RESTAPICLIENT Workflow Application

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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 OUT 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
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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.
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✏️ Note: This timeout value must be less than the IIS request timeout value.
APP_METHOD
Text
IN
API method
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The default is GET. Supports POST, PUT, DELETE, HEAD, PATCH
APP_REQUEST_CONTENT_TYPE
Text
IN
Request content type supported by the external API
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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:
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https://management.azure.com/subscriptions/457a2a46-7a7f-4afa-940d-8779e1425fa8/resourceGroups/dev-group-advantys/providers/Microsoft.EventGrid/topics/dev-topic
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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:
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Authorization: Bearer AbCdEf123456
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location: canadaeast
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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:
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param1=value1&param2=value2
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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:
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payload: { param1: "value1", "param2": "value2" }
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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:
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{
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    "person": {
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        "address": {
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            "street": "160 Guy Street",
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            "zipcode": "J4G 1U4"
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        },
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        "age": 30,
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        "name": "John"
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    }
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}
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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:
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[{
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    "person": {
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        "address": {
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            "street": "160 Guy Street",
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            "zipcode": "J4G 1U4"
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        },
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        "age": 30,
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        "name": "John"
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    }
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}]
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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:
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{
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    "person": {
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        "spokenlanguages": ["french", "english", "chinese"]
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    }
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}
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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:
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{
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    "person": {
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        "children": [{
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            "name": "child 1"
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        }, {
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            "name": "child 2"
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        }]
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    }
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}
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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:
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{
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    "person": {
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        "address": {
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            "street": "160 Guy Street",
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            "zipcode": "J4G 1U4"
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        },
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        "age": 30,
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        "name": "John"
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    }
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}
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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:
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{
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    "person": {
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      "name": "Elizabeth",
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      "children": [
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        {
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          "name": "Charles",
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          "age": 30,
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          "children": [
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            {
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              "name": "Nathalie",
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              "children": [
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                {
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                  "name": "George",
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                  "age": 8
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                },
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                {
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                  "name": "Charlotte",
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                  "age": 10
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                },
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                {
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                  "name": "Jefferson",
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                  "age": 7
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                }
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              ]
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            },
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            {
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              "name": "Harry"
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            }
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          ]
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        },
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        {
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          "name": "Bob",
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          "age": 20,
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          "children": [
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            {
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              "name": "John"
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            },
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            {
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              "name": "Mark"
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            }
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          ]
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        }
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      ]
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    }
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}
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For example, here we want to get the names of Charles's grandsons who are older than seven years old, and we also want these names separated by a | (using the APP_JSONPATH_DELIMITER IN parameter). To get this 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
DATA1_VALUE (value will be: George|Charlotte)
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).

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:
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POST https://login.microsoftonline.com/a6e70c61-fabd-4885-89f7-97121e92db7f/oauth2/token HTTP/1.1
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Host: login.microsoftonline.com
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Content-Type: application/x-www-form-urlencoded
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​
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grant_type=client_credentials&client_id=b7e29e2f-6e2b-4375-9684-8151431d4ca6&client_secret=lxy/IwKyTedHUWMeeUtyCtu7/YUy0rNGoY3NNWXXotI=&resource=https://management.core.windows.net/
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Here's the response from the Azure API:
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{  
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   "token_type":"Bearer",
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   "expires_in":"3600",
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   "ext_expires_in":"3600",
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   "expires_on":"1555951493",
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   "not_before":"1555947593",
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   "resource":"https://management.core.windows.net/",
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   "access_token":"eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsIng1d..."
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}
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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:
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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
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Host: management.azure.com
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Content-Type: application/json
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Authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsIng1d...
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location: canadaeast
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Here's the response from the Azure API:
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{  
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   "properties":{  
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      "provisioningState":"Creating",
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      "endpoint":null
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   },
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   "location":"canadaeast",
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   "tags":null,
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   "id":"/subscriptions/994e2fc0-937d-4110-b355-e7473acef822/resourceGroups/dev-evt-grid/providers/Microsoft.EventGrid/topics/test-from-wfg",
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   "name":"test-from-wfg",
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   "type":"Microsoft.EventGrid/topics"
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}
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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:
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Set-ItemProperty -Path 'HKLM:\SOFTWARE\Wow6432Node\Microsoft\.NetFramework\v4.0.30319' -Name 'SchUseStrongCrypto' -Value '1' -Type DWord
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​
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Set-ItemProperty -Path 'HKLM:\SOFTWARE\Microsoft\.NetFramework\v4.0.30319' -Name 'SchUseStrongCrypto' -Value '1' -Type DWord
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Restart your IIS server after executing the commands.
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