How to call 3rd part REST API from AEM (in server side code)

[TB3dock]

There are some old posts which discuss this, but they point to broken links.

e.g. https://experienceleaguecommunities.adobe.com/t5/adobe-experience-manager/conclusion-consuming-rest-...

points to https://helpx.adobe.com/experience-manager/using/restful-services.html which gives 404.

https://github.com/brandonmaynard/aem-restful-api has a REST client, but no documentation.

https://aem4beginner.blogspot.com/invoke-rest-services-in-aem-right-way uses OpenFeign, which is not a library I have come across, and there is not much information on how to do this with AEM.

If this was a normal Java app, we could use jersy, Jax-rs or Spring RestTemplate. I am hoping AEM has one of the standard libraries built in.

I am guessing HttpUrlConnection might be included in AEM, in which case we could write our own REST handler on top of this if all else fails.

What does everyone use to make API calls from AEM?

[Asutosh_Jena_ · Accepted solution]

Hi @TB3dock 

You can use 

CloseableHttpClient client = HttpClients.createDefault()

and execute the REST APIs on AEM side.

For this you will need to add the below dependency and rest all will work like butter

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.8</version>
</dependency>

A sample method that I personally use for making all the API requests from AEM:

public APIResponse makePostWSCall(String endPointURL, String requestBody, Map<String, String> requestParams, Map<String, String> headers) {
    try (CloseableHttpClient client = HttpClients.createDefault()) {
        final long startTime = System.nanoTime();
        endPointURL = makeEndPointURL(endPointURL, requestParams);

        final String endPoint = StringEscapeUtils.escapeJava(endPointURL);
        log.debug("RestServiceImpl :: makePostWSCall :: EndPoint URL --> {}", endPoint);

        HttpPost httpPost = new HttpPost(endPointURL);
        if (null != headers && !headers.isEmpty()) {
            for (Map.Entry<String, String> headerEntry : headers.entrySet()) {
                httpPost.addHeader(headerEntry.getKey(), headerEntry.getValue());
            }
        }

        requestBody = WebServiceUtil.getPrettyJsonString(requestBody);
        log.debug("RestServiceImpl :: makePostWSCall :: Request Body --> {}", requestBody);
        if (StringUtils.isNotEmpty(requestBody)) {
            StringEntity stringEntity = new StringEntity(requestBody, ContentType.APPLICATION_JSON);
            httpPost.setEntity(stringEntity);
        }

        APIResponse apiResponse = new APIResponse();
        CloseableHttpResponse response = client.execute(httpPost);
        final int statusCode = response.getStatusLine().getStatusCode();
        apiResponse.setStatusCode(statusCode);
        log.info("RestServiceImpl :: makePostWSCall :: Response Status Code --> {}", statusCode);

        getResponse(endPointURL, startTime, apiResponse, response, "RestServiceImpl :: WSCall :: Response --> {}");

        return apiResponse;
    } catch (Exception e) {
        log.error("RestServiceImpl :: makePostWSCall :: Exception --> ", e);
    }
    return null;
}

Hope this will be helpful!

Thanks!

[Singaiah_Chintalapudi]

I would use Apache Http Client.

https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient

The JAX-RS comes with additional dependencies (this download additional javax dependencies) which might have a conflict with Sling dependencies.

Thanks,

Singaiah

[Rohit_Utreja]

Hi @TB3dock,

You can refer to below URL, it has a detailed implementation.

https://medium.com/@codeandtheory/invoke-rest-services-in-aem-the-right-way-c5fb0af43afe