idam-forgerock-http-client

OpenAPI (fka Swagger) specification for Forgerock IDM and AM

Introduction

This project is an adaptation of the Forgerock am and idm swagger generated json spec to OpenApi 2.0 yaml.

Throw in the swagger-codegen plugin, with the feign library, and you have a 'mostly' working http client. At the very least the models are generally accurate.

Getting started

• Rip the JSON from your desired endpoint by adding ?_api to the url

http://forgerock-idm/openidm/managed/role?_api http://localhost:8080/openam/json/realm-config/agents/OAuth2Client?_api

Now you have some json:

    "{swagger":"2.0","info":{"version":"1.0","title":"OpenAM"},"host":"....

• Dump it into the swagger hub editor: https://app.swaggerhub.com/apis/

Now you have some yaml:

swagger: '2.0'
info:
  version: 5.5.0
  title: ForgeRock AM Agents API

• Make a file in src/main/resources with the yaml and checkout the section titled Fixing the yaml below

• Add the file to the build.gradle task generateApi

    generateCodeFromSwagger('src/main/resources/forgerock-am-authentication.yaml', 'am.oidc', [
            'Response'  : 'feign.Response'
    ])

the inputs are path to file, package, Object mappings

Object mappings are basically if you want to reference a definition like '#/definitions/MySpecialObject' but MySpecialObject is not defined specifically within the same yaml spec or will not be in the same package.

---

Eg. You want the feign client to return a IdmUser object, but you have already defined IdmUser in forgerock-idm-user-management.yaml so it will be built into the package:

org.forgerock.idm.user.management.IdmUser

And the yaml forgerock-idm-user-role-management.yaml would build another version of the same object into a different directory like:

org.forgerock.idm.user.role.management.IdmUser

You can just exclude the definition from forgerock-idm-user-role-management.yaml and add a mapping of:

    generateCodeFromSwagger('src/main/resources/forgerock-idm-user-role-management.yaml', 'idm.user.role', [
            'IdmUser' : 'org.forgerock.idm.user.management.IdmUser'
    ])

so it knows how to map the object return from the API method

---

Eg: You want the feign client to return a feign.Response instead of deserialize the result into some model, you can reference #/definitions/Response and map the class to the definition like shown above.

Fixing the yaml

Aka: using find-replace

• The definition names make no sense

#/definitions/urn:jsonschema:org:forgerock:openidm:managed:api:Role:assignments:items

Read this as Object Role has assignments and it's a list, each item is defined with the above definition

Find Replace :

urn:jsonschema:org:forgerock:openidm:managed:api:Role:assignments:items

To:

RoleAssignments

Which makes sense, and will make a Java class called RoleAssignments.java

• The definition names are random uuid

#/definitions/urn:uuid:f891dcb6-928e-4e64-9d0e-4767870a7a34

urn:uuid:f891dcb6-928e-4e64-9d0e-4767870a7a34 references a generated definition of a parameterized ResultSet object, like:

    {
        "result": [
            { "INSERT ANY" : "OBJECT HERE" }
        ],
        "resultCount": 1,
        "pagedResultsCookie": null,
        "totalPagedResultsPolicy": "NONE",
        "totalPagedResults": -1,
        "remainingPagedResults": -1
    }

Figure out what the object is, and rename the definition to RolesQueryResultSet or whatever

keep in mind there may be multiple generated versions of the same result set, delete the duplicates and fix the definition pointers

• Puts can be used for modification or creation

You will see PUT methods have multiple versions, usually 2 with one having an _action=create

Basically remove the extra PUT method, and add optional _action parameter to the original.

Also make sure that both the If-None-Match and If-Match headers are available.

     put:
       summary: Create with Client-Assigned ID or Update Entity
       operationId: putIfRevision
       parameters:
         - name: userId
           in: path
           required: true
           type: string
         - $ref: '#/parameters/_fields'
         - $ref: '#/parameters/_prettyPrint'
         - in: body
           name: requestPayload
           required: true
           schema:
             $ref: '#/definitions/User'
         - $ref: '#/parameters/If-None-Match-Star'
         - $ref: '#/parameters/If-Match'

• The paths seem broken! Hashes everywhere!

"/realm-config/agents/OAuth2Client#_action_getcreatabletypes"

This means if you post to this endpoint with _action set to _getCreatableTypes it will return a different result, or possibly the same result but basically it's handled by a different method so it shows up as a different endpoint.

