Copy and transform data from and to a REST endpoint - Azure Data Factory & Azure Synapse (2023)

APPLIES TO: Azure Data Factory Azure Synapse Analytics

This article outlines how to use Copy Activity in Azure Data Factory to copy data from and to 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 supports copying data from RESTful APIs.
• HTTP connector is generic to retrieve data from any HTTP endpoint, for example, to download file. Before this REST connector you may happen to use HTTP connector to copy data from RESTful APIs, which is supported but less functional comparing to REST connector.
• Web table connector extracts table content from an HTML webpage.

Supported capabilities

This REST connector is supported for the following capabilities:

① Azure integration runtime ② Self-hosted integration runtime

For a list of data stores that are supported as sources/sinks, see Supported data stores.

Specifically, this generic REST connector supports:

• Copying data from a REST endpoint by using the GET or POST methods and copying data to a REST endpoint by using the POST, PUT or PATCH methods.
• Copying data by using one of the following authentications: Anonymous, Basic, Service Principal, OAuth2 Client Credential, System Assigned Managed Identity and User Assigned Managed Identity.
• Pagination in the REST APIs.
• For REST as source, copying the REST JSON response as-is or parse it by using schema mapping. Only response payload in JSON is supported.

Prerequisites

If your data store is located inside an on-premises network, an Azure virtual network, or Amazon Virtual Private Cloud, you need to configure a self-hosted integration runtime to connect to it.

If your data store is a managed cloud data service, you can use the Azure Integration Runtime. If the access is restricted to IPs that are approved in the firewall rules, you can add Azure Integration Runtime IPs to the allow list.

You can also use the managed virtual network integration runtime feature in Azure Data Factory to access the on-premises network without installing and configuring a self-hosted integration runtime.

For more information about the network security mechanisms and options supported by Data Factory, see Data access strategies.

Get started

To perform the Copy activity with a pipeline, you can use one of the following tools or SDKs:

• The Copy Data tool
• The Azure portal
• The .NET SDK
• The Python SDK
• Azure PowerShell
• The REST API
• The Azure Resource Manager template

Create a REST linked service using UI

Use the following steps to create a REST linked service in the Azure portal UI.

1. Browse to the Manage tab in your Azure Data Factory or Synapse workspace and select Linked Services, then click New:

   • Azure Data Factory
   • Azure Synapse

   

2. Search for REST and select the REST connector.

   

3. Configure the service details, test the connection, and create the new linked service.

   

Connector configuration details

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:

For different authentication types, see the corresponding sections for details.

• Basic authentication
• Service Principal authentication
• OAuth2 Client Credential authentication
• System-assigned managed identity authentication
• User-assigned managed identity authentication
• Anonymous authentication

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:

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 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:

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": "<Azure AD resource URL e.g. https://management.core.windows.net>" }, "connectVia": { "referenceName": "<name of Integration Runtime>", "type": "IntegrationRuntimeReference" } }}

Use OAuth2 Client Credential authentication

Set the authenticationType property to OAuth2ClientCredential. In addition to the generic properties that are described in the preceding section, specify the following properties:

Example

{ "name": "RESTLinkedService", "properties": { "type": "RestService", "typeProperties": { "url": "<REST endpoint e.g. https://www.example.com/>", "enableServerCertificateValidation": true, "authenticationType": "OAuth2ClientCredential", "clientId": "<client ID>", "clientSecret": { "type": "SecureString", "value": "<client secret>" }, "tokenEndpoint": "<token endpoint>", "scope": "<scope>", "resource": "<resource>" } }}

Use system-assigned managed identity authentication

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

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" } }}

Use user-assigned managed identity authentication

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

Example

{ "name": "RESTLinkedService", "properties": { "type": "RestService", "typeProperties": { "url": "<REST endpoint e.g. https://www.example.com/>", "authenticationType": "ManagedServiceIdentity", "aadResourceId": "<Azure AD resource URL e.g. https://management.core.windows.net>", "credential": { "referenceName": "credential1", "type": "CredentialReference" } }, "connectVia": { "referenceName": "<name of Integration Runtime>", "type": "IntegrationRuntimeReference" } }}

Using authentication headers

In addition, you can configure request headers for authentication along with the built-in authentication types.

Example: Using API key authentication

{ "name": "RESTLinkedService", "properties": { "type": "RestService", "typeProperties": { "url": "<REST endpoint>", "authenticationType": "Anonymous", "authHeaders": { "x-api-key": { "type": "SecureString", "value": "<API key>" } } }, "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:

If you were setting requestMethod, additionalHeaders, requestBody and paginationRules in dataset, it is still supported as-is, while you are suggested to use the new model in activity going forward.

Example:

{ "name": "RESTDataset", "properties": { "type": "RestResource", "typeProperties": { "relativeUrl": "<relative url>" }, "schema": [], "linkedServiceName": { "referenceName": "<REST linked service name>", "type": "LinkedServiceReference" } }}

Copy Activity properties

This section provides a list of properties supported by the REST source and sink.

