Example usage for org.springframework.social.facebook.web SignedRequestException SignedRequestException

Introduction

In this page you can find the example usage for org.springframework.social.facebook.web SignedRequestException SignedRequestException.

Prototype

public SignedRequestException(String message) 

Source Link

Usage

From source file:org.springframework.social.facebook.web.SignedRequestDecoder.java

/**
 * Decodes a signed request, returning the payload of the signed request as a specified type.
 * @param signedRequest the value of the signed_request parameter sent by Facebook.
 * @param type the type to bind the signed_request to.
 * @param <T> the Java type to bind the signed_request to.
 * @return the payload of the signed request as an object
 * @throws SignedRequestException if there is an error decoding the signed request
 *///from   w  ww  .  j  ava  2 s.  com
public <T> T decodeSignedRequest(String signedRequest, Class<T> type) throws SignedRequestException {
    String[] split = signedRequest.split("\\.");
    String encodedSignature = split[0];
    String payload = split[1];
    String decoded = base64DecodeToString(payload);
    byte[] signature = base64DecodeToBytes(encodedSignature);
    try {
        T data = objectMapper.readValue(decoded, type);
        String algorithm = objectMapper.readTree(decoded).get("algorithm").textValue();
        if (algorithm == null || !algorithm.equals("HMAC-SHA256")) {
            throw new SignedRequestException("Unknown encryption algorithm: " + algorithm);
        }
        byte[] expectedSignature = encrypt(payload, secret);
        if (!Arrays.equals(expectedSignature, signature)) {
            throw new SignedRequestException("Invalid signature.");
        }
        return data;
    } catch (IOException e) {
        throw new SignedRequestException("Error parsing payload.", e);
    }
}

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