Copy data from a REST endpoint by using Azure Data Factory

This article outlines how to use Copy Activity in Azure Data Factory to copy data from a REST endpoint. The article builds on Copy Activity in Azure Data Factory, which presents a general overview of Copy Activity.

The difference among this REST connector, HTTP connector and the Web table connector are:

  • REST connector specifically support copying data from RESTful APIs;
  • HTTP connector is generic to retrieve data from any HTTP endpoint, e.g. to download file. Before this REST connector becomes available, you may happen to use HTTP connector to copy data from RESTful API, which is supported but less functional comparing to REST connector.
  • Web table connector extracts table content from an HTML webpage.

Supported capabilities

You can copy data from a REST source to any supported sink data store. For a list of data stores that Copy Activity supports as sources and sinks, see Supported data stores and formats.

Specifically, this generic REST connector supports:

  • Retrieving data from a REST endpoint by using the GET or POST methods.
  • Retrieving data by using one of the following authentications: Anonymous, Basic, AAD service principal, and managed identities for Azure resources.
  • Pagination in the REST APIs.
  • Copying the REST JSON response as-is or parse it by using schema mapping. Only response payload in JSON is supported.

Tip

To test a request for data retrieval before you configure the REST connector in Data Factory, learn about the API specification for header and body requirements. You can use tools like Postman or a web browser to validate.

Get started

You can use one of the following tools or SDKs to use the copy activity with a pipeline. Select a link for step-by-step instructions:

The following sections provide details about properties you can use to define Data Factory entities that are specific to the REST connector.

Linked service properties

The following properties are supported for the REST linked service:

Property Description Required
type The type property must be set to RestService. Yes
url The base URL of the REST service. Yes
enableServerCertificateValidation Whether to validate server side SSL certificate when connecting to the endpoint. No
(the default is true)
authenticationType Type of authentication used to connect to the REST service. Allowed values are Anonymous, Basic, AadServicePrincipal and ManagedServiceIdentity. Refer to corresponding sections below on more properties and examples respectively. Yes
connectVia The Integration Runtime to use to connect to the data store. You can use the Azure Integration Runtime or a self-hosted Integration Runtime (if your data store is located in a private network). If not specified, this property uses the default Azure Integration Runtime. No

Use basic authentication

Set the authenticationType property to Basic. In addition to the generic properties that are described in the preceding section, specify the following properties:

Property Description Required
userName The user name to use to access the REST endpoint. Yes
password The password for the user (the userName value). Mark this field as a SecureString type to store it securely in Data Factory. You can also reference a secret stored in Azure Key Vault. Yes

Example

{
    "name": "RESTLinkedService",
    "properties": {
        "type": "RestService",
        "typeProperties": {
            "authenticationType": "Basic",
            "url" : "<REST endpoint>",
            "userName": "<user name>",
            "password": {
                "type": "SecureString",
                "value": "<password>"
            }
        },
        "connectVia": {
            "referenceName": "<name of Integration Runtime>",
            "type": "IntegrationRuntimeReference"
        }
    }
}

Use AAD service principal authentication

Set the authenticationType property to AadServicePrincipal. In addition to the generic properties that are described in the preceding section, specify the following properties:

Property Description Required
servicePrincipalId Specify the Azure Active Directory application's client ID. Yes
servicePrincipalKey Specify the Azure Active Directory application's key. Mark this field as a SecureString to store it securely in Data Factory, or reference a secret stored in Azure Key Vault. Yes
tenant Specify the tenant information (domain name or tenant ID) under which your application resides. Retrieve it by hovering the mouse in the top-right corner of the Azure portal. Yes
aadResourceId Specify the AAD resource you are requesting for authorization, e.g. https://management.core.windows.net. Yes

Example

{
    "name": "RESTLinkedService",
    "properties": {
        "type": "RestService",
        "typeProperties": {
            "url": "<REST endpoint e.g. https://www.example.com/>",
            "authenticationType": "AadServicePrincipal",
            "servicePrincipalId": "<service principal id>",
            "servicePrincipalKey": {
                "value": "<service principal key>",
                "type": "SecureString"
            },
            "tenant": "<tenant info, e.g. microsoft.onmicrosoft.com>",
            "aadResourceId": "<AAD resource URL e.g. https://management.core.windows.net>"
        },
        "connectVia": {
            "referenceName": "<name of Integration Runtime>",
            "type": "IntegrationRuntimeReference"
        }
    }
}

Use managed identities for Azure resources authentication

Set the authenticationType property to ManagedServiceIdentity. In addition to the generic properties that are described in the preceding section, specify the following properties:

Property Description Required
aadResourceId Specify the AAD resource you are requesting for authorization, e.g. https://management.core.windows.net. Yes

Example

{
    "name": "RESTLinkedService",
    "properties": {
        "type": "RestService",
        "typeProperties": {
            "url": "<REST endpoint e.g. https://www.example.com/>",
            "authenticationType": "ManagedServiceIdentity",
            "aadResourceId": "<AAD resource URL e.g. https://management.core.windows.net>"
        },
        "connectVia": {
            "referenceName": "<name of Integration Runtime>",
            "type": "IntegrationRuntimeReference"
        }
    }
}

Dataset properties

This section provides a list of properties that the REST dataset supports.

For a full list of sections and properties that are available for defining datasets, see Datasets and linked services.

