# Expression Template

# Fallthrough

## Generate fallthrough WAF expression template from a set of API hosts

`client.APIGateway.ExpressionTemplate.Fallthrough.New(ctx, params) (*ExpressionTemplateFallthroughNewResponse, error)`

**post** `/zones/{zone_id}/api_gateway/expression-template/fallthrough`

Creates an expression template fallthrough rule for API Shield. Used for configuring default behavior when no other expression templates match.

### Parameters

- `params ExpressionTemplateFallthroughNewParams`

  - `ZoneID param.Field[string]`

    Path param: Identifier.

  - `Hosts param.Field[[]string]`

    Body param: List of hosts to be targeted in the expression

### Returns

- `type ExpressionTemplateFallthroughNewResponse struct{…}`

  - `Expression string`

    WAF Expression for fallthrough

  - `Title string`

    Title for the expression

### Example

```go
package main

import (
  "context"
  "fmt"

  "github.com/cloudflare/cloudflare-go"
  "github.com/cloudflare/cloudflare-go/api_gateway"
  "github.com/cloudflare/cloudflare-go/option"
)

func main() {
  client := cloudflare.NewClient(
    option.WithAPIToken("Sn3lZJTBX6kkg7OdcBUAxOO963GEIyGQqnFTOFYY"),
  )
  fallthrough_, err := client.APIGateway.ExpressionTemplate.Fallthrough.New(context.TODO(), api_gateway.ExpressionTemplateFallthroughNewParams{
    ZoneID: cloudflare.F("023e105f4ecef8ad9ca31a8372d0c353"),
    Hosts: cloudflare.F([]string{"{zone}.domain1.tld", "domain2.tld"}),
  })
  if err != nil {
    panic(err.Error())
  }
  fmt.Printf("%+v\n", fallthrough_.Expression)
}
```

#### Response

```json
{
  "errors": [
    {
      "code": 1000,
      "message": "message",
      "documentation_url": "documentation_url",
      "source": {
        "pointer": "pointer"
      }
    }
  ],
  "messages": [
    {
      "code": 1000,
      "message": "message",
      "documentation_url": "documentation_url",
      "source": {
        "pointer": "pointer"
      }
    }
  ],
  "result": {
    "expression": "(cf.api_gateway.fallthrough_detected)",
    "title": "Fallthrough Expression for [zone.domain.tld]"
  },
  "success": true
}
```