Channel¶
- class ehforwarderbot.channel.Channel(instance_id=None)[source]¶
The abstract channel class.
- channel_emoji¶
Emoji icon of the channel. Recommended to use a visually-length-one (i.e. a single grapheme cluster) emoji or other symbol that represents the channel best.
- Type
- channel_id¶
Unique identifier of the channel. Convention of IDs is specified in Packaging and Publish. This ID will be appended with its instance ID when available.
- Type
ModuleID
(str)
- __init__(instance_id=None)[source]¶
Initialize the channel. Inherited initializer MUST call the “super init” method at the beginning.
- get_message_by_id(chat, msg_id)[source]¶
Get message entity by its ID. Applicable to both master channels and slave channels. Return
None
when message not found.Override this method and raise
EFBOperationNotSupported
if it is not feasible to perform this for your platform.
- abstract poll()[source]¶
Method to poll for messages. This method is called when the framework is initialized. This method SHOULD be blocking.
- abstract send_message(msg)[source]¶
Process a message that is sent to, or edited in this channel.
Notes
Master channel MUST take care of the returned object that contains the updated message ID. Depends on the implementation of slave channels, the message ID MAY change even after being edited. The old message ID MAY be disregarded for the new one.
- Parameters
msg (
Message
) – Message object to be processed.- Returns
The same message object. Message ID of the object MAY be changed by the slave channel once sent. This can happen even when the message sent is an edited message.
- Return type
- Raises
EFBChatNotFound – Raised when a chat required is not found.
EFBMessageTypeNotSupported – Raised when the message type sent is not supported by the channel.
EFBOperationNotSupported – Raised when an message edit request is sent, but not supported by the channel.
EFBMessageNotFound – Raised when an existing message indicated is not found. E.g.: The message to be edited, the message referred in the
msg.target
attribute.EFBMessageError – Raised when other error occurred while sending or editing the message.
- abstract send_status(status)[source]¶
Process a status that is sent to this channel.
- Parameters
status (
Status
) – the status object.- Raises
EFBChatNotFound – Raised when a chat required is not found.
EFBMessageNotFound – Raised when an existing message indicated is not found. E.g.: The message to be removed.
EFBOperationNotSupported – Raised when the channel does not support message removal.
EFBMessageError – Raised when other error occurred while removing the message.
Note
Exceptions SHOULD NOT be raised from this method by master channels as it would be hard for a slave channel to process the exception.
This method is not applicable to Slave Channels.
- stop_polling()[source]¶
When EFB framework is asked to stop gracefully, this method is called to each channel object to stop all processes in the channel, save all status if necessary, and terminate polling.
When the channel is ready to stop, the polling function MUST stop blocking. EFB framework will quit completely when all polling threads end.
- class ehforwarderbot.channel.MasterChannel(instance_id=None)[source]¶
The abstract master channel class. All master channels MUST inherit this class.
- class ehforwarderbot.channel.SlaveChannel(instance_id=None)[source]¶
The abstract slave channel class. All slave channels MUST inherit this class.
- supported_message_types¶
Types of messages that the slave channel accepts as incoming messages. Master channels may use this value to decide what type of messages to send to your slave channel.
Leaving this empty may cause the master channel to refuse sending anything to your slave channel.
- Type
Set[
MsgType
]
- suggested_reactions¶
A list of suggested reactions to be applied to messages.
Reactions SHOULD be ordered in a meaningful way, e.g., the order used by the IM platform, or frequency of usage. Note that it is not necessary to list all suggested reactions if that is too long, or not feasible.
Set to
None
when it is known that no reaction is supported to ANY message in the channel. Set to empty list when it is not feasible to provide a list of suggested reactions, for example, the list of reactions is different for each chat or message.- Type
Optional[Sequence[str]]
- abstract get_chat(chat_uid)[source]¶
Get the chat object from a slave channel.
- Parameters
chat_uid (
NewType()
(ChatID
,str
)) – ID of the chat.- Returns
The chat found.
- Return type
.Chat
- Raises
EFBChatNotFound – Raised when a chat required is not found.
- abstract get_chat_picture(chat)[source]¶
Get the profile picture of a chat. Profile picture is also referred as profile photo, avatar, “head image” sometimes.
- Parameters
chat (.Chat) – Chat to get picture from.
- Returns
Opened temporary file object. The file object MUST have appropriate extension name that matches to the format of picture sent, and seek to position 0.
It MAY be deleted or discarded once closed, if not needed otherwise.
- Return type
BinaryIO
- Raises
EFBChatNotFound – Raised when a chat required is not found.
EFBOperationNotSupported – Raised when the chat does not offer a profile picture.
Examples
if chat.channel_uid != self.channel_uid: raise EFBChannelNotFound() file = tempfile.NamedTemporaryFile(suffix=".png") response = requests.post("https://api.example.com/get_profile_picture/png", data={"uid": chat.uid}) if response.status_code == 404: raise EFBChatNotFound() file.write(response.content) file.seek(0) return file
Common operations¶
Sending messages and statuses¶
Sending messages and statuses to other channels is the most
common operation of a channel. When enough information is gathered
from external sources, the channel would then further process
and pack them into the relevant objects,
i.e. Message
and Status
.
When the object is built, the channel should sent it to the coordinator for following steps.
For now, both Message
and Status
has an
attribute that indicates that where this object would be
delivered to (deliver_to
and
destination_channel
). This is used by
the coordinator when delivering the message.
Messages MUST be sent using coordinator.send_message()
.
Statuses MUST be sent using coordinator.send_status()
.
When the object is passed onto the coordinator, it will be further processed by the middleware and then to its destination.
For example, to send a message to the master channel
def on_message(self, data: Dict[str, Any]):
"""Callback when a message is received by the slave channel from
the IM platform.
"""
# Prepare message content ...
message = coordinator.send_message(Message(
chat=chat,
author=author,
type=message_type,
text=text,
# more details ...
uid=data['uid'],
deliver_to=coordinator.master
))
# Post-processing ...
About Channel ID¶
With the introduction of instance IDs, it is required to use the
self.channel_id
or equivalent instead of any hard-coded
ID or constants while referring to the channel (e.g. while
retrieving the path to the configuration files, creating
chat and message objects, etc).