RESTAPICLIENT Workflow Application

Overview

The RESTAPICLIENT workflow application allows you to call REST API endpoints to exchange information with other applications through HTTP requests, and can be used to build integrations with extendable applications (such as Azure Services and Slack).

It also allows you to call a REST API endpoint using application/json or application/x-www-form-urlencoded payloads. RESTAPICLIENT will then receive and process the response from the external API by mapping the response content with defined OUT parameters.

How it works

• The RESTAPICLIENT application requires the APP_URL parameter, which corresponds to the REST API endpoint.

• The default request payload content type (APP_REQUEST_CONTENT_TYPE) is application/json. application/x-www-form-urlencoded is also supported.

• The default HTTP request method (APP_METHOD) is GET. Other request methods (POST, PUT, DELETE, etc.) are also supported.

• In case of error, when the APP_RESPONSE_IGNORE_ERROR IN parameter is defined and has Y as its value, the error will be ignored and defined OUT parameters (APP_RESPONSE_STATUS or APP_RESPONSE_CONTENT) will be mapped. Otherwise, an exception will be thrown.

• Since the application parameters are case sensitive, parameters must use the API’s accepted notation.

• The default request timeout is 30,000 milliseconds (30 seconds); this default value can be modified by setting the RestApiClientRequestTimeout parameter value in the web.config file. The request timeout can also be defined in the APP_TIMEOUT IN parameter; the maximum timeout is 3,600,000 milliseconds (1 hour).

  ✏️ Note: This timeout value must be less than the IIS request timeout value.

• The HTTP request headers can be defined with the APP_HEADER_xxx parameters, where xxx is the header field name. For more information, see the Header parameters section.

• The request payload can be defined in the APP_REQUEST_CONTENT_FILE or APP_REQUEST_CONTENT IN parameters. When both parameters are defined, the APP_REQUEST_CONTENT_FILE parameter has priority. For more information on these parameters, see the Request payload section.

• The response from the REST API can be mapped to the APP_RESPONSE_CONTENT_FILE or APP_RESPONSE_CONTENT OUT parameters. Both parameters can be defined at the same time. For more information on these parameters, see the Response payload section.

• Besides the optional parameters listed below, you can also add additional custom IN and OUT parameters to send and receive custom user-defined data to and from the external API. For more information on and examples of these custom IN and OUT parameters, see the Request payload and Response payload sections.

• The application supports the JSONPath query language (see https://github.com/json-path/JsonPath), which allows extraction of specific data from a JSON response (similar to XPath expressions in XML). For information on how to use this with the application along with examples, see the Response payload section.

• Application logs are available and can be specified by setting the RestApiClientLogLevel parameter value in the web.config file to 0 to disable logging (default), 2 for simple logs, or 3 for debug logs.

• The default maximum response length is 4194304 characters (4 MB); this default value can be modified by setting the RestApiClientMaxResponseLength parameter value in the web.config file.

• Automatic deletion of temporary files can be disabled by setting the RestApiClientEnableFilesCleanUp parameter value to N in the web.config file; the default value is Y.

Required parameter

Parameter	Type	Direction	Description
APP_URL	Text	IN	External API URL

Optional parameters

General

Parameter	Type	Direction	Description
APP_TIMEOUT	Numeric	IN	Maximum time interval between sending the request and receiving the response The default is 30,000 milliseconds (30 seconds) and the maximum is 3,600,000 milliseconds (1 hour); the default can be modified by setting the RestApiClientRequestTimeout parameter value in the web.config file. ✏️ Note: This timeout value must be less than the IIS request timeout value.
APP_METHOD	Text	IN	API method The default is GET. Supports POST, PUT, DELETE, HEAD, PATCH
APP_REQUEST_CONTENT_TYPE	Text	IN	Request content type supported by the external API The application supports application/json and application/x-www-form-urlencoded); the default is application/json.
APP_RESPONSE_IGNORE_ERROR	Text	IN	When set to Y, the application will ignore the error when a WebException occurs or the external API returns a response status equal to or greater than 300; the default is N.

