WebSocket Validator

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Looking for the plugin's configuration parameters? You can find them in the WebSocket Validator configuration reference doc.

Validate individual WebSocket messages against to a user-specified schema before proxying them.

Message schema can be configured by type (text or binary) and sender (client or upstream).

When an incoming message is invalid according to the schema, a close frame is sent to the sender (status: 1007) and the peer before closing the connection.

Usage

Note: Currently, the only supported validation type is JSON schema draft4, so all examples will use this.

At least one of the following complete message validation configurations must be defined:

• config.client.text.type and config.client.text.schema
• config.client.binary.type and config.client.binary.schema
• config.upstream.text.type and config.upstream.text.schema
• config.upstream.binary.type and config.upstream.binary.schema

Validate client text frames

This example validates that client text frames:

• Are valid JSON
• Are a JSON object ({})
• Have a name attribute (of any type)

curl -i -X POST http://HOSTNAME:8001/services/SERVICE/plugins \
  --data "name=websocket-validator" \
  --data "config.client.text.type=draft4" \
  --data 'config.client.text.schema={ "type": "object", "required": ["name"] }'

plugins:
- name: websocket-validator
  service: SERVICENAME
  config:
    client:
      text:
        schema: '{ "type": "object", "required": ["name"] }'
        type: draft4

Here’s an example sequence for this configuration:

 
sequenceDiagram
autonumber
    activate Client
    activate Kong
    Client->>Kong: text(`{ "name": "Alex" }`)
    activate Upstream
    Kong->>Upstream: text(`{ "name": "Alex" }`)
    Client->>Kong: text(`{ "name": "Kiran" }`)
    Kong->>Upstream: text(`{ "name": "Kiran" }`)
    Client->>Kong: text(`{ "missing_name": true }`)
    Kong->>Client: close(status=1007)
    Kong->>Upstream: close()
    deactivate Upstream
    deactivate Kong
    deactivate Client