Improved receive error handling

Better errors and messages returned by the push tx API. And better
message in the command line receive. Fixes #585

api/src/client.rs

@@ -19,6 +19,7 @@ use hyper::client::Response;
 use hyper::status::{StatusClass, StatusCode};
 use serde::{Deserialize, Serialize};
 use serde_json;
+use std::io::Read;
 
 use rest::Error;
 
@@ -57,15 +58,26 @@ fn check_error(res: hyper::Result<Response>) -> Result<Response, Error> {
 	if let Err(e) = res {
 		return Err(Error::Internal(format!("Error during request: {}", e)));
 	}
-	let response = res.unwrap();
+	let mut response = res.unwrap();
 	match response.status.class() {
 		StatusClass::Success => Ok(response),
-		StatusClass::ServerError => Err(Error::Internal(format!("Server error."))),
+		StatusClass::ServerError => {
+			Err(Error::Internal(format!("Server error: {}", err_msg(&mut response))))
+		}
 		StatusClass::ClientError => if response.status == StatusCode::NotFound {
 			Err(Error::NotFound)
 		} else {
-			Err(Error::Argument(format!("Argument error")))
+			Err(Error::Argument(format!("Argument error: {}", err_msg(&mut response))))
 		},
 		_ => Err(Error::Internal(format!("Unrecognized error."))),
 	}
 }
+
+fn err_msg(resp: &mut Response) -> String {
+	let mut msg = String::new();
+	if let Err(_) = resp.read_to_string(&mut msg) {
+		"<no message>".to_owned()
+	} else {
+		msg
+	}
+}

api/src/handlers.rs

@@ -440,13 +440,16 @@ where
 			tx.inputs.len(),
 			tx.outputs.len()
 		);
-		self.tx_pool
+	
+		let res = self.tx_pool
 			.write()
 			.unwrap()
-			.add_to_memory_pool(source, tx)
+			.add_to_memory_pool(source, tx);
-			.map_err(|e| Error::Internal(format!("Addition to transaction pool failed: {:?}", e)))?;
 
-		Ok(Response::with(status::Ok))
+		match res {
+			Ok(()) => Ok(Response::with(status::Ok)),
+			Err(e) => Err(IronError::from(Error::Argument(format!("{:?}", e))))
+		}
 	}
 }
 

src/bin/grin.rs

@@ -435,7 +435,15 @@ fn wallet_command(wallet_args: &ArgMatches, global_config: GlobalConfig) {
 			file.read_to_string(&mut contents).expect(
 				"Unable to read transaction file.",
 			);
-			wallet::receive_json_tx_str(&wallet_config, &keychain, contents.as_str()).unwrap();
+			if let Err(e) =
+				wallet::receive_json_tx_str(
+					&wallet_config, &keychain, contents.as_str()) {
+
+				println!("Error receiving transaction, the most likely reasons are:");
+				println!(" * the transaction has already been sent");
+				println!(" * your node isn't running or can't be reached");
+				println!("\nDetailed error: {:?}", e);
+			}
 		}
 		("send", Some(send_args)) => {
 			let amount = send_args.value_of("amount").expect(