FILTERS.md

Filters

When a new Processor is requested using the endpoint /api/v1/bridges/{id}/processors it is possible to specify one or more filters to apply to the ingress event. If there is a match, then the action of the processor is called.

Every filter has 3 properties to specify:

• type: the type of the filter. This can be StringEquals, StringBeginsWith, StringContains.
• key: The field in the event data that you're using for filtering. It can be a number, boolean, string. Arrays are not supported yet.
• values: The value or values to compare to the key.

For events in Cloud Events schema, you can use the values for the key: eventid, source, eventtype, eventtypeversion, or event data (like data.key1). You can navigate the object with the . (dot) notation.

Filter types

The available filter types are:

StringEquals

The StringEquals evaluates to true if the key value is equals to the specified filter value.

Assuming that the Filter is the following

{
  "filters": [
    {
      "type": "StringEquals", 
      "key": "data.name",
      "value": "Jacopo"
    }
  ]
}

Then an event like

{
  ...
  "data": {
    "name": "Jacopo"
  }
}

Would evaluate the Filter to true.

StringContains

The StringContains evaluates to true if the key value contains any of the values specified in the filter values.

Assuming that the Filter is the following

{
  "filters": [
    {
      "type": "StringContains", 
      "key": "data.name",
      "value": ["opo", "Marco"]
    }
  ]
}

Then an event like

{
  ...
  "data": {
    "name": "Jacopo"
  }
}

Would evaluate the Filter to true.

StringBeginsWith

The StringBeginsWith evaluates to true if the key value starts with any of the values specified in the filter values.

Assuming that the Filter is the following

{
  "filters": [
    {
      "type": "StringBeginsWith", 
      "key": "data.name",
      "value": ["Jac", "Mar"]
    }
  ]
}

Then an event like

{
  ...
  "data": {
    "name": "Jacopo"
  }
}

Would evaluate the Filter to true.