Sending and Receiving Messages
CSML is able to handle many types of messages by default.
To send a message to the end user, simply use the keyword say
followed by the message type you want to send.
Styling text
You can style text using Markdown. Some channels however only partially support Markdown (Messenger for example only allows bold, italic, strikethrough, but not tables), so don't get too fancy there.
Quick Markdown reference
Message types
Below is a list of default valid message components, which are automatically converted to nicely formatted messages for the channel in which the user is talking with the bot.
Components may receive additional optional parameters to accommodate the needs of certain channels.
For example, in the Messenger channel you can add a button_type="quick_reply"
parameter to the Question
component to provide a different type of buttons.
Asking Questions
A conversation with a chatbot is not very different from a human-to-human dialogue: sometimes the user talks, sometimes the bot talks.
CSML provides a solution when you need the chatbot wait for the user's input: using the hold
keyword, the chatbot will remember its position in the conversation and simply wait until the user says something, then continue from there.
Receiving messages
When receiving an event from an end-user, the CSML interpreter will try to:
match it with a new flow,
or consume it in the existing conversation,
or trigger the default flow as defined in the bot settings,
by order of priority.
CSML Events are made available in the script when a step is triggered by a user's input. The event
object is a complex structure which contains a lot more than just the string that was typed by the user. It contains a lot of information that is used by the CSML interpreter, for example the custom button payload to match a list of choices offered to the user. This makes it easy to handle both a click on a "OK" button or the user typing the word "yes".
By default, events are only expected when:
the flow was just triggered, the current step being triggered is
start
the bot asked something to the user, and is waiting for the user's input at the same step
In those cases, a local variable, event
, is made available, with the content of the user request. When no event is available, event is set to NULL
.
⚠️ Limitations
The maximum theoretical size of a say
payload is 16KB. However, each channel will have different limitations depending on the type of component. For a Text
component for example, most channels are limited to a few hundred characters.
Please refer to each channel's official documentation to find out the practical limitations of each component.
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