APP_URL optional parameters

Parameter	Type	Direction	Description
APP_URL_xxx	Text	IN	API URL optional parameter where xxx is the URL parameter name It must be defined in the APP_URL parameter value between brackets (e.g. APP_URL_subscriptionId for the URL https://management.azure.com/subscriptions/{subscriptionId})

📌 Example

Parameter	Type	Direction	Value
APP_URL	Text	IN	https://management.azure.com/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.EventGrid/topics/{topicName}
APP_URL_subscriptionId	Text	IN	457a2a46-7a7f-4afa-940d-8779e1425fa8
APP_URL_resourceGroupName	Text	IN	dev-group-advantys
APP_URL_topicName	Text	IN	dev-topic

The parameters defined above will generate the following URL in APP_URL:

https://management.azure.com/subscriptions/457a2a46-7a7f-4afa-940d-8779e1425fa8/resourceGroups/dev-group-advantys/providers/Microsoft.EventGrid/topics/dev-topic

Header parameters

Parameter	Type	Direction	Description
APP_HEADER_xxx	Text	IN	External API header parameters where xxx is the header field name

📌 Example

Parameter	Type	Direction	Value
APP_HEADER_Authorization	Text	IN	Bearer AbCdEf123456
APP_HEADER_location	Text	IN	canadaeast

The parameters defined above will generate two headers in the request payload:

Authorization: Bearer AbCdEf123456
location: canadaeast

Authorization parameters

The application also supports some predefined authorization header parameters in order to avoid adding these HTTP header parameters with the APP_HEADER_xxx parameter name.

Parameter	Type	Direction	Description
APP_AUTH_BASIC_USERNAME	Text	IN	API authorization Basic username
APP_AUTH_BASIC_PASSWORD	Text	IN	API authorization Basic password; must be used with APP_AUTH_BASIC_USERNAME parameter
APP_AUTH_BEARER_TOKEN	Text	IN	API authorization Bearer token
APP_AUTH_AZ_SAS_TOKEN	Text	IN	API authorization Azure SAS token

• Only one authorization header can be defined, otherwise an exception is thrown.

• APP_AUTH_BEARER_TOKEN is equivalent to defining the header parameter APP_HEADER_Authorization.

Request payload

There are two different ways to prepare the request payload. The first way is when you have access to the whole request payload (see Set the whole request payload via a parameter below); the second way is by building the JSON or URL encoded payload via IN parameters (see URL encoded request payload and JSON request payload below).

Set the whole request payload via a parameter

The following parameters can be used when you have access to the whole request payload, or the request content type is neither application/json nor application/x-www-form-urlencoded. You can set this request payload in a file/text data or directly in the text value.

Parameter	Type	Direction	Description
APP_REQUEST_CONTENT_FILE	File	IN	Request payload in a file
APP_REQUEST_CONTENT	Text	IN	Request payload

• APP_REQUEST_CONTENT_FILE has priority over APP_REQUEST_CONTENT.

• APP_REQUEST_CONTENT has priority over IN parameters used to build a JSON or an URL encoded payload.

URL encoded request payload

The following examples show how to build a request payload with application/x-www-form-urlencoded as content type.

Standard URL encoded request payload

The following parameters are used to build a standard URL encoded request payload:

Parameter	Type	Direction	Description
param1	Text	IN	value1
param2	Text	IN	value2

The parameters defined above will generate the following request payload:

param1=value1&param2=value2

JSON request payload encoded into a key name

The following parameters are used to build a JSON payload encoded into a key name:

Parameter	Type	Direction	Description
param1	Text	IN	value1
param2	Text	IN	value2
APP_REQUEST_CONTENT_PAYLOAD_NAME	Text	IN	payload

The parameters defined above will generate the following request payload:

payload: { param1: "value1", "param2": "value2" }

The APP_REQUEST_CONTENT_PAYLOAD_NAME parameter is only supported with the application/x-www-form-urlencoded request content type.

JSON request payload

The following examples show how to build a request payload with application/json as content type.