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:

Example 1: Using the Get method with pagination

"activities":[ { "name": "CopyFromREST", "type": "Copy", "inputs": [ { "referenceName": "<REST input dataset name>", "type": "DatasetReference" } ], "outputs": [ { "referenceName": "<output dataset name>", "type": "DatasetReference" } ], "typeProperties": { "source": { "type": "RestSource", "additionalHeaders": { "x-user-defined": "helloworld" }, "paginationRules": { "AbsoluteUrl": "$.paging.next" }, "httpRequestTimeout": "00:01:00" }, "sink": { "type": "<sink type>" } } }]

Example 2: Using the Post method

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

REST as sink

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

REST connector as sink works with the REST APIs that accept JSON. The data will be sent in JSON with the following pattern. As needed, you can use the copy activity schema mapping to reshape the source data to conform to the expected payload by the REST API.

[ { <data object> }, { <data object> }, ...]

Example:

"activities":[ { "name": "CopyToREST", "type": "Copy", "inputs": [ { "referenceName": "<input dataset name>", "type": "DatasetReference" } ], "outputs": [ { "referenceName": "<REST output dataset name>", "type": "DatasetReference" } ], "typeProperties": { "source": { "type": "<source type>" }, "sink": { "type": "RestSink", "requestMethod": "POST", "httpRequestTimeout": "00:01:40", "requestInterval": 10, "writeBatchSize": 10000, "httpCompressionType": "none", }, } }]

Mapping data flow properties

REST is supported in data flows for both integration datasets and inline datasets.

Source transformation

Sink transformation

You can set the delete, insert, update, and upsert methods as well as the relative row data to send to the REST sink for CRUD operations.

Sample data flow script

Notice the use of an alter row transformation prior to the sink to instruct ADF what type of action to take with your REST sink. I.e. insert, update, upsert, delete.

AlterRow1 sink(allowSchemaDrift: true,validateSchema: false,deletable:true,insertable:true,updateable:true,upsertable:true,rowRelativeUrl: 'periods',insertHttpMethod: 'PUT',deleteHttpMethod: 'DELETE',upsertHttpMethod: 'PUT',updateHttpMethod: 'PATCH',timeout: 30,requestFormat: ['type' -> 'json'],skipDuplicateMapInputs: true,skipDuplicateMapOutputs: true) ~> sink1

Pagination support

When copying data from REST APIs, normally, the REST API limits 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 contains 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 expressions in "paginationRules" returns null.

Supported keys in pagination rules:

Supported values in pagination rules:

Pagination rules examples

This section provides a list of examples for pagination rules settings.

Example 1: Variables in QueryParameters

This example provides the configuration steps to send multiple requests whose variables are in QueryParameters.

Multiple requests:

baseUrl/api/now/table/incident?sysparm_limit=1000&sysparm_offset=0,baseUrl/api/now/table/incident?sysparm_limit=1000&sysparm_offset=1000,...... baseUrl/api/now/table/incident?sysparm_limit=1000&sysparm_offset=10000

Step 1: Input sysparm_offset={offset} either in Base URL or Relative URL as shown in the following screenshots:

or

Step 2: Set Pagination rules as either option 1 or option 2：

• Option1: "QueryParameters.{offset}" : "RANGE:0:10000:1000"

• Option2: "AbsoluteUrl.{offset}" : "RANGE:0:10000:1000"

Example 2：Variables in AbsoluteUrl

This example provides the configuration steps to send multiple requests whose variables are in AbsoluteUrl.

Multiple requests:

BaseUrl/api/now/table/t1BaseUrl/api/now/table/t2...... BaseUrl/api/now/table/t100

Step 1: Input {id} either in Base URL in the linked service configuration page or Relative URL in the dataset connection pane.

or

Step 2: Set Pagination rules as "AbsoluteUrl.{id}" :"RANGE:1:100:1".

Example 3：Variables in Headers

This example provides the configuration steps to send multiple requests whose variables are in Headers.

Multiple requests:
RequestUrl: https://example/table
Request 1: Header(id->0)
Request 2: Header(id->10)
......
Request 100: Header(id->100)

Step 1: Input {id} in Additional headers.

Step 2: Set Pagination rules as "Headers.{id}" : "RARNGE:0:100:10".

Example 4：Variables are in AbsoluteUrl/QueryParameters/Headers, the end variable is not pre-defined and the end condition is based on the response

This example provides configuration steps to send multiple requests whose variables are in AbsoluteUrl/QueryParameters/Headers but the end variable is not defined. For different responses, different end condition rule settings are shown in Example 4.1-4.6.

Multiple requests:

Request 1: baseUrl/api/now/table/incident?sysparm_limit=1000&sysparm_offset=0, Request 2: baseUrl/api/now/table/incident?sysparm_limit=1000&sysparm_offset=1000,Request 3: baseUrl/api/now/table/incident?sysparm_limit=1000&sysparm_offset=2000,...... 

