Issue-52: Refactoring and adding unit tests to cover the compression functionality

src/main/java/io/jsonwebtoken/CompressionCodec.java

@@ -16,15 +16,29 @@
 package io.jsonwebtoken;
 
 /**
- * CompressionCodec
+ * Defines how to compress and decompress byte arrays.
  *
- * @since 0.59
+ * @since 0.5.2
  */
 public interface CompressionCodec {
 
+    /**
+     * The algorithm name that would appear in the JWT header.
+     * @return the algorithm name that would appear in the JWT header
+     */
     String getAlgorithmName();
 
+    /**
+     * Takes a byte array and returns a compressed version.
+     * @param payload bytes to compress
+     * @return compressed bytes
+     */
     byte[] compress(byte[] payload);
 
+    /**
+     * Takes a compressed byte array and returns a decompressed version.
+     * @param compressed compressed bytes
+     * @return decompressed bytes
+     */
     byte[] decompress(byte[] compressed);
 }

src/main/java/io/jsonwebtoken/CompressionCodecResolver.java

@@ -16,12 +16,16 @@
 package io.jsonwebtoken;
 
 /**
- * CompressionCodecResolver
+ * Resolves "calg" header to an implementation of CompressionCodec.
  *
  * @since 0.5.2
  */
 public interface CompressionCodecResolver {
-
+    /**
+     * Examines the header and returns a CompressionCodec if it finds one that it recognizes.
+     * @param header of the JWT
+     * @return CompressionCodec matching the "calg" header, or null if there is no "calg" header.
+     */
     CompressionCodec resolveCompressionCodec(Header header);
 
 }

src/main/java/io/jsonwebtoken/impl/compression/BaseCompressionCodec.java

@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2015 jsonwebtoken.io
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.jsonwebtoken.impl.compression;
+
+import io.jsonwebtoken.CompressionCodec;
+import io.jsonwebtoken.CompressionException;
+import io.jsonwebtoken.lang.Assert;
+
+import java.io.IOException;
+
+/**
+ * Base class that asserts arguments and wraps IOException with CompressionException.
+ *
+ * @since 0.5.2
+ */
+public abstract class BaseCompressionCodec implements CompressionCodec {
+    /**
+     * Implement this method to do the actual work of compressing the payload
+     * @param payload the bytes to compress
+     * @return the compressed bytes
+     * @throws IOException if the compression causes an IOException
+     */
+    protected abstract byte[] doCompress(byte[] payload) throws IOException;
+
+    /**
+     * Asserts that payload is not null and calls doCompress
+     * @param payload bytes to compress
+     * @return compressed bytes
+     * @throws CompressionException if doCompress throws an IOException
+     */
+    @Override
+    public final byte[] compress(byte[] payload) {
+        Assert.notNull(payload, "payload cannot be null.");
+
+        try {
+            return doCompress(payload);
+        } catch (IOException e) {
+            throw new CompressionException("Unable to compress payload.", e);
+        }
+    }
+
+    /**
+     * Asserts the compressed bytes is not null and calls doDecompress
+     * @param compressed compressed bytes
+     * @return decompressed bytes
+     * @throws CompressionException if doCompress throws an IOException
+     */
+    @Override
+    public final byte[] decompress(byte[] compressed) {
+        Assert.notNull(compressed, "compressed bytes cannot be null.");
+
+        try {
+            return doDecompress(compressed);
+        } catch (IOException e) {
+            throw new CompressionException("Unable to decompress bytes.", e);
+        }
+    }
+
+    /**
+     * Implement this method to do the actual work of decompressing the compressed bytes.
+     * @param compressed compressed bytes
+     * @return decompressed bytes
+     * @throws IOException if the decompression runs into an IO problem
+     */
+    protected abstract byte[] doDecompress(byte[] compressed) throws IOException;
+}

src/main/java/io/jsonwebtoken/impl/compression/CompressionCodecs.java

@@ -22,13 +22,16 @@ import io.jsonwebtoken.CompressionCodec;
  *
  * @since 0.5.2
  */
-public abstract class CompressionCodecs {
+public interface CompressionCodecs {
 
-    private CompressionCodecs(){}
-
-    public static final CompressionCodec DEFLATE = new DeflateCompressionCodec();
-
-    public static final CompressionCodec GZIP = new GzipCompressionCodec();
+    /**
+     * Codec implementing the <a href="https://en.wikipedia.org/wiki/DEFLATE">deflate</a> compression algorithm
+     */
+    CompressionCodec DEFLATE = new DeflateCompressionCodec();
 
