Merge pull request #475 from seratch/issue-474

Fix #474 by making redirect_uri optional

Author: seratch

slack-api-client/src/main/java/com/slack/api/methods/impl/MethodsClientImpl.java

@@ -1680,7 +1680,9 @@ public MpimOpenResponse mpimOpen(RequestConfigurator<MpimOpenRequest.MpimOpenReq
     public OAuthAccessResponse oauthAccess(OAuthAccessRequest req) throws IOException, SlackApiException {
         FormBody.Builder form = new FormBody.Builder();
         form.add("code", req.getCode());
-        form.add("redirect_uri", req.getRedirectUri());
+        if (req.getRedirectUri() != null) {
+            form.add("redirect_uri", req.getRedirectUri());
+        }
         form.add("single_channel", req.isSingleChannel() ? "1" : "0");
         String authorizationHeader = Credentials.basic(req.getClientId(), req.getClientSecret());
         return postFormWithAuthorizationHeaderAndParseResponse(form, endpointUrlPrefix + Methods.OAUTH_ACCESS, authorizationHeader, OAuthAccessResponse.class);
@@ -1695,7 +1697,9 @@ public OAuthAccessResponse oauthAccess(RequestConfigurator<OAuthAccessRequest.OA
     public OAuthV2AccessResponse oauthV2Access(OAuthV2AccessRequest req) throws IOException, SlackApiException {
         FormBody.Builder form = new FormBody.Builder();
         form.add("code", req.getCode());
-        form.add("redirect_uri", req.getRedirectUri());
+        if (req.getRedirectUri() != null) {
+            form.add("redirect_uri", req.getRedirectUri());
+        }
         String authorizationHeader = Credentials.basic(req.getClientId(), req.getClientSecret());
         return postFormWithAuthorizationHeaderAndParseResponse(form, endpointUrlPrefix + Methods.OAUTH_V2_ACCESS, authorizationHeader, OAuthV2AccessResponse.class);
     }

slack-api-client/src/test/java/test_locally/api/methods/OAuthTest.java

@@ -41,6 +41,13 @@ public void test() throws Exception {
                 .isOk(), is(true));
     }
 
+    @Test
+    public void issue_474() throws Exception {
+        assertThat(slack.methods(ValidToken).oauthAccess(r -> r.clientId("abc").clientSecret("xyz").code("xxx")).isOk(), is(true));
+        assertThat(slack.methods(ValidToken).oauthToken(r -> r.clientId("abc").clientSecret("xyz").code("xxx")).isOk(), is(true));
+        assertThat(slack.methods(ValidToken).oauthV2Access(r -> r.clientId("abc").clientSecret("xyz").code("xxx")).isOk(), is(true));
+    }
+
     @Test
     public void test_async() throws Exception {
         assertThat(slack.methodsAsync(ValidToken).oauthAccess(r ->