Access External REST Services

The external REST service lets you access remote REST services at the openidm/external/rest context path or by specifying the external/rest resource in your scripts. Note that this service is not intended as a full connector to synchronize or reconcile identity data, but as a way to make dynamic HTTP calls as part of the IDM logic. For more declarative and encapsulated interaction with remote REST services, and for synchronization or reconciliation operations, use the scripted REST implementation of the Groovy connector.

An external REST call via a script might look something like the following:

openidm.action("external/rest", "call", params);

The call parameter specifies the action name to be used for this invocation, and is the standard method signature for the openidm.action method.

An external REST call over REST might look something like the following:

curl \
--header "X-OpenIDM-Username: openidm-admin" \
--header "X-OpenIDM-Password: openidm-admin" \
--header "Content-Type: application/json" \
--header "Accept-API-Version: resource=1.0" \
--request POST \
--data '{
  "url": "http://urlecho.appspot.com/echo?status=200&Content-Type=application%2Fjson&body=%5B%7B%22key%22%3A%22value%22%7D%5D",
  "method": "GET"
}' \
"http://localhost:8080/openidm/external/rest?_action=call"
[
  {
    "key": "value"
  }
]

Configure the External REST Service

You can edit the external REST configuration over REST at the config/external.rest endpoint, or in an external.rest.json file in your project’s conf directory.

The following sample external REST configuration sets up the external REST service:

Using REST
Using the filesystem

curl \
--header "X-OpenIDM-Username: openidm-admin" \
--header "X-OpenIDM-Password: openidm-admin" \
--header "Accept-API-Version: resource=1.0" \
--header "Content-type: application/json" \
--request PUT \
--data '{
  "socketTimeout" : "10 s",
  "connectionTimeout" : "10 s",
  "reuseConnections" : true,
  "retryRequests" : true,
  "maxConnections" : 64,
  "tlsVersion" : "&{openidm.external.rest.tls.version}",
  "hostnameVerifier" : "&{openidm.external.rest.hostnameVerifier}",
  "proxy" : {
    "proxyUri" : "",
    "userName" : "",
    "password" : ""
  }
}' \
"http://localhost:8080/openidm/config/external.rest"
{
  "_id": "external.rest",
  "socketTimeout": "10 s",
  "connectionTimeout": "10 s",
  "reuseConnections": true,
  "retryRequests": true,
  "maxConnections": 64,
  "tlsVersion": "&{openidm.external.rest.tls.version}",
  "hostnameVerifier": "&{openidm.external.rest.hostnameVerifier}",
  "proxy": {
    "proxyUri": "",
    "userName": "",
    "password": ""
  }
}

Copy the config to the external.rest.json file in your project’s conf directory:

{
    "socketTimeout" : "10 s",
    "connectionTimeout" : "10 s",
    "reuseConnections" : true,
    "retryRequests" : true,
    "maxConnections" : 64,
    "tlsVersion" : "&{openidm.external.rest.tls.version}",
    "hostnameVerifier" : "&{openidm.external.rest.hostnameVerifier}",
    "proxy" : {
        "proxyUri" : "",
        "userName" : "",
        "password" : ""
    }
}

External REST Configuration Properties

socketTimeout (string)

The TCP socket timeout, in seconds, when waiting for HTTP responses. The default timeout is 10 seconds.

connectionTimeout (string)

The TCP connection timeout for new HTTP connections, in seconds. The default timeout is 10 seconds.

reuseConnections (boolean, true or false)

Specifies whether HTTP connections should be kept alive and reused for additional requests. By default, connections will be reused if possible.

retryRequests (boolean, true or false)

Specifies whether requests should be retried if a failure is detected. By default requests will be retried.

maxConnections (integer)

The maximum number of connections that should be pooled by the HTTP client. At most 64 connections will be pooled by default.

tlsVersion (string)

The TLS version that should be used for connections.

By default, TLS connections made via the external REST service use TLS version 1.2. In some cases, you might need to specify a different TLS version, for example, if you are connecting to a legacy system that supports an old version of TLS that is not accommodated by the backward-compatibility mode of your Java client. If you need to specify that the external REST service use a different TLS version, uncomment the openidm.external.rest.tls.version property towards the end of the resolver/boot.properties file and set its value, for example:

openidm.external.rest.tls.version=TLSv1.3

Valid versions for this parameter include TLSv1.1, TLSv1.2, and TLSv1.3.

hostnameVerifier (string)

Specifies whether the external REST service should check that the hostname to which an SSL client has connected is allowed by the certificate that is presented by the server.

