REST API Principles

REST APIs follow a request-response pattern.

A request contains a target and an action. A response contains a status and data.

For example, to delete map 3, use DELETE /maps/3:

• Request: action=DELETE target=/maps/3
• Response: status=204 data={} (empty JSON)

The REST API call is:

$ curl -X DELETE -i http://192.168.25.25:8090/maps/3
HTTP/1.1 204 No Content
date: Thu, 17 Mar 2022 05:06:59 GMT
server: uvicorn
Vary: Accept, Cookie
Content-Length: 0

204 - No Content means an object was deleted successfully.

TARGET

There are two types of targets: list and single. For example:

• /maps - Map list
• /maps/3 - Map 3 (single)
• /chassis/moves - Move action list
• /chassis/moves/1150 - Move action 1150 (single)
• /services - Service list
• /services/imu/recalibrate - IMU calibration service (single)

ACTION

Common actions are query, create, delete, modify, and overwrite. The corresponding HTTP request methods are GET, POST, DELETE, PATCH, and PUT.

The common patterns are summarized below. In particular:

• POST to a list endpoint creates a new object.
• DELETE a list endpoint deletes all objects in that list.

Action	Target	Description
POST	/maps	Create a new map with provided data
GET	/maps	Get the list of all maps
GET	/maps/1	Get the detail of map 1
PUT	/maps/1	Overwrite map 1 with provided data
PATCH	/maps/1	Partially update map 1
DELETE	/maps/1	Delete map 1
DELETE	/maps	Delete all maps

STATUS

Response status codes follow the standard HTTP Status Codes (opens new window).

• 2xx are successful responses.
• 4xx are client error responses.
• 5xx are server error responses.

The most common status codes are:

• 200 OK
• 201 Created - The object was created or the service was executed.
• 204 No Content - Deleted successfully.
• 400 Bad Request - The request parameters are malformed, or some other precondition was not met.
• 404 Not Found - The resource doesn't exist (Bad URL).
• 500 Internal Server Error - The server encountered an error.

DATA

Response data is in JSON format and can be:

• An object
• A list

For example, listing all maps returns a list:

curl http://192.168.25.25:8090/maps/ | jq

[
  {
    "id": 1,
    "uid": "620620f9c0fd0ecb0f66d981",
    "map_name": "5th Floor",
    "create_time": 1644568815,
    "map_version": 9,
    "overlays_version": 14,
    "thumbnail_url": "http://192.168.25.25:8090/maps/1/thumbnail",
    "image_url": "http://192.168.25.25:8090/maps/1.png",
    "url": "http://192.168.25.25:8090/maps/1"
  },
  {
    "id": 2,
    "uid": "61ee4c3ac0fd0ecb0f66d165",
    "map_name": "Lobby",
    "create_time": 1643007028,
    "map_version": 2,
    "overlays_version": 8,
    "thumbnail_url": "http://192.168.25.25:8090/maps/2/thumbnail",
    "image_url": "http://192.168.25.25:8090/maps/2.png",
    "url": "http://192.168.25.25:8090/maps/2"
  },
  {
    "id": 3,
    "uid": "61e95264c0fd0ecb0f66c71e",
    "map_name": "Hallway",
    "create_time": 1642680851,
    "map_version": 1,
    "overlays_version": 3,
    "thumbnail_url": "http://192.168.25.25:8090/maps/3/thumbnail",
    "image_url": "http://192.168.25.25:8090/maps/3.png",
    "url": "http://192.168.25.25:8090/maps/3"
  }
]

Requesting the details of a specific map returns an object:

curl http://192.168.25.25:8090/maps/1 | jq

{
  "id": 1,
  "map_name": "5层地图",
  "uid": "620620f9c0fd0ecb0f66d981",
  "map_version": 9,
  "create_time": 1644568815,
  "last_modified_time": 1647333821,
  "grid_origin_x": -53.1968,
  "grid_origin_y": -25.0135,
  "grid_resolution": 0.05,
  "overlays_version": 14,
  "overlays": "{\"type\": \"FeatureCollection\", \"features\": [{\"id\": ...",
  "thumbnail_url": "http://192.168.25.25:8090/maps/1/thumbnail",
  "image_url": "http://192.168.25.25:8090/maps/1.png",
  "download_url": "http://192.168.25.25:8090/maps/1/download",
  "pbstream_url": "http://192.168.25.25:8090/maps/1.pbstream"
}