmium.org",
       "ok": false,
       "payload": {
           "errID": "urn:cadmium:chats:private:banned",
           "errText": "The user banned you"
       }
   }
   

2. Receiving message on other side:

   {
       "id": "abcd",
       "type": "urn:cadmium:chats:message",
       "from": "@user1@cadmium.im",
       "ok": true,
       "payload": {
           "messageID": "3b5135a5-aff5-4396-a629-a254f383e82f",
           "originServerTimestamp": 1599327584,
           "type": "urn:cadmium:chats:message:types:general",
           "content": {
               "text": "hello world",
           }
       }
   }
   

6.2. Exchanging media

1. Upload the media to Content Service (explanation out of scope of this document)

2. Send message containing the metadata of uploaded media:

    {
        "id": "abcd",
        "type": "urn:cadmium:chats:message",
        "to": ["@user2@cadmium.im"],
        "payload": {
            "type": "urn:cadmium:chats:message-types:general",
            "content": {
                "text": "",
                "media": [
                    {
                        "id": "4a771ac1-f0b2-4a4a-9700-f2a26fa2bb67@content.cadmium.im"
                    }
                ]
            }
   
        }
    }
   

   Response:

   {
        "id": "abcd",
        "type": "urn:cadmium:chats:message",
        "from": "cadmium.im",
        "ok": true,
        "payload": {
            "messageID": "7a1b9a72-1677-4476-9b22-ef7fdbcff52e",
            "originServerTimestamp": 1599329232
        }
    }
   

   Note: The Cadmium server will validate media ID which was provided by client. If it doesn't exist or invalid, server will respond with corresponding error.

3. Receive message with media on other side:

   {
        "id": "defg",
        "type": "urn:cadmium:chats:message",
        "from": "@user1@cadmium.im",
        "ok": true,
        "payload": {
            "messageID": "7a1b9a72-1677-4476-9b22-ef7fdbcff52e",
            "originServerTimestamp": 1599329232,
            "type": "urn:cadmium:chats:message:types:general",
            "content": {
                "text": "",
                "media": [
                    {
                        "id": "4a771ac1-f0b2-4a4a-9700-f2a26fa2bb67@content.cadmium.im",
                        "type": "urn:cadmium:chats:media:photo",
                        "attrs": {
                            "width": 512,
                            "height": 512 
                        },
                        "size": 96413, // 96kb
                    }
                ]
            }
        }
    }
   

6.3. Read messages

1. Read message

   {
       "id": "abcd",
       "type": "urn:cadmium:chats:read",
       "to": ["@user1@cadmium.org"],
       "payload": {
           "messageID": "7a1b9a72-1677-4476-9b22-ef7fdbcff52e",
       }
   }
   

   Response:

   {
       "id": "abcd",
       "type": "urn:cadmium:chats:read",
       "from": "cadmium.im",
       "ok": true,
       "payload": {}
   }
   

2. Receive notification about message reading on other side:

   {
       "id": "defg",
       "type": "urn:cadmium:chats:read",
       "from": "@user2@cadmium.im",
       "ok": true,
       "payload": {
           "messageID": "7a1b9a72-1677-4476-9b22-ef7fdbcff52e"
       }
   }
   

6.4. Typing message

1. Typing message

   {
       "id": "abcd",
       "type": "urn:cadmium:chats:typing",
       "to": ["@user1@cadmium.org"],
       "payload": {}
   }
   

2. Receive notification about typing message on other side:

   {
       "id": "defg",
       "type": "urn:cadmium:chats:typing",
       "from": "@user2@cadmium.im",
       "ok": true,
       "payload": {}
   }
   

7. Business Rules

7.1. Typing message notification

• Client sends typing notification message every second when he is typing. If there is no notifications about typing more than one second then consider that user is stopped the typing.

7.2. Message/Media ID

• This is typically Federated Entity ID of message/media (as described and reserved in core specs) which was stored in server's database/content service storage.

8. JSON Schema

Send message (urn:cadmium:chats:message)

Request:

interface SendMessagePayload {
    type: string; // the type of message
    reply?: string; // message id on which this message is replying
    content: Content // the payload of message (depends on type)
}

Response:

interface SendMessageResponsePayload {
    messageID: string; // the message id (stored in chat timeline)
    originServerTimestamp: number // unix timestamp of sent message on the origin server
}

Content sections

• urn:cadmium:chats:message:types:general:

  interface GeneralMessageContent {
      text: string; // the text (body) of message
      media?: Media[]; // media content
  }
  
  interface Media {
      id: string; // media ID
      type: string; // type of media
      size: int; // size of media in bytes
      fileName?: string; // filename of media (with optional extension by dot)
      attrs: MediaAttrs; // media payload (additional attributes)
  }
  
  // Media attributes definitions
  
  interface MediaAttrs {}
  
  // urn:cadmium:chats:media:audio
  interface AudioAttrs : MediaAttrs {
      voice: bool; // whether it is voice message
      duration: int; // duration of audio
      title?: string; // audio title
      artist?: string; // audio artist
      voiceWaveForm?: []byte; // voice wave form
  }
  
  // urn:cadmium:chats:media:sticker
  interface StickerAttrs : MediaAttrs {
      associatedEmoji: string; // the associated emoji with this 
      stickerSetID: string; // id of sticker set which is associated with this sticker
      isAnimated: boolean; // is client need to animate this sticker
  }
  
  // urn:cadmium:chats:media:video
  interface VideoAttrs : MediaAttrs {
      isVideoMessage: bool; // is this a rounded video message
      duration: int; // duration of video
      width: int; // width of video
      height: int; // height of video
  }
  
  // urn:cadmium:chats:media:photo
  interface PhotoAttrs : MeditAttrs {
      width: int; // width of photo
      height: int; // height of photo
  }
  

• urn:cadmium:chats:message:types:geolocation:

  interface GeolocationMessageContent {
      lat: number; // the GPS latitude
      lon: number; // the GPS longitude
  }
  

Receive message (urn:cadmium:chats:message)

interface ReceiveMessagePayload {
    messageID: string; // the id of received message
    originServerTimestamp: number; // unix timestamp of received message on the origin server
    type: string; // the type of message
    reply?: string; // message id on which this message is replying
    content: Content; // the payload of message (depends on type)
}

Read message (urn:cadmium:chats:read)

Request:

interface ReadMessagePayload {
    messageID: string; // the message id of read message
}

Response:

None.

Receive read message notification (urn:cadmium:chats:read)

interface ReceiveReadMessageNotifPayload {
    messageID: string; // the message id of read message
}