Standard JSON request payload

The following parameters are used to build a simple JSON request payload:

Parameter	Type	Direction	Value
person.address.street	Text	IN	160 Guy Street
person.address.zipcode	Text	IN	J4G 1U4
person.age	Text	IN	30
person.name	Text	IN	John

The parameters defined above will generate the following request payload:

{
    "person": {
        "address": {
            "street": "160 Guy Street",
            "zipcode": "J4G 1U4"
        },
        "age": 30,
        "name": "John"
    }
}

If you want to convert this JSON into an array, you have to set the APP_REQUEST_CONTENT_IS_ARRAY parameter value to Y.

Parameter	Type	Direction	Description
APP_REQUEST_CONTENT_IS_ARRAY	Text	IN	When set to Y, the application will convert the JSON request payload into an array; the default is N Only supported when building JSON request payload with IN parameters.

Setting the APP_REQUEST_CONTENT_IS_ARRAY parameter to Y will generate the following request payload:

[{
    "person": {
        "address": {
            "street": "160 Guy Street",
            "zipcode": "J4G 1U4"
        },
        "age": 30,
        "name": "John"
    }
}]

To see how to build more complex JSON, see Setting a JSON array into a JSON property and Setting a JSON object/array into a JSON property using the __JSON suffix parameter sections below.

Setting a JSON array into a JSON property

To set an array into a JSON property, you have to define the property path (e.g. person.spokenlanguages) followed by the __X suffix, where X is the array index number.

The following parameters are used to set a JSON array into a JSON property:

Parameter	Type	Direction	Value
person.spokenlanguages__0	Text	IN	french
person.spokenlanguages__1	Text	IN	english
person.spokenlanguages__2	Text	IN	chinese

The parameters defined above will generate the following request payload:

{
    "person": {
        "spokenlanguages": ["french", "english", "chinese"]
    }
}

If you want to set a JSON array of JSON objects (e.g. "spokenlanguages": [{"spokenlanguage":"french"}, {"spokenlanguage":"english"}]) into a JSON property, see the next section.

• The array parameters will be ordered depending on their index number.

• Index numbers have no limit (e.g. person.spokenlanguages__9999).

• A correct index sequence is not mandatory (e.g. person.spokenlanguages__90, person.spokenlanguages__30). The __30 parameter value will be the first array parameter, and __90 the second one.

• An exception will be thrown if there is more than one JSON property specified in the IN parameters (e.g. person.spokenlanguages and person.spokenlanguages__0).

• The __X suffix uses two underscore characters.

• The parameter value can only be a text value.

Setting a JSON object/array into a JSON property using the __JSON suffix parameter

To set a JSON object/array into a JSON property, you have to define the property path (e.g. person.children) followed by the __JSON suffix with the JSON object/array as the parameter value.

The following parameters are used to set a JSON object/array into a JSON property:

Parameter	Type	Direction	Value
person.children__JSON	Text	IN	[{"name": "child 1"}, {"name": "child 2"}]

The parameters defined above will generate the following request payload:

{
    "person": {
        "children": [{
            "name": "child 1"
        }, {
            "name": "child 2"
        }]
    }
}

• An exception will be thrown if there is more than one JSON property specified in the IN parameters. (e.g. person.children and person.children__JSON).

• The __JSON suffix uses two underscore characters.

Response payload

The application supports OUT parameters to be mapped with the HTTP response:

Parameter	Type	Direction	Description
APP_RESPONSE_STATUS	Text/Numeric	OUT	Response status code
APP_RESPONSE_CONTENT_TYPE	Text	OUT	Response content type
APP_RESPONSE_CONTENT_FILE	File	OUT	Response payload or error message in a file
APP_RESPONSE_CONTENT	Text	OUT	Response payload or error message
APP_RESPONSE_CONTENT_IS_ARRAY	Text	OUT	Returns Y if the JSON payload is an array Only supported for application/json content type responses.

Mapping a JSON response payload with OUT parameters

The application also supports additional custom OUT parameters to map simple JSON response payloads.