+    /**
+     * Codec implementing the <a href="https://en.wikipedia.org/wiki/Gzip">gzip</a> compression algorithm
+     */
+    CompressionCodec GZIP = new GzipCompressionCodec();
 
 }

src/main/java/io/jsonwebtoken/impl/compression/DefaultCompressionCodecResolver.java

@@ -23,7 +23,8 @@ import io.jsonwebtoken.lang.Assert;
 import io.jsonwebtoken.lang.Strings;
 
 /**
- * DefaultCompressionCodecResolver
+ * Default implementation of {@link CompressionCodecResolver}.  This implementation will resolve DEF to
+ * {@link DeflateCompressionCodec} and GZIP to {@link GzipCompressionCodec}.
  *
  * @since 0.5.2
  */
@@ -31,22 +32,25 @@ public class DefaultCompressionCodecResolver implements CompressionCodecResolver
 
     @Override
     public CompressionCodec resolveCompressionCodec(Header header) {
-        Assert.notNull(header, "header cannot be null.");
+        String cmpAlg = getAlgorithmFromHeader(header);
 
-        String cmpAlg = header.getCompressionAlgorithm();
-
-        if (!Strings.hasText(cmpAlg)) {
+        final boolean hasCompressionAlgorithm = Strings.hasText(cmpAlg);
+        if (!hasCompressionAlgorithm) {
             return null;
         }
-
         if (CompressionCodecs.DEFLATE.getAlgorithmName().equalsIgnoreCase(cmpAlg)) {
             return CompressionCodecs.DEFLATE;
         }
-
         if (CompressionCodecs.GZIP.getAlgorithmName().equalsIgnoreCase(cmpAlg)) {
             return CompressionCodecs.GZIP;
         }
 
         throw new CompressionException("Unsupported compression algorithm '" + cmpAlg + "'");
     }
+
+    protected final String getAlgorithmFromHeader(Header header) {
+        Assert.notNull(header, "header cannot be null.");
+
+        return header.getCompressionAlgorithm();
+    }
 }

src/main/java/io/jsonwebtoken/impl/compression/DeflateCompressionCodec.java

@@ -15,9 +15,6 @@
  */
 package io.jsonwebtoken.impl.compression;
 
-import io.jsonwebtoken.CompressionCodec;
-import io.jsonwebtoken.CompressionException;
-import io.jsonwebtoken.lang.Assert;
 import io.jsonwebtoken.lang.Objects;
 
 import java.io.ByteArrayOutputStream;
@@ -27,11 +24,10 @@ import java.util.zip.DeflaterOutputStream;
 import java.util.zip.InflaterOutputStream;
 
 /**
- * DeflateCompressionCodec
- *
+ * Codec implementing the <a href="https://en.wikipedia.org/wiki/DEFLATE">deflate</a> compression algorithm
  * @since 0.5.2
  */
-public class DeflateCompressionCodec implements CompressionCodec {
+public class DeflateCompressionCodec extends BaseCompressionCodec {
 
     private static final String DEFLATE = "DEF";
 
@@ -41,8 +37,7 @@ public class DeflateCompressionCodec implements CompressionCodec {
     }
 
     @Override
-    public byte[] compress(byte[] payload) {
-        Assert.notNull(payload, "payload cannot be null.");
+    public byte[] doCompress(byte[] payload) throws IOException {
 
         Deflater deflater = new Deflater(Deflater.BEST_COMPRESSION);
 
@@ -55,17 +50,13 @@ public class DeflateCompressionCodec implements CompressionCodec {
             deflaterOutputStream.write(payload, 0, payload.length);
             deflaterOutputStream.flush();
             return outputStream.toByteArray();
-        } catch (IOException e) {
-            throw new CompressionException("Unable to compress payload.", e);
         } finally {
             Objects.nullSafeClose(outputStream, deflaterOutputStream);
         }
     }
 
     @Override
-    public byte[] decompress(byte[] compressed) {
-        Assert.notNull(compressed, "compressed cannot be null.");
-
+    public byte[] doDecompress(byte[] compressed) throws IOException {
         InflaterOutputStream inflaterOutputStream = null;
         ByteArrayOutputStream decompressedOutputStream = null;
 
@@ -75,8 +66,6 @@ public class DeflateCompressionCodec implements CompressionCodec {
             inflaterOutputStream.write(compressed);
             inflaterOutputStream.flush();
             return decompressedOutputStream.toByteArray();
-        } catch (IOException e) {
-            throw new CompressionException("Unable to decompress compressed payload.", e);
         } finally {
             Objects.nullSafeClose(decompressedOutputStream, inflaterOutputStream);
         }

src/main/java/io/jsonwebtoken/impl/compression/GzipCompressionCodec.java

@@ -16,8 +16,6 @@
 package io.jsonwebtoken.impl.compression;
 
 import io.jsonwebtoken.CompressionCodec;
-import io.jsonwebtoken.CompressionException;
-import io.jsonwebtoken.lang.Assert;
 import io.jsonwebtoken.lang.Objects;
 
 import java.io.ByteArrayInputStream;
@@ -27,11 +25,11 @@ import java.util.zip.GZIPInputStream;
 import java.util.zip.GZIPOutputStream;
 