• Delete this endpoint from the spec, make sure that _action in the base post:

  /json/realms/root/realms/{realm}/realm-config/agents/OAuth2Client:
    post:
      summary: 'Action: getAllTypes'
      operationId: actionGetAllTypes
      parameters:
        - $ref: '#/parameters/_action'
      responses:
        '200':
          description: Success
          schema:
            type: '#/definitions/Response'
      description: Call the endpoint with various actions
      tags:
        - OAuth2 Client Agents

Has all the required actions in its enum:

  _action:
    name: _action
    in: query
    required: true
    type: string
    enum:
      - getAllTypes
      - getCreatableTypes
      - nextdescendents
      - schema
      - template

and if you want to use this endpoint for one of these actions..

    new ObjectMapper().readValue(response.body().asInputStream(), <Whatever>.class);

Cast it to whatever the result will be from that action, which will probably just take some testing with postman or you can print the result as a string to see the JSON.

How to use

The ApiClient is basically a holder for the configuration your Feign Clients will be built from.

It has a FeignBuilder, some Authorization stuff, holds the interceptors for clients built from it.

Now that last part is important. If you have ApiClient (idmApiClient) and ApiClient (amApiClient) and you build the Feign Client from the wrong ApiClient you will end up with the wrong interceptors.

• Define the Client bean with your configuration classes by:

    @Bean
    public ApiClient idmApiClient(ErrorDecoder errorDecoder,
                                  Client httpClient, Encoder encoder) {
        ApiClient client =  new ApiClient();
        client.getFeignBuilder().errorDecoder(errorDecoder)
            .requestInterceptors(idmInterceptors)
            .client(httpClient).encoder(encoder);
        return client;
    }

• Build your clients :

    @Bean
    public RoleApi roleApi(@Qualifier("idmApiClient") ApiClient client) {
        return buildFeignClient(client, RoleApi.class);
    }
    
    private <T> T buildFeignClient(ApiClient client, Class<T> clazz) {
        return client.getFeignBuilder()
            .logger(new Slf4jLogger(clazz))
            .target(clazz, <Target AM/FR URL>); //Here is the URL of the Target server (http://host:port/openam)
    }

Work Around

• Feign doesnt remove headers that are null

Instead they will show up like this: Authorization: {authorization}

The following method in a feign.RequestInterceptor will solve the problem :

    class HeaderSanitizingInterceptor implements RequestInterceptor {
        @Override public void apply(RequestTemplate template) {
            Map<String, Collection<String>> headers = template.headers();
            Map<String, Collection<String>> sanitizedHeaders = Maps.newConcurrentMap();
            headers.entrySet().stream()
                .filter(e -> e.getValue().stream().noneMatch(s -> s.matches("\\{.*\\}")))
                .forEach(e -> sanitizedHeaders.put(e.getKey(), e.getValue()));
            template.headers(null);
            template.headers(sanitizedHeaders);
        }
    }

Doing it like this makes it thread safe, using the single replace cannot be done whilst iterating over the collection

• Swagger generator makes snake_case form parameters into camelCase

The following method in a feign.RequestInterceptor will solve the problem :

    class AccessTokenRequestInterceptor implements RequestInterceptor {
        @Override public void apply(RequestTemplate template) {
            if (template.url().contains("access_token")) {
                String newBody = new String(template.body());
                newBody = newBody.replace("grantType", "grant_type");
                newBody = newBody.replace("redirectUri", "redirect_uri");
                newBody = newBody.replace("clientId", "client_id");
                newBody = newBody.replace("clientSecret", "client_secret");
                template.body(newBody.getBytes(), UTF_8);
            }
            if (template.url().contains("idtokeninfo")) {
                String newBody = new String(template.body());
                newBody = newBody.replace("idToken", "id_token");
                template.body(newBody.getBytes(), UTF_8);
            }
        }
    }

Basically just replace them, this is due to how the Api is generated.

There is no better work around as far as I know.

• Feign doesnt handle 3xx HTTP Responses

• feign.Responses to the rescue

If the call might return a 3xx response like say the OAuth2 Code request, make the return feign.Response and then you can handle it instead of Feign throwing exceptions

            Response feignResponse = openIdConnectApi.oauth2Authorize(IPLANET_COOKIE_NAME+"="+token.getTokenId(),
                token.getTokenId(), "scope1 scope2",
                new OpenIdConnectApi.Oauth2AuthorizeQueryParams()
                    .clientId("test_client")
                    .responseType("code")
                    .realm("realm")
                    .decision("Allow")
                    .redirectUri("http://www.test_client.com"));

            String code = UriComponentsBuilder.fromUriString(feignResponse.headers().get(HttpHeaders.LOCATION)
                .stream().findFirst().orElse("")).build()
                .getQueryParams().getFirst("code");