OS2Forms REST API

We use Webform REST to expose a number of API endpoints.

Installation

composer require os2forms/os2forms_rest_api
vendor/bin/drush pm:enable os2forms_rest_api

Authentication

We use Key auth for authenticating api users.

A user can access the Webform REST API if

1. it has the “OS2Form REST API user” (os2forms_rest_api_user) role,
2. has been granted access to the form (see Custom access control )
3. has a generated key (User > Edit > Key authentication; /user/«user id»/key-auth).

The “OS2Form REST API user” role gives read-only access to the API. To get write access, a user must also have the “OS2Form REST API user (write)” (os2forms_rest_api_user_write) role.

Endpoints

Name	Path	Methods
Webform Elements	/webform_rest/{webform_id}/elements	GET
Webform Fields	/webform_rest/{webform_id}/fields	GET
Webform Submission	/webform_rest/{webform_id}/submission/{uuid}	GET
Webform Submissions	/webform_rest/{webform_id}/submissions	GET
Webform Submit	/webform_rest/submit	POST
File	/entity/file/{file_id}	GET

Examples

Get file content from webform submission

Example uses some_webform_id as webform id, some_submission_id as submission id and dokumenter as the webform file element key.

Request:

> curl --silent --header 'api-key: …' https://127.0.0.1:8000/webform_rest/some_webform_id/submission/some_submission_uuid

Response:

{
  …,
  "data": {
    "navn": "Jack",
    "telefon": "12345678"
    "dokumenter": {
      "some_document_id",
      "some_other_docuent_id"
    }
  }
}

Use the file endpoint from above to get information on a file, substituting {file_id} with the actual file id (some_document_id) from the previous request.

Request:

> curl --silent --header 'api-key: …' https://127.0.0.1:8000/webform_rest/entity/file/some_document_id

Response:

{
  …,
  "uri": [
    {
      "value": "private:…",
      "url": "/system/files/webform/some_webform_id/…"
    }
  ],
  …
}

Finally, you can get the actual file by combining the base url with the url from above response:

> curl --silent --header 'api-key: …' http://127.0.0.1:8000/system/files/webform/some_webform_id/…

Response:

The actual document content.

Submit webform

Request:

> curl --silent --location --header 'api-key: …' --header 'content-type: application/json' https://127.0.0.1:8000/webform_rest/submit --data @- <<'JSON'
{
  "webform_id": "{webform_id}",
  "//": "Webform field values (cf. /webform_rest/{webform_id}/fields)",
  "navn_": "Mikkel",
  "adresse": "Livets landevej",
  "mail_": "[email protected]",
  "telefonnummer_": "12345678"
}
JSON

Response:

{"sid":"6d95afe9-18d1-4a7d-a1bf-fd38c58c7733"}

(the sid value is a webform submission uuid).

Webform submissions

You can filter results based on submission time by adding query parameters to the URL:

Name	Value	Example
starttime	PHP Date and Time Formats	yesterday
endtime	PHP Date and Time Formats	2023-10-23

If left out, filtering upon the left out parameter will not be done.

This example requests all submissions on or after October 1st, 2023:

Request:

> curl --silent --header 'api-key: …' 'https://127.0.0.1:8000/webform_rest/some_webform_id/submissions?starttime=2023-10-01'

Response:

{
  "webform_id": "some_webform_id",
  "starttime": "2023-10-01",
  "submissions": {
    "123": "https://127.0.0.1:8000/da/webform_rest/some_webform_id/submission/44b1fe1b-ee96-481e-b941-d1219d1dcb55",
    "124": "https://127.0.0.1:8000/da/webform_rest/some_webform_id/submission/3652836d-3dab-4919-b880-e82cbbf3c24c"
  }
}

Custom access control

To give access to webforms, you need to specify a list of API users that are allowed to access a webform's data via the API.

Go to Settings > Access > View any submissions > Users to specify which users can access a webform's data.

Technical details

The custom access check is implemented in an event subscriber listening on the KernelEvents::REQUEST event. See EventSubscriber::onRequest for details.

In order to make documents accessible for api users the Key auth authentication_provider service has been overwritten to be global. See os2forms_rest_api.services.

Linked data

To make using the REST API easier we add linked data to GET responses:

{
  …
  "data": {
    "file": "87",
    "name": "The book",
    "linked": {
      "file": {
        "87": {
          "id": "87",
          "url": "http://os2forms.example.com/system/files/webform/os2forms/1/cover.jpg",
          "mime_type": "image/jpeg",
          "size": "96757"
        }
      }
    }
  }
}

Attachments

Attachment elements are added to GET responses:

{
  …
  "data": {
    …
    "attachments": {
      "attachment_pdf": {
        "name": "Attachment (pdf)",
        "type": "pdf",
        "url": "http://os2forms.example.com/da/webform/os2forms/submissions/42/attachment/pdf/pdf.pdf"
      },
      …
    }
  }
}

Technical details on linked data and attachments

In order to add linked data, we apply a patch, webform_rest_submission.patch, to the Webform REST module and implement an event subscriber, WebformSubmissionDataEventSubscriber, to add the linked data.