Package org.dspace.app.rest

Class AltchaCaptchaRestController

java.lang.Object

org.dspace.app.rest.AltchaCaptchaRestController

All Implemented Interfaces:

InitializingBean

@RequestMapping("/api/captcha")
@RestController
public class AltchaCaptchaRestController
extends Object
implements InitializingBean

ALTCHA (Proof of Work, cookie-less) controller to handle challenge requests. A salt, challenge hash will be sent and the client will have to calculate the number and send it back to implementing controllers (e.g. request-a-copy) for validation. The proof-of-work makes spam uneconomic, without requiring annoying puzzle tests or 3rd party services.

Author:

Kim Shepherd

See Also:

• RequestItemRepository
• Altcha docs>

Constructor Summary

Constructors

Constructor	Description
AltchaCaptchaRestController()

Method Summary

Modifier and Type	Method	Description
void	afterPropertiesSet()
static String	bytesToHex(byte[] bytes)	Encode bytes to hex string
static String	calculateHash(String input, String algorithm)	Calculate a hex string from a digest, given an input string
ResponseEntity	getAltchaChallenge(jakarta.servlet.http.HttpServletRequest request, jakarta.servlet.http.HttpServletResponse response)	Calculate a challenge for ALTCHA captcha See https://altcha.org/docs/server-integration for implementation details and examples

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

AltchaCaptchaRestController

public AltchaCaptchaRestController()

Method Details

getAltchaChallenge

@GetMapping("/challenge")
@PreAuthorize("permitAll()")
public ResponseEntity getAltchaChallenge(jakarta.servlet.http.HttpServletRequest request,
 jakarta.servlet.http.HttpServletResponse response)

Calculate a challenge for ALTCHA captcha See https://altcha.org/docs/server-integration for implementation details and examples

Parameters:

request - HTTP request

response - HTTP response

Returns:

response entity with JSON challenge for client to begin proof-of-work

bytesToHex

public static String bytesToHex(byte[] bytes)

Encode bytes to hex string

Parameters:

bytes - bytes to encode

Returns:

hex string

calculateHash

public static String calculateHash(String input,
 String algorithm)
                            throws NoSuchAlgorithmException

Calculate a hex string from a digest, given an input string

Parameters:

input - input string

algorithm - algorithm key, eg. SHA-256

Returns:

Throws:

NoSuchAlgorithmException

afterPropertiesSet

public void afterPropertiesSet()
                        throws Exception

Specified by:

afterPropertiesSet in interface InitializingBean

Throws:

Exception