CsrParser.java

package io.fathom.cloud.secrets.services.ca;

import java.io.IOException;
import java.io.StringReader;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CodingErrorAction;

import org.bouncycastle.pkcs.PKCS10CertificationRequest;
import org.bouncycastle.util.io.pem.PemObject;
import org.bouncycastle.util.io.pem.PemReader;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.base.Charsets;

public class CsrParser {
    private static final Logger log = LoggerFactory.getLogger(CsrParser.class);

    public CsrParser() {
    }

    // static final String BEGIN_PEM = "-----BEGIN CERTIFICATE REQUEST-----";
    // static final String END_PEM = "-----END CERTIFICATE REQUEST-----";

    public Object parse(byte[] data) {
        Object key = null;

        if (key == null) {
            String s = tryDecodeAsString(data);
            if (s != null) {
                key = parse(s);
            }
        }

        return null;
    }

    public PKCS10CertificationRequest parse(String s) {
        PKCS10CertificationRequest key = null;

        if (key == null) {
            try {
                key = parsePemFormat(s);
            } catch (Exception e) {
                log.debug("Cannot debug as PEM", e);
            }
            // if (s.contains(BEGIN_PEM)) {
            // String payload = s.substring(s.indexOf(BEGIN_PEM) +
            // BEGIN_PEM.length());
            //
            // if (payload.contains(END_PEM)) {
            // payload = payload.substring(0, payload.indexOf(END_PEM) +
            // END_PEM.length());
            //
            // try {
            // key = parsePemFormat(payload);
            // } catch (Exception e) {
            // log.debug("Cannot debug as PEM", e);
            // }
            // }
            // }
        }

        // if (key == null) {
        // try {
        // // TODO: Check if looks like base64??
        // byte[] fromBase64 = CryptoUtils.fromBase64(s);
        //
        // key = parse(fromBase64);
        // } catch (Exception e) {
        // log.debug("Cannot decode as base64", e);
        // }
        // }

        return key;
    }

    private String tryDecodeAsString(byte[] data) {
        try {
            // We do this so we get strict input processing
            CharsetDecoder decoder = Charsets.UTF_8.newDecoder();
            decoder.onMalformedInput(CodingErrorAction.REPORT);
            decoder.onUnmappableCharacter(CodingErrorAction.REPORT);

            ByteBuffer byteBuffer = ByteBuffer.wrap(data);
            CharBuffer charBuffer = decoder.decode(byteBuffer);
            return charBuffer.toString();
        } catch (Exception e) {
            log.debug("Cannot decode as string", e);
            return null;
        }
    }

    private PKCS10CertificationRequest parsePemFormat(String data) throws IOException {
        PemReader reader = new PemReader(new StringReader(data));
        PemObject pemObject = reader.readPemObject();
        reader.close();

        PKCS10CertificationRequest csr = new PKCS10CertificationRequest(pemObject.getContent());
        return csr;
    }
}