SSE support

[andrewfg]

Issue

Old style REST API devices have GET/PUT commands whereby the client can read/write data to the server (i.e. a client driven, polling mechanism). But nowadays many REST API devices also support Server Sent Eventing (SSE) whereby the server can inform the client directly if anything changes. (i.e. a server event driven mechanism).

Example

This is often the case in home automation devices (e.g. Philips Hue) where the server device can (say) notify the client that a light was turned on or a temperature has changed.

Analog

Some implementers use SSE to send event notifications. But some use WebSockets instead. The implementation is slightly different, but the purpose is the same. => So see #83

Proposed Solution

Mockoon should add the following features..

• Ability for a client to open an SSE connection to Mockoon server.
• (Ditto ability for the client to open a WebSocket connection to Mockoon server).
• Ability to define response payloads (usually JSON) that Mockoon server can send over the SSE (resp. WebSocket) connection.
• Above mentioned responses are sent with a delay of (0 .. n seconds) after the connection is opened (or even a random delay to simulate real life events).
• Above mentioned responses would allow variable contents, as with existing Mockoon responses, to simulate real life.

Signed-off-by: Andrew Fiddian-Green software@whitebear.ch

[isuru89]

I think this issue could get more popular with the rise of the "GPT" world. Because, those GPT APIs uses SSEs to transfer the real-time generating contents.

The reasons I see:

1. Popularity of GPT APIs.
2. Cost of Usage: Also, these APIs are commercialized or rate-limited. So, using actual APIs are limited in development or test environments due to the additional incurring cost to the organization. Hence, developers would expect a mocking API in their local machine/non-production environments.
3. Predictability: Such GPT APIs tend to produce non-deterministic results even with the same inputs. So, sometime troubleshooting a scenario would not be easy and may require a help from mocking API to simulate with such troublesome responses and behaviors.

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Edit:
Would love to start a PoC around this

[yunqiangwu]

我也想要这种功能