spin-redirect

This is a simple HTTP redirect component written in Go.

This is not a Spin application in itself but a component that can be used in applications to redirect a route.

Configuration

The spin-redirect component can be configured to address your needs in different scenarios. spin-redirect tries to load configuration data from multiple places in the specified order:

1. Spin component configuration
2. Environment variables

The following table outlines available configuration values:

Key	Description	Default Value
destination	Where should the component redirect to	/
statuscode	What HTTP status code should be used when redirecting	302
include_path	Whether to include the original request path on the destination redirect; see wildcard redirects	false
trim_prefix	A specific prefix portion of the original request path to trim (when include_path is true)

The spin-redirect component tries to look up the config value in the Spin component configuration using the keys shown in the table above (lower case). If desired key is not present, it transforms the key to upper case (e.g., DESTINATION) and checks environment variables.

Valid redirection status codes

The spin-redirect component supports the following HTTP status codes to perform a redirect:

• 301 Moved Permanently
• 302 Found (Moved Temporarily)
• 303 See Other: Only supported for PUT and POST requests
• 307 Temporary Redirect
• 308 Permanent Redirect

Example usage

The following snippet shows how to add and configure spin-redirect in your spin.toml using environment variables

spin_manifest_version = "1"
description = ""
name = "test"
trigger = { type = "http", base = "/" }
version = "0.1.0"

# Redirect / to /index.html using HTTP status code 301
[[component]]
id = "redirect-sample"
source = "path/to/redirect.wasm"
environment = { DESTINATION = "/index.html", STATUSCODE = "301" }

[component.trigger]
route = "/"

Alternatively, you can use component configuration to configure spin-redirect as shown below:

spin_manifest_version = "1"
description = ""
name = "test"
trigger = { type = "http", base = "/" }
version = "0.1.0"

# Redirect / to /index.html using HTTP status code 301
[[component]]
id = "redirect-sample"
source = "path/to/redirect.wasm"

[component.config]
destination="/index.html"
statuscode="301"

[component.trigger]
route = "/"

Wildcard redirects

Wildcard redirects can be enabled by setting include_path to true. In the example below, all requests to the application will be redirected to /foo, with the original request path included, e.g. /bar will redirect to /foo/bar, /baz will redirect to /foo/baz and so on.

spin_manifest_version = 2

[application]
name = "wildcard-redirect"
version = "0.1.0"

[[trigger.http]]
id = "trigger-redirect-to-foo"
component = "redirect-to-foo"
route = "/..."

[component.redirect-to-foo]
source = "modules/redirect.wasm"
environment = { DESTINATION = "/foo", INCLUDE_PATH = "true" }

A prefix portion of the original request path can be trimmed via the trim_prefix configuration.

In this example, the /v1/ prefix is trimmed, such that requests to /v1/bar will redirect to /v2/bar and so on.

spin_manifest_version = 2

[application]
name = "wildcard-redirect"
version = "0.1.0"

[[trigger.http]]
id = "trigger-redirect-v1-to-v2"
component = "redirect-v1-to-v2"
route = "/v1/..."

[component.redirect-v1-to-v2]
source = "modules/redirect.wasm"
environment = { DESTINATION = "/v2", INCLUDE_PATH = "true", TRIM_PREFIX = "/v1/" }