To copy data from REST, the following properties are supported:

Property Description Required
type The type property of the dataset must be set to RestResource. Yes
relativeUrl A relative URL to the resource that contains the data. When this property isn't specified, only the URL that's specified in the linked service definition is used. No
requestMethod The HTTP method. Allowed values are Get (default) and Post. No
additionalHeaders Additional HTTP request headers. No
requestBody The body for the HTTP request. No
paginationRules The pagination rules to compose next page requests. Refer to pagination support section on details. No

Example 1: Using the Get method with pagination

{
    "name": "RESTDataset",
    "properties": {
        "type": "RestResource",
        "linkedServiceName": {
            "referenceName": "<REST linked service name>",
            "type": "LinkedServiceReference"
        },
        "typeProperties": {
            "relativeUrl": "<relative url>",
            "additionalHeaders": {
                "x-user-defined": "helloworld"
            },
            "paginationRules": {
                "AbsoluteUrl": "$.paging.next"
            }
        }
    }
}

Example 2: Using the Post method

{
    "name": "RESTDataset",
    "properties": {
        "type": "RestResource",
        "linkedServiceName": {
            "referenceName": "<REST linked service name>",
            "type": "LinkedServiceReference"
        },
        "typeProperties": {
            "relativeUrl": "<relative url>",
            "requestMethod": "Post",
            "requestBody": "<body for POST REST request>"
        }
    }
}

Copy Activity properties

This section provides a list of properties that the REST source supports.

For a full list of sections and properties that are available for defining activities, see Pipelines.

REST as source

The following properties are supported in the copy activity source section:

Property Description Required
type The type property of the copy activity source must be set to RestSource. Yes
httpRequestTimeout The timeout (the TimeSpan value) for the HTTP request to get a response. This value is the timeout to get a response, not the timeout to read response data. The default value is 00:01:40. No
requestInterval The time to wait before sending the request for next page. The default value is 00:00:01 No

Example

"activities":[
    {
        "name": "CopyFromREST",
        "type": "Copy",
        "inputs": [
            {
                "referenceName": "<REST input dataset name>",
                "type": "DatasetReference"
            }
        ],
        "outputs": [
            {
                "referenceName": "<output dataset name>",
                "type": "DatasetReference"
            }
        ],
        "typeProperties": {
            "source": {
                "type": "RestSource",
                "httpRequestTimeout": "00:01:00"
            },
            "sink": {
                "type": "<sink type>"
            }
        }
    }
]

Pagination support

Normally, REST API limit its response payload size of a single request under a reasonable number; while to return large amount of data, it splits the result into multiple pages and requires callers to send consecutive requests to get next page of the result. Usually, the request for one page is dynamic and composed by the information returned from the response of previous page.

This generic REST connector supports the following pagination patterns:

  • Next request’s absolute or relative URL = property value in current response body
  • Next request’s absolute or relative URL = header value in current response headers
  • Next request’s query parameter = property value in current response body
  • Next request’s query parameter = header value in current response headers
  • Next request’s header = property value in current response body
  • Next request’s header = header value in current response headers

Pagination rules are defined as a dictionary in dataset which contain one or more case-sensitive key-value pairs. The configuration will be used to generate the request starting from the second page. The connector will stop iterating when it gets HTTP status code 204 (No Content), or any of the JSONPath expression in "paginationRules" returns null.

Supported keys in pagination rules:

Key Description
AbsoluteUrl Indicates the URL to issue the next request. It can be either absolute URL or relative URL.
QueryParameters.request_query_parameter OR QueryParameters['request_query_parameter'] "request_query_parameter" is user-defined which references one query parameter name in the next HTTP request URL.
Headers.request_header OR Headers['request_header'] "request_header" is user-defined which references one header name in the next HTTP request.

Supported values in pagination rules:

Value Description
Headers.response_header OR Headers['response_header'] "response_header" is user-defined which references one header name in the current HTTP response, the value of which will be used to issue next request.
A JSONPath expression starting with "$" (representing the root of the response body) The response body should contain only one JSON object. The JSONPath expression should return a single primitive value, which will be used to issue next request.

Example:

Facebook Graph API returns response in the following structure, in which case next page's URL is represented in paging.next:

{
    "data": [
        {
            "created_time": "2017-12-12T14:12:20+0000",
            "name": "album1",
            "id": "1809938745705498_1809939942372045"
        },
        {
            "created_time": "2017-12-12T14:14:03+0000",
            "name": "album2",
            "id": "1809938745705498_1809941802371859"
        },
        {
            "created_time": "2017-12-12T14:14:11+0000",
            "name": "album3",
            "id": "1809938745705498_1809941879038518"
        }
    ],
    "paging": {
        "cursors": {
            "after": "MTAxNTExOTQ1MjAwNzI5NDE=",
            "before": "NDMyNzQyODI3OTQw"
        },
        "previous": "https://graph.facebook.com/me/albums?limit=25&before=NDMyNzQyODI3OTQw",
        "next": "https://graph.facebook.com/me/albums?limit=25&after=MTAxNTExOTQ1MjAwNzI5NDE="
    }
}

The corresponding REST dataset configuration especially the paginationRules is as follows:

{
    "name": "MyFacebookAlbums",
    "properties": {
            "type": "RestResource",
            "typeProperties": {
                "relativeUrl": "albums",
                "paginationRules": {
                    "AbsoluteUrl": "$.paging.next"
                }
            },
            "linkedServiceName": {
                "referenceName": "MyRestService",
                "type": "LinkedServiceReference"
            }
    }
}

Export JSON response as-is

You can use this REST connector to export REST API JSON response as-is to various file-based stores. To achieve such schema-agnostic copy, skip the "structure" (also called schema) section in dataset and schema mapping in copy activity.

Schema mapping

To copy data from REST endpoint to tabular sink, refer to schema mapping.

Next steps

For a list of data stores that Copy Activity supports as sources and sinks in Azure Data Factory, see Supported data stores and formats.