---
uuid: e7ee491d-88d7-4e67-80c8-f74781bb247c
type:
- TestCase
- ConformanceTestingRule
ruleType: atomic
name: |
ActivityPub server serves an object in response to GET request for AS2 media type
description: |
This rule checks that URLs of ActivityPub objects can be resolved to a representation with well-known media type for further processing.
requirementReference:
- id: urn:uuid:00330762-59a2-4072-8d93-87ee4c30411c
url: https://socialweb.coop/activitypub/behaviors/08549639-2888-4ee2-a320-97fc7ee32e00/
inputs:
- name: URL of AS2 Object served by an ActivityPub Server
type: URL
# https://www.w3.org/QA/WG/2005/01/test-faq#review
# *submitted, accepted, reviewed*, *returned for revision*, or *rejected*
testCaseState: submitted
eleventyComputed:
title: "{{ name }}"
respec:
config:
editors:
- name: bengo
url: "https://bengo.is"
w3cid: 49026
---
# ActivityPub Servers Must Serve Objects in Response to an HTTP GET Request Accepting ActivityStreams 2.0 Media Type
## Background
[ActivityPub][activitypub] [ยง3.2 Retrieving Objects](https://www.w3.org/TR/activitypub/#retrieving-objects):
> Servers... MUST present the ActivityStreams object representation in response to `application/ld+json; profile="https://www.w3.org/ns/activitystreams"`
## About This Test
This is a Test Case describing a rule to determine whether an ActivityPub Object is in partial conformance with the following behaviors required by [ActivityPub][activitypub].
* [requirement 08549639-2888-4ee2-a320-97fc7ee32e00](https://socialweb.coop/activitypub/behaviors/08549639-2888-4ee2-a320-97fc7ee32e00/) - ActivityPub server must present object in response to GET request with AS2 Accept Header
### Identifier
The identifier of this test is `urn:uuid:e7ee491d-88d7-4e67-80c8-f74781bb247c`.
## Test Subject
The subject of this test is an ActivityPub Server.
ActivityPub Servers host ActivityPub Objects and are responsible for serving them to clients that request a representation of them.
The Test Subject can be identified by a URI for an ActivityPub Object. The ActivityPub Object can be requested via HTTP, and the ActivityPub Server is the system that is expected to respond to the HTTP request.
## Inputs
This test requires the following [inputs](https://www.w3.org/TR/act-rules-format/#input):
1. `id` - identifier of an ActivityPub Object hosted at an ActivityPub Server
* required: yes
* type: binary
* constraints
* MUST be a URI, i.e. an [ActivityPub Object Identifier](https://www.w3.org/TR/activitypub/#obj-id) that is not `null`
2. `authorization` - proof of authorization to retrieve the object identified by input `id`
* required: no
* if this input is omitted, no `Authorization` will be provided in the HTTP request send by this test
* type: binary
* constraints
* If present, this should be valid as the value of an HTTP `Authorization` header
3. `time` - amount of time allowed to run test. This is meant to configure the limit for how long this test will wait for network requests.
* required: yes
* example: `T0.0021S`
* type: binary
* constraints
* MUST be an [RFC3339 `dur-time`](https://datatracker.ietf.org/doc/html/rfc3339#appendix-A)
## Applicability
This test applies to a server hosting the ActivityPub Object identified by input `id`.
If input `id` is not a URI, outcome is `inapplicable`.
If input `id` URI scheme is not `https` or `http`, outcome is `inapplicable`. (This test may be revised later to handle other URI schemes).
If input `time` is not parseable as an RFC3339 `dur-time`, outcome is `inapplicable`.
### Test Targets
* `response` - the HTTP response that is the result of retrieving the ActivityPub Object identified by input `id`.
* how to derive `response` from inputs
1. start a timer with duration from input `time`. If the timer reaches zero before this derivation is complete, the whole test outcome is `inapplicable` because we weren't able to determine the `response` test target within the required time.