📌 Example

JSON response payload:

{
    "person": {
        "address": {
            "street": "160 Guy Street",
            "zipcode": "J4G 1U4"
        },
        "age": 30,
        "name": "John"
    }
}

The following parameters allow you to map the response payload into different process data:

Parameter	Type	Direction	Retrieve the value into a data
person.address.street	Text	OUT	DATA_STREET
person.address.zipcode	Text	OUT	DATA_ZIPCODE
person.age	Text	OUT	DATA_AGE
person.name	Text	OUT	DATA_NAME

For mapping complex JSON, see the next section.

Mapping a JSON response payload with OUT parameters using JSONPath query language

The application supports the JSONPath query language (similar to XPath expressions in XML). This language allows you to retrieve specific data from a JSON. For more details regarding the JSONPath syntax, see https://github.com/json-path/JsonPath.

📌 Example

JSON response payload:

{
    "person": {
      "name": "Elizabeth",
      "age": 85,
      "dob": "1937-09-23T00:00:00Z",
      "children": [
        {
          "name": "Charles",
          "age": 60,
          "children": [
            {
              "name": "Nathalie",
              "children": [
                {
                  "name": "George",
                  "age": 8
                },
                {
                  "name": "Charlotte",
                  "age": 10
                },
                {
                  "name": "Jefferson",
                  "age": 7
                }
              ]
            },
            {
              "name": "Harry"
            }
          ]
        },
        {
          "name": "Bob",
          "age": 57,
          "children": [
            {
              "name": "John"
            },
            {
              "name": "Mark"
            }
          ]
        }
      ]
    }
}

For example, here we want to get the names of Charles's grandchildren who are older than seven years old, and we also want these names separated by a | (using the APP_JSONPATH_DELIMITER IN parameter). At the same time, we are also getting Elizabeth's age and date of birth. To get the information, the following parameters must be defined:

Parameter	Type	Direction	IN Value	OUT Value
APP_JSONPATH_DELIMITER	Text	IN	|
PARAM1__JSONPATH	Text	INOUT	person.children[?(@.name == 'Charles')].children[*].children[?(@.age > 7)].name	data DATA1_VALUE (value will be: George|Charlotte)
AGE__JSONPATH	Text	IN	$.person.age
AGE	Numeric	OUT		data AGE_VALUE (value will be: 85)
DOB__JSONPATH	Text	IN	$.person.dob
DOB	DateTime	OUT		data DOB_VALUE (value will be: 1937-09-23T00:00:00Z)

• In the PARAM1__JSONPATH parameter name, the PARAM1 name is not relevant, but it must be followed by the __JSONPATH suffix (two underscores are used in the suffix).

• To retrieve a value into a Text process data, you can use a single INOUT Text parameter (e.g. PARAM1__JSONPATH parameter as in the example above).

• To retrieve a value into a Numeric or DateTime process data, you must use separate parameters: an IN Text parameter for the JSONPath query and an OUT parameter that maps to the Numeric or DateTime process data. Both parameters must share the same name prefix (e.g. AGE__JSONPATH and AGE parameters as in the example above).

• The default value of APP_JSONPATH_DELIMITER is a comma (,) when this parameter is not defined.

Usage example with Azure REST API to obtain an OAuth 2.0 access token and then create an Event Grid topic

This example shows how to obtain an access token and use it to create an Event Grid topic. This can be done by creating a process with two actions having RESTAPICLIENT as application. The workflow below illustrates this example:

The next sections describe the parameters that must be declared for each action.

GET_TOKEN action: Obtaining an OAuth 2.0 access token

The following parameters are needed to get an access token to use the Azure Resource management API. This token will be stored in the access_token OUT parameter and will be used when creating an Event Grid topic in the next section.