 /**
- * GzipCompressionCodec
+ * Codec implementing the <a href="https://en.wikipedia.org/wiki/Gzip">gzip</a> compression algorithm
  *
  * @since 0.5.2
  */
-public class GzipCompressionCodec implements CompressionCodec {
+public class GzipCompressionCodec extends BaseCompressionCodec implements CompressionCodec {
 
     private static final String GZIP = "GZIP";
 
@@ -41,29 +39,7 @@ public class GzipCompressionCodec implements CompressionCodec {
     }
 
     @Override
-    public byte[] compress(byte[] payload) {
-        Assert.notNull(payload, "payload cannot be null.");
-
-        ByteArrayOutputStream outputStream = null;
-        GZIPOutputStream gzipOutputStream = null;
-
-        try {
-            outputStream = new ByteArrayOutputStream();
-            gzipOutputStream = new GZIPOutputStream(outputStream, true);
-            gzipOutputStream.write(payload, 0, payload.length);
-            gzipOutputStream.finish();
-            return outputStream.toByteArray();
-        } catch (IOException e) {
-            throw new CompressionException("Unable to compress payload.", e);
-        } finally {
-            Objects.nullSafeClose(outputStream, gzipOutputStream);
-        }
-    }
-
-    @Override
-    public byte[] decompress(byte[] compressed) {
-        Assert.notNull(compressed, "compressed cannot be null.");
-
+    protected byte[] doDecompress(byte[] compressed) throws IOException {
         byte[] buffer = new byte[512];
 
         ByteArrayOutputStream outputStream = null;
@@ -79,10 +55,20 @@ public class GzipCompressionCodec implements CompressionCodec {
                 outputStream.write(buffer, 0, read);
             }
             return outputStream.toByteArray();
-        } catch (IOException e) {
-            throw new CompressionException("Unable to decompress compressed payload.", e);
         } finally {
             Objects.nullSafeClose(inputStream, gzipInputStream, outputStream);
         }
     }
+
+    protected byte[] doCompress(byte[] payload) throws IOException {
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        GZIPOutputStream compressorOutputStream = new GZIPOutputStream(outputStream, true);
+        try {
+            compressorOutputStream.write(payload, 0, payload.length);
+            compressorOutputStream.finish();
+            return outputStream.toByteArray();
+        } finally {
+            Objects.nullSafeClose(compressorOutputStream, outputStream);
+        }
+    }
 }

src/test/groovy/io/jsonwebtoken/JwtsTest.groovy

@@ -20,9 +20,12 @@ import io.jsonwebtoken.impl.DefaultHeader
 import io.jsonwebtoken.impl.DefaultJwsHeader
 import io.jsonwebtoken.impl.TextCodec
 import io.jsonwebtoken.impl.compression.CompressionCodecs
+import io.jsonwebtoken.impl.compression.DefaultCompressionCodecResolver
+import io.jsonwebtoken.impl.compression.GzipCompressionCodec
 import io.jsonwebtoken.impl.crypto.EllipticCurveProvider
 import io.jsonwebtoken.impl.crypto.MacProvider
 import io.jsonwebtoken.impl.crypto.RsaProvider
+import io.jsonwebtoken.lang.Strings
 import org.junit.Test
 
 import javax.crypto.Mac
@@ -109,6 +112,7 @@ class JwtsTest {
 
         def token = Jwts.parser().parse(jwt);
 
+        //noinspection GrEqualsBetweenInconvertibleTypes
         assert token.body == claims
     }
 
@@ -331,6 +335,27 @@ class JwtsTest {
         assertNull claims.getId()
     }
 
+    @Test
+    void testUncompressedJwt() {
+
+        byte[] key = MacProvider.generateKey().getEncoded()
+
+        String id = UUID.randomUUID().toString()
+
+        String compact = Jwts.builder().setId(id).setAudience("an audience").signWith(SignatureAlgorithm.HS256, key)
+                .claim("state", "hello this is an amazing jwt").compact()
+
+        def jws = Jwts.parser().setSigningKey(key).parseClaimsJws(compact)
+
+        Claims claims = jws.body
+
+        assertNull jws.header.getCompressionAlgorithm()
+
+        assertEquals id, claims.getId()
+        assertEquals "an audience", claims.getAudience()
+        assertEquals "hello this is an amazing jwt", claims.state
+    }
+
     @Test
     void testCompressedJwtWithDeflate() {
 