The property can take the following values:

STRICT - hostnames are validated
ALLOW_ALL - the external REST service does not attempt to match the URL hostname to the SSL certificate Common Name, as part of its validation process

By default, this property is set in the resolver/boot.properties file and the value in conf/external.rest.json references that setting. For testing purposes, the default setting in boot.properties is:

openidm.external.rest.hostnameVerifier=ALLOW_ALL

If you do not set this property (by removing it from the boot.properties file or the conf/external.rest.json file), the behavior is to validate hostnames (the equivalent of setting "hostnameVerifier": "STRICT"). In production environments, you should set this property to STRICT.

proxy

Lets you set a proxy server specific to the external REST service. If you set a proxyUri here, the system-wide proxy settings described in HTTP Clients are ignored. To configure a system-wide proxy, leave these proxy settings empty and configure the HTTP Client settings instead.

Invocation Parameters

The following parameters are passed in the resource API parameters map. These parameters can override the static configuration (if present) on a per-invocation basis.

url

The target URL to invoke, in string format.

method

The HTTP action to invoke, in string format.

Possible actions include POST, GET, PUT, DELETE, and OPTIONS.

headers (optional)

The HTTP headers to set, in a map format from string (header-name) to string (header-value). For example, Accept-Language: en-US.

contentType (optional)

The media type of the data that is sent, for example "contentType" : "application/json". This parameter is applied only if no Content-Type header is included in the request. (If a Content-Type header is included, that header takes precedence over this contentType parameter.) If no Content-Type is provided (in the header or with this parameter), the default content type is application/json; charset=utf-8.

body (optional)

The body or resource representation to send (for PUT and POST operations), in string format.

base64 (boolean, optional)

Indicates that the body is base64-encoded, and should be decoded prior to transmission.

forceWrap (boolean, optional)

Indicates that the response must be wrapped in the headers/body JSON message format, even if the response was JSON, and would otherwise have been passed through unchanged.

If you need to disambiguate between HTTP 20x response codes, you must invoke the external REST service with forceWrap=true. For failure cases, the HTTP status code is present within the wrapped response embedded in the exception detail, or through the resource exception itself. For example:

curl \
--header "X-OpenIDM-Username: openidm-admin" \
--header "X-OpenIDM-Password: openidm-admin" \
--header "Content-Type: application/json" \
--header "Accept-API-Version: resource=1.0" \
--request POST \
--data '{
  "url": "http://urlecho.appspot.com/echo?status=203&Content-Type=application%2Fjson&body=%5B%7B%22key%22%3A%22value%22%7D%5D",
  "method": "GET",
  "forceWrap": true}' \
"http://localhost:8080/openidm/external/rest?_action=call"
{
  "headers": {
    "Access-Control-Allow-Origin": [
      "*"
    ],
    "Cache-Control": [
      "max-age=3600"
    ],
    "Content-Length": [
      "17"
    ],
    "Content-Type": [
      "application/json"
    ],
    "Date": [
      "Fri, 17 Jul 2020 10:55:54 GMT"
    ],
    "Server": [
      "Google Frontend"
    ],
    "X-Cloud-Trace-Context": [
      "11e4441659a85832e47af219d6e657af"
    ]
  },
  "code": 203,
  "body": [
    {
      "key": "value"
    }
  ]
}

authenticate

The authentication type, and the details with which to authenticate.

IDM supports the following authentication types:

basic authentication with a username and password, for example:

"authenticate" : {
    "type": "basic",
    "user" : "john",
    "password" : "Passw0rd"
}

bearer authentication, with an OAuth token instead of a username and password, for example:
```
"authenticate" : {
    "type": "bearer",
    "token" : "ya29.iQDWKpn8AHy09p....."
}
```

If no authenticate parameter is specified, no authentication is used.

Support for Non-JSON Responses

The external REST service supports any arbitrary payload (currently in stringified format). If the response is anything other than JSON, a JSON message object is returned:

For text-compatible (non-JSON) content, IDM returns a JSON object similar to the following:
```
{
    "headers": { "Content-Type": ["..."] },
    "body": "..."
}
```
Content that is not text-compatible (such as JPEGs) is base64-encoded in the response body and returned as follows:
```
{
    "headers": { "Content-Type": ["..."] },
    "body": "...",
    "base64": true
}
```

If the response format is JSON, the raw JSON response is returned. If you want to inspect the response headers, set forceWrap to true in your request. This setting returns a JSON message object with headers and body, similar to the object returned for text-compatible content.

IDM 7.3.1

Access External REST Services

Configure the External REST Service

External REST Configuration Properties

Invocation Parameters

Support for Non-JSON Responses