psbt: impl Display as Base64 encoding

psbt/Cargo.toml

@@ -16,6 +16,7 @@ license = { workspace = true }
 amplify = { workspace = true }
 bp-std = { path = "../std" }
 indexmap = { workspace = true }
+base64 = "0.21.4"
 chrono = "0.4.31"
 serde_crate = { workspace = true, optional = true }
 

psbt/src/coders.rs

@@ -20,10 +20,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use std::io;
-use std::io::{Cursor, Read, Write};
+use std::fmt::{self, Display, Formatter};
+use std::io::{self, Cursor, Read, Write};
 
 use amplify::{IoError, Wrapper};
+use base64::Engine;
 use bp::{
     ComprPubkey, ConsensusEncode, Idx, KeyOrigin, LegacyPubkey, LockTime, RedeemScript, Sats,
     ScriptBytes, ScriptPubkey, SeqNo, SigScript, Tx, TxOut, TxVer, Txid, UncomprPubkey, Vout,
@@ -35,6 +36,22 @@ use crate::{
     ModifiableFlags, Output, OutputKey, Psbt, PsbtVer, SighashType,
 };
 
+impl Display for Psbt {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        let engine = base64::engine::GeneralPurpose::new(
+            &base64::alphabet::STANDARD,
+            base64::engine::GeneralPurposeConfig::new(),
+        );
+        let ver = match f.width().unwrap_or(0) {
+            0 => PsbtVer::V0,
+            2 => PsbtVer::V2,
+            _ => return Err(fmt::Error),
+        };
+        engine.encode(self.serialize(ver));
+        Ok(())
+    }
+}
+
 #[derive(Clone, Debug, Display, Error, From)]
 #[display(inner)]
 pub enum DecodeError {