@@ -373,6 +398,58 @@ class JwtsTest {
         assertEquals "hello this is an amazing jwt", claims.state
     }
 
+    @Test
+    void testCompressedWithCustomResolver() {
+        byte[] key = MacProvider.generateKey().getEncoded()
+
+        String id = UUID.randomUUID().toString()
+
+        String compact = Jwts.builder().setId(id).setAudience("an audience").signWith(SignatureAlgorithm.HS256, key)
+                .claim("state", "hello this is an amazing jwt").compressWith(new GzipCompressionCodec() {
+            @Override
+            String getAlgorithmName() {
+                return "CUSTOM"
+            }
+        }).compact()
+
+        def jws = Jwts.parser().setSigningKey(key).setCompressionCodecResolver(new DefaultCompressionCodecResolver() {
+            @Override
+            CompressionCodec resolveCompressionCodec(Header header) {
+                String algorithm = getAlgorithmFromHeader(header);
+                if ("CUSTOM".equals(algorithm)) {
+                    return CompressionCodecs.GZIP
+                } else {
+                    return null
+                }
+            }
+        }).parseClaimsJws(compact)
+
+        Claims claims = jws.body
+
+        assertEquals "CUSTOM", jws.header.getCompressionAlgorithm()
+
+        assertEquals id, claims.getId()
+        assertEquals "an audience", claims.getAudience()
+        assertEquals "hello this is an amazing jwt", claims.state
+
+    }
+    @Test(expected = CompressionException.class)
+    void testCompressedJwtWithUnrecognizedHeader() {
+        byte[] key = MacProvider.generateKey().getEncoded()
+
+        String id = UUID.randomUUID().toString()
+
+        String compact = Jwts.builder().setId(id).setAudience("an audience").signWith(SignatureAlgorithm.HS256, key)
+                .claim("state", "hello this is an amazing jwt").compressWith(new GzipCompressionCodec() {
+            @Override
+            String getAlgorithmName() {
+                return "CUSTOM"
+            }
+        }).compact()
+
+        Jwts.parser().setSigningKey(key).parseClaimsJws(compact)
+    }
+
     @Test
     void testCompressStringPayloadWithDeflate() {
 
@@ -643,6 +720,7 @@ class JwtsTest {
         def token = Jwts.parser().setSigningKey(key).parse(jwt);
 
         assert [alg: alg.name()] == token.header
+        //noinspection GrEqualsBetweenInconvertibleTypes
         assert token.body == claims
     }
 
@@ -657,6 +735,7 @@ class JwtsTest {
         def token = Jwts.parser().setSigningKey(key).parse(jwt)
 
         assert token.header == [alg: alg.name()]
+        //noinspection GrEqualsBetweenInconvertibleTypes
         assert token.body == claims
     }
 
@@ -678,6 +757,7 @@ class JwtsTest {
         def token = Jwts.parser().setSigningKey(key).parse(jwt);
 
         assert token.header == [alg: alg.name()]
+        //noinspection GrEqualsBetweenInconvertibleTypes
         assert token.body == claims
     }
 }

src/test/groovy/io/jsonwebtoken/impl/compression/BaseCompressionCodecTest.groovy

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2015 jsonwebtoken.io
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.jsonwebtoken.impl.compression
+
+import io.jsonwebtoken.CompressionCodec
+import io.jsonwebtoken.CompressionException
+import org.junit.Test
+
+/**
+ * @since 0.5.2
+ */
+class BaseCompressionCodecTest {
+    static class ExceptionThrowingCodec extends BaseCompressionCodec {
+
+        @Override
+        protected byte[] doCompress(byte[] payload) throws IOException {
+            throw new IOException("Test Exception")
+        }
+
+        @Override
+        String getAlgorithmName() {
+            return "Test"
+        }
+
+        @Override
+        protected byte[] doDecompress(byte[] payload) throws IOException {
+            throw new IOException("Test Decompress Exception");
+        }
+    }
+
+    @Test(expected = CompressionException.class)
+    void testCompressWithException() {
+        CompressionCodec codecUT = new ExceptionThrowingCodec();
+        codecUT.compress(new byte[0]);
+    }
+
+    @Test(expected = CompressionException.class)
+    void testDecompressWithException() {
+        CompressionCodec codecUT = new ExceptionThrowingCodec();
+        codecUT.decompress(new byte[0]);
+    }
+}