PSBT Display & FromStr using Base64 serialization

src/util/psbt/error.rs

@@ -100,7 +100,7 @@ impl fmt::Display for Error {
                 write!(f, "Preimage {:?} does not match {:?} hash {:?}", preimage, hash_type, hash )
             }
             Error::MergeConflict(ref s) => { write!(f, "Merge conflict: {}", s) }
-            Error::ConsensusEncoding => f.write_str("bitcoin consensus encoding error"),
+            Error::ConsensusEncoding => f.write_str("bitcoin consensus or BIP-174 encoding error"),
         }
     }
 }

src/util/psbt/mod.rs

@@ -91,6 +91,30 @@ impl PartiallySignedTransaction {
     }
 }
 
+#[cfg(feature = "base64")]
+mod _base64encoding {
+    use super::{PartiallySignedTransaction, Error};
+    use std::fmt::{Display, Formatter, self};
+    use std::str::FromStr;
+
+    impl Display for PartiallySignedTransaction {
+        fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+            use consensus::encode::serialize;
+            use ::base64::display::Base64Display;
+            write!(f, "{}", Base64Display::with_config(&serialize(self), ::base64::STANDARD))
+        }
+    }
+
+    impl FromStr for PartiallySignedTransaction {
+        type Err = Error;
+
+        fn from_str(s: &str) -> Result<Self, Self::Err> {
+            use consensus::encode::deserialize;
+            Ok(deserialize(&::base64::decode(s).map_err(|_| Error::ConsensusEncoding)?)?)
+        }
+    }
+}
+
 impl Encodable for PartiallySignedTransaction {
     fn consensus_encode<S: io::Write>(
         &self,