[JAVA] Create an RSA encryption-enabled JSON API with wicket

environment

• Eclipse Photon (4.8)
• Java 8
• Wicket 7.10
• Tomcat 8
• jackson 2.9.2
• jsencrypt

background

I want to communicate using JSON on the wicket page! By the way, with an encrypted request ...

Request with jsencrypt for RSA encryption

Set the public key to pubKey.

myjsencrypt.js

my.jsencrypt = {
        pubKey: '-----BEGIN PUBLIC KEY-----\
Public key content
-----END PUBLIC KEY-----\
'

Initialize.

myjsencrypt.js

        // encryption setting
        var encrypt = new JSEncrypt();
        encrypt.setPublicKey(my.jsencrypt.pubKey);

Throw a request.

myjsencrypt.js

        // request
        var xhr = new XMLHttpRequest();
        xhr.open("POST",Destination URL, true);
        xhr.setRequestHeader("content-type", "application/json");
        xhr.send( encrypt.encrypt(JSON.stringify(data)) );

Library for json

There seem to be various things, but jackson seemed to be good, so I tried using it. It's actually easy to use. Just set the installation in pom.xml.

pom.xml

		<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core -->
		<dependency>
			<groupId>com.fasterxml.jackson.core</groupId>
			<artifactId>jackson-core</artifactId>
			<version>2.9.2</version>
		</dependency>

Page processing with Wicket

Get the request and make it a parameter. For RSAUtil, refer to RSA Encryption / Decryption with java 8.

MyJsonPage.java

		RequestCycle requestCycle = getRequestCycle();
		final WebRequest webRequest = (WebRequest) getRequest();
		final HttpServletRequest rawRequest = (HttpServletRequest) webRequest.getContainerRequest();

		BufferedReader br = null;
		JsonFactory jsonFactory = new JsonFactory();
		ObjectMapper jsonMapper = new ObjectMapper(jsonFactory);

		// <Parameter name,value>Make a Map of
		TypeReference<ConcurrentHashMap<String,String>> typeRef = new TypeReference<ConcurrentHashMap<String,String>>(){};

		try {
			StringBuffer sb = new StringBuffer();
			br = rawRequest.getReader();

			for (String line = br.readLine(); line != null; line = br.readLine()) {
				sb.append(line);
			}

			// decrypt RSA input
			PrivateKey privKey = RSAUtil.readPrvateKeyFromPem(Private key file);
			String decrypted = RSAUtil.decryptWithPrivateKey(sb.toString(), privKey);

			// decrypted params to json map
			inputJsonMap = jsonMapper.readValue(decrypted, typeRef);

		} catch (Exception e) {
			/*Error handling*/
		}

Now that the parameters have been obtained, process on this page ...

Prepare a method for setting Content-Type.

MyJsonPage.java

	// Set content-type
	protected String getContentType() {
		final String encoding = getApplication().getRequestCycleSettings().getResponseRequestEncoding();
		return "application/json; charset=" + encoding;
	}

Returns JSON for the result.

MyJsonPage.java

		// build JSON response
		try {
			jsonResponse = jsonMapper.writerWithDefaultPrettyPrinter().writeValueAsString(returnObject);
		} catch (JsonProcessingException e) {
			/*Error handling*/
		}

		requestCycle.scheduleRequestHandlerAfterCurrent(
				new ResourceStreamRequestHandler(
					new StringResourceStream(jsonResponse)	) {

					@Override
					public void respond(IRequestCycle requestCycle) {
						((WebResponse) requestCycle.getResponse()).setContentType(getContentType());
						super.respond(requestCycle);
					}
				}
				);

It's convenient because it converts from Object to JSON. PrettyPrinter is included because it is easy to see.

that's all. Thank you for your hard work!