Generate Access Token
[AEM Forms as a Cloud Service]{class="badge informative"}
An access token is a credential used to authenticate and authorize requests to a REST API. It is typically issued by an authentication server (such as OAuth 2.0 or OpenID Connect) after a user or application successfully logs in. When calling a secured Forms Document Services API, an access token is included in the request header to verify the client’s identity.
The following is an example request of sending access token
POST /api/data HTTP/1.1
Host: example.com
Authorization: Bearer eyJhbGciOiJIUzI1...
The following code was used to generate the access token
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class AccessTokenService {
private static final Logger logger = LoggerFactory.getLogger(AccessTokenService.class);
public String getAccessToken() {
ClassLoader classLoader = AccessTokenService.class.getClassLoader();
try (InputStream inputStream = classLoader.getResourceAsStream("credentials/server_credentials.json")) {
if (inputStream == null) {
logger.error("File not found: credentials/server_credentials.json");
throw new IllegalArgumentException("Missing credentials file");
}
try (InputStreamReader reader = new InputStreamReader(inputStream, StandardCharsets.UTF_8);
CloseableHttpClient httpClient = HttpClients.createDefault()) {
JsonObject jsonObject = JsonParser.parseReader(reader).getAsJsonObject();
String clientId = jsonObject.get("clientId").getAsString();
String clientSecret = jsonObject.get("clientSecret").getAsString();
String adobeIMSV3TokenEndpointURL = jsonObject.get("adobeIMSV3TokenEndpointURL").getAsString();
String scopes = jsonObject.get("scopes").getAsString();
HttpPost request = new HttpPost(adobeIMSV3TokenEndpointURL);
request.setHeader("Content-Type", "application/x-www-form-urlencoded");
String requestBody = "grant_type=client_credentials&client_id=" + clientId +
"&client_secret=" + clientSecret +
"&scope=" + scopes;
request.setEntity(new StringEntity(requestBody, ContentType.APPLICATION_FORM_URLENCODED));
logger.info("Requesting access token from {}", adobeIMSV3TokenEndpointURL);
try (CloseableHttpResponse response = httpClient.execute(request)) {
String responseString = EntityUtils.toString(response.getEntity());
JsonObject jsonResponse = JsonParser.parseString(responseString).getAsJsonObject();
if (!jsonResponse.has("access_token")) {
logger.error("Access token not found in response: {}", responseString);
return null;
}
String accessToken = jsonResponse.get("access_token").getAsString();
logger.info("Successfully obtained access token.");
return accessToken;
}
}
} catch (Exception e) {
logger.error("Error fetching access token", e);
}
return null;
}
}
The AccessTokenService class is responsible for retrieving an OAuth access token from ÃÛ¶¹ÊÓƵ’s IMS authentication service. It reads client credentials from a JSON file (server_credentials.json), constructs an authentication request, and sends it to the ÃÛ¶¹ÊÓƵ token endpoint. The response is then parsed to extract the access token, which is used for secure API calls. The class includes proper logging and error handling to ensure reliability and easier debugging.