2. let `request` be a new HTTP Request whose URI is input `id`
3. add an http request header to `request` whose name is `Accept` and whose value is `application/ld+json; profile="https://www.w3.org/ns/activitystreams"`
4. if input `authorization` was provided, add an http request header to `request` whose name is `Authorization` and whose value is input `authorization`
5. send the HTTP request and await a response
6. assign the HTTP response to the `response` test target
## Expectations
* `response` body is parseable as JSON
* `response` body parsed JSON is a JSON Object
* `response` body must be an "ActivityStreams object representation"
* see issue [AP-ec50](#AP-ec50) below
## Assumptions
## Implementation Considerations
Though the spec only *requires* serving the object in response to this `Accept` header value, servers seeking to interop widely may also want to serve the same object in response to Accept header values like:
* `application/ld+json` (but without the `profile=` parameter)
* `application/activity+json`
* `application/json`
## Test Cases
These are test cases for this test itself.
### simple passed case
outcome: `passed`
inputs
* `id`: `https://bengo.is/actor.json`
* `time`: `T1M`
test targets
* `response`:
```http
HTTP/2 200
content-type: application/json
content-length: 484
{
"@context": [
"https://www.w3.org/ns/activitystreams",
"https://w3id.org/security/v1"
],
"id": "https://bengo.is/",
"type": "Person",
"preferredUsername": "bengo",
"name": "bengo",
"url": "https://bengo.is/",
"inbox": "https://mastodon.social/users/bengo/inbox",
"attachments": [
{
"type": "PropertyValue",
"name": "Website",
"value": "https://bengo.is"
}
],
"outbox": "https://bengo.is/activitypub/actors/bengo/outbox.json"
}
```
* outcome: `passed`
### nginx 404 response body
outcome: `failed`
* rationale: test target `response` does not meet expectation of containing an ActivityPub Object representation in the response body
inputs
* `id`: `https://bengo.is/404`
* `time`: `T1M`
test targets
* `response`:
```http
HTTP/2 404
content-type: text/html; charset=UTF-8
content-length: 153
404 Not Found
404 Not Found
nginx/1.25.2
```
* outcome: `failed`
### non-URI input `id`
outcome: `inapplicable`
* rationale: input `id` is not a URI
inputs
* `id`: `bafybeib5mvfjatmpswc3jnh7ydz4zxe25cm63xp6aafpg3j2awakf63qma`
* `time`: `T1M`
test targets
* `response` - undefined
* irrelevant because `id` does not meet syntax requirements
### non-RFC3339-duration input `time`
outcome: `inapplicable`
* rationale: input `time` does not meet syntax requirements
inputs
* `id`: `https://bengo.is/actor.json`
* `time`: `5 minutes`
test targets
* `response` - undefined
* irrelevant because `time` input is malformed regardless of resolved `resposne`
## Glossary
### `outcome`
An outcome is a conclusion that comes from evaluating a test on a test subject. An outcome can be one of the three following types:
* `inapplicable`: No part of the test subject matches the applicability
* `passed`: A test target meets all expectations
* `failed`: A test target does not meet all expectations
## Requirements Mapping
* [ActivityPub requirement 08549639-2888-4ee2-a320-97fc7ee32e00](https://socialweb.coop/activitypub/behaviors/08549639-2888-4ee2-a320-97fc7ee32e00/) - ActivityPub server must present object in response to GET request with AS2 Accept Header
* Required for Conformance to [ActivityPub][activitypub]
* Outcome Mapping
* when test target `response` has outcome `passed`, requirement is satisfied
* when test target `response` has outcome `failed`, requirement is not satisfied
* when test target `response` has outcome `inapplicable`, further testing is needed to determine requirement satisfaction
## Change Log
* (~) 2023-10-15T00:00:00Z - sketch as first test case
* 2023-11-07T21:07:59.214Z - update to be internally consistent and a good first draft
* 2023-12-29T21:08:32.432Z - clean up test case formatting
## Issues List
* AP-ec50: clarify how to verify response body is an "ActivityStreams object representation"
* When rendered to HTML and [published here](https://socialweb.coop/activitypub/test-cases/actor-must-serve-as2-object-to-get/#simple-passed-case), the `response` test targets HTTP response syntax highlighting separates the HTTP headers from the response body. This is a quirk of the rendering process.
[activitypub]: https://www.w3.org/TR/activitypub/