Add support for passing json values for header and payload

lib/build.gradle

@@ -72,7 +72,7 @@ javadoc {
 }
 
 dependencies {
-    implementation 'com.fasterxml.jackson.core:jackson-databind:2.13.4.2'
+    implementation 'com.fasterxml.jackson.core:jackson-databind:2.14.0'
 
     testImplementation 'org.bouncycastle:bcprov-jdk15on:1.70'
     testImplementation 'junit:junit:4.13.2'

lib/src/main/java/com/auth0/jwt/JWTCreator.java

@@ -98,6 +98,24 @@ public Builder withHeader(Map<String, Object> headerClaims) {
             return this;
         }
 
+        /**
+         * Add specific Claims to set as the Header.
+         * If provided json is null then nothing is changed
+         *
+         * @param headerClaimsJson the values to use as Claims in the token's Header.
+         * @return this same Builder instance.
+         * @throws JsonProcessingException if json value has invalid structure
+         */
+        public Builder withHeader(String headerClaimsJson) throws JsonProcessingException {
+            if (headerClaimsJson == null) {
+                return this;
+            }
+
+            Map<String, Object> headerClaims = mapper.readValue(headerClaimsJson, HashMap.class);
+
+            return withHeader(headerClaims);
+        }
+
         /**
          * Add a specific Key Id ("kid") claim to the Header.
          * If the {@link Algorithm} used to sign this token was instantiated with a KeyProvider,
@@ -467,6 +485,30 @@ public Builder withPayload(Map<String, ?> payloadClaims) throws IllegalArgumentE
             return this;
         }
 
+        /**
+         * Add specific Claims to set as the Payload. If the provided json is null then
+         * nothing is changed.
+         *
+         * <p>
+         * If any of the claims are invalid, none will be added.
+         * </p>
+         *
+         * @param payloadClaimsJson the values to use as Claims in the token's payload.
+         * @return this same Builder instance.
+         * @throws IllegalArgumentException if any of the claim keys or null,
+         *                                  or if the values are not of a supported type.
+         * @throws JsonProcessingException if json value has invalid structure
+         */
+        public Builder withPayload(String payloadClaimsJson) throws IllegalArgumentException, JsonProcessingException {
+            if (payloadClaimsJson == null) {
+                return this;
+            }
+
+            Map<String, Object> payloadClaims =  mapper.readValue(payloadClaimsJson, HashMap.class);
+
+            return withPayload(payloadClaims);
+        }
+
         private boolean validatePayload(Map<String, ?> payload) {
             for (Map.Entry<String, ?> entry : payload.entrySet()) {
                 String key = entry.getKey();

lib/src/test/java/com/auth0/jwt/JWTCreatorTest.java

@@ -3,6 +3,7 @@
 import com.auth0.jwt.algorithms.Algorithm;
 import com.auth0.jwt.interfaces.ECDSAKeyProvider;
 import com.auth0.jwt.interfaces.RSAKeyProvider;
+import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import org.junit.Rule;
 import org.junit.Test;
@@ -81,14 +82,37 @@ public void shouldAddHeaderClaim() {
     }
 
     @Test
-    public void shouldReturnBuilderIfNullMapIsProvided() {
+    public void shouldReturnBuilderIfNullMapIsProvided() throws JsonProcessingException {
+        Map<String, Object> nullMap = null;
+        String nullString = null;
         String signed = JWTCreator.init()
-                .withHeader(null)
+                .withHeader(nullMap)
+                .withHeader(nullString)
                 .sign(Algorithm.HMAC256("secret"));
 
         assertThat(signed, is(notNullValue()));
     }
 
+    @Test
+    public void shouldSupportJsonValueHeaderWithNestedDataStructure() throws JsonProcessingException {
+        String stringClaim = "someClaim";
+        Integer intClaim = 1;
+        List<String> nestedListClaims = Arrays.asList("1", "2");
+        String claimsJson = "{\"stringClaim\": \"someClaim\", \"intClaim\": 1, \"nestedClaim\": { \"listClaim\": [ \"1\", \"2\" ]}}";
+
+        String jwt = JWTCreator.init()
+                .withHeader(claimsJson)
+                .sign(Algorithm.HMAC256("secret"));
+
+        assertThat(jwt, is(notNullValue()));
+        String[] parts = jwt.split("\\.");
+        String headerJson = new String(Base64.getUrlDecoder().decode(parts[0]), StandardCharsets.UTF_8);
+
+        assertThat(headerJson, JsonMatcher.hasEntry("stringClaim", stringClaim));
+        assertThat(headerJson, JsonMatcher.hasEntry("intClaim", intClaim));
+        assertThat(headerJson, JsonMatcher.hasEntry("listClaim", nestedListClaims));
+    }
+
     @Test
     public void shouldOverwriteExistingHeaderIfHeaderMapContainsTheSameKey() {
         Map<String, Object> header = new HashMap<>();
@@ -105,6 +129,7 @@ public void shouldOverwriteExistingHeaderIfHeaderMapContainsTheSameKey() {
         assertThat(headerJson, JsonMatcher.hasEntry(HeaderParams.KEY_ID, "xyz"));
     }
 
+
     @Test
     public void shouldOverwriteExistingHeadersWhenSettingSameHeaderKey() {
         Map<String, Object> header = new HashMap<>();
@@ -714,9 +739,12 @@ public void withPayloadShouldAddBasicClaim() {
     }
 
     @Test
-    public void withPayloadShouldCreateJwtWithEmptyBodyIfPayloadNull() {
+    public void withPayloadShouldCreateJwtWithEmptyBodyIfPayloadNull() throws JsonProcessingException {
+        Map<String, Object> nullMap = null;
+        String nullString = null;
         String jwt = JWTCreator.init()
-                .withPayload(null)
+                .withPayload(nullMap)
+                .withPayload(nullString)
                 .sign(Algorithm.HMAC256("secret"));
 
         assertThat(jwt, is(notNullValue()));
@@ -921,6 +949,26 @@ public void withPayloadShouldSupportNullValuesEverywhere() {
         assertThat(headerJson, JsonMatcher.hasEntry("objClaim", objClaim));
     }
 
+    @Test
+    public void withPayloadShouldSupportJsonValueWithNestedDataStructure() throws JsonProcessingException {
+        String stringClaim = "someClaim";
+        Integer intClaim = 1;
+        List<String> nestedListClaims = Arrays.asList("1", "2");
+        String claimsJson = "{\"stringClaim\": \"someClaim\", \"intClaim\": 1, \"nestedClaim\": { \"listClaim\": [ \"1\", \"2\" ]}}";
+
+        String jwt = JWTCreator.init()
+                .withPayload(claimsJson)
+                .sign(Algorithm.HMAC256("secret"));
+
+        assertThat(jwt, is(notNullValue()));
+        String[] parts = jwt.split("\\.");
+        String payloadJson = new String(Base64.getUrlDecoder().decode(parts[1]), StandardCharsets.UTF_8);
+
+        assertThat(payloadJson, JsonMatcher.hasEntry("stringClaim", stringClaim));
+        assertThat(payloadJson, JsonMatcher.hasEntry("intClaim", intClaim));
+        assertThat(payloadJson, JsonMatcher.hasEntry("listClaim", nestedListClaims));
+    }
+
     @Test
     public void shouldCreatePayloadWithNullForMap() {
         String jwt = JWTCreator.init()