google api - Decode Email body in GMAIL (ios) -

i have problems reading email gmail.

this how each email:

- (void)displayresultmessagewithticket:(gtlserviceticket *)ticket                     finishedwithobject:(gtlgmailmessage *)email                                  error:(nserror *)error {     if (error == nil) {         nsmutablestring *labelstring = [[nsmutablestring alloc] init];          gtlgmailmessagepart* payload=email.payload;         nslog(@"payload =%@",payload);          for(gtlgmailmessagepart* part in payload.parts)         {             gtlgmailmessagepartbody* body = part.body;             nslog(@"body =%@",body);             nslog(@"data =%@",body.data);         }         self.output.text = labelstring;     }     else     {         [self showalert:@"error" message:error.localizeddescription];     } } 

i think body encoded base64, i'm not sure.

this example of get:

q3j1bmnoierhawx5dqonclrvzgf5j3mgvg9wifn0b3jpzxmgly8gsnvsidysidiwmtugumvhzcbtb3jligf0ihrly2hjcnvuy2guy29tidwjpibjzib5b3ugzg8gbm90ihdhbnqgdg8gcmvjzwl2zsb0aglzlcb5b3ugy2fuihvuc3vic2nyawjlihdpdgggb25lignsawnrighlcmugpgh0dha6ly9saw5rlnrly2hjcnvuy2guy29tlzu0zwq3zdc2zmexm2exywqymjhinta2zjjzcgjnlmc4as9vqnj0tnfndnvhmefyvwxlqja5ywq-lg0kdqpuzwnoq3j1bmnoidqxmcbub3duc2vuzcbtdhjlzxqsifnhbibgcmfuy2lzy28sienbidk0mta3dqoncskpidiwmtigqu9mieluyy4gqwxsihjpz2h0cybyzxnlcnzlzc4guhjpdmfjesbqb2xpy3kgpgh0dha6ly9saw5rlnrly2hjcnvuy2guy29tlzu0zwq3zdc2zmexm2exywqymjhinta2zjjzcgjnlmc4as9vqnj0tnfndnvhmefyvwxlq2ninwe-ifrlcm1zig9mifnlcnzpy2ugpgh0dha6ly9saw5rlnrly2hjcnvuy2guy29tlzu0zwq3zdc2zmexm2exywqymjhinta2zjjzcgjnlmc4as9vqnj0tnfndnvhmefyvwxlrdrkzju-dqoncklmihlvdsbizwxpzxzlihroaxmgagfzigjlzw4gc2vudcb0byb5b3ugaw4gzxjyb3isihbszwfzzsbzywzlbhkgdw5zdwjzy3jpymugpgh0dha6ly9saw5rlnrly2hjcnvuy2guy29tl29jlzu0zwq3zdc2zmexm2exywqymjhinta2zjjzcgjnlmc4as84yziyn2zinz4u 

how can decode it??

body of message base64url encoded. need decode replace "_" "/" , "-" "+" in encoded string before base64 decoding it.