Get Comparison - Changed Elements

REST API Overview

Reference

Changed Elements

Download API definition:

GET https://dev-api.bentley.com/changedelements/comparison[?projectId][&iTwinId]&startChangesetId&endChangesetId&iModelId

Obtains which elements have changed in the iModel between the given start and end changesets.

This information will only be available after change tracking has been enabled and the processing operation completes.

Understanding Change

The comparison returns a ChangedElements object. This interface contains different arrays of the same size. Each element is specified by a single index in all arrays. Some of the relevant arrays to understand what changes occurred to an element are listed below:

opcodes: Contains the operation codes that tells us if the element was inserted, updated, or deleted in the change. See DbOpcode for more information. The appropriate values are listed below:

Element was deleted

Element was modified

Element was inserted

type: Contains the type of change that occurred to the element. This number is a bit-flag and can be used to know whether the element had property changes, geometric changes, placement changes, indirect changes, and hidden property changes. See TypeOfChange for more information. Below is a table with the values and their meaning:

Property

A property in the element changed

Geometry

The geometry of the element changed

Placement

The placement of the element changed. This means that the element changed its volume, origin or rotation.

Indirect

Indirect change occurred to this element by a related instance that provides properties for it

Hidden

Hidden properties of the element changed

Authentication

Requires Authorization header with valid Bearer token for scope changedelements:read.

For more documentation on authorization and how to get access token visit OAUTH2 Authorization page.

Request

Request parameters

projectId

[Deprecated] Id of the iTwin the iModel resides in.

iTwinId

Id of the iTwin where the iModel resides.

startChangesetId

Yes

Changeset Id for the beginning of the comparison range.

endChangesetId

Yes

Changeset Id for the ending of the comparison range.

iModelId

Yes

Id of iModel to get a comparison for.

Request headers

Authorization

Yes

OAuth access token with scope changedelements:read

Yes

Setting to application/vnd.bentley.itwin-platform.v1+json is recommended.

Response

Response 200 OK

json

{
    "changedElements": {
        "elements": ["0x30000000f69"],
        "classIds": ["0x670"],
        "opcodes": [23],
        "modelIds": ["0x20000000002"],
        "type": [1],
        "properties": [
            ["UserLabel"]
        ],
        "oldChecksums": [
            [1448094486]
        ],
        "newChecksums": [
            [362149254]
        ],
        "parentIds": ["0"],
        "parentClassIds": ["0"]
    }
}

Response 401 Unauthorized

This response indicates that request lacks valid authentication credentials. Access token might not been provided, issued by the wrong issuer, does not have required scopes or request headers were malformed.

json

{
    "error": {
        "code": "HeaderNotFound",
        "message": "Header Authorization was not found in the request. Access denied."
    }
}

Response 403 Forbidden

The user has insufficient permissions for the requested operation.

json

{
    "error": {
        "code": "InsufficientPermissions",
        "message": "The user has insufficient permissions for the requested operation."
    }
}

Response 404 Not Found

This response indicates that provided comparison results are not ready or unexistent.

json

{
    "error": {
        "code": "ComparisonNotFound",
        "message": "Requested comparison for the given changesets is not available."
    }
}

Response 422 Unprocessable Entity

A URL parameter was malformed or there are missing required parameters.

json

{
    "error": {
        "code": "InvalidChangedElementsRequest",
        "message": "Could not get comparison.",
        "details": [{
                "code": "MissingRequiredParameter",
                "message": "Query parameter must be provided.",
                "target": "iModelId"
            },
            {
                "code": "MissingRequiredParameter",
                "message": "Query parameter must be provided.",
                "target": "projectId"
            },
            {
                "code": "MissingRequiredParameter",
                "message": "Query parameter must be provided.",
                "target": "startChangesetId"
            },
            {
                "code": "MissingRequiredParameter",
                "message": "Query parameter must be provided.",
                "target": "endChangesetId"
            },
            {
                "code": "InvalidValue",
                "message": "'abc' is not a valid 'iModelId'.",
                "target": "iModelId"
            },
            {
                "code": "InvalidValue",
                "message": "'abc' is not a valid 'projectId'.",
                "target": "projectId"
            },
            {
                "code": "InvalidValue",
                "message": "'abc' start changeset Id results in invalid comparison.",
                "target": "startChangesetId"
            },
            {
                "code": "InvalidValue",
                "message": "'abc' end changeset Id results in invalid comparison.",
                "target": "endChangesetId"
            }
        ]
    }
}

Response 429 Too many requests

This response indicates that the user has sent too many requests in a given amount of time.

json

{
    "error": {
        "code": "TooManyRequests",
        "message": "More requests were received than the subscription rate-limit allows."
    }
}

Response headers

retry-after

The number of requests exceeds the rate-limit for the client subscription.

Definitions

Changed Elements (get)

changedElements.elements

element-id[]

Array of changed elements' Ids

changedElements.classIds

class-id[]

Array of changed element's class Id

changedElements.modelIds

model-id[]

Array of changed elements' model Ids

changedElements.parentIds

element-id[]

Array of changed elements' parent Ids

changedElements.parentClassIds

class-id[]

Array of changed elements' parent class Ids

changedElements.opcodes

opcode[]

Array of changed elements' operation codes

changedElements.type

type-of-change[]

Array of changed elements' type of change

changedElements.properties

element-properties[]

Array of changed elements' array of changed properties

changedElements.oldChecksums

checksum-list[]

Array of changed elements' array of old checksums for each property

changedElements.newChecksums

checksum-list[]

Array of changed elements' array of new checksums for each property

Element Id

Element Id in hex string representation of an element.

Model Id

Model Id in hex string representation of a model.

Class Id

EC Class Id in hex string representation of an element.

Operation Code

Operation code of change that occurred to an element. Delete: 9, Insert: 18, Update: 23.

Type Of Change

Type of change that occurred to an element in bitflags. To be used with iModelJs 'TypeOfChange' class

Element Properties

Array of properties that have changed in the element between the two changesets

Checksum List

Array of checksums for the properties of an element

Error

Contains error information.

code

String

One of a server-defined set of error codes.

message

String

A human-readable representation of the error.

target

String, null

The target of the error.

Error Response

Gives details for an error that occurred while handling the request. Note that clients MUST NOT assume that every failed request will produce an object of this schema, or that all of the properties in the response will be non-null, as the error may have prevented this response from being constructed.

error

Error

Error information.