Two responses encountered in this example:

Response 1：

{ Data: [ {key1: val1, key2: val2 }, {key1: val3, key2: val4 } ]}

Response 2：

{ Data: [ {key1: val5, key2: val6 }, {key1: val7, key2: val8 } ]}

Step 1: Set the range of Pagination rules as Example 1 and leave the end of range empty as "AbsoluteUrl.{offset}": "RANGE:0::1000".

Step 2: Set different end condition rules according to different last responses. See below examples:

• Example 4.1: The pagination ends when the value of the specific node in response is empty

  The REST API returns the last response in the following structure:

  { Data: []}

  Set the end condition rule as "EndCondition:$.data": "Empty" to end the pagination when the value of the specific node in response is empty.

  

• Example 4.2: The pagination ends when the value of the specific node in response does not exist

  The REST API returns the last response in the following structure:

  {}

  Set the end condition rule as "EndCondition:$.data": "NonExist" to end the pagination when the value of the specific node in response does not exist.

  

• Example 4.3: The pagination ends when the value of the specific node in response exists

  The REST API returns the last response in the following structure:

  { Data: [ {key1: val991, key2: val992 }, {key1: val993, key2: val994 } ], Complete: true}

  Set the end condition rule as "EndCondition:$.Complete": "Exist" to end the pagination when the value of the specific node in response exists.

  

• Example 4.4: The pagination ends when the value of the specific node in response is a user-defined const value

  The REST API returns the response in the following structure:

  { Data: [ {key1: val1, key2: val2 }, {key1: val3, key2: val4 } ], Complete: false}

  ......

  And the last response is in the following structure:

  { Data: [ {key1: val991, key2: val992 }, {key1: val993, key2: val994 } ], Complete: true}

  Set the end condition rule as "EndCondition:$.Complete": "Const:true" to end the pagination when the value of the specific node in response is a user-defined const value.

  

• Example 4.5: The pagination ends when the value of the header key in response equals to user-defined const value

  The header keys in REST API responses are shown in the structure below:

  Response header 1: header(Complete->0)
  ......
  Last Response header: header(Complete->1)
  

  Set the end condition rule as "EndCondition:headers.Complete": "Const:1" to end the pagination when the value of the header key in response is equal to user-defined const value.

  

• Example 4.6: The pagination ends when the key exists in the response header

  The header keys in REST API responses are shown in the structure below:

  Response header 1: header()
  ......
  Last Response header: header(CompleteTime->20220920)
  

  Set the end condition rule as "EndCondition:headers.CompleteTime": "Exist" to end the pagination when the key exists in the response header.

  (Video) Copy Data From An HTTP Endpoint By Using Azure Data Factory - ADF Tutorial 2021

  

Example 5：Set end condition to avoid endless requests when range rule is not defined

This example provides the configuration steps to send multiple requests when the range rule is not used. The end condition can be set refer to Example 4.1-4.6 to avoid endless requests. The REST 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 last response is:

{ "data": [], "paging": { "cursors": { "after": "MTAxNTExOTQ1MjAwNzI5NDE=", "before": "NDMyNzQyODI3OTQw" }, "previous": "https://graph.facebook.com/me/albums?limit=25&before=NDMyNzQyODI3OTQw", "next": "Same with Last Request URL" }}

Step 1: Set Pagination rules as "AbsoluteUrl": "$.paging.next".

Step 2: If next in the last response is always same with the last request URL and not empty, endless requests will be sent. The end condition can be used to avoid endless requests. Therefore, set the end condition rule refer to Example 4.1-4.6.

Example 6：Set the max request number to avoid endless request

Set MaxRequestNumber to avoid endless request as shown in the following screenshot:

Example 7：The RFC 5988 pagination rule is supported by default

The backend will automatically get the next URL based on the RFC 5988 style links in the header.

Example 8: The next request URL is from the response body when use pagination in mapping data flows

This example states how to set the pagination rule and the end condition rule in mapping data flows when the next request URL is from the response body.

The response schema is shown below:

The pagination rules should be set as the following screenshot:

By default, the pagination will stop when body .{@odata.nextLink} is null or empty.

But if the value of @odata.nextLink in the last response body is equal to the last request URL, then it will lead to the endless loop. To avoid this condition, define end condition rules.

• If Value in the last response is Empty, then the end condition rule can be set as below:

  

• If the value of the complete key in the response header equals to true indicates the end of pagination, then the end condition rule can be set as below:

  

Example 9: The response format is XML and the next request URL is from the response body when use pagination in mapping data flows

This example states how to set the pagination rule in mapping data flows when the response format is XML and the next request URL is from the response body. As shown in the following screenshot, the first URL is https://<user>.dfs.core.windows.net/bugfix/test/movie_1.xml

The response schema is shown below:

The pagination rule syntax is the same as in Example 8 and should be set as below in this example:

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.