GET /entity/<type>/<id>/<field>: Flow PT REST endpoint

Params

part	value
`<field>`	an `image` or `url` field. Anything else is a 400
`?alt`	`original` or `thumbnail`. Redirects to the stored file instead of describing it
`Range`	forwarded to storage, and only with `?alt`

Sample requests

ID = 17055
c.get(f"/entity/versions/{ID}/sg_uploaded_movie").json()

{"data": {"url": "<presigned URL>", "name": "charA.jpg", "content_type": "image/jpeg",
          "link_type": "upload", "type": "Attachment", "id": 1430},
 "links": {"self": "/api/v1/entity/versions/17055/sg_uploaded_movie"}}

An image field answers the URL as a bare string:

{"data": "<presigned URL>", "links": {"self": "/api/v1/entity/versions/17055/image"}}

Any other field:

{"errors": [{"status": 400, "code": 103,
             "title": "Field Version.code is not an image or attachment.",
             "source": null, "detail": null}]}

The bytes, rather than the field:

r = c.get(f"/entity/versions/{ID}/image", params={"alt": "thumbnail"})
r.status_code, r.headers["Content-Type"], len(r.content)   # 200 'image/jpeg' 51730, after a 302

r = c.get(f"/entity/versions/{ID}/image", params={"alt": "original"},
          headers={"Range": "bytes=0-100"})
r.status_code, r.headers["Content-Range"]                  # 206 'bytes 0-100/196291'

Response codes

status	when
200	the field hash, or the file when a redirect was followed
206	`Range` sent with `?alt`
302	`?alt` given, `Location` is the presigned storage URL
400	`Field Version.code is not an image or attachment.`
400	`source: {"alt": ["alt must be one of: original, thumbnail"]}`
404	`Field 'Version.sg_not_a_field' does not exist.`, code 103
404	`Field sg_uploaded_movie is empty.`, code 104, for `?alt` on an empty `url` field
404	`File not found`, code 104, for `?alt` on an empty `image` field
406	a dotted path, with a one-byte `text/html` body

Edge cases

`<field>`	result
`image`, an `image` field	200, `data` is a URL string
`sg_uploaded_movie`, a `url` field	200, `data` is the attachment hash
`code`, `sg_status_list`, `id`	400 `is not an image or attachment`
`entity`, `playlists`	400, the same message. Use `relationships/<field>`
`entity.Shot.code`	406, one byte
a name the type does not have	404, code 103

A dotted path 406s because the segment after the last dot is read as a format extension, not as a field. There is no single-field read for a dotted path.
Range without ?alt is ignored and the field hash comes back at 200. The header only reaches storage once the redirect is in play.
Reading image here costs about the same as GET /entity/<type>/<id>?fields=image, because the presigned URL is most of both bodies.
An empty field answers 200 with "data": null. Add ?alt to the same call and it is a 404, worded differently per data type: Field sg_uploaded_movie is empty. for url, File not found for image. Read the field first if the difference between empty and missing matters.

GET /entity/<type>/<id>/<field>

Links

Endpoints

Field types

Findings