Setup a basic WebSocket mock in AWS ApiGateway - websocket

Question

I am trying to setup an extremely simple WebSocket mock within AWS ApiGateway. However, every attempt I've tried gives me an error:
13:36:52 (X33uOGUfIAMFq7w=) Extended Request Id: X33uOGUfIAMFq7w=
13:36:52 (X33uOGUfIAMFq7w=) Verifying Usage Plan for request: X33uOGUfIAMFq7w=. API Key: API Stage: redacted/prod
13:36:52 (X33uOGUfIAMFq7w=) API Key authorized because route '$connect' does not require API Key. Request will not contribute to throttle or quota limits
13:36:52 (X33uOGUfIAMFq7w=) Usage Plan check succeeded for API Key and API Stage redacted/prod
13:36:52 (X33uOGUfIAMFq7w=) Starting execution for request: X33uOGUfIAMFq7w=
13:36:52 (X33uOGUfIAMFq7w=) WebSocket Request Route: [$connect]
13:36:52 (X33uOGUfIAMFq7w=) Client [UserAgent: null, SourceIp: redacted] attempts to connect to WebSocket API [redacted].
13:36:52 (X33uOGUfIAMFq7w=) Execution failed due to configuration error: statusCode should be an integer which defined in request template
13:36:52 (X33uOGUfIAMFq7w=) Client [UserAgent: null, SourceIp: redacted] failed to connect to API [redacted].
As far as I can tell, I've followed the most basic configuration possible. I do not need any responses or templates, just simple a WebSocket connection that allows me to connect to it and do nothing, or perhaps respond to ping requests with a pong eventaully.
All authorizations and API keys are disabled. No request templates or integration responses are setup since I do not need them. Again, the goal is to just be able to have a dumb WebSocket that can be connected to.
However, whenever I try to connect to it, I get a 500 error with the error logs from above about a status code.
WebSocket connection to 'wss://redacted.execute-api.us-east-1.amazonaws.com/prod' failed: Error during WebSocket handshake: Unexpected response code: 500

Answer 1

Using the following sources (below), I was able to get a quick and loose example AWS API Gateway connection working use MOCK endpoints with web sockets. I'm sure this can be flushed out more to provide an even better understanding of different request/response body messages and codes..
First, go to API Gateway, click Create API
For Choose the protocol, select WebSocket
Give the API a name, and use the example $request.body.message for the route selection expression
Click the Create API button
Select the new API from the side pane, and click Routes
Select the $connect route
Under Route overview, select the Mock radio button for endpoint
For the Request Template, enter an expression (using 200 for example).
For Template Key, enter a key (using 200 for example)
For the popup window on passthrough behavior, select No, Use Current Settings for now
Click on the Template Key 200, and enter a template: {"statusCode" : 200} and then click the Save button.
Select Route Overview to go back to the $connect overview page and then select the Add Integration Response button
Create a response key of $default, which will reference the $default key under Routes
For the $disconnect route, please repeat steps 7 - 13 for this specific route.
Once done setting up the $disconnect route, please select the $default route under the Routes pane.
Create an Integration Request the same way that was done for $connect and $disconnect (steps 7 - 11)
For Integration Response under $default, we will be setting the route response up slightly different than $connect and $disconnect as those 2 routes' responses actually reference the $default response within their own respective Integration Responses.
Create a response key of $default
Enter a Template Selection Expression (using 200 for this example)
Then create a Template Key (using 200 for this example)
Click on the Template Key 200, and enter a template: {"statusCode" : 200, "connectionId" : "$context.connectionId"} and then click the Save button.
{"connectionId" : "$context.connectionId"} was added to the response payload to show how variables can be used within the response to represent an actual value of the connection.
Finally, under the Actions dropdown, select Deploy API, and enter a deployment stage name. This should generate a WebSocket URL that can now be connected to e.g. (wss://#######.execute-api.us-east-1.amazonaws.com/Test)
Using wscat via cli, I am now able to connect to my WebSocket URL (see source below for installing wscat): wscat -c wss://#######.execute-api.us-east-1.amazonaws.com/Test
Sources:
https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-how-to-call-websocket-api-wscat.html
https://forums.aws.amazon.com/thread.jspa?threadID=299642&tstart=0

Answer 2

I've automated the steps described by Woodrow using CloudFormation so now anyone can reproduce it more easily.
The template can be found here: https://gist.github.com/maatthc/9d2dfe0448733f0ee1624d658fbac80f .
To create a new stack using it you should:
Download the template to your machine.
Head to Cloudformation in the AWS Console (https://ap-southeast-2.console.aws.amazon.com/cloudformation/) - Change your AWS Region.
Click in "Create Stack"
Choose "Upload a template file" and use the template you've downloaded.
Click Next, give the stack a name and click Next again.
Click Next and "Create Stack".
I hope it helps.
Cheers