Parameter	Type	Direction	Value
APP_URL	Text	IN	https://login.microsoftonline.com/{tenandId}/oauth2/token
APP_URL_tenantId	Text	IN	a6e70c61-fabd-4885-89f7-97121e92db7f
APP_METHOD	Text	IN	POST
APP_REQUEST_CONTENT_TYPE	Text	IN	application/x-www-form-urlencoded
grant_type	Text	IN	client_credentials
client_id	Text	IN	b7e29e2f-6e2b-4375-9684-8151431d4ca6
client_secret	Text	IN	lxy/IwKyTedHUWMeeUtyCtu7/YUy0rNGoY3NNWXXotI=
resource	Text	IN	https://management.core.windows.net/
access_token	Text	OUT	DATA_ACCESS_TOKEN

The parameters defined above will generate the following request payload:

POST https://login.microsoftonline.com/a6e70c61-fabd-4885-89f7-97121e92db7f/oauth2/token HTTP/1.1
Host: login.microsoftonline.com
Content-Type: application/x-www-form-urlencoded

grant_type=client_credentials&client_id=b7e29e2f-6e2b-4375-9684-8151431d4ca6&client_secret=lxy/IwKyTedHUWMeeUtyCtu7/YUy0rNGoY3NNWXXotI=&resource=https://management.core.windows.net/

Here's the response from the Azure API:

{  
   "token_type":"Bearer",
   "expires_in":"3600",
   "ext_expires_in":"3600",
   "expires_on":"1555951493",
   "not_before":"1555947593",
   "resource":"https://management.core.windows.net/",
   "access_token":"eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsIng1d..."
}

The access_token OUT parameter is mapped with the access_token JSON property.

For more details about how to get an access token to use the Azure Resource API, see https://docs.microsoft.com/en-us/azure/active-directory/develop/v1-oauth2-client-creds-grant-flow#request-an-access-token.

CREATE_TOPIC action: Creating an Event Grid topic

The following parameters are needed to create an Event Grid topic using the Azure Resource management API.

Parameter	Type	Direction	Value
APP_URL	Text	IN	https://management.azure.com/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.EventGrid/topics/{topicName}?api-version={api-version}
APP_URL_subscriptionId	Text	IN	235765d9-5d62-43f4-a730-2ed71a3f8adb
APP_URL_resourceGroupName	Text	IN	dev-group-advantys
APP_URL_topicName	Text	IN	new-topic-example
APP_URL_api-version	Text	IN	2018-09-15-preview
APP_METHOD	Text	IN	PUT
APP_REQUEST_CONTENT_TYPE	Text	IN	application/json
APP_AUTH_BEARER_TOKEN	Text	IN	DATA_ACCESS_TOKEN
location	Text	IN	canadaeast

The parameters defined above will generate the following request payload:

PUT https://management.azure.com/subscriptions/235765d9-5d62-43f4-a730-2ed71a3f8adb/resourceGroups/dev-group-advantys/providers/Microsoft.EventGrid/topics/new-topic-example?api-version=2018-09-15-preview
Host: management.azure.com
Content-Type: application/json
Authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsIng1d...
location: canadaeast

Here's the response from the Azure API:

{  
   "properties":{  
      "provisioningState":"Creating",
      "endpoint":null
   },
   "location":"canadaeast",
   "tags":null,
   "id":"/subscriptions/994e2fc0-937d-4110-b355-e7473acef822/resourceGroups/dev-evt-grid/providers/Microsoft.EventGrid/topics/test-from-wfg",
   "name":"test-from-wfg",
   "type":"Microsoft.EventGrid/topics"
}

For more information about how to create an Event Grid topic and the Azure REST API, see https://docs.microsoft.com/en-us/rest/api/eventgrid/topics/createorupdate.

Enabling SSL/TLS

In case of a Could not create SSL/TLS secure channel error, strong encryption must be enabled by executing the following code in PowerShell:

Set-ItemProperty -Path 'HKLM:\SOFTWARE\Wow6432Node\Microsoft\.NetFramework\v4.0.30319' -Name 'SchUseStrongCrypto' -Value '1' -Type DWord

Set-ItemProperty -Path 'HKLM:\SOFTWARE\Microsoft\.NetFramework\v4.0.30319' -Name 'SchUseStrongCrypto' -Value '1' -Type DWo

Restart your IIS server after executing the commands.